Densification of Private Living Space and its Impact on Emission Reduction

Densification of Private Living Space and its Impact on Emission Reduction Case Study of a Student Housing in Trondheim, Norway

NTNU - Norwegian University of Science and Technology Department - Faculty of Architecture and Design Course - Emissions as Design Drivers Theory Report by Florian Betat Mentor: Nicola Lolli June 2018

Table of Contents

1.

Abstract

2

2.

Introduction

2

3.

Objective

4

4.

Method

6

4.1

Densifying Private Living Space

6

4.2

Material Demand Reduction

6

4.3

Energy Demand Reduction

7

5.

01

Results

8

5.1

Densifying Private Living Space

8

5.2

Material Demand Reduction + Emission Savings

14

5.3

Energy Demand Reduction + Emission Savings

18

6.

Discussion

22

7.

Conclusion

23

8.

Bibliography

24

1. Abstract To tackle global warming it is needed to reduce the greenhouse gas emissions significantly. As emissions from the building sector have more than doubled over the last four decades, it is essential to find ways to lower the sectors emissions.

With a view to Norway and its very clean energy, savings of energy have not much impact on the reduction of buildings emissions.

Hence, focusing on lowering the emissions from materials is necessary. Therefore, more environmentally friendly materials could be used. It is also possible to reduce the material demand by using material saving construction technics or by planning more space efficient.

emissions. Therefore, it is searched for ways and guidelines to plan private rooms more space efficient.

The study shows that standard student rooms in Trondheim could be built up to five times smaller, without skipping any needed functions. Consequently, the emissions from materials can be reduced by up to 76 %. Space heating and lighting demand of a person can be lowered, if the densification of the private rooms is used to decrease the buildings size or to accommodate more people. Though, analysis of the case study in Norway demonstrates that emission reduction from energy savings is a fractional amount of the ones from reducing the material demand.

The latter is the focus of this study which analyses the impact densifying private rooms in a student accommodation have on the

2. Introduction In the western world, buildings account for approximately a third of both all energy use and of greenhouse gas emissions (IEA, 2015). To tackle the climate change efficiently it is needed to reduce greenhouse gas emissions of the building sector as much as possible by lowering its energy and material demand.

Currently, space heating accounts for over 60 % of the residential energy consumption in Norway (Figure 1) (IFE, 2013). Therefore, space heating represents the largest opportunity to reduce buildings energy consumption and GHG-emissions. While the thermal properties of the building envelopes got improved in the

last two decades (Hestnes and Eik-Nes, 2017), the living area per capita increased by 0.9 % every year since 1990. Instead of 46 m² in 1990 a Norwegian had in average 54 m² of living area in 2010 (Figure 2) (IFE, 2013). Therefore, forecasts predict that households use 23 % less energy in 2050 compared to 2007 while the energy use per person will lower by only 6 % due to decreasing capitas per household and expanding living areas per person (IFE, 2013).

That's why it is important to focus on the advantages of space efficient planning. Thereby it is possible to look at theoretical and built examples.

02

60

water heater 15%

2.45

space heating + misc.

64 %

cooling 5 % cooking 2 %

2.35 2.30

50

2.25 2.20 2.15

45

washing 3 % PC with accessories 2 % electronics 3 %

Figure 1: Percent shares of electrical end-uses in Norway 2006/2007. data from: (Institute for Energy Technology, 2013)

The thought of densifying living space is not a new trend. Already in the year 1929 the International Congresses of Modern Architecture (CIAM) held a series of meetings to the topic of „The Minimum Dwelling“ in Germany. The intention was to find answers how to provide a dwelling that would at least satisfy the basic minimal requirements for healthy living - an answer to the high demand on small and inexpensive apartments for the working class at that time. As the main driver for high dwelling cost was seen the mechanical installations as toilets, gas and electric installations. This was mainly the reason why the price of a flat drops not equal to its size. To illustrate it better: the cost of a single-room flat is usually not five times less in comparison to the one of a five-room flat. Instead, the cost is often a third or even half of the price of the larger apartment. What has been suggested is to find ways to share the more expensive installations of a dwelling. Especially kitchens can become communal and bathrooms in a dwelling can get reduced to their functional minimum resulting in a collective architecture. With this shift from private to public area the question arises what the minimum requirements for a private space are.

