Smart Energy - Technology Analysis Energy Efficiency in buildings by Smart Energy Project

Smart Energy Network of Excellence ID 5403 [1]

DRAFT WP 1.1 COMPETENCY MAP Technology Analysis Energy Efficiency in buildings

WP 1.1 â&#x20AC;&#x201C; COMPETENCY MAP â&#x20AC;&#x201C; Technology Analysis [2]

Index 1

Introduction ...............................................................................................................................................4

Energy efficiency in buildings: overview ...................................................................................................5 2.1

Strategic objectives at EU level ..........................................................................................................5

2.1.1

Regulatory framework................................................................................................................5

2.1.2

Financial support mechanism.....................................................................................................7

2.2

Market status .....................................................................................................................................8

2.2.1

2.3

Market potential ..............................................................................................................................11

2.4

Barriers to large scale deployments .................................................................................................11

Technological state of the art ..................................................................................................................13 3.1

Energy efficiency standards..............................................................................................................13

3.2

The construction chain .....................................................................................................................15

3.2.1

Construction of new neutral/energy positive buildings. ..........................................................15

3.2.2

Refurbishment of existing buildings. ........................................................................................16

3.3

Energy efficiency technologies .........................................................................................................17

3.3.1

Insulation materials ..................................................................................................................18

3.3.2

Transparent elements ..............................................................................................................21

3.3.3

Multiple skin facades ................................................................................................................23

3.4

HVAC systems ...................................................................................................................................23

3.4.1

Heat pumps ..............................................................................................................................24

3.4.2

Heat recovery systems. ............................................................................................................25

3.4.3

Thermal solar heating systems .................................................................................................25

3.4.4

Solar cooling systems ...............................................................................................................31

3.4.5

District heating .........................................................................................................................31

3.4.6

Micro energy generation ..........................................................................................................32

3.5

Market status of heating and cooling equipment ....................................................................11

Cross-cutting technologies ...............................................................................................................32

3.5.1

Materials...................................................................................................................................32

3.5.2

Thermal energy storage ...........................................................................................................32

3.5.3

Information and communication technologies ........................................................................35

Promising R&D areas and research challenges .......................................................................................36 4.1

Refurbishment of existing buildings .................................................................................................37

WP 1.1 – COMPETENCY MAP – Technology Analysis [3]

4.2

New buildings ...................................................................................................................................39

4.3

EE district communities ....................................................................................................................43

4.4

Promising research technologies .....................................................................................................44

4.4.1

Thermal insulation materials ....................................................................................................44

4.4.2

Transparent materials, promising areas...................................................................................46

4.4.3

Multiple skin façades ................................................................................................................47

4.4.4

RHC technologies......................................................................................................................47

4.4.5

District heating .........................................................................................................................49

4.4.6

Lighting .....................................................................................................................................50

4.5

4.5.1

Materials research....................................................................................................................50

4.5.2

Thermal energy storage ...........................................................................................................52

4.5.3

Information and Communication Technologies (ICT). .............................................................54

4.6

Promising research for cross-cutting technologies ..........................................................................50

Indicators .......................................................................................................................................... 56

4.6.1

Number of patents involved.....................................................................................................56

4.6.2

Number of publications involved .............................................................................................58

4.6.3

European funded projects ........................................................................................................59

Conclusions ..............................................................................................................................................60 5.1

Promising research technologies in EE in buildings .........................................................................60

5.2

Cross cutting technologies challenges .............................................................................................62

References ........................................................................................................................................................64

WP 1.1 – COMPETENCY MAP – Technology Analysis [4]

1 Introduction Buildings account for 40% of total energy consumption in the European Union. Therefore, reduction of energy consumption and the use of energy from renewable sources in the buildings sector constitute important measures needed to reduce the Union’s energy dependency and greenhouse emissions (1). Reducing these emissions is a big challenge but can also be seen as a great opportunity, in fact the construction sector can make a significant contribution to reducing the impacts of climate change and to decreasing fossil fuel dependence. Furthermore the construction sector accounts for 30% of industrial employment in the European Union, contributing about 10,4% of the Gross Domestic Product, with 3 million enterprises, 95% of which SMEs (2). The RHC report (3) asserts that the “European research efforts currently suffer from being dispersed and insufficiently coordinated to fully realise the performance potential and ensure long term EU leadership on renewable heating and cooling (RHC) technologies”. This affirmation can be extended also in other research fields, such as EE in buildings and RES. Under the Horizon 2020 programme 6,5 billion € is to be allocated to research and innovation in “Secure, clean and efficient energy” in 2014-2020 (4). The aim of this report is to identify and prioritise important EE in buildings technologies and highlight relevant topics of project-oriented research.

WP 1.1 – COMPETENCY MAP – Technology Analysis [5]

2 Energy efficiency in buildings: overview Buildings1 account for 40% of total energy consumption in the European Union (1). In Europe thousands of buildings are built or renovated every year. The construction sector is one of the largest employers with 16,4 million jobs, contributing to about 10,4% of the Gross Domestic Product (GDP) with 2,7 million of business being SMEs (2). Within the construction market, the buildings industrial sector is the largest economic sector, as their construction and refurbishment account for 80% (1.200 billion €) of the total construction sector output of EU27 in 2007.

2.1 Strategic objectives at EU level European Union emphasized that “Energy Efficiency is one of the most cost effective ways to enhance security of energy supply, and to reduce emissions of greenhouse gases and other pollutants. In many ways, energy efficiency can be seen as Europe’s biggest energy resource” (4). In March 2007, the European Council set clear goals for 2020: – – –

Increase energy efficiency to achieve a reduction of 20% of total energy use below 2005 levels; 20% contribution of renewable energies to total energy use; 20% reduction of Greenhouse Gases (GHG) below 1990 emissions.

The calculations of the impact assessment document (5), shows that the EU is not on track to realise the objective of saving 20% of the EU energy consumption. The reduction in energy consumption is estimated to be only about 9% in 2020. In reaction to this, the European Council on Energy in February 2011 emphasised that this “requires determined action to tap the considerable potential for higher energy savings of buildings, transport and products and processes” (6). Responding to this call, the Commission has therefore developed a new Energy Efficiency Plan (4). The plan focuses “on instruments to trigger the renovation process in public and private buildings and to improve the energy performance of the components and appliances used in them. It promotes the exemplary role of the public sector, proposing to accelerate the refurbishment rate of public buildings through a binding target and to introduce energy efficiency criteria in public spending. It also foresees obligations for utilities to enable their customers to cut their energy consumption” (4).

2.1.1 Regulatory framework The main regulatory instrument in the EU for undertaking the energy consumption of buildings is the Directive 2010/31/EU (1) on the Energy Performance of Buildings. A proper implementation and enforcement of the Directive’s provision will make an important contribution to improving the energy performance of buildings. Member States have minimum performance requirements for building insulation and ventilation that are defined in national building codes and regulation. Differences occur due to climate, construction techniques and culture. For low energy buildings, the following indicators are given of feasible insulation levels (7): – – 1

Low U-values (high thermal resistance) can be reached of 0,1-0,15 W/m2K; Triple pane, low emissivity and gas-filled windows in warm edged frames can reach 0,7-0,9 W/m2K; Buildings are intended as houses, public and private offices, shops and other buildings.

WP 1.1 – COMPETENCY MAP – Technology Analysis [6]

–

Air tightness of the building, in combination with heat recovery ventilation systems can obtain levels of 0,4 – 0,6 ACH (air changes per hour) with an energy efficiency of the installation over 80%.

The minimum energy performance requirements must be ensured by the Member States for the following categories of intervention: construction of new buildings, major renovation2 of existing buildings and optimising the energy use of technical building systems. The recast of the Energy Performance of Buildings directive (EPBD) introduced, among other measures, the so called “nearly Zero Energy Buildings” (nZEB) as a future requirement to be implemented from 2019 onwards for public buildings and from 2021 onwards for all new buildings. In addition to the EPBD recast, the Commission is also elaborating various implementing measures under the Eco-design3 and the Energy Labelling Directives4. In response to the identified gap in reaching the 20% energy savings objective in 2020, the Commission proposed in June 2011 a new EE Directive aimed at putting the EU back on track towards achieving this target. The proposal covers a number of measures regarding the energy efficiency of buildings and related financing, including (8): –

–

A legal obligation to establish energy saving schemes in all Member States: energy distributor or retail energy sales companies will be obliged to save every year 1,5% of their energy sales, by volume, through the implementation of energy efficiency measures such as improving the efficiency of heating system, installing double glazed windows or insulating roofs, among final energy customers. Requirements for public bodies to purchase energy efficient buildings, products and services. They will further have to progressively reduce the energy consumed on their own premises by carrying out every year the required renovation works covering at last 3% of their total floor area. Measures to ensure easy and free-of-charge access to data on real-time and historical energy consumption through more accurate individual metering, so as top empower consumers to better manage their energy consumption. Billing should be based on the actual consumption well reflecting data from the metering. A requirement for Member States to take appropriate measures to remove regulatory and nonregulatory barriers to energy efficiency, notably as regards the split of incentives between the owner and the tenant of a building or among owners.

About the nZEB, there are several steps that remain to be made by EU and its Member States to implement this concept. According to the BPIE document (9): – – – – –

– 2

Agreement on a concrete outline of a definition for nZEB, based on the EPBD recast (1); Create benchmarks for suitable nZEB in different Member States as a basis of comparison; Agree for the threshold value for nZEB; Generate a common reporting format for Member States to be used for national plans; Facilitate and support implementation of new nZEB by helping the investors to deal with the necessary initial investments, to elaborate planning and to develop capacities for the new energy efficient technologies; Elaborate a definition for buildings renovation at nZEB levels.

Major renovation means the renovation of a building where Member States may choose to apply one of the following options: a) the total cost of the renovation relating to the building envelope or the technical building system is higher than 25% of the value of the building, excluding the value of the land upon which the building is situated; or b) more than 25% of the surface of the building envelope undergoes renovation; 3 Directive 2009/125/EC of the European Parliament and of the Council of 21 October 2009 establishing a framework for the setting of ecodesign requirements for energy related products. 4 Directive 2010/30/EU oft the European Parliament and of the Council of 19 May 2010 on the indication by labelling and standard product information of the consumption of energy and other resources by energy related products.

WP 1.1 – COMPETENCY MAP – Technology Analysis [7]

2.1.2 Financial support mechanism Union financial instruments and other measures are being put into place or adapted with the aim of stimulating energy efficiency-related measures. Such financial instruments include: – –

–

– – –

–

– –

–

– – 5

Regulation (EC) N0 1080/20065 amended to allow increased investments in energy efficiency in actual housing; Public Private Partnerships (PPP) on a “European energy-efficient buildings” initiative to promote green technologies and the development energy efficient systems and materials in new and renovated buildings. The EC-European Investment Bank (EIB) initiative “EU sustainable energy financing initiative” which aims to enable, among others, investments for energy efficiency and the EIB-led “Marguerite Fund”: the 2020 European Fund for Energy, Climate Change and Infrastructure; Council Directive 2009/47/EC6: structural and cohesion funds instrument Jeremie7; Energy Efficiency Finance Facility, this programme is built to financially assist the IPA countries8; Intelligent energy Europe programme II (IEE), focuses on removal of non-technological barriers to energy efficiency and renewable energy market uptake. Under the 2007-2013 programming period, 730 million € is available. The IEE helps creating favourable market conditions, shaping policy development and implementation, preparing the ground for investments, building capacity and skills, informing stakeholders and fostering commitment. This also includes projects on financing EE in public buildings. Under the IEE, the so-called ELENA9 Technical Assistance Facility was launched in 2009, aimed at providing co-financing (of up to 90% of eligible costa) to local and regional authorities for the development and launch of sustainable energy investments in their territories. The EU support must lead to investments with a leverage of at least 1:20. So far, around 27 million € has been assigned to projects which should trigger investments approaching 1,5 billion €. About a third of these investments are addressing the buildings sector and energy performance contracting; Other action of the IEE is the MLEI10, aimed at small scale sustainable energy investments projects; The Covenant of Majors: is an European movement involving local and regional authorities, voluntarily committing to increasing energy efficiency and use of RES on their territories. By their commitment, Covenant signatories aim to meet and exceed the European Union 20% CO2 reduction objective by 2020; The Entrepreneurship and Innovation programme (EIP), one of the specific programmes under the CIP, seeks to support innovation and SMEs in the EU focusing on, among others, eco innovation pilot and market replication projects for the testing in real conditions of innovative products; The ICT Policy Support Programme 2010; The European Energy efficiency Fund (EEE F), launched on 2011, provide different types of loans, guarantees and/or equity to local, regional and national public authorities. EEE F aims at financing EE

Regulation (EC) N0 1080/2006 of the European Parliament and of the Council of 5 July 2006 on the European Regional Development Fund. 6 Council Directive 2009/47/EC of 5 May 2009 amending Directive 2006/112/EC as regard reduced rates of value added tax 7 Jeremie: Joint European resources for micro to medium enterprises. 8 Albania, Bosnia and Herzegovina, Croatia, Montenegro, Serbia including Kosovo, Turkey, and the former Yugoslav Republic of Macedonia 9 ELENA: European Local Energy Assistance. 10 Mobilising Local energy Investments

WP 1.1 – COMPETENCY MAP – Technology Analysis [8]

– – –

(70%), RES (20%) and clean urban transport projects through innovative instruments, in particular promoting the application of energy performance contracting. A technical assistance grant support (20 million €) is available for project development services (technical, financial) linked to the investments financed by the fund. The Programme for the competitiveness of enterprises and SMEs (COSME) 2014-2020; Seventh Research Framework Programme (FP7) The European Bank for Reconstruction and Development provides funding with the aim of stimulating energy-efficiency-related measures.

Looking forward, the Commission has proposed to concentrate funding from the European regional Development Fund (ERDF) in this area: 20% of the ERDF should be spent on EE and RES in more developed and transition regions; 6% in less-developed regions. Based on the amounts proposed, this would result in a minimum allocation of some 17 billion € (8). Moreover, under the Horizon 2020 programme 6,5 billion € is to be allocated to research and innovation in “Secure, clean and efficient energy” in 2014-2020. A relevant share of this budget will be allocated to the “Market uptake of energy innovation” for projects facilitating the energy policy implementation, in the spirit and continuation of the IEE Programme activities (8). These instruments should be used to give practical effect to the objectives of the EPBD, without however substituting national measures (1).

2.2 Market status The building construction sector knows a wide area of technologies, for which a brief overview is given in section 2.4. In line with the energy performance requirements, the market is focused on more sustainable construction techniques, materials and building components that will enter the market, in order to contribute to a decrease in overall energy consumption. The buildings sector is composed of two main categories of buildings: residential buildings and non residential buildings. Non residential buildings are heterogeneous and they are usually classified by type and by branch of activity. According to the IEA report (10), the population in the European Union will remain relatively stable until 2050. However is expected a growth in terms of residential floor area and in terms of services floor area. The following table explain the building situation and the expected evolution in building stock in Europe. Table 1. Key activity for the building sector in the European Union

Population (million) Number of households (million) 2

Residential floor area (million m ) 2

Services floor area (million m )

2009

2015

2030

2050

500

506

516

512

206

217

238

252

19.500

20.514

22.554

24.666

7.250

7.767

9.250

10.112

Source: IEA. Energy Technology Perspectives 2012. Pathways to a Clean Energy System.

The climatic conditions, the building type and the living preferences vary greatly within the EU. In the regions with long heating seasons and a low cooling demand are situated two-thirds of the services sector floor space (10).

WP 1.1 – COMPETENCY MAP – Technology Analysis [9]

It is estimated that annual growth rates in the residential sector are around 1% while most countries encountered a decrease in the rate of new build in the recent years, reflecting the impact of the current financial crisis on the construction sector. Residential buildings accounts for 75% of the EU building stock, non residential buildings accounts for 25% of the total stock in Europe (11).The BPIE survey (11) indicates that, across the focus countries in this study, 64% of the residential building floor area is associated with single family house and 36% with apartments. The typology of buildings vary greatly in terms of age, size and location. In the residential sector, the age of a building is often strongly linked to the level of energy use for the majority of buildings that have not undergone renovation to improve energy performance. The BPIE survey (11) has classified buildings in three different classes linked with different chronological periods for each country: – – –

Old: typically representing buildings up to 1960 Modern: typically representing buildings from 1960 to 1990 Recent: typically representing buildings from 1991 to 2010. South

North & West

Central and East

Italy

Austria

Buildings pre 1960

37%

42%

35%

40%

33%

Buildings 1961-1990

49%

39%

48%

52%

42%

Buildings 1991-2010

14%

19%

17%

23%

Source: BPIE. Europe's building under the microscope. A country-by-country review of the energy performance of buildings. 2011.

One third of the European residential building stock was built before 1960, and almost 84% are at least 20 years old. Energy use is usually linked to age of the building therefore there is a great energy savings potential in upgrading building envelopes and building systems to modern standards (10). According to Eurostat database, the energy use in buildings is a rising trend with an increase from around 400 Mtoe to 450 Mtoe over the last 20 years. The electricity increased by 50% over the last 20 years and the use of oil and solid fuels decreased by 27% and 75% respectively.

Figure 1. Historical final energy consumption in the building sector since 1990 for the EU27, Switzerland and Norway (11).

WP 1.1 â&#x20AC;&#x201C; COMPETENCY MAP â&#x20AC;&#x201C; Technology Analysis [10]

The specific annual energy consumption per square meter for space heating decreased in the most part of EU countries since 1997 (12). The recent Euroconstruct overview shows the following details in residential and non residential constructions (13).

Table 2. Residential construction: new and renovation (million euro at 2009 prices) New residential construction Country 2007 2009 2007-2009 % Austria 8.630 8.391 -2,8 Italy 42.585 30.532 -28,3 Western Europe (EC-15) 349.073 217.222 -37,8 Eastern Europe (EC-4) 12.152 11.135 -8,4 Total countries 361.225 228.357 -36,8 Source: Euroconstruct (13)

Residential renovation 2007 2009 2007-2009 % 4.149 4.224 1,8 58.902 56.782 -3,6 346.412 336.250 -2,9 5.235 5.334 1,9 351.647 341.584 -2,9

Table 3. Non-residential construction: new and renovation (million euro at 2009 prices)

Country Austria Italy Western Europe (EC-15) Eastern Europe (EC-4) Total countries Source: Euroconstruct (13)

New non-residential construction 2007 2009 2007-2009 % 7.360 6.107 -17,0 28.002 23.506 -16,1 258.778 225.634 -12,8 19.552 18.397 -5,9 278.330 244.031 -12,3

Non-Residential renovation 2007 2009 2007-2009 % 2.526 2.443 -3,3 33.467 30.459 -9,0 193.320 187.186 -3,2 7.561 7.986 5,6 200.881 195.172 -2,8

Table 4. Renovation activity in construction market: residential and non-residential (%)

Country Austria Italy Western Europe (EC-15) Eastern Europe (EC-4) Total countries Source: Euroconstruct (13)

Rate of renovation in residential 2007 2009 2007-2009 % 32% 33% 3,1% 58% 65% 12,0% 50% 61% 22,0% 30% 32% 7,6% 49% 60% 21,5%

Rate of renovation in non-residential 2007 2009 2007-2009 26% 29% 11,8% 54% 56% 3,7% 43% 45% 6,0% 28% 30% 8,5% 42% 44% 6,0%

The construction sector suffered causing by the global economic crisis, renovation activity was represented by over 49% of the total construction output in 2009. In Italy, a country with a strong export dependency, renovation is the principal construction market by 65% (in 2009) of the total building construction market, and urban regeneration and revitalization remains a crucial factor of the Italian construction activity in the following years (13). Renovation activities increased by 12% from 2007 to 2009.

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In Austria and some parts of southern Germany there are different programmes to promote passive houses. In the Upper Austria province, the passive houses had a market share of 7% of the market for one family houses in 2006 (14). Renovation activities covers 33% of the construction market in the Austrian residential sector.

2.2.1 Market status of heating and cooling equipment EeB PPP report (15) claims that the global market for heating and cooling is very large (about 70 USD billion in 2008) and the value of the residential boiler market in 22 EU countries was estimated to be 5,6 billion EUR in 2004. Furthermore, the market of the micro-CHP is still in the early stages of development. Global sales were worth 346 USD million in 2009 (16).

2.3 Market potential The EPBD requires that from 2020 all new buildings are nearly zero-energy buildings (nZEB), but, according to IEA perspectives (10), the new buildings have limited impact because of the low number of new constructions. Existing buildings represent the greatest opportunity for efficiency improvements and sustainable development. The following table gives an overview of the market growth factors needed to satisfy future demand in the case that all new buildings were built according to nZEB principles and shows current market sizes according to the BPIE document (9). Table 5. Overview of the EU market growth factors needed to satisfy future demand Markets

Current market size

Required growth factor

2.010

2÷3

1.500.000

>10

Ventilation systems with heat recovery (units)

130.000

8÷10

Heat pumps (units)

185.000

2÷3

43.000

2÷3

3.700.000

2÷3

Insulation materials (Mio €) 2

Triple glazing windows (m )

Pellet boilers (units) 2

Solar thermal systems (m ) Source: elaboration CETA from BPIE (9) data

2.4 Barriers to large scale deployments The low number of new building compared to the existing building stock is the reason that the potential energy savings are not leading to the desired overall energy savings. Operational energy in residential or commercial buildings to be renovated should be the first aspect to be taken into account when considering the improvement of the energy performance of building stocks (7). The high investment costs involved, the lack of information on energy-efficient solutions at all levels and scarce availability of solutions to specific conditions, are considered as the major barriers to the implementation of energy-efficiency measures in buildings as identified by a cost-optimal methodology (7).

WP 1.1 – COMPETENCY MAP – Technology Analysis [12]

The E2B roadmap (17) observe that ”the introduction of new products and new technologies in the construction sector is very slow (technological inertia), due to lack of information under real conditions of the performance of these products in buildings. The BPIE document (9) assert that a possible barrier may be a “market that is not able to satisfy the increasing demand for new technologies”. The building energy related industry is directly affected by the development in the construction market. The construction market reflects the impact of the economic and financial crisis, the oversupply of construction and reduced confidence (7). Problems with the implementation of the Directives into national regulations (and in relation to European standards) are seen as an additional barrier. Currently, in the construction industry chain exists a certain inertia in the use of conventional or well established materials, as there is a prevalent commercial network that generally leads to a lower price, linked to scepticism with respect other more environmentally friendly solution. Hesitant investments in the implementation of the energy efficient measures is considered as a barrier also (7).

WP 1.1 – COMPETENCY MAP – Technology Analysis [13]

3 Technological state of the art The building sector uses a wide array of technologies and materials in the building shell, in space heating and cooling systems, in water heating systems, in lighting, in appliances and electric consumer products, and in business equipment. From an energy perspective, buildings are complex systems, in which the interaction of technologies almost always influences energy demand (10).

3.1 Energy efficiency standards The most common energy efficiency standards for buildings are: – – – – –

Low Energy Buildings; Passive Houses; Zero Energy Buildings (ZEB) and Zero Carbon Buildings; Plus Energy Buildings; Green buildings.

Other types of buildings also aim at higher standards beyond the requirements in energy efficiency standards and building codes, for example, Intelligent Buildings, Sustainable Buildings. Low energy buildings. This term is generally used to indicate that buildings have a better energy performance than the typical new building or the energy efficiency requirements in building regulation, and that the building hence will have a low energy consumption compared to a standard building (14). The Recast of the Directive 2010/31/EU (1) assert that Member States shall ensure that by 31 December 2020, all new buildings are nearly zero energy buildings and after 31 December 2018, new buildings occupied and owned by public authorities are nearly zero energy buildings. But the Recast of the Directive 2010/31 does not prescribe a uniform approach for implementing nZEB and neither does it describe a calculation methodology for energy balance. The national plans will have to translate the concept of nZEB into practical and applicable measures and definitions. BPIE document (9) argue that a new built nZEB standard is achievable with existing technologies and the heat pump solutions seem to be suitable because of the expected greening of grid electricity and the possibility of direct compensation by production of electricity producted on site. Furthermore that document argue that a big potential is also evident in district heating systems with higher shares of renewable energy. Passive Houses. A passive house is a building in which a comfortable indoor climate can be obtained without a traditional heating or cooling system. A passive house make maximum exploitation of passive technologies (eventually adopting also some active solar technology), assuring a comfortable indoor climate during summer and winter without needing any conventional heating or cooling system (18). Compared to traditional building they use far less energy. In order to be a passive house a building must fulfil the following conditions: – – –

The building must use 15 kWh/m2 a or less in heating energy; The specific heat load for heating source at design temperature must be less than 10 W/m2; With the building pressurised to 50 Pa by a blower door test, the building must not leak more air than 0,6 times the house volume per hour (n50≤0,6/h);

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–

Total primary energy consumption11 must not be more than 120 kWh/m2 a.

A passive house, in practice, require the following characteristics: – – –

– – –

High insulation. All the building parts for walls, roofs and floors are insulated with U-values within 0,1 – 0,15 W/m2 K; Thermal bridges must be avoided; Windows in a passive house are efficient and have three layers of glass, coating on multiple sides and are filled with gas. They will also have warm edges and special energy efficient frames. Overall U-values for these windows are 0,7 – 0,85 W/m2 K; Special care must be taken in order to obtain very air tight; Efficient mechanical ventilation in order to secure a controlled air exchange on 0,40 times per hour. Heating and cooling of these buildings are typically supplied by innovative systems which include a heat exchanger. Typically this will be combined with a heat pump or a highly efficient small heating system.

Passive houses are not bound to a specific type of constructions and examples have been designed on different types of buildings, such as concrete, bricks, and wooden frame houses. Furthermore, even if the standard is called “Passive House” it is also used for large residential buildings, commercial and public buildings such as schools, shops or office buildings. The Passive House standard is defined for the central European climate, typically a heating based climate where there is only a limited cooling need for comfort reasons. The IEA document (14) asserts that there is a need to define a further standard, which define the standards and solutions for the cooling based and hot climates and which can be useful in all climates. Zero Energy Buildings. A zero energy building (ZEB) is a residential or commercial building that do not use fossil fuels but only get all their required energy from solar energy and other RESs (14). At the heart of the ZEB concept is the idea that buildings can meet all their energy requirements from low-cost, locally available, non-polluting, renewable sources. According to the definition presented by Torcellini et al. (18), the renewable energy supply option hierarchy can be explained through the following table:

Table 6. ZEB renewable energy supply option hierarchy

On-site options

Off-site options

supply

ZEB supply-side options

Examples

Reduce site energy use through low-energy building technologies

– – – –

High thermal insulation Daylighting, High-efficiency HVAC equipment, Natural ventilation

Use renewable energy sources available within the building’s footprint

– – –

Photovoltaic Solar hot water Wind located on the building

Use renewable energy sources available at the site

– – – –

Photovoltaic on-site Solar hot water on-site Wind located on-site Low-impact hydro

Use renewable energy sources available off site to generate energy (electricity and/or heat) on site

– –

Biomass (wood, pellet, ethanol, biodiesel) Waste streams from on-site processes

Primary energy for heating, hot water and electricity.

WP 1.1 – COMPETENCY MAP – Technology Analysis [15] 4.

Purchase sources

off-site

renewable

energy

– –

Utility-based wind, PV, Hydro Emission credits

Source: elaboration CETA from “Zero Energy Buildings: A critical Look at the Definition” (18) data

As the current generation of electric storage technologies are limited, achieving a ZEB without the grid is almost impossible. A ZEB uses traditional energy sources such as the electric and natural gas utilities when on-site generation does not meet the loads. When the on-site generation is greater than the building’s loads, excess electricity is exported to the utility grid (18). Plus energy buildings. Plus energy buildings are buildings that deliver more energy to the supply systems than they use. Over a year, these buildings produce more energy than they consume (14). Green buildings. Green Buildings are those with increased energy efficiency, but at the same time reductions are made on water consumption, use of materials and assessment of the general impact on health and environment. Green buildings can include a long list of requirements including resources, indoor air-quality and requirements that all products for the building must come from a local region (14).

3.2 The construction chain The Energy Efficient Buildings PPP beyond 2013 (15) asserts that the today’s fragmented nature of the construction chain still gives little freedom for innovations that are indispensable to define a more sustainable built environment.

3.2.1 Construction of new neutral/energy positive buildings. Technologies and methods exist to build neutral or energy positive buildings. Energy efficiency measures include design strategies and features that reduce the demand-side loads such as: high performance envelopes (ambient exposed surface area), sun control and shading devices, windows and glazing, passive solar heating, natural ventilation, day-lighting, air barrier systems, water conservation. The Energy Efficient Buildings PPP beyond 2013 (15) asserts that the fragmented nature of construction chain still gives little freedom for innovations. The whole construction chain is described as follows: – – – – –

Design stage; Technology building blocks, including the structural parts of the building, the building envelope, and the energy equipment; Construction process; Performance monitoring; End of life.

Design (15). It is at this phase that the most part of the building performances is set both in terms of energy savings and cost of ownership over the life cycle before refurbishment. The main drivers of this element are described as follows: – – –

Integrated design and improved modelling tools make building performance more predictable and easier to optimise at the design stage; Emerging standards for Building Information Modelling (BIM), among these, the IFC format is becoming an official ISO/IS 16739 international Standard. Recognized market value of LCA-based green building certification, even though the most widely recognised environmental assessment methodologies in the construction industry use LCA approaches, the LCA databases that are applicable for the whole Europe are still of limited quality.

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Technology building blocks. In line with Europe’s 20-20-20 target, EU GHGs emissions have to be cut by at least 20% below 1990 levels by 2020. The Energy Efficient Buildings PPP beyond 2013 (15) asserts that the focus must be put on the embedded CO2 with comes from the materials (Concrete, steel, aluminium, timber). –

–

GHG emission abatment, in line with Europe’s 20-20-20 target, with the development and successful market introduction of cement and concrete with significantly reduced embodied CO2. Cement production accounts for an estimated 5% of the world’s CO2 emissions (19). Furthermore, an increasing competition from the Chinese cement industry, it is important for Europe that innovative construction materials and related manufacturing processes leading to drastically reduced embodied CO2, in order to maintain and improve the European competitiveness. Raw material availability such as natural sands and aggregates are in decreasing availability. Furthermore the growing public awareness to protect remaining resources, alternative solutions have to be identified and developed.

With regards the building envelope, new insulation materials and techniques for construction materials, windows and doors are available for new buildings and refurbishment. Air tightness and thermal bridges of the whole construction receives more attention than before to reduce overall energy consumption (7). Many buildings leak heat through gaps in the joints of their windows or doors. Heat losses by ventilation can be strongly reduced by improving the air tightness of the building. An energy efficient building envelope contains both a thermal barrier and an air barrier. The main drivers of this element are following described: –

– –

Development of mass customization and standardization. The Energy Efficient Buildings PPP beyond 2013 (15) claims that factory-made modules, produced in a controlled industrial environment, could facilitate the proper integration of modules during the construction phase, allowing a better achievement of the building performance targets at commissioning and during its life time and a reduction of the final cost. New functionalities brought by innovative materials New functionalities brought by ICT

Another important building block element are the energy equipments. EeB PPP report (15) claims that the global market for heating and cooling is very large (about 70 USD billion in 2008) and the value of the residential boiler market in 22 EU countries was estimated to be 5,6 billion EUR in 2004. Construction process. It is a part of the critical path to reach the final energy performance because any defect can lead disorders and even pathologies which can compromise the durability of the building performance (15). Performance monitoring during the building life. The EeB PPP (15) argue that performance monitoring, both at commissioning and during the building life, could enable users to oversee and control their own consumption, allows detecting potential misuses of building and potential pathologies of the building (15). End of life. The building demolition is an important environmental issue and it can be addressed, both at design (e.g. reusable components) and demolition levels (e.g. reusable materials). Currently, the demolition of buildings at the end of their service life makes it very difficult to separate the different materials, in fact most of these materials end up in landfills or incinerators (20). The building industry is already involved in significant waste recovery.