Certain guidelines were developed during the CIAM-meetings: (i) each adult individual must have its own separate space, (ii) the private space should serve private functions only, (iii) the dwelling should provide enough space to fulfil all indispensable needs of its inhabitant and (iiii) common

03

55 m²/capita

lighting 6 %

Capita/household

2.40

2.10 40 1990

1995

2000

2005

2010

2.05

Area/capita Capita/household Figure 2: Area per capita and persons per households in Norway 1990-2010. data from: (Institute for Energy Technology, 2013)

facilities are the natural extensions of a small apartment and therefore highly needed. (Teige, 2002) The last point leads to the work of the Russian state planning official L. M. Sabsovich from the same time. Important for this work was to define the centre of gravity of the dwelling. Is it the common spaces or the complex of individual rooms? He argued that the free time is spent mostly in the collective spaces and therefore the individual cells could host only space for sleeping and individual rest, reducing the private area to four or five square meters per person. (Stites, 1989) Later, in the 1950s, starting during the Chinese Civil War, a large number of Chinese mainlanders migrated to Hong Kong. This resulted in a strong population increase, a rising low-cost housing demand and eventually in a housing crisis. As an outcome of this process emerged the cage housing or also called bedspace apartments - more than twelve, only by cage enclosed bunk beds in a single room. Even today more than 100.000 people in Hong Kong live in such inadequate conditions. (SoCO, 2008) Further on, the topic of densifying living space was also part of the metabolist thinking. Here, in contrast to the cage housing life quality was

an important aspect. The metabolist movement originated from the CIAM 10 meetings and the World Design Conference in Tokyo in 1960. The main situation metabolists faced was the shift of lifestyle towards a mobile society as well as increasing housing costs in the inner cities of Japan. Due to the connections to the CIAM-meetings the metabolists orientated on similar guidelines how to densify living space as the ones declared in 1929.

One of the architectural approaches were the capsule apartments, modules which contain all necessary living functions in a minimum volume.

All other functions, going beyond the basic survival needs, were considered outside the capsule, also seen as the extension of the living space. In traditional Japanese architecture privacy is gradually layered. „Ma“ is the space in between complete privateness and complete publicness.

Originally, it translates as timing, silence, boundary zone or void. Therefore, it can be understood as a buffer zone with a lot of possibilities, becoming a key element in the works of the metabolists. With the further development towards a mobile working society capsule hotels emerged. Here, once more the volume of the capsules was reduced to the absolute minimum to still fulfil their purpose as temporary shelter. (Kurokawa, 1977) A strong focus on the ecological and economical aspects has the current tiny house movement with its origin in the USA. Typical tiny houses have a floor space between 10 and 40 square meters. Due to building that small

and compact costs for constructing a tiny house are in average ten times lower than for an average American standard-sized house. Therefore, 68% of all tiny house owners have no mortgages compared to 29.3 % of all U.S. homeowners (PAD, 2017). In addition to low building and maintenance costs building small can encourage the residents to live a less cluttered and simple lifestyle and thereby reduce their ecological impact (Lulu, 2016).

When comparing Norwegian, especially Trondheim's student housing to the previous discussed examples, new spatial efficient cost and emission saving concepts for student accommodations can still be explored.

Furthermore, the impact of densifying space in a building in terms of sustainability has not been addressed so far. The majority of discussions deal with the topic of densification on a city or district scale but not in a smaller one, such as the scale of a building.

To assess the possibilities of densifying private living space it is therefore important to look at this topic with focus on the inhabitants as well as the sustainable outcomes. Important is to find results to what extent living space can be optimized without affecting the life quality negatively.

3. Objective The aim of this research is to find answers to what extent a densification of private space in a building will result in material and energy savings throughout its lifetime.

The research will be done by a literature study, consisting of i.e. the publication of the second CIAM-meeting to the topic of „The Minimum Dwelling“ from 1929 and by studying the Japanese Metabolist architecture of the late 1950s to early 1970s. The gathered information will form a set of guidelines helping to design a densified micro living unit for student housing (Figure 3) which can be compared later to average sized student units. Hereby, a big focus will lie additionally on the importance of the ratio of private and common space and its space-, material- and energy saving potential.

Therefore, the study is divided into three parts. The outcome of the first chapter about densification of private space will be taken as basis for the second chapter about the material demand, where with the use of Life Cycle Assessment the emissions for the production and construction stage of the micro unit can be calculated and compared. Further on, the third chapter deals with the energy demand. Life Cycle Assessment is used once more to estimate the emissions saved during the use stage of the unit.

Altogether, this will give a solid base to assess the importance of area optimized private space for sustainable and low-cost living.

04

STUDENT ROOM

CAPSULE APARTMENT

MICRO UNIT

CAPSULE HOTEL

L: 400, W: 250, H: 240 Area: 10.0m² Volume: 24.0m³

L: 380, W: 230, H: 210 Area: 8.74m² Volume: 18.4m³

-

L: 200, W: 100, H: 125 L: 180, W: 80, H: 90 Area: 2.0m² Area: 1.44m² Volume: 2.5m³ Volume: 1.3m³

Berg, Trondheim

05

Tokyo

Trondheim

Japan

CAGE HOUSING Hong Kong

Figure 3: Dimensions of different space saving private rooms.

4. Method 4.1 Densifying Private Living Space To research the possibilities of private living space densification the context of student housing in the Norwegian city Trondheim is chosen. First it is important to get an overview of the different student accommodations and their private room dimensions. The gathered information will help to set a reference room dimension, typical for Trondheim, possible to use for further comparisons. Furthermore, the functions and actions needed to be performed in a typical student private room have to be analysed. Therefore, the analysis can be done by studying built examples and their furnishing as well. With this information a list of the typical furniture of student rooms

and their typical dimensions can be created. Knowing which actions have to be performed on or with which furniture it is possible to search for ways how to reduce the area as well as the volume the respective items take in a room. Therefore, a look at physical ergonomics will be required. Combined with the guidelines from the literature study to the topic of the „The Minimum Dwelling“ from the CIAM-meetings in 1929 and the Japanese Metabolist architecture of the late 1950s to early 1970s, it is possible to design a densified private room for student accommodations.

4.2 Material Demand Reduction

Benefits and loads beyond the system boundary

A2

A3

A4

A5

B1

B2

B3

B4

B5

B6

B7

C1

C2

C3

C4

Construction installation process

Use

Maintenance

Repair

Replacement

Refurbishment

Operational energy use

Operational water use

Deconstruction / Demolition

Transport

Waste processing

Disposal

End of Life

Transport

Use Stage

Manufacturing

Raw material supply

A1

Contruction Process Stage

Transport

Product Stage

of the densified and the average student room. The next step after having determined the change in the material demand is to estimate the emissions saved through building smaller with the help of Life Cycle Assessment. The environmental declarations of the chosen materials, provided by the respective companies will give an overview of the emissions caused during the product stage (A1-3) and the construction stage (A4-5) as well as for the emissions through replacement of material during the use stage of the building (B4) (Figure 4).

D Reuse-RecoveryRecycling potential

The result of the densifying private living space chapter will form a private room for student accommodations optimized in its area and volume. To be able to compare the material savings of a densified unit in contrast to a typical student room both rooms have to be planned with the same construction method and materials. That means that detailed construction plans for both rooms have to be drawn, including the construction layer, interior cladding and the insulation. The use of a 3D model is therefore recommended as this will help to calculate the different material demand

Figure 4: Life cycle stages of a building according to EN15978:2011 (CEN, 2011).

06

4.3 Energy Demand Reduction To determine the energy demand of the densified and average student room a list of all electric end-uses has to be created. Hereby, lighting and space heating is important. In general, there is no kitchen and sanitary within the private rooms, wherefore the end-uses cooking, washing and water heating are not looked at. The energy use for private plug loads of the inhabitants is as well excluded from the energy calculation, as the energy demand for this end-use will not change noticeably within a building by changing room sizes as done in this study. With the lighting and space heating as the point of interest for this calculation, specific products can be chosen and placed in the rooms. Based on the product descriptions from the manufacturer the energy demand for the operational energy use

(Figure 4, B6) of the two different private rooms can be determined.

Additionally, it is important to focus not only on the private room alone.

Through reducing the dimensions of the private rooms in a student accommodation more common space can be created. The second calculation will therefore include also the common space. This will allow comparing the energy demand of the two scenarios: small private rooms and large common space or large private rooms and small common space (Figure 5). The dimensions of common space and private space together will be set by the average dimensions of some of the in Trondheim existing student accommodations.

Scenario 1: small private rooms, large common space private room

2*

2*

large common space densification (4.1)

reduced material demand (4.2)

less GHG-emissions

reduced energy demand (4.3)

less costs

Scenario 2: large private rooms, small common space private room

small common space

07

Figure 5: Two scenarios for comparing energy demand.

Figure 6: Advantages of space optimized building.

5. Results 5.1 Densifying Private Living Space As first step of researching possibilities of densifying private rooms in student accommodations a reference project in Trondheim, Norway was searched. The private rooms of the Trondheim student accommodations managed by the student welfare organisation Sit have a size between 5 and 23 square meters (Sit, 2018) (Table 1). The 2017 finished and rewarded Moholt 50/50 in Trondheim has 13 square meter rooms with included bathrooms. The room sizes of the 2010 built Berg-Studentby range between 10 and 17 square meters whereby most of the rooms have the smaller size. In contrast to many other accommodations no private bathrooms are included. Therefore, the 10 square meter room of the Berg-Studentby was chosen as reference room, as they are the closest to the typical private student room size in Trondheim. The 2.5 times 4 meter large reference room is equipped with a standard sized bed, desk and chair and storage place in form of a wardrobe. In addition, it provides space for a floor or table lamp, a mirror, a trash can and place to hang private items.