3.2.2 Refurbishment of existing buildings. The impact in terms of decrease of energy use and CO2 emissions will be strong, considering that in Europe 80% of the 2030 building stock already exists and today 30% of existing buildings are historical buildings

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(17). To retrofit building fabrics is vitally important to reduce energy demand in buildings. The insulation for solid walls is possible trough internal or external solutions. The external solutions often comprises of an insulation layer fixed to the existing wall, such as a protective render or decorative cladding. Timber panels, stone or clay tiles, brick slips or aluminium panels are often used for cladding. Benefits of external wall insulation for solid walls include no internal living space loss, minimum disruption, heat losses through thermal bridges and condensation risk are reduced. The internal solid wall insulation typically consists of either dry lining in the form of flexible thermal linings, laminated insulation plasterboard, or built-up system using fibrous insulation such as mineral wood held in place using wood or metal frame. Cavity wall insulation is one effective energy efficiency measure (21). Commonly used insulation materials include the following materials: mineral wool, expanded polystyrene, urea formaldehyde foam and organic plant fibber materials. The thermal performances of the organic plant materials can be compromised if they comes into contact with moisture. Water vapour barriers are often used in internal insulation in order to avoid condensation. The heat losses by ventilation through gaps in the joints of the windows or doors can be strongly reduced by improving the air tightness of the buildings.

3.3 Energy efficiency technologies The energy performance of buildings can be classified in four consumption categories: a. Building energy needs (savings). This is directly related to indoor and outdoor climate conditions for working and living in buildings and to the heat transfer through the building envelope and the ventilation. b. Building systems energy (EE). The combined efficiency of the installations for heating, cooling, ventilation, hot water, and electricity are the relevant factors in the end-use of energy consumption. The EU harmonises national measures relating to the publication of information on the consumption of energy and of other essential resources by households appliances. c. Occupancy energy consumption (behavioural). The use of energy depends strongly on how the occupant make use of the building. Household appliances, such as washing machines, refrigerators, etc.. and entertainment apparatus, such as TV and computers, consume mainly electricity that is converted for a great part into auxiliary heat. Occupancy behaviour is covering also variable aspects as the opening of windows, temperature setting, clothing habits,â&#x20AC;Ś d. Energy consumption in the building manufacture, transport and installation. The building industry uses great quantity of raw materials that also involve energy consumption. Often products that are presented as cheap in the medium term can have very high environmental cost that are never recovered. A building could be subdivided in four systems: structure, envelope, mechanical, interior. In this categorisation, the envelope has to respond to natural forces that include rain, snow, wind and sun (22). Numerous applications for innovation and requested technologies for the built environment offer opportunities to reduce the energy consumption. Low energy buildings can become reality when the design process takes into account the energy flows from passive solar landscape design (orientation and immediate environment, including soil) integrated with architectural design (7). This design will have to incorporate technologies that are related to: building energy needs, building system energy.

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3.3.1 Insulation materials In EU, commonly used insulation materials include mineral wool, expanded polystyrene and urea formaldehyde foam. Organic plant fiber insulation is another useful group of materials. The impact of conventional insulation with high level of industrial processing is clearly higher than the impact of natural materials such as cork, wood fibre, reed or straw and recycled ones. In this document, the insulation materials are subdivided into three categories: 1.Conventional thermal insulation materials; 2.Eco-efficient building materials; 3.Innovative insulation materials. The following tables collect the characteristics of different typologies of building materials taking into account the following parameters: – – – – – –

The format of the product; λ: thermal conductivity (W/mK); ρ: Density (kg/m3); c: thermal capacity of the material (J/kgK); GWP storage: global warming potential storage embodied into a slab of 1 x 1 x 0,1 m of the material (kg CO2eq); CO2 from process: CO2 emissions associated with the manufacture of a slab with a volume of 1 x 1 x 0,1 m of the material (kg CO2eq).

Conventional thermal insulation materials. Are included into this category mineral materials and synthetic materials. Table 7. Conventional thermal insulation materials

Materials Calcium silicate Pumice

format

Granular, Panels, slab bulk granular material kneaded material Granular Expanded perlite Panels bulk granular material Vermiculite kneaded material panels Rockwool felts panels Glass wool felts Foam glass panels Polyester fibers Panels, slabs, Polyurethane rigid foam Panels Polystyrene extruded HFC panels Polystyrene extruded C02 panels EPS Polystyrene expanded panels Source: elaboration CETA (23)

W/mK

kg/m

c 3

kg CO2 eq.

0,043 115 850-1000 0,1 490÷900 900 0,16÷0,2 800÷900 900 0,047÷0,06 80÷130 900 0,05÷0,06 600÷1400 1400 0,05÷0,07 80÷100 1000 0,08÷0,09 380÷600 800 0,04÷0,045 40÷95 800÷900 0,035÷0,04 30÷50 800÷900 0,045÷0,05 40÷95 800 0,035÷0,04 30÷50 800 0,038÷0,05 105÷165 840 0,054 20 1700 0,020÷0,030 40÷50 1600 0,030÷0,040 20÷50 1500 0,032÷0,040 20÷50 1500

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

n.a. n.a. n.a. n.a. n.a. n.a. n.a. 19,3 19,3 19,6 19,6 24,4 n.a. 17,0 365,1 15,9

0,035÷0,040

12,4

15÷30

J/kg K

CO2 GWP storage process

1500

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Eco-efficient building insulation materials. Organic plant fibber insulation is another useful group of materials that are becoming increasingly popular. Natural fibres can be divided, according to their origin, into vegetable and animal. The most used are the vegetable ones due to their wide availability and renewability in short time respect to others. A great advantage of the insulation based on natural fibres is not only a low value of thermal conductivity but also the natural character of input fibres. Another advantage is that it is a renewable material which does not place any significant strain on the environment. Despite these positive features, however, the construction market is still dominated by synthetic insulating materials. This is caused by some negative characteristics of materials based on natural fibres (25): -

High wettability and absorbability due to an open pore structure, in fact, their performance can be compromised if they comes into contact with moisture. Water vapour barriers are often used in internal insulation to avoid condensation; The need to protect natural materials against biological attacks; Flammability of these materials.

The materials based on natural fibres can be largely modified by chemical treatment in order to solve the problems listed above. Table 8. Eco-efficient building materials

Materials

Expanded clay aggregate

format

bulk granular material Panels, slabs Common reed panels Panels, slabs Common straw panels bale Cork panels Panels expanded Panels compressed Wood fibres Rigid panels Coconut fibre insulation Panels Sheep wool insulation Panels Cellulose fiber insulation Flakes Cellulose fiberboards Panels Kenaf fibers Panels Cotton fibers Flakes, panels Source: elaboration CETA (23)

W/m K

kg/m

c 3

0,090÷0,130 320÷450 0,160÷0,310 600÷1.200 0,045÷0,056 130÷190 0,040÷0,050 100 0,035÷0,040 120 0,039÷0,050 200 0,038÷0,052 150÷300 0,043÷0,047 50÷150 0,037÷0,044 30÷80 0,037÷0,041 25÷65 0,040 60÷90 0,039÷0,045 20÷80 0,040 20÷30

GWP CO2 storage process

J/kg K

kg CO2 eq.

900 900 1.000 600 1.900 1.900 2.100 1.500 1.700 1.900 2.000 1.700 1.500

0 0 -31,6 -20,3 -15,7 -18,8 -27,4 -15,3 -4,8 -6,3 -5,1 -

5,7 24,8 1,5 1,6 3,5 4,1 14,5 19,2 6,4 5,1 1,9 -

Innovative insulation building materials. Today’s state of the art thermal insulation solutions cover vacuum insulation panels (VIPs), gas filled panels (GFPs), reflective insulation materials, and aerogels. In addition, although not strictly a thermal insulation solution, Phase Changing Materials (PCMs) may also be mentioned as they contribute to the total thermal building envelope performance thanks to the heat storage and release during solid state to liquid phase transformations (24). The following table collect the characteristics of the today’s state of the art of innovative building materials.

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Table 9. Innovative insulation building materials

Materials

Vacuum insulation panels Gas filled panels Aerogel Phase changing materials Reflective insulation Source: elaboration CETA

format

panels Panels Panels filled Panels Foils

W/m K

kg/m

0,004÷0,008 0,040 0,013 -

c 3

GWP CO2 storage process

J/kg K

kg CO2 eq.

-2,1 -

70,7 -

Vacuum insulation panels (VIPs). The VIPs have thermal conductivities ranging between 0,003 W/mK and 0,004 W/mK, one order of magnitude lower than the typical thermal conductivity for traditional insulation material. However, with time water vapour and air are diffusing through the VIP foil envelope and into the open pore structure of VIPs, increasing the thermal conductivity up to typically 0,008 W/mK after 25 years aging. Furthermore, perforating the VIP envelope causes an increase in the thermal conductivity to about 0,02 W/mK. Another disadvantage of this type of technology is that cannot be cut or adjusted at the building site and care has to be taken in order to not perforate it during building assembly and through its service life (26). Gas filled panels (GFPs). Although much lower theoretical values have been calculated, the lowest reported thermal conductivities are around 0,04 mW/mK in the pristine condition, similar to the traditional insulation materials. The GFPs applying a gas less thermal conductive than air, e.g. argon, krypton, and xenon, exhibit the same major disadvantage of the VIPs (26). Aerogels. The aerogels represent another state of the art innovative thermal insulation solution and are one of the most promising high performance thermal insulation materials for building applications today. With a thermal conductivity down to 13 mW/(mK) for commercial products they show remarkable characteristics compared to traditional thermal insulation materials. Using carbon black to suppress the radiative transfer, thermal conductivities as low as 0,004 W/mK may be reached at a pressure of 50 mbar. Also the possibility of high transmittances in the solar spectrum is of high interest for the construction sector. With the proper knowledge they give both the architect and engineer the opportunity of reinventing architectural solution (25). Reflective insulation. These materials consist of several layers of thin metallic foil or metallised polymer film with a low emission coefficient combined with spacer materials in-between. Because of the low emission coefficient of the foils, radiation through the insulation material is significantly reduced as a result of which these materials are claimed to have very high thermal resistance, even up to 5 or 6 m2 K/W (26). However, it has noticed that reflective materials degrade over time as dust accumulating on the surface diminish its performance (21). Multiple-layer insulation (21). Multiple layers of insulation are usually used to achieve better thermal performance exploiting the properties of insulation materials and reflective materials. For instance using a series of reflective layers interspersed with layers of thermal insulation materials. Phase changing materials (PCMs). PCM materials are not insulation materials but they are included in that category thanks to the performance improvements that they can lead to the envelope. Inclusion of thermal storage materials in building elements increases the functionality of the elements, the possibilities to

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enhance the storage capacity of the building and reduce thermal cycling of heat pumps or burners, without the need to fit dedicated thermal energy stores (3). In recent years the use of thermal energy storage with PCM has become a topic with a lot of interest within the research community and also within architects and engineers. Passive applications include the addition of microencapsulated PCM impregnated in wall board, which will act to offset air-conditioning plant by allowing the wall or the ceiling to absorb heat acting effectively as mass (e.g. slowing the response of the building to solar gains in summer).

3.3.2 Transparent elements Windows and other types of transparent areas in the building envelope determine the penetration of solar radiation into the building, daylight entrance, natural ventilation rates and heat flow to or from the environment. In order to improve the performances of the transparent components, the following actions are required: – – – – –

enhance the penetration of solar radiation during the heating period; minimize the solar radiation during the cooling period; decrease heat flow through the openings; improve day lighting; permit a more efficient airflow during the summer season.

The following tables collect the characteristics of different typologies of transparent elements taking into account the following parameters: – – – –

Ug: thermal transmittance of the material (W/m2K); g value: a coefficient that measure the solar energy transmittance of the glass; GWP storage: Global warming Potential storage embodied into a slab of 1 x 1 x 0,1 m of the material (kg CO2eq); CO2 from process: CO2 emissions associated with the manufacture of a slab with a volume of 1 x 1 x 0,1 m of the material (kg CO2eq).

Vacuum glazing systems with very low Ug values have employed multiple glass panes, inert gases and numerous low emittance coated surfaces. These systems usually require three or more panes of glass (21).

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Table 10. Transparent conventional technologies Type

Thickness

GWP storage

CO2 from process

Single glazing

(mm) 6

(W/m K) 5,8

0,87

kg CO2 eq.

14,40

Double glazing

4/12air/4

2,9

0,77

24,89

4/20air/4

2,8

0,77

24,91

4/8air/4/8air/4

1,7

0,68

41,10

Double glazing low-emission, Argon, ε=0,1

4/16Argon/4

1,3

0,64

24,95

Double glazing low-emission, Argon, ε=0,05

4/16Argon/4

1,2

0,60

Double glazing low-emission, Argon, ε=0,04

4/16Argon/4

1,1

0,56

Double glazing low-emission, Krypton, ε=0,1

4/16Krypton/4

1,1

0,56

27,93

4/12Argon/4/12Argon/4

0,74

0,52

50,20

4/12Krypton/4/12Krypton/4

0,60

0,61

52,17

Triple glazing

Triple glazing, Argon Triple glazing, Krypton

g 2

Source: elaboration CETA

Transparent insulation materials (TIM) (21). TIM materials can allow solar energy transmittance of more than 50% and thermal conductivity of less than 0,2 W/m2K. This type of materials can be produced by utilising different type of optical absorber or cavity structures. Generally overheating control and cost issues are the two major issues associated with transparent insulation. Electrochromic materials. Electrochromism is the phenomenon displayed by some materials of reversibility changing colour when a burst of charge is applied electrochromic materials are used to control the amount of light and heat allowed to pass through windows. The electrochromic materials are generally coatings that can be deposited both on glass or plastic. The layers include a transparent outer conductive layer, an active electrochromic layer, a passive counterelectrode layer, and an ion-conducting electrolyte layer (27). Photochromic materials. Photochromic glass is characterized by a decrease of the transmission of the glass in the presence of light. Upon removal of such incident light, the glass regains the original high level of transmittance present before introduction to the light (28). Thermochromic materials. They are particular coatings that change colour in relation to their temperature. For high temperatures, thermochromic coatings have the ability to reflect solar energy, reducing the surface’s temperature, absorb solar energy. Thermochromic systems can function as energy saving systems, in fact, applied thus on external building surfaces, they have the potential for the reduction of heating and cooling loads. Holographic optical elements (HOE). Holographic optical elements have useful properties for diffuse light transmission and radiation control. A holographic optical element is a new class of optics that operates on the principle of diffraction. The holograms are produced on films, which are laminated between two panes of floatglass. By the physical effect of diffraction different forms of light manipulation are possible, comparable to those mirrors, prisms, lenses and other optical elements. Laminated glass with light directing holograms allows a great variety of applications in architecture for utilisation of solar energy, improvement of room comfort as well as design of solar light-and colour effects (31). Prismatic panels. They are planar, sawtooth devices made of clear acrylic (or other transparent materials). When used as a shading system, they refract direct sunlight and transmit diffuse skylight.

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Laser-cut panels. A laser-cut panel is a daylight redirecting system produced by making laser cuts in a thin panel made of clear acrylic material. The laser cutting divides the panel into an array of rectangular elements. Each cut surface then becomes a small internal mirror that deflects light passing through the panel.

3.3.3 Multiple skin facades The building envelope performs a number of functions, among of these are included: control of physical environment factors, structural support for the building, fire safety, security, energy conservation and aesthetics. Wiggins and Harris (30) asserts that a building’s façade can account for between 15% and 40% of the total construction budget and may be a significant contributor to the cost of up to 40% more through its impact on the cost of the building’s services. Multiple skin facades (MSFs) (also known as active envelopes, second skin facades, twin facades, etc.) consists of two panes separated by a cavity through which air flows. The driving force for the airflow is natural or mechanical ventilation. In the cavity, usually a shading device is provided. Generally, distinction is made between naturally and mechanically ventilated MSFs (31). The principles to reduce the energy demand in buildings strongly depend on the chosen typology of MSF. Exists a complex interaction between air flow in the façade and the HVAC system and the building energy management system. In order to come to a correct assessment of the energy performance, it is important to couple simulation of the building and the building components. Dynamic façades coupled with intelligent systems were introduced and Lawrence Berkeley National Laboratory developed a description for the dynamic façade that enable the building to optimize the solar gains during the winter and reduce the cooling loads during summer. The adaption of dynamic envelopes offer the potential to achieve a near-optimum energy efficient system and minimizing the energy cost and environmental impact.