The functions this room has to have are exclusively private as the room adjoins common space. Through studying the different actions an inhabitant can perform in this room it became clear that most of the actions are for personal recreation or studying and can be carried out in lying or sitting position. Standing or walking is mostly required if the resident wants to move from one function or furniture to another one which is out of reach in lying or sitting position.

volume a standard one without functions under or above needs. The large study desk as in the reference room can be part of the common area and be shared in the densified scenario. A little fold-out desk can be installed in the private room instead, still large enough for a book or laptop and for reading, writing and eating (Figure 8, Example 1). Only at few occasions a larger desk in the common area will be needed. Fold-out mechanisms are in general good ways to use a space multifunctional. So, the bed could be covered with a floor plate in daytime, making the space usable for plenty other actions and functions then sleeping. It would allow using this as workspace and sitting space in daytime for example. The chair should also be foldable, or be multifunctional. A design combining storage space and sitting options can be considered for example (Figure 8, Example 3). The lighting system can consist out of LEDs as they are not only space saving but also reduce the energy demand significantly (Figure 8, Example 2).

The aim was to keep all the functions of the reference room also in the densified one. Therefore, a list with all the items standing in the reference room was created including the area and volume they take in it (Figure 07).

It was taken into consideration if the area or the volume the items take can be reduced and if they necessarily have to be private or can be placed in the common areas of a student accommodation instead. Especially the large items appeared to have a large potential for saving space. While the space a bed occupied cannot be reduced, much of the space above or under can be used differently, as it is only needed to lie or sit in a bed. The space between bed and ceiling has to be therefore only 135 centimetres. This means that a more space efficiently planned bed needs only 56 % of the

Considering all the facts, the resulting micro unit has an inner length of 220 centimetres and a width of 167.2 centimetres (Figure 9). This dimension allows to fit all the furniture and functions in the micro unit, according to the before mentioned steps. As all the functions and furniture are positioned very close to each other and the area is not much larger than the size of a bed, walking in the unit becomes unnecessary. Therefore, the dimensions a person needs in sitting and lying positions are determining the final volume of the unit. 135 centimetres is the height needed for sitting (Neufert et al., 2002), wherefore the height of the unit is only 5 centimetres higher to have enough space for the door mechanism and other installations. All in all the micro unit has a volume of 5.15 cubic meters what

The applied strategies of optimizing space use matches with the ones set through the CIAM-meetings in 1929. First, the number of furniture has to be reduced as much as possible. Furtheron, the dimensions of the furniture have to be reduced to a minimum to still fulfil their function and fit the anthropometric determinations of human dimensions. Therefore, folding furniture is recommended to reduce the size of furniture also temporarily.

(Teige, 2002)

08

corresponds to only 21.5 % of the volume of the reference room with its 24.0 cubic meters. In addition, the height of 140 centimetres allows having two of the micro units above each other, comparable to the Japanese capsule hotels (Figure 10). Such arrangement allows using only 1.84 square meters per private room or unit per floor in contrast to 10.0 square meters needed for the reference room. This saved space can help to plan a building

more dense to save building material and therefore costs from building and maintenance later on, or it can be used to host more other functions. By reducing the private room size in student accommodations a larger common space can be created, having the option to provide more various functions for the residents then in a traditional accommodation.

Table 1: Trondheims student accommodations with private or single rooms hold by Sit. Data from: (Sit, 2018)

Student accommodation

private room size (m²)

facilities

Karinelund

5 -12 (mostly 12)

shared

Nedre Singsakerslette

7 -18 (mostly 12)

shared

Klostergata 20

8 - 17

shared

Magnus den godes gate 2

9 -23

shared

Moholt

10

shared

Klostergata 18

10 -14

shared

Berg

10 - 17 (mostly 10)

shared

Teknobyen

11 - 13 *

private

Lerkendal

11 -13

shared

Frode Rinnansvei

12

shared

Klostergata 56

12

shared

Bloksberg

13 *

private

Steinan

12 -19 (mostly 12)

shared

Moholt 50/50

13 - 18 * (mostly 13)

private

Moholt, studio apartments

16 - 20 *

private

* bathroom included in area of private room

09

reference 10m² private room Berg Studentby - Trondheim 400.0

area 400cm*250cm = 10.0m² volume

250.0

ceiling height = 240cm = 24.0mÂł

window

bed (90*200) workplace (150*160) 1 desk (80*160) 1 chair (50*60) 1 lamp 1 trash can

place for pictures or posters

mirror

actions lying:

wardrobe and shelves (50*125*200)

Figure 7: Dimensions and functions of a reference student room in Trondheim.

sleeping, relaxing, reading, browsing, watching TV, listening to music sitting: learning, writing, working, reading, eating, browsing, watching TV, playing computer standing: getting dressed

10

standard dimensions (required space in room)

area Can the required area be reduced? (possible reduction to x% of the standard dimension)

volume Can the required volume be reduced? (possible reduction to x% of standard volume)

minimal need dimensions Can the item be placed in the common area instead?

bed (90*200*240)

no

100%

yes

56%

no

(90*200*135)

desk (80*160*240)

yes

20%

yes

11%

yes

(42.5*59.5*135)

chair (50*60*240)

yes

53%

yes

30%

yes

(40*40*135)

lamp (30*30*60)

yes

-

yes

-

no

-

trash can

no

-

no

-

maybe

-

wardrobe and shelves (50*100*200)

-

no

100%

no

1,5mÂł volume

personal items

-

-

-

-

no

-

mirror

-

-

-

-

maybe

-

window

-

-

-

-

no

10% floor area

example01 1 example

desk

lamp

example02 2 example

chair

example 3

160.0 80.0

LED part of storage

42.5

59.5

11

Figure 8: Space saving potential of an average student room in Trondheim.

B

area 220cm*167.2cm = 3.68m²

220.0

volume ceiling height = 140cm = 5.15mÂł A

B

167.2

A

window place for pictures or posters

fold-out table (43.5*65)

over head door mirror

chair + storage (40*40*40)

bed (100*200)

wardrobe and shelves (56.4*140*140)

actions lying:

sitting: fold-out lamp

Figure 9: Dimensions and functions of the optimized micro unit.

fold-out floor (105*70)

sleeping, relaxing, reading, browsing, watching TV, listening to music learning, writing, working, reading, eating, browsing, watching TV, playing computer, getting dressed

12

section AA

section BB

top unit

263.5

anteroom

window place for pictures or posters

140.0

bottom unit

over head door bed fold-out (100*200) floor (105*70) fold-out lamp

13

bed (100*200)

wardrobe and shelves (56.4*140*140)

fold-out table (43.5*65)

Figure 10: Section AA and BB of the micro unit according to Figure 9.

5.2 Material Demand Reduction + Emission Savings To be able to compare the material demand of the micro unit and the reference room in detail, for both rooms the same construction method was set. A glulam beam structure was used to mount CNC-milled plywood construction boxes (Figure 11). These boxes are small and light enough to be installed by one or two workers on the building site without the need of any heavy machines. After their installation they get filled through their inlets with cellulose insulation and as last step the plywood indoor cladding and built in furniture is added. The plywood construction boxes and the cellulose insulation have a lifetime of 60 years, while the indoor plywood cladding and built in furniture has a shorter one of 20 years due to its higher wear.

For constructing two over each other mounted micro units 2.7 cubic meters of plywood are needed for the construction plywood boxes, 1.6 cubic meters of plywood for the interior cladding and 2.7 cubic meters of loose fill cellulose insulation (Figure 12). For a buildings lifetime of 60 years the amount of needed plywood increases due to needed replacements of the indoor cladding. Therefore, the material demand of one single micro unit over a buildings lifetime of 60 years is 3.7 cubic meters of plywood and 1.3 cubic meters of cellulose insulation. To construct the reference room it needs 11.5 cubic meters for the construction plywood boxes, 0.5 cubic meters of plywood indoor cladding and 12.3 cubic meters of cellulose insulation (Figure 13). It is to note that no built in furniture is added in the material demand estimation for the reference room as in such sized rooms standard furniture is commonly used. During a 60 years use of the reference room 13.0 cubic meters of plywood and 12.3 cubic meters of cellulose insulation will be needed. When this is compared to the material demand of one micro unit the demand of plywood is over 3.5 times and the one for cellulose insulation over 9 times higher.

The emissions for the production and construction process stage are strongly reduced for the micro unit in comparison to the standard sized room (Table 2). Only at the stage of replacement of material the micro unit accounts for more emissions. This is to explain by having the built in furniture implemented in the calculation only for the micro unit. In total the micro unit accounts for 76.7 % less emissions then the reference room which equals to 74.9 kilogram of CO2 eq saved per year (Table 3).

cellulose insulation plywood 18mm

Figure 11: Plywood construction boxes as main construction element for the micro unit and reference room.

14

glulam support structure

plywood building structure

est. lifetime: 100 yrs

est. lifetime: 60 yrs 2.748 m³ birch plywood, uncoated

plywood indoor cladding + furniture est. lifetime 20 yrs 1.556 m³ birch plywood, uncoated

cellulose insulation est. lifetime: 60 yrs 2.668 m³ loose fill cellulose insulation

material demand per private room during building lifetime (60 yrs): birch plywood, uncoated (furniture included) 3.708 m³ loose fill cellulose insulation 1.334 m³

15

Material demand of the micro unit including the importance of lifetime of different construction layers.

glulam support structure

plywood building structure

est. lifetime: 100 yrs

est. lifetime: 60 yrs 11.461 m³ birch plywood, uncoated

plywood indoor cladding est. lifetime 20 yrs 0.520 m³ birch plywood, uncoated

cellulose insulation est. lifetime: 60 yrs 12.295 m³ loose fill cellulose insulation

material demand per private room during building lifetime: birch plywood, uncoated (no furniture included) 13.021 m³ = + 351 % loose fill cellulose insulation 12.295 m³ = + 922 %

Figure 13: Material demand of the reference room including the importance of lifetime of different construction layers.