3.4 HVAC systems Heating, ventilating and air-conditioning (HVAC) generally includes a variety of active mechanical/electrical systems employed to provide thermal control in buildings. The objective of an HVAC system is to control the temperature, moisture, air movement, and air cleanliness, normally with mechanically means, in order to achieve thermal comfort. HVAC systems may be designed as local system or as central system. This section gives an overview of the best available technologies employed in the service and the residential sector according to the best available technologies (BAT) for heat and cooling market in EU (32). Gas boilers. In gas boilers, the gas combusted and the generated flue gas passes through a heat exchanger where the warm flue gas transfers heat to another media, which normally is water. Condensing gas boilers are considered the best available technology in the market of this type of boilers but they have only a minor possible efficiency improvements left. The advantage of the gas boiler system is that many countries have large distribution networks of natural gas. The disadvantages of this technology are that it uses a fossil-based energy source and the pollutants that are emitted from the combustion process are carbon dioxide (CO2), nitrogen oxides (NOx), carbon monoxide (CO) and methane (CH4). Electric boilers (32). An electric boiler is used for producing hot water directly from electricity. Heating elements using electrical resistance are used for small applications. The temperature range is flexible.

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Among of the advantages of the system are that the it can use excess of electric energy when the production of electricity is very high, it has a simple design, it is reliable and easy to regulate. The disadvantage is that this solution has limited use because the electricity costs in some countries. Biomass (21). Biomass for energy could reduce carbon life cycle and GHG emissions from the combustion of fossil fuels. The efficiency of biofuel system boilers tends to be lower than that of fossil fuels boilers. However, recent technological developments have increased the efficiency of bioenergy systems considerably. Combined heat and power (CHP). CHP utilise the waste heat produced during the generation of electricity, improving the efficiency by over 30% comparing to generating heat and electricity separately. Furthermore, using CHP to provide also cooling can make this technology more economically attractive (21). The main advantage of the system is that it produces two types of energy needs simultaneously with a higher total efficiency in heat energy conversion. The main disadvantage is the cost of investment (32).

3.4.1 Heat pumps Heat pumps employ the same technology as refrigerators, moving heat from a low-temperature location to a warmer location. Compression heat pumps consume electricity and the absorption heat pumps use heat (e.g. steam, hot water or flue gas) (32). The heat pump technology may have low CO2 emissions if the efficiency is high especially in the case of electrically driven heat pumps, if the electricity is produced with a large part of renewable energy. The BPIE document (9) argues that the efficiency of actual heat pumps and compression chillers, fans and pumps is already very close to the theoretical achievable optimum. The input to the absorption cycle heat pumps is a heat source and energy to drive the process. The following heat sources are used. Ambient air, water, ground or waste heat from industrial process. The common heat pumps that are used for space heating and for domestic hot water are as follows: – – – –

Ground source closed loop brine/water heat pump; Exhaust air/water heat pump; Ambient air/water heat pump; Ambient air/air heat pump.

The advantage of the heat pump system may have low CO2 emissions. The disadvantage is the cost of the necessary equipment. Electrically driven heat pumps. This type of heat pump use a vapour compression cycle driven by an electric motor. The same machine can provide heating and cooling in alternating order or in parallel. Thermally driven heat pumps. They use the same thermodynamic cycle as electrically driven compression heat pumps, however the compressor is replaced by a thermal sorption cycle. Therefore thermal energy is needed to drive the cycle and electricity is needed only for auxiliary components. Thermally driven machines are mainly used for cooling purposes in combination with waste heat or heat produced by renewable sources. However, they can also work as heat pumps (3). The most important representatives of heat-driven cooling/heat pump systems are liquid absorption and solid adsorption cycles. In absorption devices the refrigerant is absorbed in the liquid sorption medium changing its concentration. In case of solid sorption heat pumps/chillers, the refrigerant is either adsorbed in the pores of the solid adsorption medium, or chemically absorbed into the crystal lattice of the solid (3). The current market for sorption heat pumps is very small because of the following reasons: high costs, lower thermal efficiency than liquid sorption systems and operate within a narrow window of operating temperatures. The configuration of an absorption heat pump consists of the following components: –

a reactor called generator, where the sorbent (liquid or solid) is heated;

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– – –

the condenser, where the desorbed refrigerant vapour is condensed into liquid; the evaporator, where the cooling effect is produced; a reactor called absorber that receives refrigerant vapour from the evaporator.

A heat-driven heat pump/chiller works at three levels of temperature: – – –

the machine is driven by a heat source; heat is rejected at medium temperature; collected at low temperature.

When heat is required from the system, the relevant output is the heat rejected at medium temperature.

3.4.2 Heat recovery systems. A heat recovery system conserves energy by remove heat from extracted air to the incoming air. With central systems it is possible to preheat the outside air with the discharged air in winter or to precool the warm outside air with the cooler indoor air in summer. Some types of regenerative heat recovers are able to humidify or dry the outside air. Special forms of heat exchangers are ground-coupled heat exchangers that use the geothermal heat capture and dissipation function to warm or cool air.

3.4.3 Thermal solar heating systems Solar heating systems can be applied for heating of domestic hot water alone or combined with space heating. The solar thermal systems are composed by three essential elements: solar collectors, solar thermal systems and heat storage systems (32).

3.4.3.1 Solar energy collectors The major component of any solar system is the solar collector which absorbs the incoming solar radiation, converts it into heat, and transfers this heat to a fluid flowing through the collector. The table below summarise the typologies of solar collectors available in the market:

Table 11. Solar collectors available in the market Collector type

Absorber type

Concentration ratio

Indicative temperature range (°C)

Unglazed flat plate collectors Unglazed collectors Glazed flat plate collectors Evacuated tube collectors Compound parabolic collector

Flat Flat Flat Flat Tubular

1 1 1 1 1-5

30÷60 15÷30 30÷80 50÷200 60÷240

Source: elaboration CETA from Kalagirou (33)

Unglazed collectors. They consist only of an absorber and they can be used in various applications such as water preheating for domestic or industrial use, heating of swimming pools, space heating and air heating for industrial or agricultural applications. They are also sometimes found as a selective coated stainless

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steel absorber. This type of collector has a lower performance at equal operating temperature than a glazed flat-plate collector as it lacks the glass cover, housing and thermal insulation. Advantages: – – –

it is very cheap due to its simple construction; the absorber can replace the wall skin, for example, and offer more aesthetic solution for sheet metal façades than glass collectors; suitable for diversity of roof-façade forms and it can easily adapted to slight curves.

Disadvantages: – –

because of the lower specific performance, it requires more surface area than a flat glazed collector; Because of the higher heat losses, the surface temperature increase and could be dangerous in some cases;

Glazed flat-plate collectors (GPFC). Almost all glazed flat plate collectors currently available on the market consist of a metal absorber in a flat opaque rectangular housing. The collector is thermally insulated on its back and edges, and is provided with a transparent cover on the upper surface. Two pipe connections for the supply and return of the heat transfer medium are fitted, usually to the side of the collector. A typical glazed flat plate collector is shown in the Figure 2.

Figure 2. Glazed flat plate collector (33) When solar radiation passes through a transparent cover and impinges on the blackened absorber surface of high absorptivity, a large portion of this energy is absorbed by the plate and then transferred to the transport medium in the fluid tubes to the carried away for storage or use. The underside of the absorber plate and the side of casing are well insulated to reduce conduction losses. The transparent cover is used to reduce convection losses from the absorber plate through the restrain of the stagnant air between the absorber plate and the glass and reduces radiation losses from the collector as the glass is transparent to the short wave radiation received by the sun but it is nearly opaque to long wave thermal radiation emitted by the absorber plate (such as the greenhouse effect) (33). The core piece of a glazed flat-plate collector is the absorber. This consists of a heat –conducting metal sheet with a dark coating. The absorber plate is selective coated, and the commercial solar absorbers coatings are made by electroplating, anodization, evaporation, sputtering and by applying solar selective paints. Typical selective surfaces consist of a thin upper layer, which is highly absorbent to shortwave solar radiation but relatively transparent to long-wave thermal radiation. Materials most frequently used for collector plates are copper, aluminium, and stainless steel (35).

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The tubes for the heat transfer fluid are in the most cases either in meander (snake) shape or in parallel (harp absorber) and usually have a distance of 100 – 120 mm. The thickness of the absorber plate is typically in the range between 0.15 and 0.3 mm depending on the material used (34). Glass is widely used to glaze solar collectors because it can transmit as much as 90% of the incoming shortwave solar irradiation while transmitting virtually none of the long-wave radiation emitted outward by the absorber plate. Glass with low iron content has a relatively high transmittance for solar radiation but its transmittance is essentially zero for the long-wave thermal radiation emitted by sun-heated surfaces. Advantages (35): – – – –

It is cheaper than a vacuum collector; It offers multiple mounting options (on-roof, façade mounting and free installation); It has a good performance ratio; It has good possibilities for do-it yourself assembly.

Disadvantages (35): – – – –

It has a lower efficiency than vacuum collectors; It is not suitable for generating higher temperatures, as required for example in steam generation; Do not admit the passage of the light; Needs high conductive and expensive materials as solar absorbers in order to conduct to the pipes the heat.

Evacuated tube collectors (ETC). A large number of variations of the absorber shape of ETC are on the market (36). Evacuated tubes with CPC reflectors are also commercialized by several manufacturers (33). These solar collectors consist of a heat pipe inside a vacuum-sealed tube. The vacuum envelope reduces convection and conduction losses, so the collectors can operate at higher temperatures than flat plate collectors. ETC use liquid-vapour phase change materials to transfer heat at high efficiency. These collectors feature a heat pipe (a highly efficient thermal conductor) placed inside a vacuum-sealed tube. When these tubes are mounted, the metal tips up, into a heat exchanger as shown in Figure 3. Water, or glycol, flows through the manifold and picks up the heat from the tubes. The heated liquid circulates through another heat exchanger and gives off its heat to a process or to water that is stored in a solar storage tank (33).

Figure 3. Schematic diagram of an evacuated tube collector (33).

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Advantages: – It achieves a high efficiency even with large temperature difference between absorber and surroundings, and with low radiation; – It achieves high temperatures; – It can be easily transported to any installation location because of its low weight; – By turning the absorbing strips (in the factory or during the assembly) it can be aligned towards the sun. Disadvantages: – It is more expensive than a glazed flat-plate collector; – It cannot be used for horizontal installation for heat pipe systems (inclination must be at least 25°). Compound parabolic collector (CPC). CPC are non-imaging concentrators. These have the capability of reflecting to the absorber all of the incident radiation within wide limits. The necessity of moving the concentrator to accommodate the changing solar orientation can be reduced by using through with two sections of a parabola facing each other, as shown in Figure 4. CPC can accept incoming radiation over a relatively wide range of angles. By using multiple internal reflections, any radiation that is entering the aperture, within the collector acceptance angle, finds its way to the absorber surface located at the bottom of the collector.

Figure 4. Schematic diagram of a compound parabolic collector (CPC) (33) The absorber can take a variety of configurations. CPCs are usually covered with glass to avoid dust and other materials from entering the collector and thus reducing the reflectivity of its walls. CPC can also be stationary but radiation will only be received the hours when the sun is within the collector acceptance angle. Two basic types of CFC collectors have been designed; the symmetric and the asymmetric. These usually employ two main types of absorbers; fin type pipe and tubular absorbers (33). Façade integrated collectors. In principle, collectors can be mounted on façades or roof. A collector that is installed on the façade receives a lower annual global irradiance than a roof installation. However, it has a more uniform yield profile per year, and is subject to lower thermal loads: that is, there are fewer stagnation periods (35). Davidson et al. (37) developed and evaluated a Semi-transparent building –integrated photovoltaic thermal system (STBIPV/T). It is constructed of PV cells laminated on solar absorbers placed in a window behind the glazing. This system requires parabolic reflectors that increase the cost of the overall system. A Solar Thermal Façade Collector with evacuated tubes in office buildings, which is being supported by the BMU and under the management of the Institute for Building construction and Design L2 at the University of Stuttgart was developed12. The important technical aspects, such as visual transparency, even distribution of light throughout the room, thermal insulation and protection from the sun are uniquely combined in this product. As a result, the CPC evacuated tube collector is an aesthetic and integral

http://www.paradigma-iberica.es/descargas/sistema_de_fachadas_con_tubos_cpc.pdf

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component of this office façade system. The dimensions of the system are strictly bonded with the length of the evacuated tube collectors. A transparent solar thermal collector for window integration 13 based on low-cost window technology is currently developed by Permasteelisa group (coordinator), Interpane, Berchtold Ingenieure and Fraunhofer ISE. This façade component will at the same time allow visual contact to the exterior, provide solar and glare control and it will generate heat. In summer the collector will be used as a heat source for solar cooling systems. This approach is to integrate apertures with angular selective transmittance into the absorber of a solar thermal collector which is integrated in the transparent part of the façade. These apertures will selectively shield the direct irradiation of the sun (coming from directions with higher solar altitude angles) while retaining visibility through the window horizontally or downwards. A system way to control and prevent overheating in buildings and can generate thermal energy for heating and cooling purposes is proposed (38). The idea is to use the facade, or part of the facade, as a solar thermal collector for energy generation and daylight control. It is proposed that a special venetian blind tracks the sun along its path and its shape and materials can be adapted to absorb most of solar thermal energy.

3.4.3.2 Solar thermal systems. The heat absorbed by a heat transfer fluid, passing through the solar collectors, can be stored or used directly. In solar water heating systems, potable water can either be heated directly in the collector (direct systems) or indirectly by a heat transfer fluid that is heated in the collector, passes through a heat exchanger to transfer its heat to the domestic or service water (indirect systems). The heat transfer fluid is transported either naturally (passive systems) or by forced circulation (active systems). Except for thermosiphon and integrated collector storage (ICS) systems, which need no control, solar domestic and service hot water systems are controlled using differential thermostats. Four types of solar energy systems are used to heat domestic and service hot water: thermo-siphon, ICS, direct circulation and indirect circulation. The first two are called passive and no pump is employed, whereas the others are called active systems because a pump or fan is employed in order to circulate the fluid (33). Integrated collector storage systems (ICS) (passive) - ICS systems use hot water storage as part of the collector, i.e. the surface of the storage tank is used also as an absorber. As in all other systems, to improve stratification, the hot water is drawn from the top of the stratification, the hot water is drawn from the top of the tank and cold make-up water enters to the bottom of the tank on the opposite side (33). Disadvantage of this system is high thermal losses from the storage tank to the surrounding some of the area is intentionally exposed for the absorption of solar radiation. Direct circulation systems (active)-In direct circulation systems is shown schematically in Figure 5A pump is used to circulate potable water from storage to the collectors when there is enough available solar energy to increase its temperature and then return the heated water to the storage tank until it is needed. As a pump circulates the water, the collectors can be mounted either above or below the storage tank. Direct circulation systems often use a single storage tank equipped with an auxiliary water heater. It can be used with water supplied from a cold water storage tank or connected directly to city water mains. Pressurereducing valves and pressure relief valves are required however when the city water pressure is greater than the working pressure of the collectors. Direct water heating systems should be not used in areas where the water is extremely hard or acidic because scale deposits may clog or corrode the collectors. 13

http://www.cost-effectiverenewables.eu/includes/images/Publications/Files/6c449715a9306252d04344c05969c1ac.pdf

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A variation of the direct circulation system is the drain-down system. When a freezing condition or an overheating occur, the system drains automatically by isolating the collector array and exterior piping from the make-up water supply and draining it using the two normally open valves.

Figure 5. Schematic diagram of a direct circulation system (33) Indirect water heating systems (active) - Indirect water heating systems, shown in Figure 6 circulate a heat transfer fluid through the closed collector loop to a heat exchanger, where its heat is transferred to the potable water. The most commonly used heat transfer fluids are water/ethylene glycol solutions, although other heat transfer fluids such as silicone oils and refrigerants can also be used. The heat exchanger can be located inside the storage tank, around the storage tank (tank mantle) or can be external. It should be noted that the collector loop is closed and therefore an expansion tank and a pressure relief valve are required. Additional over-temperature protection may be needed to prevent the collector heat transfer fluid from decomposing or becoming corrosive. The solar circuit is composed by the following main elements: pipelines, solar liquid, solar pumps, solar circuit heat exchanger, fittings and equipment for filling, the safety equipment and a controller system (35).Furthermore a solar thermal system needs of the following elements: a return-flow prevention, flow meters, safety valves, membrane expansion vessels. In several systems on the market, the functions of pump, control unit, valves and connections have been integrated into a single unit, a soâ&#x20AC;&#x201C;called solar station (35). A variation of indirect water heating systems is the drain-back system. Drain-back systems are generally indirect water heating systems that circulate water through the closed collector loop to a heat exchanger, where its heat is transferred to the potable water. Circulation continues as long as usable energy is available. The collector fluid drains by gravity to the drain-back tank when the circulation pump stops. If the system is pressurized the tank serves also as an expansion tank when the system is operating and in this case it must be protected with a temperature and pressure relief valves. In the case of an unpressurised system the tank is open and vented to the atmosphere. As the collector loop is isolated from the potable water, no valves are needed to actuate draining, and scaling is not a problem, however, the collector array and exterior piping must be adequately sloped to drain completely (33).

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Figure 6. Schematic diagram of an indirect water heating system (33)

3.4.3.3 Heat storage system. The energy supplied by the sun rarely matches the times when heat is required, therefore the generated solar heat must be stored. The solar stores generally are able to contain the hot water consumption of about one or two days. The heat storage systems are described in the subsection 3.5.2.

3.4.4 Solar cooling systems The use of the summer excess heat for solar thermal cooling offers a great opportunity because solar radiation usually coincides with cooling loads. Two main technologies can use solar thermal collectors for air conditioning in buildings (16): closed process and open processes. –

–

Closed processes. In this processes the cooling medium is not in direct contact with the environment. The cold water produced can be used in chilled ceilings, in concrete core conditioning, or also in the classical way in the air cooler of an air-conditioning system. Among the closed processes is possible to distinguish between the absorption and adsorption processes (35). Open cycles: the air is conditioned by coming into direct contact with the cooling medium. They are also referred to as desiccant evaporative cooling systems and are used for direct treatment of air in a ventilation system.

3.4.5 District heating District heating is a system for distributing heat generated in a centralised location for heating requirements such as space heating and water heating through a piping network. Sources of the heat could include combined heat and power plants, biomass, capturing geothermal heat and natural sources for heating and cooling, or recuperating industrial waste heat (39). District heating plants has been expected to provide higher efficiencies and better pollution control than localized heating sources due to the factors that district heating systems will be more likely to be maintained, operated and controlled more professionally (21).

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3.4.6 Micro energy generation Most applications in daily life will rely on electricity and renewable heat energies. Micro-generation is the generation of zero or low carbon heat and/or power to meet own energy demand on site. Among of microgeneration technologies heat solar, PV panels and wind are the most promising ones.

3.5 Cross-cutting technologies With the term “cross-cutting technologies” in this report we intend to describe any technology which can be used to increase the energy efficiency of the elements described above. Three key technologies have been identified: materials, thermal energy storage and ICT.

3.5.1 Materials The advanced materials sector is one of the traditional strengths of European industry. The EU Commission staff working paper on Materials Roadmap (40) asserts that the construction sector is the largest raw material consuming industry, with a volume that in Europe alone exceeds 2 billion metric tons per year. Research and development of new materials is crucial to increase the energy efficiency of buildings and renewable heating and cooling. The most important improvements in development in new insulation materials and in energy efficient materials of the last years comes from materials research.

3.5.2 Thermal energy storage Thermal energy storage can be stored as a change in internal energy of a material as a: sensible heat, latent heat, thermochemical heat and combination of these (41). An overview of major technique of storage of the thermal energy is shown in the following diagram. Liquids Sensible Heat Solids Thermal energy storage

Thermal

Latent Heat

Solid-Liquid

Liquid-Gaseous Thermal Chemical Pipe line Chemical

Heat of reaction Heat Pump

Figure 7. Different types of thermal storage

Solid-Solid

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Sensible heat storage. In these systems thermal energy is stored by raising the temperature of a solid or liquid. Sensible heat storage system utilizes the heat capacity and the change in temperature of the material during the process of charging and discharging. The amount of heat stored is in relation of the specific thermal capacity of the medium, the temperature change and the amount of storage material (41). In the range of temperature from 0-100°C water appears the best liquid available because it is inexpensive and has a high specific heat. The most usual practice is to employ vertical cylindrical hot water tanks as the storage medium which is a well-known technology and by large, the most extended one. The performance of heat storage using hot water tanks is increased by thermal stratification, which is caused by the different density of the hot and cold layers of water within the tank so the hot water remains in the top of the tank and the cold water in the bottom. The stratification makes it possible to have higher temperatures to be sent to the load and lower ones to the heat source. Thus, reducing the mixing, and therefore the destruction of exergy, the global performance of the plant is improved. Some additional issues have to be taken into account when studying the real performance of hot water tanks: during the charging and discharging process some mixing between the hot and cold water is unavoidable; despite the good insulation of the tanks, some heat is lost through the walls of the tank decreasing the temperature of the stored water; the conduction through the walls of the tank allows the heat transfer between the cold and hot zones within the tank decreasing stratification and widening the thermocline: in the operation of the plant there are variations in the temperatures of charging and discharging (Th and Tl) which suppose mixing in the high and low temperature zones (Figure 8). These variations are caused by part load operation, variable heat loads, etc.

Figure 8. Schematic representation of the stratification effect in a hot water storage tank14. Seasonal thermal storage can play a significant role in balance heat demand and renewable energy supply (22). The most used technologies are described as follows: –

–

Tank thermal energy storage (TTES). These tanks are normally constructed from concrete or steel. They are relatively expensive compared to constructions in which the ground is used as a structural or thermal component. The BAT document (32) asserts that their advantage is that their properties are easier to control and the tighness is better because they are not influenced by the local soil conditions. Pit thermal energy storage (PTES). These type of tanks are an opening in the ground lined by waterproof membrane, filled with water and covered by a floating and insulating lid. The storage capacity is 60-80kWh/m3a. Borehole thermal energy storage (BTES). Another possible technology is the application of tubes in boreholes. They are used whith heat pumps and they operate at low temperatures. The storage can

A. Campos Celador ⇑, M. Odriozola, J.M. Sala Implications of the modelling of stratified hot water storage tanks in the simulation of CHP plants Energy Conversion and Management 52 (2011) 3018–3026

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–

reach efficiencies in the range of 90 to 100% when the storage operates around the annual average temperatures of the ground and there is no strong natural ground water flow. Acquifer thermal energy storage (ATES). These storage systems are constructed in underground aquifers by using direct heat exchange in vertical wells.The aquifers are used typically for lowtemperature applications in combimnation with heat pumps for cooling during summer and heating during winter.

Latent heat storage. Latent heat storage is based on the heat absorption or release when a storage material undergoes a phase change from solid to liquid or liquid to gas or vice versa (42). Phase change can be in the following form: solid-solid, solid-liquid, solid-gas, liquid-gas and vice versa. Solid-solid PCM offer the advantages of less stringent container requirements and greater design flexibility (43). The main characteristic of this technology is that during the phase change the materials remain, theoretically, at constant temperature. At its melting temperature, the PCM remains in the solid phase while it absorbs a fixed amount of heat known as the latent heat of fusion. Once the PCM absorbs the latent heat of fusion it changes phase from solid to liquid. As heat is removed from a PCM, its temperature decreases until it reaches the PCM’s melting temperature. Latent heat storage materials can store 5-14 (42) times more heat per unit volume than sensible storage materials such as water, masonry, or rock. PCMs themselves cannot be used as heat transfer medium. A separate heat transfer medium must be employed with heat exchanger in between to transfer energy from the source to the PCM and from PCM to the load. The heat exchanger to be used has to be designed specially, in view of the low thermal diffusivity of PCM materials. The volume changes of the PCMs on melting would also necessitate special volume design of the containers. Any latent heat storage system possess at least the following three components: a suitable PCM with its melting point in the desired temperature range, a suitable heat exchange surface and a suitable container compatible with the PCM. The prior art has several heat storage devices employing PCMs as heat storage material. For example, U.S. Pat. N° 4,403,645 discloses a PCM heat storage/transfer device having a heat exchanger tube surrounded by PCM. A pump is provided to circulate the PCM, while in its liquid state, around the tube to prevent stratification of the PCM. Patent n°5,687,706 (D.Yogi Goswami, Chung K. Hsieh, Chand K. Jotshi, J. F. Klausner: Phase change material storage heater, November 18, 1997) discloses a storage heater for storing heat and for heating a fluid, such as water, that has an enclosure defining a chamber therein. The chamber has a lower portion and an upper portion with a heating element being disposed within the enclosure. A tube through which the fluid flows has an inlet and an outlet both being disposed outside of the enclosure and has a portion interconnecting the inlet and the outlet that passes through the enclosure. A densely packed bed of phase changing material pellets is disposed within the enclosure and is surrounded by a viscous liquid such as propylene glycol that is in thermal communication with the heating element (pellets) and the tube and transfers heat from the heating element to the pellets and from the pellets to the tube. The viscosity allows a frictional pressure drop of the fluid in contact with the PCM pellets that substantially reduces vertical thermal convection in the fluid. As the fluid flows through the tube the heat is transferred from the viscous liquid to the fluid flowing through the tube, thereby hating the tube. The existent devices do not naturally inhibit the vertical convection. Heat applied to the bottom of these devices naturally rises to the top of the device, thereby stratifying the heat storage materials. Because of this, the storage material at the bottom of these devices tends to be under-used decreasing the overall efficiency of the storage device. Thermochemical storage. Sensible and latent heat storage techniques have a number of disadvantages for long-term heat storage, such as heat loss and relatively low energy density requiring large volumes (44). The energy is stored in reversible chemical reactions, can achieve densities 3-12 times greater than sensible

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stores (3). It is possible to store energy by means of chemical processes in thermochemical materials, making use of reversible chemical reactions like as follows: ↔ The main advantage of thermochemical storage compared to PCM is that losses only occur during charging and discharging, but not over time, making these systems preferable for long term storage (3). This technology is divided into chemical reactions and sorption systems. The following table summarise the different energy capacities, power efficiency and storage time of different thermal energy storage technologies. Table 12. Energy capacities, power efficiency, and storage time of thermal energy storage systems TES technology

Capacity

Power

Efficiency

Storage time

Cost

kWh/t

Hot water tank

20÷80

1÷2.000

50÷90

hour-week

0,1÷0,13

Chiller water tank

10÷20

1÷.2.000

70÷90

Hour-week

0,1÷0,13

ATES low temperature

5÷10

500÷10.000

50÷90

Day-year

Varies

BTES low temperature

5÷30

100÷5.000

50÷90

Day-year

Varies

PCM-general

50÷150

1÷1.000

75÷90

Hour-week

13÷65

Thermal-chemical

120÷150

10÷1.000

75÷100

day-year

10÷52

USD/kWh

Source: elaboration CETA from IEA data (16)

3.5.3 Information and communication technologies Information and communication technologies (ICT) plays an increasing role in increasing the energy efficiency and enabling renewable (heating and electric) systems to satisfy a higher share of the energy demand. By monitoring and directly managing energy consumption, ICT can enable efficiency improvements in all applications which require a thermal energy supply. ICT technologies can be exploited in control technologies in order to improve the energy efficiency of buildings by responding to changes in both the internal and external environment and delivering real-time information on the performance of building systems and components. Building controls also enable cost-saving opportunities such as peakshifting and participation in demand-response programs by communicating with the external utility grid. (45).

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4 Promising R&D areas and research challenges As mentioned in the EPBD, the requirement of nearly zero energy buildings from 2018-2020, will need the development of a new design approach, based more on energy flows in buildings. Furthermore, according to the European Strategic Energy Technology Plan (7) the trend for energy consumption in buildings is a decrease of thermal energy for space conditioning and an increase of electricity for installations and appliances. Renovation of the buildings is an important option to reduce energy consumption15. Furthermore the integration of renewable energy technologies (RETs) in the built environment is a valuable option to support the reduction of energy consumption (7). The multi-annual Roadmap and longer term strategy (17) asserts that the following research challenges need to be addressed for a sustainable strategy for energy-efficient buildings: –

–

– –

Definition of energy –efficient solutions for renovation. Many innovative solutions are directed towards new buildings but only a few are aptimisde for the existing stock. Moreover, buildings, especially residential buildings are never considered as a whole. R&D has to ptopose integrated solutions taking into account the various constrainsof existing buildings. Building Industry transformation.The gaps are on systemic approaches for refurbishment, building design and quality of installation. The Energy Efficient building PPP (17) asserts that there is a real need to develop solutions suitable for use by the construction industry: affordable packages solutions or kits which are easy to install. Market transformation. Low carbon technologies have to grow strongly the next years. Acceptability by customers. Each technology must be though through in terms of the behavioural correlates and opportunities

The Energy Efficient building PPP (17) describe the research challenges in energy efficiency in buildings subdividing the argument in three application areas: refurbishment of existing buildings, new buildings and energy efficient district/communities.

Table 13. Research challenges in EE in buildings according to the Energy Efficient building PPP Application areas – Refurbishment to transform existing buildings into EE buildings

– – – –

New buildings – – Energy efficient district/communities

– –

Renovation of the Buildings

Systems and equipment for energy use for existing buildings Envelope (for existing buildings) Solutions for cultural heritage Systemic approach for existing buildings Systems and equipment for energy use for new buildings Systemic approach for new buildings Interaction between buildings, grid, heat, network Systems and equipment for energy production District and urban design

Cross cutting technologies – – – – – – – – – – – – –

Technological aspects Systems and equipment for energy use Storage of energy Quality indoor environment Design-Integration of new solutions Envelope and components Industrialization and mass customization Automation and control Lyfe cycle analysis (LCA) Energy Management Systems Labelling and standardization Materials: embodied energy and multifunctionality Diagnosis and predictive maintenance

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Systems and equipment for energy – use – Storage of energy (district): thermal, – electrical or other – Retrofitting (district) Source: elaboration CETA from the energy efficiency PPP data (17)

Systems and production Diagnosis

Equipment

for

energy

4.1 Refurbishment of existing buildings The impact in terms of decrease of energy use and CO2 emissions will be strong, considering that in Europe 80% of the 2030 building stock already exists and today 30% of existing buildings are historical buildings (17). The diversity of architectures and climates in Europe requires a whole value chain innovation process where design, technology choice and construction are even more intertwined than for new buildings. The Energy Efficient building PPP argue that in order to optimize the refurbishment of the existing buildings, needs to integrate various solutions in the following research areas: – – – –

Envelope for existing buildings; Solutions for historic buildings and cultural heritage; Systems and equipment for energy use; Systemic approach for existing buildings.

Envelope for existing buildings. Innovations are needed in the area of new materials, products and components to address energy efficiency in buildings. There is a need to develop materials, products, components and building techniques used in new buildings specifically designed and adapted for the energy efficient retrofitting of existing and occupied buildings. According to the Risø Report (46) the following table highlight some R&D needs over the next decades in the thermal envelope sector:

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Table 14. R&D needs in envelope of existing buildings over the next decades according to the Risø report (46) R&D needs

Characteristics

Insulation systems specifically designed for the energy efficient retrofitting of existing and occupied buildings

– – – – – – –

Long life products Thin materials High performances materials Advance materials with low thermal conductivity Adapted products Aesthetic aspect Easy to install

Advanced window technologies (windows using advance materials with low thermal conductivity; windows with built-in solar cells)

–

Advance transparent materials with low thermal conductivity Advance framing materials with low thermal conductivity Advance in sun control glass coatings and films Advance in smart lighting control of the light in transparent surfaces

– – –

Thermal storage materials

– – –

Advance in cost effectiveness, Adapted products Advance in reliable and safety materials

Building materials using recyclable materials Building materials with low embodied energy Source: elaboration CETA from Risø Report (46)

Solutions for historic buildings and cultural heritage. The Energy Efficient building PPP (17) claims that there is a need for novel sustainable strategies, concepts, methodologies and techniques to improve the energy efficiency of cultural heritage buildings. Innovative methodologies need to be developed to improve the planned maintenance and conservation policies at EU level considering the adaptability to new building-useages and minimum intervention impact.