Table 2: Emission comparison for product and construction process stage and replacement of material.

Table 3: Emission comparison summary of the micro unit and an reference student room. micro unit

1461.7

1500

reference student room

kg CO2 eq/ private room

1400 1300

6000

5855.1

kg CO2 eq/ private room

1006.4

1200 1100 1000

5000 4000

900 683.7

A1 A2 A3

Metsä Wood birch plywood, uncoated

17

434.6

480.8

530.4

B4

A1 A2 A3

134.8

A4 A5

0

A1-5 + B4

0.0 0.0

14.8

47.1

52.2

57.6

155.4

182.3

A4 A5

2000 1000

16.9

0

33.4

100

81.8

200

122.8

300

180.8

400

262.5

500

329.7

455.3

600

3000 492.9

700

1362.8

800

B4

loose fill cellulose insulation pitched roof application

PRODUCT STAGE A1-A3 (A1 raw material supply, A2 transport, A3 manifacturing) CONSTRUCTION PROCESS STAGE A4-A5 (A4 transport to building site, A5 installation into building) USE STAGE (B4 replacement)

saved CO2 eq/ micro unit/ year: 76.7 % = 74.9 kg

5.3 Energy Demand Reduction + Emission Savings To determine the possible energy savings in a shared flat by reducing the densifying private space, a flat arrangement with six micro units is compared to one with four standard sized private rooms (Figure 14). First, it was looked at the lighting demand of this both arrangements. Therefore, a possible scenario of usage for the two different flats was created (Figure 15), taking in account the time inhabitants will use the private or common spaces on workdays, weekend or holidays (Table 4). To determine the need of lighting to the different use times, the daylight hours on site were analysed (Figure 16) and the lighting need throughout a day and year was calculated (Figure 17). At last, lamps were placed in both test arrangements (Table 5). Thereby the private rooms are for both scenarios equipped with a main light and reading light with nearly identical electricity demand. The small common space in the shared flat with four standard sized rooms has one lamp, while the larger common space of the micro unit flat has two. The energy demand for lighting is 16.1 % reduced in the flat with the micro unit (Table 6). The main reduction is to find in the private units with 34.2 % less energy demand, as the amount of time spent in the private rooms of the micro unit is less than in a standard room. Thus, in a micro unit flat the common space is more often used, as it can provide more living functions for its inhabitants. Therefore, and due to the difference in area the energy demand per person for the common space of the micro unit flat is 161.5 % of the one of the standard flat.

To estimate the energy demand for space heating for both scenarios both flats were set at the boarder of passive house standard with 15 kWh energy demand for space heating per square meter per year (Passive House Institute, 2015). The heating demand in the micro unit flat is 32.6 % lower per person then in the standard sized flat. Again, the savings are most to find in the private rooms while the energy demand of the common space is slightly higher than in the standard flat.

The CO2 emission factor from power production in Norway is estimated at 17 g / kWh (NVE, 2016). Therefore, the emissions from the micro unit flat are 3.425 kg CO2eq per year per person (Table 07) and the ones from the standard sized flat 5.078 kg CO2eq per year per person. With having six micro units instead of four standard private rooms in a shared flat, 32.6 % of emissions can be saved, which equals to 1,7 kg CO2eq per year.

2* 2* 2* 6 private rooms = 22.1 (11.0) m² common space = 65.0 m²

4 private rooms = 40.0 m² common space = 36.0 m²

LED strip lighting reading lamp socket ceiling mounted luminair electric radiator

Figure 14: The placement of electric devices in the micro unit and reference room and the arrangement of the both shared flats as base for the comparison of the energy demand.