Systems and equipment for energy use. Innovation is needed in new methodologies to integrate comfort systems, energy management systems and local energy generation into existing buildings. The Energy Efficient buildings PPP argue that specific efforts should be devoted to space heating and hot domestic water that is the largest part of energy use in the buildings.

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Table 15. R&D needs in envelope of existing buildings over the next decades according to the Risø report (46) R&D needs

Characteristics

Heat pump

– – –

More efficient Small size for retrofitting Easy to install

Thermal storage systems/materials

– – –

More efficient Small size for retrofitting Easy to install

Low power bulbs and solid state lighting

– –

Advance in cost effectiveness, Adapted products for retrofitting

New concepts of heating and/or cooling sources

– –

Micro Combined Heat and Power (CHP) based on fuel cells Alternative refrigeration means Stirling cycles, Brayton cycles, and acoustic, magnetic and thermal-electric technologies

Intelligent systems/smart buildings

– – –

Automated diagnostics Advanced sensors Integrated control networks

Source: elaboration CETA from Risø Report (46)

Systemic approach for existing buildings. Optimizing the refurbishment of existing buildings should integrate various technological solutions in envelope, in systems, and in RESs which will interact with each other and with the existing building elements.

4.2 New buildings Considering the new buildings, in this report will be considered the challenges of the most promising research and innovation areas taking into account the entire construction chain of a new building. Design challenges. In this phase more than 80% of the building performance is fixed both in terms of energy savings and cost of ownership (15).

WP 1.1 – COMPETENCY MAP – Technology Analysis [40] Design challenges in new buildings Integrated design

– – – – –

Eco design

– – – –

–

Building information modelling BIM tools that are cost-effective and interoperable thanks to a standard exchange format. Energy efficient building design tools like, dynamic building simulation models/software New modelling and simulation approaches are needed to take into account the overall physics and behaviour of the envelope Harmonized Life Cycle assessment methods at the whole-building level and up to district scale Innovation in education and training practice Building’s operation, maintenance and end of life Buildings components reuse and recycling potential Building material durability and recycling potential Complex multi-criteria optimization process that covers the environmental impact and the value for the users taking into account comfort, productivity, aesthetics, public health Reliable material and equipment database

Source: elaboration CETA from EeB PPP (15)

Structure. In line with Europe’s 20-20-20 target, EU GHGs emissions have to be cut by at least 20% below 1990 levels by 2020. Cement production accounts for an estimated 5% of the world’s CO2 emissions (19). The Energy Efficient Buildings PPP beyond 2013 (15) asserts that the focus must be put on the embedded CO2 with comes from the materials (Concrete, steel, aluminium, timber). Furthermore, an increasing competition from the Chinese cement industry, it is important for Europe that innovative construction materials and related manufacturing processes leading to drastically reduced embodied CO2, in order to maintain and improve the European competitiveness. Raw material availability such as natural sands and aggregates are in decreasing availability. Furthermore the growing public awareness to protect remaining resources, alternative solutions have to be identified and developed. In areas where it is adequate, for instance in areas with large wood resources located in reasonable proximity to the construction site, or timber harvested in forests where sustainable forestry is practised, it is very promising. Structure challenges in new buildings Cement and concrete with low embodied CO2

–

Development of composite cements with largely reduced clinker contents Incorporate into the cement significant amounts of industrial inorganic products Blending with recycled concrete fines or slags

Use of timber for the construction in areas with large wood resources

– –

Construction of individual homes Construction of multi-storey buildings

Innovative structural materials with low embodied CO2

– –

Use of reclaimed materials Use innovative materials

Local sourcing materials

–

Building materials which are entirely or partly based on raw materials extracted close to the building site

–

Source: elaboration CETA from EeB PPP (15)

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Envelope. Innovative materials could contribute to the reduction of embodied energy and manufacturing cost reduction. Envelope challenges in new buildings Innovative materials and prefabricated components

–

– – –

Better insulation materials, thinner, cheaper and easier to install. Nanofoams, aerogels, vacuum insulation materials, multi-material composites, Thermal reflective materials, reflective layers Materials for switchable glazing (smart windows) Improved insulation concrete: concrete based on composite cement used in connection with innovative insulation solutions

Envelope energy harvesting

– –

Solar thermal integrated façade systems Building Integrated Photovoltaic BIPV

Low embodied energy materials

– –

Eco-efficient building materials Recycled materials

Smart building envelope

–

Provide response to regular variations, envelope adaptable to a dynamic and complex environment Adapt to user needs and behaviour, and to the effects of their presence Multi-criteria optimisation

– – Optimization of all envelope design constrains

–

– – – –

Performance constrains: acoustic, fire resistance, indoor air quality, thermal comfort, energy performance, daylight control, legislation, aesthetics, cultural heritage, Environmental constrains: availability of products, embodied CO2 Methodologies and tools for evaluate the energy performances (e.g. software, methodologies) Implement data on material characteristics and energy needs Development of mass customisation and standardisation (e.g. modular homes, prefabricated building components, etc)

Source: elaboration CETA from EeB PPP (15)

Energy equipment. The EeB PPP report (15) claims that “Beyond existing technologies, breakthrough solutions can be expected from energy storage (heat and electricity) refrigeration and building integrated solutions”.

WP 1.1 – COMPETENCY MAP – Technology Analysis [42] System and equipment challenges Optimise the renewable energy sources integrated in building elements

– –

Reduce the costs of integrated RES in buildings Increase the energy efficiency of integrated RES through advance in materials and configuration

Heating systems

– – –

Increase the efficiency of heat pumps and ground heat pumps Increase the efficiency of ventilation systems and heat recovery systems Combined heat and Power systems (CHP) from biomass

Energy storage systems

–

Thermal energy storage systems: wall mass, hot water storage, PCM materials, thermochemical heat storage Electricity storage systems: batteries, flywheel systems, hydrogen, compressed air, etc.

– Lighting solutions

– –

New technologies in lighting solutions (LED, OLED) Intelligent Management of Daylight

Building management Systems (BEM)

–

Manage the energy flows by taking advantage of inertia in heating and cooling systems and by using energy storage equipment Envelope and energy equipment synergically integrated by innovative BEMS Energy management systems and management protocols in order to optimize generation, storage and distribution at district level Implement smart metering systems

– – –

Source: elaboration CETA from EeB PPP (15)

Construction process. The construction sector has to guarantee that the energy performances meet pre-set contractual values. Any defect in this phase can lead to disorders and even pathologies which can compromise the durability of the building performance. The increasing complexity of the construction process involves a variety of skills and expertise located in various company sizes that have different roles and responsibilities in each of the construction processes. Then appropriate education and training are needed. Construction process challenges prefabrication

– – –

Pre-assembled parts of the envelope Prefabricated structural components Improvement of the processes

Improvement of the processes

– – –

Increase the efficiency in refurbishment processes Advanced and automated processes that favour the use of prefabrication More efficient construction practices in order to reduce material requirements and minimize CO2 emissions during the transport of materials and the construction processes

Dedicated tools

– –

Building information Modelling tools have to be developed Methods for self-inspection technologies

Training of the workers

–

Qualified worker base ready to meet the potential deployment growth of energy efficient buildings Skilled intermediate management to improve construction quality

–

Source: elaboration CETA from EeB PPP (15)

WP 1.1 – COMPETENCY MAP – Technology Analysis [43]

Monitoring and management during the building life. A performance monitoring systems could enable the users to control their own consumption, allows detecting potential misuses of a buildings and allows detecting potential pathologies of the monitored building. Management challenges Performance monitoring

–

Low cost and low maintenance sensors of: air infiltration, heat conduction, solar heat gains Energy performance monitoring systems with advanced functionalities Dynamic building simulation models

– –

Source: elaboration CETA from EeB PPP (15)

Building’s end of life. In the perspective of resource efficiency and sustainability of buildings, building destruction practices must evolve towards more sustainable approaches.

Building’s end of life challenges Building deconstruction

– – – –

Decision making tools of the choice demolition/deconstruction/rehabilitation

–

Technical solutions enabling a more widespread use of recycled material, e.g. concrete Cost–effective technological solutions to separate composite construction materials (e.g. reinforced concrete) Selective deconstruction systems Technical solutions for producing construction materials and prefabricated elements based on recycled materials Develop reliable evaluation methods/tools that use the Life Cycle Assessment and Life Cycle Costing approach

Source: elaboration CETA from EeB PPP (15)

4.3 EE district communities According to the report of the EeB PPP (17) the following six research challenges are linked with Energy Efficient districts/communities. – – – – – –

District and urban design. Systems and equipment for energy production at district level (e.g. district heating from waste heat). Systems and equipment for energy use at district level (e.g. district heating heat exchangers) Storage of energy: thermal, electrical or other. Interaction between buildings, grid, heat, networks, etc. Retrofitting.

WP 1.1 – COMPETENCY MAP – Technology Analysis [44]

4.4 Promising research technologies 4.4.1 Thermal insulation materials Continuous increase of insulation thickness can result in more complex design, construction and maintenance, an adverse net-to gross floor area and possible heavier load bearing constructions. The traditional thermal insulation materials like the materials listed in Table 7, have thermal conductivities between 0,03 W/mK to 0,1 W/mK. In order to avoid too thick building envelopes, other thermal insulation materials or solutions are needed. The ASHRAE document (24) asserts that the thermal insulation materials and solutions of tomorrow need to have as low thermal conductivity as possible. Furthermore the thermal conductivity should not increase too much over a 100 years or more lifespan time and should be able to maintain their low thermal conductivity even if they are perforated by external objects. The following list summarises the proposed requirements of the high performance thermal insulation materials: – – – – – – – – –

Thermal conductivity: < 0,004 W/mK; Thermal conductivity after 100 years: < 0,005 W/mK; Not to be influenced significantly by perforation vulnerability; Possibility to cut for adaption at building site; Resistant to climate aging durability; Resistant to biological growth; Water resistant; Competitive costs vs. other thermal insulation materials; Low environmental impact (including energy and material use in production, emission of polluting agents and recycling issues).

A range of lower λ insulation materials have been developed and utilised such as aerogel, multi-layer insulation, transparent insulation, gas filled insulation, and vacuum insulation. According to the EU Materials Roadmap (40), are described the following promising research areas.

4.4.1.1 Nanotechnology based insulation materials. In order to reduce building operational energy, needs to develop advanced and high-performance nanotechnology based insulation materials. Among others, the following materials are described and discussed in the Riso report (46) and in to the E2B Advisory Group (17): Vacuum insulation materials (VIM). A VIM is basically a homogeneous material with a closed small pore structure filled with vacuum with an overall thermal conductivity of less than 0,004 W/mK in the pristine condition. Due to its closed pore structure the VIM can be cut and adapted at the building site with no loss of low thermal conductivity. Furthermore , perforating the VIM with an external object would only result in a local heat bridge (26). Gas insulation materials (GIM). A GIM is basically the same as a VIM, except that the vacuum inside the closed pore structure is substituted with a low-conductance gas. A GIM is a homogeneous material with a closed small pore structure filled with a low-conductance gas, e.g. argon, krypton, or xenon, with an overall thermal conductivity of less than 0,004 W/mK in the pristine conditions (26). Nano insulation materials (NIM). A NIM is a homogeneous material with a closed or open small nano-pore structure with an overall thermal conductivity of less than 0,04 W/mK in the pristine condition. These

WP 1.1 – COMPETENCY MAP – Technology Analysis [45]

materials achieve their low thermal conductivity thanks to the so-called Knudsen effect (or nano-pore effect). In fact, decreasing the pore size within a material below a certain level, i.e. a pore diameter of the order of 40 nm or below for air, the gas thermal conductivity, and thereby the overall thermal conductivity, becomes very low. This is due to the Knudsen effect where the mean free path of the gas molecules is larger than the pore diameter. The NIMs do not need to prevent air and moisture penetration into their pore structure during their service life for at least 100 years. Dynamic insulation materials (DIM). A DIM is a material where the thermal conductivity can be controlled within a desiderable range. Thermal conductivity control may be achieved by being able to change in a controlled manner the following parameters (26): -

The inner pore gas content or concentration including the mean free path of the gas molecules and the gas-surface interaction; The emissivity of the inner surfaces of the pores; The solid state thermal conductivity of the lattice.

The thermal insulation regulating abilities of DIMs give these conceptual materials a great potential but until now has to be demonstrated that such materials can be manufactured.

4.4.1.2 Bio-based insulation materials The use of natural materials which provide a similar of higher level of insulation and thermal comfort buildings can contribute to the GHG reduction due to the less CO2 emissions during the production phase and because of the sequestrating CO2 into the material. The following materials have huge potential and need further development in order to achieve competitivity with conventional materials: – – – – – – –

Biotic renewables (sheep’s wool, woodfibre insulation, hemp insulation,…); Nano-technology based biofibers, regenerated fibers; Development of bio-based polymers and plastics; Chemistry and manufacture of nanotechnology based biopolymers and fibres from various sources; Natural fibre insulation with thermal bonding technology using bio-based plastics; Evaluation of potential gains in term of embodied energy compared to conventional materials by LCA of bio-based materials; Laboratory-scale prototypes of production processes embedding results from basic research.

4.4.1.3 Reduction in embodied energy for traditional (synthetic and mineral based) insulation materials Exists a huge potential in reduction embodied energy and CO2 emissions through developing advanced processes for traditional insulation materials. –

– – –

LCA-based measures to reduce environmental impact in production of fossil fuel or mineral based insulation materials: increase recycling contents, manufacturing efficiency and renewables in production; Use CO2 as a foaming agent substituting HFC in production processes of XPS foams and polyurethane foams insulation; Substitution towards of bio-based materials; Laboratory-scale prototypes of production processes embedding results from basic research.

WP 1.1 – COMPETENCY MAP – Technology Analysis [46]

4.4.1.4 Phase changing materials The use of phase changing materials (PCMs) in building’s envelope allow to reduce building space conditioning energy consumption. But the high cost and product availability are the main barriers to the large scale deployment. The following research activities could be implemented in this research area: – – –

Basic research for material optimization and applied research to investigate material integration in new constructive solutions (e.g. combination between reinforcement, insulating materials and PCMs); Improvement of thermal inertia in lightweight materials with the use of additives; Incorporation in a huge range of new and ordinary construction materials;

4.4.2 Transparent materials, promising areas The most promising R&D areas in transparent materials can be summarized in two major areas: 1. develop advanced and high performance windows to reduce building operational energy and 2. reduce the embodied energy developing advanced production process for glass and transparent materials production.

4.4.2.1 Advanced and high performance transparent materials In order to reduce building operational energy it is has been developed advanced and high performance windows to reduce building operational energy and in particular: low-emissivity; reflection surfaces; vacuum glazing optimization of solar energy and daylight transmittance; insulated frames; passive frames; light directing elements; sun pipes; prismatic rooflights or hologhraphic-optical elements; Intelligent windows. Glass with controlled heat transfer, energy-harvesting glasses, aerogel glazing. Electrochromistic materials. Smart windows technology could start the potentials of future improving glassing products and building control systems. Monitoring and evaluation of the performance of smart windows is a key to established impacts of new glazing techniques on whole building performance (21). The review of Rowley (47) summarise the class of electrochromic materials and the possible applications. –

Transition metal oxides: potential use in smart windows, thermal control of satellites and electrochromic writing paper;

–

Prussian blue systems: potential use in displays;

–

Viologens: used in car rear view mirrors and potential use in displays;

–

Conducting polymers: potential use in smart windows and displays;

–

Transition metal and lanthanide coordination complexes and metal-polymers: potential use in switchable mirror;

–

Metal phthalocyanines: potential use in displays.

Controlled photochromic. Traditional photochromic glass is characterized by a decrease of the transmission of the glass in the presence of light. In order to have photochromic devices that are capable of controlling transmission at the discretion of the user, a great interest to the market is the user controlled photochromic device by modifying the electrical potential. Gasochromic materials. A gas such as hydrogen alone or mixed with inert carriers in cooperation with an electrocatalytic layer serves as the source of ions for insertion into an electro-chromic electrode. Upon application of a potential between the electrocatalytic layer and the transparent conductor, the ions formed at the catalyst can be transported through an ionic conductor and into the electrochromic layer

WP 1.1 – COMPETENCY MAP – Technology Analysis [47]

causing coloration of the device. Reversal of the potential results in the removal of the ions from the electrochromic electrode and a decolourising of the device (28). Thermochromic materials. Needs further research in order to improve the thermochromic coating’s performance by preventing photo-degradation. Adaptive liquid crystal glasses. To develop advanced and cost effective technologies consisting of liquid crystal film deposited on a flexible substrate. Holographic optical elements (HOE). Develop new manufacturing processes for holographic elements in large formats and on large scale in order to make their use in architecture possible and attractive. Further applied research need to be developed in order to better adapt the holographic films with the requirements of shielding and redirection of the light. Prismatic panels. They are planar, saw-tooth devices made of clear acrylic (or other transparent materials). Further applied research need to be developed in order to better adapt the laser cut processing with the requirements of shielding and redirection of light. Laser-cut panels. A laser-cut panel is a daylight redirecting system produced by making laser cuts in a thin panel made of clear acrylic material. Further applied research need to be developed in order to better adapt the laser cut processing with the requirements of shielding and redirection of light.

4.4.2.2 Reduce embodied energy Develop advanced production processes for glass production in order to reduce the embodied energy and the embodied CO2 emissions. –

Use of alternative fuels instead of fossil fuels;

–

Increase of recycled raw materials;

–

Use and introduction of new burner technologies.

4.4.3 Multiple skin façades The research challenges in multiple skin façades can be summarized as follows. –

Create more advanced integrated envelope solutions in order to optimize the energy consumption of buildings,

–

Develop responsive façades integrating intelligent and responsive materials, e.g. shape memory alloy, PCMs,

–

Develop new materials and devices bio-inspired, studying nature’s mechanisms, processes and imitates these designs and processes in order to develop responsive and more efficient façades,

–

Develop new materials with lower embodied energy

4.4.4 RHC technologies Heating, ventilating and air-conditioning (HVAC) generally includes a variety of active mechanical/electrical systems employed to provide thermal control in buildings. Further research and development is required for all the systems.

WP 1.1 – COMPETENCY MAP – Technology Analysis [48]

In this report will be investigated only the RHC technologies that exploit the principle of the heat pump and exploit solar energy.

4.4.4.1 Heat Pumps. Electrically driven heat pumps. The RHC report (3) claims that there is a “significant room for further improvement” and then next generation of heat pumps should satisfy the following characteristics: –

be more efficient;

–

use natural refrigerants;

–

use low quantity of refrigerants: 25-40 gram/kW in relation to the different circuits;

–

be cost and energy effective

–

have efficient and flexible modulation capacity;

–

apply improved strategies and designs for defrosting ;

–

apply improved strategies and designs for noise handling;

–

be designed to maximise seasonal efficiency;

–

enable maximum integration with other heat sources;

–

integrate smart controls and integrate with standard communications interface to the internet and to smart meters/smart grids;

–

be as small as possible;

–

be less expensive;

–

minimise maintenance needs;

Research is primary required in improved components described as follows: –

heat exchangers, requiring enhanced heat transfer surfaces, minimising refrigerant volume, efficient draining of the condensate and efficient approaches to defrosting;

–

compressors, require research and development in order to facilitate and promote the use of natural refrigerants as an efficient solution, furthermore incorporation of latest electrical motor and latest electronically commutated motors will increase efficiency considerably through speed variation;

–

fans and pumps used for transport the different media inside and outside the heat pumps;

–

expansion valves.

Furthermore needs integrate heat pumps with solar thermal systems in order to produce hot water at higher temperature. Thermally driven heat pumps. Absorption heat pumps (liquid absorption cycles) is considered a mature technology, RHC report (3) asserts that R&D is required in the following fields: –

Materials: development of new working fluids;

–

Components: development of new compacting heat exchangers, improvement of reliability;

–

Smart controls: development of smart dedicated controls and optimal operation and adaptation to the thermal demand;

–

Development of heat pumps with advanced cycles and control strategies;

–

Demonstration and in field assessment of absorption heat pumps in different climates;

WP 1.1 – COMPETENCY MAP – Technology Analysis [49]

–

Application with different renewable heat sources (e.g. solar thermal, waste heat, etc.).

Solid adsorption heat pumps. RHC report claims that the solid adsorption heat pumps have been less developed than liquid absorption ones meaning they still have significant potential for improvements. RHC report (3) asserts that R&D is required in the following fields: –

Materials: needs develop sorption materials accepting wider window of driving temperatures in order to improve the seasonal efficiency performance and capable to stay stable over several thousands of cycles;

–

Components for sorption heat pumps, in particular compact sorption heat exchanger, heat exchanger techniques to increase heat transfer rates, evaporators and condensers for different working fluids at very low pressure;

–

Solid sorption heat pump systems.

4.4.4.2 Solar thermal The RHC strategic research and agenda (48) claims that the R&D priorities for solar heating and cooling systems in residential buildings should focus on the following areas: Solar collector improvements. Higher performing collector materials, design and processes through the development of the following elements: –

development of transparent cover materials with high optical transmission;

–

switchable coatings that reduce the stagnation temperatures;

–

new absorber materials with low-emission coatings;

–

temperature resistant insulating materials;

–

highly reflective and light materials for reflectors,

–

improvement in the collector construction design and manufacturing processes.

Solar thermal system improvements. Higher performing solar systems, in particular: –

development of compact solar based heating systems;

–

development of hybrid systems combining solar system with a heat-pump or a pellet boiler;

–

increase the overall thermal performance of the system;

–

improved hydraulic design and components in order to reduce losses;

–

new controller systems in order to better manage the heat fluxes;

–

develop innovative storage tanks

–

reduction in costs.

4.4.5 District heating Numerous techniques and measures are possible to reduce costs and raise the efficiency for heat distribution and the Energy Technology Initiatives (39) describe the following four possible research areas: New heat distribution methods like low-pressure, low temperature systems connected directly to a radiator system, without heat exchanger. Replacing the electricity consumed in households appliances (e.g.

WP 1.1 – COMPETENCY MAP – Technology Analysis [50]

dishwashers, clothes washers or dryers). New improving heating pipes and substations and improving the relationship between supply and demand through thermal storage and system optimisation.

4.4.6 Lighting The U.S. Department of Energy document (45) asserts that the goal of lighting R&D is to develop lighting technologies with significantly increased efficiency compared with today’s most efficient lighting products, in particular focusing on the following areas: –

Solid State Lighting (SSL) materials and devices, which include both light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs);

–

The EeB PPP (17) argue that one of the research challenges in lighting is the integration of advanced lighting like OLEDs with sensors and actuators as well as with suitable intelligent power electronics and control systems;

–

Improving manufacturing techniques to reduce costs and enhance product quality.

4.5 Promising research for cross-cutting technologies The term cross-cutting technology is intended, in this document, as any technology or area or system which can be used to reach energy efficiency in buildings. A number of cross-cutting technologies are commonly involved in energy efficiency in buildings and some of them are described in this section.

4.5.1 Materials research As referred by the European Technology Platform (49), “the advanced materials sector is one of the traditional strengths of European industry and materials research is at the core of sustainable technologies”. Materials research presents a lot of opportunities for synergies and complementary between different applications. Hereinafter will be described the research challenges included in the working paper dedicated to “Materials Roadmap Enabling Low Carbon Energy Technologies” (50) subdivided in the following areas: Develop advanced and high performance building products. Transfer the knowledge from other research areas (e.g. aerospace, automotive, etc.) to building applications. –

– – – – – – – –

Improved use of nanotechnologies to increase insulation and thermal inertia properties of concrete or composite structures, including thermal concrete, thermally insulated products, thermal inertia of concrete. Concrete with stabilised PCM encapsulated. Development of new products based on aerogels plus concrete or nanoporous concrete. New ceramic materials for advanced facades with renewable energy storage integrated Materials with embedded sensor for life-long advanced monitoring and control New adhesive for cost-effective installations Development of ceramic tiles with layers of insulating materials and higher thermal inertia, and advanced surface properties. Nanotechnologies coatings with variable surface optical properties Use of nanotechnologies for advanced aerogel, hybrid aerogels, new nano-materials

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Develop advanced production processes to reduce embodied energy/carbon. –

–

Reduce the impacts in ceramic products with technological improvements in their manufacture. Bribian et al. (20) claims that the replacement like the replacement of old kilns with new ones more efficient can increase the energy efficiency of 20%, the use of high speed burners and the recovery of the heat from the kiln smoke to preheat/dry the product to be fired achieving a reduction in the consumption of the kiln of 5% and 8% respectively and the installation of cogeneration system with a reduction of 10% in the primary power. Reduce the impacts in cement/steel industry adopting new techniques of heat recovery

Develop advanced and high performance products to reduce building embodied energy/carbon. Using, in areas where it is adequate, timber as material of the building’s structure construction or other natural materials like wood fibres, cork, cellulose fibres, kenaf fibres, cotton fibres, lamb wool. Furthermore, the use of animal or vegetal origin in buildings involves a prior capture of CO2 (e.g. in the forests) and storage of this CO2 for the whole useful life of the building. Bribian et al. (20) asserts that the use of sheep’s wool for produce thermal insulation in buildings is an opportunity because in many cases the lamb’s wool has seen in the market as a waste product. At the same time, obtaining cork in the forests and farms in the south of Europe (mainly Portugal and Sardinia) is one of the most ecological production types there is, as the cork is extracted from the tree during the summer every 10 years not damaging the tree. – – – –

Biotic renewables Nanotechnology-based biofibres, Development of bio-based polymers and plastics leading on the long-term to replace building materials Evaluation of potential gains in terms of embodied energy compared to conventional materials by LCA of bio-based materials

Develop advanced and high performance materials with high use of recycled materials. It is necessary to promote a radical change in the design of buildings in order to favour the disassembly of the construction materials and facilitate the recycling of the different components by selecting the materials at the end of their service life. Bribian et al. (20) propose to use reversible joints between the different materials, avoiding adhesion as far as possible (e.g. bolted joints), transferring technologies, for instance, from automotive industry, where this conceptual design is reality. – – – –

Technologies to increase the use of waste streams from other sectors to fuel cement kilns Increase the recycled aggregate and/or waste fraction Regenerated fibbers (e.g. from waste paper or waste timber or waste cloathings, etc.) Increase the recycled fraction in bricks using paper fibres for lightweight bricks;

Develop new advanced methods for evaluation of material durability. –

–

Generate fundamental understanding of mechanism that influence the durability of the different properties of construction materials, products and components, included LCA analysis tools and reliable models. Definition and application of common metrics and the development of processes to generate improved durability, including reliable test methods and inspection procedures.

WP 1.1 – COMPETENCY MAP – Technology Analysis [52]

4.5.2 Thermal energy storage According to the RHC report (3), the most promising research priorities in thermal energy storage are described as follows. Control strategies for integrating sensible stores into the Smart Grid. Heat pumps could play an important role in smart electricity grids if thermal production can be decoupled from thermal demand. There is a need to develop, in line with smart-grid/smart-homes technologies, methods to accurately determine the state of charge, controls and control algorithms so that heating and cooling is optimally generated from the RES when available, while still providing the consumer with their needs at time of their choosing. Advanced monitoring of storage systems. Development of low-cost sensors of pressure, composition and internal energy are needed specifically for latent and thermochemical systems. System evaluation. A number of research priorities relevant to all TES systems are: – – – –

Methods and criteria to transfer research results from laboratories to industry Life-cycle assessment of different thermal energy storage concepts. Integration of thermal energy storage sub-system in the complete system. Business models for storage.

Advanced control strategies. The storage of heat (or cold) is a time-dependent process. The RHC report asserts that new strategies should be developed that correctly model the time-dependent and systemdynamic behaviour of system with thermal energy storage. Advanced control strategies could be applied to: – – – –

District heating with seasonal storage; Heat demand of industrial buildings with buffer storage elements; Industrial heat production systems incorporating seasonal storage systems; Use of industrial surplus heat.

According to the RHC report (3), the most promising research priorities of the three major types of thermal energy storage are described as follows.

4.5.2.1 Sensible heat storage Flexible volume tank systems. Today’s systems for short-term and seasonal storage use tanks with constant volume. In seasonal storage, especially when two tanks are used, two times the required volume is used for storage. Concepts such as one tank with flexible diaphragms or with flexible walls should be developed (3). Reduction of heat losses (see materials research). New cheaper vacuum insulation materials New sensible thermal energy materials (TES) with high conductivity. Optimisation of hydraulics in advanced water stores. Advancements are possible in the following areas: – – – – –

Optimisation of the internal heat exchangers; Internal free convection in water tanks; Heat losses due to parasitic heat convection in pipes; Integration of PCM in water tanks in order to increase energy density; Reduction of mixing and increase stratification.

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New methods to analyse TES materials. The RHC report (3) asserts that most analytical methods for investigating thermal properties are not precisely tailored to the study of TES materials. There are properties which cannot be assessed through analytical methods currently available for such applications. Water pit energy storage. The BAT document (32) asserts that one of the challenges of this type of storage is maintaining the membrane 100% watertight over many years of thermal cycling. In-fact the groundwater flow cause heat loss, since this type of storage sometimes is not well insulated at the bottom.

4.5.2.2 Latent heat storage The main advantages of PCM heat storage are higher energy density and the delivery of heat at constant temperature. The following research areas are described as research priorities according to the RHC report (3). Optimisation of phase change heat storage. Work in this topic requires mainly basic and applied research. The technology of PCM storage could be improved as follows: – – –

Increasing the storage density in order to make possible to integrate PCMs into buildings and HVAC systems; Developing heat exchangers that can also encapsulate the PCM; Develop new and environment friendliness materials and/or mixtures with PCM properties.

Integration of PCMs in building element materials. This topic requires mainly applied research and development to be carried out through collaborative R&D between the building industry and research institutes. The R&D could be focused as follows: – – – –

Incorporate PCM in polymers for window frames; Incorporate PCMs in drainage systems; Incorporate PCMs in materials for wall, floor and ceiling; Research to determine the fire-risk of these materials when embedded into construction materials is required.

Fluids combining heat transfer and heat storage. The RHC document (3) asserts that the energy consumption for HVAC can be reduced if higher efficiency components are used, including heat transfer fluids and thermal energy storage materials. If these two features are combined, the material use can be optimised because less pumping will be needed and heat transfer will improve. Software algorithms and codes for PCM behaviour. Development and test of algorithms, procedures and new codes in order to better predict the behaviour of PCM materials.

4.5.2.3 Thermochemical storage The RHC report (3) claims that the main bottleneck in the development of compact, seasonal house-scale heat storage is the current lack of stable, high performance, cost effective storage materials and processes and the main research priorities in this field are: Materials for thermochemical heat storage. This area needs of basic and applied research. Novel thermochemical reactancts and combination of materials have to be identified. Knowledge of how to synthesise, characterise and compare materials and their performance must be gained. Environment friendliness is an important parameter to consider in the development of new thermal energy storage materials. Furthermore these materials can be tailored to the application, which will have a specific requirement for temperature level, energy and power density, an open or closed reaction process, reversibility, cost and toxicity or multiple purposes such as combining heat transfer and heat storage. In order to better understand the behaviour of these materials and for design new compact storage materials, computer simulation of the physical processes governing materials can be used.

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Optimisation of thermochemical heat storage processes. This topic requires mainly applied research. Process design and optimisation is needed using tools that simulate molecular and ionic interactions, reaction kinetics and bulk scale mass flow are needed. The design of novel reactors and heat exchanger principles are needed. Further applied research should focus on: design of process, control of the system, predicting annual performance, integrating the storage system in building applications. Materials for storage containment. New storage materials need to be developed, including cheap thin polymeric materials, with properties such as: – – – –

High thermal insulation; High mechanical strength; High thermal stability; Unreactive with the thermal storage materials.

4.5.3 Information and Communication Technologies (ICT). ICT are expected to have significant impact on improving energy efficiency in buildings. REEB16 has identified five key research areas where ICT enables both new applications and integration: Integrated design and production management, Intelligent and integrated control, User awareness and decision support, Energy management & trading, Integration technologies. Integrated design and production management –

Integrated engineering : integration of various tools to support a holistic process bringing together the views of different stakeholders to address the whole life of buildings.