18

sleeping

washing

freetime

dinner

freetime

homework/ study

commute

university

commute

breakfast

washing

sleeping

shared flat with reference rooms weekday private rooms common space

11:00

5:00

6:00

7:00

8:00

9:00

10:00

11:00

2:00

3:00

4:00

5:00

6:00

7:00

8:00

9:00

2:00

3:00

4:00

5:00

6:00

7:00

8:00

9:00

12:00 13:00 14:00 15:00 16:00

17:00

18:00 19:00 20:00

17:00

18:00 19:00 20:00

21:00

22:00 23:00 24:00 sleeping

10:00

washing

4:00

sleeping

9:00

freetime

3:00

8:00

dinner

2:00

shared flat with micro units weekday

7:00

freetime

6:00

homework/ study

5:00

commute

4:00

university

3:00

commute

2:00

breakfast

1:00

washing

0:00

private rooms

washing

22:00 23:00 24:00

freetime

21:00

dinner

freetime

lunch

sleeping

shared flat with reference rooms weekend / holiday*

12:00 13:00 14:00 15:00 16:00

freetime

1:00

washing

0:00

breakfast

common space

private rooms common space 22:00 23:00 24:00 washing

21:00

freetime

18:00 19:00 20:00

dinner

17:00

freetime

12:00 13:00 14:00 15:00 16:00

lunch

11:00

freetime

sleeping

shared flat with micro units weekend / holiday*

10:00 breakfast

1:00

washing

0:00

private rooms common space 0:00

1:00

10:00

11:00

12:00 13:00 14:00 15:00 16:00

Figure 15: Scenarios of usage for a shared flat with micro units or reference rooms at workdays and weekends or holidays and the resulting demand for lighting in private and common space.

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17:00

18:00 19:00 20:00

21:00

22:00 23:00 24:00 no light standard room light reading light

I II III IV V VI VII VIII IX X XI XII 0:00

1:00

2:00

3:00

4:00

5:00

6:00

7:00

8:00

9:00

10:00

11:00

12:00 13:00 14:00 15:00 16:00

17:00

18:00 19:00 20:00

21:00

22:00 23:00 24:00

Figure 16: Sunshine hours in Trondheim, Norway, 2018. data from: (Gaisma, 2018) 100% 100% 100% 91.5% 77.3% 66.4% 54.3% 40.3% 25.8% 10.7% 0.3%

0:00

1:00

2:00

3:00

4:00

5:00

6:00

7:00

8:00

9:00

10:00

Figure 17: Distribution of artificial lighting need throughout a year in Trondheim, Norway.

Table 4: Holiday and weekend distribution for students of the NTNU, Trondheim throughout 2018. academic calendar 2018 - NTNU

lighting demand according to Figure 16

198 work days

workdays

78 weekend days

weekend / holiday

4 days public holidays

weekend / holiday

85 days holidays (christmas, spring-break, summer)

weekend / holiday - 50% of demand

0%

11:00

0%

0%

2.5%

17.5% 27.1% 34.3% 44.8% 51.3% 60.1% 70.4% 81.4% 96.3%

12:00 13:00 14:00 15:00 16:00

17:00

18:00 19:00 20:00

21:00

22:00 23:00 24:00

Table 5: Electric devices used for calculating the energy demand. private rooms

common space

shared flat with 6 micro unis

6* LED strip lighting Philips Hue LightStrip + White / Color 2m 1 600 lm, 20.5 W max. (usally 12.8W) 6* reading lamp IKEA LED-lamp, 10 W, 600 lm 6* electric heater 0.5 kW

2* ceiling mounted luminair IKEA LED-lamp E27, 11 W, 1000 lm 2* electric heater 3.0 kW

shared flat with 4 reference rooms

4* ceiling mounted luminair IKEA LED-lamp E27, 11 W, 1000 lm 4* reading lamp IKEA LED-lamp, 10 W, 600 lm 4* electric heater 1.25 kW

1* ceiling mounted luminair IKEA LED-lamp E27, 11 W, 1000 lm 1* electric heater 3.0 kW

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Table 7: Emission comparison summary of the micro unit and an reference student room with and without common space.

(B6)

Table 6: Energy demand comparison for operational energy use. kWh/year/ person

common private space room

common space

125

4 3

2.739

5 135.0

150

5.078

150.0

6

3.425

private room

162.5

2

100

1

75

0.5078

175

kg CO2 eq/ year/person

space heating

shared flat with 6 micro units shared flat with 4 reference student rooms

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reference room

reference room+ common space

2.6

lighting

space heating

lighting

space heating

space heating

lighting

0

lighting

4.2

7.3

25

11.1

27.5

50

micro unit + common space

micro unit

0

saved CO2 eq/ micro unit flat/ year: 32.6 % = 1.7 kg

6. Discussion During the last forty years, the average temperature of earth was rising 0.25°C per decade. The rising temperatures are caused by an increased amount of greenhouse gases due to human activity since the industrial revolution. Upon the next years hundreds of million people worldwide will be directly affected by the consequences of the global warming, as by the rise of seawater level and extremely enhanced possibility for droughts.

(Gillis, 2017)

can be designed or chosen based on its carbon footprint. However, loose furniture would depend on the user and is therefore harder to control. The lifetime of the furniture could also be extended, as it is not moving with the respective user and is harder to replace. Of course, it is not everywhere possible to use built-in furniture and a look at modular and foldable furniture systems is recommended to find also space saving solutions for individual arrangements.

Therefore, it is necessary to reduce the greenhouse gas emissions significantly during the next years. In the European Union buildings account for 36 % of the total CO2 emissions and for 40 % of the total energy demand (IEA, 2015). Thus, an important question in the field of architecture should be how the energy demand and the emissions caused by the building sector can be sustainably reduced.