–

Design for Energy Efficiency tools, covering a broad range of CAD and BIM tools and other applications such as performance estimation tools (e.g. simulation, whole life costing and life cycle impact assessment)

–

Production management that covers contracts & supply network management, procurement, logistics, on-site and off-site production management.

Intelligent and integrated control. –

Automation and control: methodologies, procedures and ICT systems that are able to manage all energy production and usage in a building, according to information received from inside the building and outside in order to ensure comfort, while optimizing the energy consumption of the building.

–

Monitoring: relying on the instrumentation of the building with smart meters, other sensors, actuators, micro-chips, micro and nano-embedded systems that allow collecting, filtering and producing information locally and wireless sensors network.

REEB-European strategic research Roadmap to ICT enabled Energy-Efficiency in Buildings and constructions. The REEB project is a Co-ordination action addressing the strategic objective: ICT for environmental management and energy efficiency for the construction sector http://www.ict-reeb.eu

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User awareness and decision support –

Performance management: create tools to the end-user for performance improvement and decision support

–

Visualization of energy use, REEB report (51) claims that the ongoing research projects on this topic need to be further continued through multidisciplinarity pilot projects.

–

Behavioural change by real-time pricing because new technologies for energy metering and local energy generation will change the customer relationship with the energy providers.

Energy management & trading –

Real-time response and Predictive management through embedded sensing, automation and control.

–

Distributed generation and demand response

Integration technologies –

Process integration developing collaboration support tools

–

System integration

–

Knowledge sharing meaning as access to knowledge repositories, long term data archival and recovery

–

Virtualization of built environment

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4.6 Indicators The number of patents, the number of publications and the number and typology of European funded projects may be considered as indicators of the technologies that are currently being pursued for R&D and commercial applications.

4.6.1 Number of patents involved Patents are a useful tool to point out trends and priorities in technological progress for a given field. The aim of this section is to analyse technological advances in energy efficiency in buildings based on the number of patents in some relevant areas. Patents reflect the inventive activities in the technology fields considered. The patent system is one method firms use to protect their inventions, the patents are registered by government bodies. In standard technology, the patent activity should be visible before the introduction of the corresponding product or process into the market. A specific advantage of patent statistics is the possibility of tracing technology activities for long periods on the basis of patent classification codes17.

Table 16. Number of patents involved in energy Efficiency of buildings, in Europe and in the World Regions

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

AUT: Austria BEL: Belgium CZE: Czech Republic DNK: Denmark FIN: Finland FRA: France DEU: Germany GRC: Greece HUN: Hungary IRL: Ireland ITA: Italy NLD: Netherlands POL: Poland PRT: Portugal SVK: Slovak Republic SVN: Slovenia ESP: Spain SWE: Sweden GBR: United Kingdom Total Europe TOTAL: World Total

6 2 1 1 3 12 58 0 4 1 7 54 1 1 0 1 0 4 21 175 408

3 4 0 4 5 11 58 0 1 1 8 75 1 0 0 1 0 6 41 219 516

6 2 1 4 3 16 107 0 0 1 7 72 2 0 1 0 1 5 31 259 664

7 2 0 4 3 8 91 1 0 0 9 49 0 0 0 2 0 7 22 205 758

8 3 1 4 2 15 120 0 1 1 6 64 1 0 0 1 2 5 33 269 971

3 5 1 4 0 13 115 0 5 0 16 55 0 0 1 0 1 10 26 254 721

9 3 2 4 9 25 123 0 0 3 10 92 0 0 0 1 4 8 19 315 810

13 9 2 13 1 15 148 0 11 0 12 90 0 0 1 0 5 7 27 355 976

18 8 3 2 5 28 112 1 10 1 9 95 3 0 0 0 2 8 32 340 960

22 11 2 12 7 24 118 2 2 1 15 81 3 0 0 1 6 12 44 365 1.088

22 6 1 2 6 31 137 0 15 1 8 71 3 1 0 1 6 11 25 348 1.162

Source: Elaboration CETA from WIPO data (52)

E. Jochem, Improving the Efficiency of R&D and the Market Diffusion of Energy Technologies, Karlsruhe: Springer Dordrecht Heidelberg , 2009.

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Table 17. Number of patents published per each technology in the European Patent Register.

Thermal insulation Aerogel Vacuum insulation Electrochromic materials Thermochromic materials Photochromic materials Reflective insulation systems Holographic layer Low emissivity glass/coating Façade system Thermal storage PCM Phase Changing materials Heat recovery systems Heat pumps Ground heat exchanger Solar thermal Radiant heating HVAC system

2003 15 4 6 2 0 1 0 0 0 2 3 7 8 31 0 2 3 2

2004 8 5 3 1 1 0 0 0 0 6 4 6 10 19 0 2 4 3

2005 18 3 4 1 1 1 0 1 1 5 3 1 7 21 0 5 5 3

2006 19 4 8 0 2 2 0 0 0 2 7 4 16 36 0 5 4 14

2007 16 6 5 1 0 3 1 0 0 3 6 6 25 40 2 9 3 6

2008 19 7 9 1 0 4 0 0 2 5 8 8 22 64 1 9 3 4

2009 32 3 5 0 0 2 1 1 1 6 9 6 24 65 1 19 3 4

2010 26 3 6 1 0 1 0 3 1 9 14 5 27 73 1 27 5 9

2011 26 10 10 0 1 2 0 0 1 10 10 2 40 114 3 48 4 6

2012 35 10 12 0 0 2 0 0 0 9 24 5 47 142 3 40 1 7

Source: Elaboration CETA from European Patent Register data (53)

Table 18. Number of patents published per each technology in the World Intellectual Property Organisation register Patents Energy efficiency in buildings Thermal insulation materials Aerogel Vacuum insulation panels Gas filled materials Electrochromic materials Thermochromic materials Photochromic materials Reflective insulation Holographic layer Low emission glass Low emission coatings Façade system Thermal storage Thermochemical heating storage PCM materials Bio-based materials Heat recovery systems Heat pumps Ground heat pumps/exchangers Radiant heating Solar thermal

2005 41 1136 88 76 51 22 6 28 65 27 51 69 26 728 5 39 25 231 2819 60 410 148

Source: elaboration CETA from WIPO (54)

2006 43 1153 140 80 52 18 9 33 66 21 57 97 31 754 1 42 47 253 3090 72 395 189

2007 41 1151 105 94 71 25 7 31 43 28 49 107 34 812 2 52 33 297 3069 107 380 253

2008 55 1062 138 75 69 21 11 32 52 19 58 103 33 800 0 58 46 288 3096 96 352 346

2009 65 1067 108 63 40 24 7 22 57 18 46 71 43 848 0 59 41 313 3276 99 348 506

2010 61 983 156 56 55 19 12 18 56 22 31 55 82 839 3 56 43 383 3349 109 387 679

2011 83 985 154 93 41 41 7 20 37 8 44 64 47 948 4 57 76 465 3260 127 369 866

2012 69 716 191 102 41 32 6 19 26 12 34 44 41 643 2 57 71 385 2303 70 290 714

WP 1.1 – COMPETENCY MAP – Technology Analysis [58]

4.6.2 Number of publications involved The analysis of the publication statistics is another valid tool for describing the development and the importance of technologies. The following table collect the number of publications per each technology found in the ScienceDirect database (54). The publication search has been done by the use of keywords, in order to simplify the search. Table 19. Number of publications published per each technology in the Elsevier database 2005 2006 Energy efficiency in buildings 1.614 1.932 Thermal insulation materials 2.232 2.316 Aerogel 326 380 Vacuum insulation panels 12 25 Gas filled materials 111 115 Electrochromic materials 97 145 Thermochromic materials 5 7 Photochromic materials 29 40 Reflective insulation 142 159 Holographic layer 328 367 Low emission glass 56 73 Low emission coatings 16 21 Façade system 10 13 Thermal storage 391 477 Thermochemical heating storage 4 2 PCM materials 71 130 Bio-based materials 27 20 Heat recovery systems 48 47 Heat pumps 84 108 Ground heat pumps/exchangers 5 2 Radiant heating 27 27 Solar thermal 392 437 Source: elaboration CETA from Sciverse database (55)

2007 1.785 2.488 384 19 122 137 8 26 173 360 78 18 21 527 4 153 42 50 105 15 34 460

2008 1.862 2.729 464 26 126 186 11 40 226 332 75 10 12 558 4 178 58 49 139 10 24 560

2009 2.228 3.119 512 29 139 144 9 45 254 356 70 24 21 651 2 189 79 77 110 11 39 673

2010 2.551 3.172 515 15 157 136 9 41 298 313 79 20 19 661 3 250 145 88 141 24 43 740

2011 3.362 3.912 618 30 141 156 7 57 517 383 93 29 32 849 3 347 181 115 169 33 46 1.116

2012 4.321 4.783 708 45 176 182 16 48 448 339 115 28 40 1.136 20 492 232 135 222 39 62 1.410

WP 1.1 – COMPETENCY MAP – Technology Analysis [59]

4.6.3 European funded projects Energy efficiency is addressed by a relevant number of European programmes and initiatives. The Energy Theme of the current Research Framework programme (FP7), focuses on increasing the efficiency in energy generation, the efficient energy use in the manufacturing industry, poly-generation and socio-economic research. It also comprises the large-scale integration of renewable energy supply and energy efficiency in buildings with “Eco building Initiative” and “CONCERTO Initiative”. The NMP Theme18 allow research for advanced materials and has set up a Joint Technology Initiative (JTI) on Energy Efficient Buildings bringing together all the different stakeholders active in the building sector. Furthermore the technologies involved in ICT have a particular focus on energy-smart homes and building and on smart lighting (55). The following table collect the number of research projects funded by the EU.

Table 20. Number of projects funded

Thermal insulation Aerogel Vacuum insulation Electrochromic materials Thermochromic materials Photochromic materials Reflective insulation systems Holographic layer Low emission glass/coatings Façade system Thermal storage PCM materials Heat recovery systems Heat pumps Ground heat exchanger Solar thermal systems

FP5

FP6

FP7

7 5 1 1 4 2 3 2 12 2 2 12

8 9 4 5 1 3 7 9 10 4 9 1 42

26 33 10 10 7 1 3 8 34 19 29 46 23 2 38

Source: Elaboration CETA from Cordis data (56)

Nanosciences, Nanotechnologies, materials and New Production Technologies theme.

WP 1.1 – COMPETENCY MAP – Technology Analysis [60]

5 Conclusions In this section are summarized the research priorities for EE in buildings technologies elaborated from the European strategic agendas. The table below summarise some of the most promising technologies and the research challenges for reduce the CO2 emissions in energy efficiency in buildings. Table 21. Summary of the most promising technologies in the field of energy efficiency in buildings

Envelope (new buildings and refurbishment)

RHC Renewable heating and cooling for new buildings and refurbishment

Cross-cutting technologies

– – – – – – – – – – – –

Advanced insulation technologies (in roof, walls and floor); Advanced transparent elements-materials; Building materials using recyclable materials; Building materials obtained from natural sources; Thermal storage materials. More efficient heat pumps; Thermal storage materials and technologies; Advanced solar thermal systems; Alternative refrigeration means Stirling cycles, brayton cycles, and acoustic, magnetic and thermal-electric technologies; Advance in materials; Thermal energy storage; ICT.

Source: Elaboration CETA

5.1 Promising research technologies in EE in buildings Table 22. R&D priorities in building’s envelope Envelope Advanced insulation technologies in opaque elements

Reduction of embodied energy in opaque elements Advanced transparent elementsmaterials Reduction of embodied energy in transparent elements Multiple skin façades

– – – – – – – – – – – – – – – –

Source: Elaboration CETA

Vacuum insulation materials (VIM) improvements; Gas insulation materials (GIM) improvements; Nano insulation materials (NIM) improvements; Aerogel insulation materials improvements; Bio-based insulation materials; Improve the production processes; Increase the rate of recyclable materials. Advanced and high performance transparent materials; Adaptive and controlled windows-smart surfaces. Use of alternative fuels instead of fossil fuels; Increase of recycled raw materials; Use and introduction of new burner technologies. Develop advanced integrated envelope solutions; Develop responsive façades integrating intelligent and responsive materials; Develop new materials and devices bio-inspired; Develop new materials with lower embodied energy;

WP 1.1 – COMPETENCY MAP – Technology Analysis [61]

Table 23. R&D priorities in RHC technologies RHC technologies Electrically driven heat pumps

– – – – – – –

Increase the efficiency of heat exchangers; Increase the efficiency of compressors; Increase the efficiency and the reliability of the components; Integrate the heat pumping systems with other RHC technologies; Integrate with smart meters, smart controls; Develop new refrigerants more environmental friendly; Develop new refrigeration cycles systems.

Thermally driven heat pumps

– – – – – – –

Development of new working fluids; Development of new compact heat exchangers; Development of heat pumps with advanced cycles; Application with different renewable heat source; Develop new adsorption heat pump systems; Develop new solid sorption materials; Develop new components for adsorption heat pumps;

Solar thermal collectors

–

development of transparent cover materials with high optical transmission; switchable coatings that reduce the stagnation temperatures; new absorber materials with low-emission coatings; temperature resistant insulating materials; highly reflective and light materials for reflectors, improvement in the collector construction design and manufacturing processes.

– – – – – Solar thermal systems

– – – – – –

Source: elaboration CETA

development of compact solar based heating systems; development of hybrid systems combining solar system with a heatpump or a pellet boiler; increase the overall thermal performance of the system; improved hydraulic design and components in order to reduce losses; new controller systems in order to better manage the heat fluxes; develop innovative storage tanks.

WP 1.1 – COMPETENCY MAP – Technology Analysis [62]

5.2 Cross cutting technologies challenges Table 24. R&D priorities in advanced materials Materials Advanced high performance products

Use of nanotechnologies

Reduce embodied energy

– – – – – – – – – – – – – – –

Increase thermal insulation of materials; Increase thermal inertia of materials; New PCM materials; Transfer knowledge from aerospace to building applications; Develop new ceramic materials; Increase the thermal durability of the materials; Develop new insulation materials: (aerogel, vacuum insulation materials, nano-porous materials,..); New materials with high thermal inertia; Develop new high selective coatings. Develop advanced production processes; Develop biotic materials; Develop nanotechnology-based biofibres; Develop bio-bsed polymers and plastics; Develop advanced materials with high use of recycled materials; LCA analysis.

Source: elaboration CETA

Table 25. R&D priorities in thermal energy storage Thermal energy storage Sensible heat storage

Latent heat storage

Thermochemical heat storage

– – – –

Flexible volume tank systems; Reduction of heat losses; Develop of new sensible heat storage materials; New methods for TES materials analysis.

– – – – – – – – – – – – – – – –

New sustainable TES materials; Enhanced thermal storage stratification; Optimisation hydraulics in advanced water stores. New heat exchangers with PCM; New PCM with adjusting melting temperature; New PCM materials with a greater number of cycles; New PCM materials more environmental friendly; Corrosion-resistant storage materials; Software algorithms and codes for PCM materials; Integration of PCM in building envelope materials; PCM for thermal inertia in buildings. New thermochemical heat storage materials; New thermochemical reactancts; Develop seasonal thermal storage systems Develop new and environmental friendly materials; Optimisation of thermochemical heat storage processes;

WP 1.1 – COMPETENCY MAP – Technology Analysis [63] – Develop numerical models; – Develop solutions for single–family houses; – Develop materials and systems for chemical storage cointainment. Source: elaboration CETA from RHC document (3)

Table 26. R&D priorities in ICT ICT: Information and Communication Technologies Integrated design and production management

– Design for energy efficiency tools (LCA analysis); – Performance estimation tools with integrated LCA; – Production management tools; – Modelling (BIM) instruments with integrated LCA. Intelligent and integrated control – Automation and control; – Monitoring; – Quality of service; – Advanced sensors; – Automated diagnostics; – Wireless sensors networks. User awareness and decision support – Visualization of energy use; – Behavioural change by real-time pricing. Energy management & trading – Real-time response and Predictive management tools; – Distributed generation and Demand Response. Integration technologies – Interoperability & Standards; – Knowledge sharing; – Virtualization of built environment. Source: elaboration CETA from REEB data (51)

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