A reduction of space can have a large influence on the emissions. For the example of student housing, the optimized private rooms use 3.5 times less construction material and 9 times less insulation during their estimated lifetime of 60 years. All in all the micro rooms are responsible for 76.7 % less emissions than standard sized student rooms. The materials used for this study have a low carbon footprint but still 74.9 kg of CO2 eq can be saved per year in comparison to a standard room.

As the household sizes in Norway shrink and the living area per person is expanding every year (IFE, 2013), the material and heating demand is rising as a result. Through, building with low emission materials, improved building envelopes and energy saving appliances emissions can be saved.

However, the potential of emission reduction due to space saving architecture stays widely unused. Therefore, it is necessary to have a closer look how buildings can be spatially optimized. This report gives an example how guidelines for space optimized planning can be created based on the study of historic and current architecture movements and their theories.

The results shown in this work demonstrate impressively that a space optimized planning can have an immense impact on saving emissions.

Nevertheless, the guidelines can change depending on the respective project, its function and the historic and cultural context.

On the example of student housing it was possible to show the options of saving space and consequently material, energy and emissions. It was possible to shrink a standard room to a nearly five times smaller size, without losing any needed functions. Due to built-in furniture and multifunctional usage possibilities a lot of space can be saved. Especially, a good use of a room’s height to stack functions over each other can contribute in a large scale. Built-in furniture helps to save emissions, as it

As space heating is usually the largest electrical end-use in residential buildings it has a large potential for lowering the energy demand and therefore emissions. In the study, the heating demand could get reduced by 32.6 %. Indeed, the CO2 emission factor from the power production in Norway is very low due to the large-scale use of renewable hydro power.

Therefore, the savings in energy have only a very small impact on the final savings of emissions. This helps to understand, that especially in Norway or other countries with a low-carbon energy supply the energy saving should be not the first aim. A more important way might be the use of low-emission construction materials and the reduction of material demand due to space optimization.

It is to mention, that it is of course not possible to reduce the private space of a person only with the aim of emission reduction. Indeed, one of the main concerns should always be the life quality of the inhabitants. As mentioned in this work, building space efficient has the advantage of lowering the costs for material, construction and maintenance of a building and therefore can result in lower rents, what is the main concept of the current tiny house movement (Lulu, 2016). In addition, the micro student housing, emerging in 2012 with the Bokompakt student flats in Lund, Sweden,

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follows this terms. These micro student flats are actually smaller than usually allowed in Sweden. However, the project received permission to be built to deal efficiently with a local housing crisis and the high demand for cheap living space for students. As such type of student housing is very new, not much information regarding the life quality can be found. However, students stated in interviews, that there is no reduction in life quality, rather a cosy and more intimate way to live (Treehugger, 2016).

Furthermore, this report shows that reducing only parts of a building, as in this case the private space of a student housing, can result in a lot of opportunities to gain more quality. By reducing the private space, a lot of options occur how to proceed with the gained space. The best suited one to compensate the small private rooms in a student accommodation is probably a more spacious common living area. So, instead of reducing the building size or the living area of a person, it is possible to shift the space only from private to common and still save emissions. Less material for internal walls would be needed and space heating demand could be better predicted, as the only individual controlled spaces are the small private units. It is possible that the lighting demand would rise in such arrangement but as the results show, impact of the material, construction and space heating on the emissions are far higher than the ones from lighting.

With the view on Trondheim with over 30.000 students and more than 3000 international ones, such accommodation would be a good alternative to the existing student housings. With its strong economic but also ecological advantages it can contribute to sensitise young people to save emissions.

In a lot of fields it has been already possible to raise awareness of the emissions or waste people produce in their daily life. Regulations and campaigns set by the governments help to live more sustainable. A good working example is the extensive switch from plastic bags in supermarket to more ecological ones. Moreover, in the European Union a ban of disposable items out of plastic is discussed. These measures would help to reduce CO2 emissions by 3.4 million tonnes (WiWo, 2018). By comparison, the building sector has the potential to contribute to way higher savings.

Therefore, it is crucial to give the general public an understanding of sustainable building and living strategies.

This study is therefore a good contribution to the topic, to understand better to what extent emissions can be saved by space efficient planning and an intelligent ratio of zones in a building. As this study is focusing at a very specific aspect of housing further studies have the chance to assess the emission saving potential through space saving planning at other housing types. For Norway, an analysis of detached one-family houses would be needed, as they constitute over 60 % of the buildings in this Scandinavian country (SSB, 2013).

7. Conclusion A common way to reduce emissions in the building sector is to improve the buildings envelope and appliances, as well as to consider low-emission construction materials. Often overseen is the large impact space saving planning can have on the emissions.

This study is showing that especially in Norway with its comparable clean energy the reduction of energy demand has a much lower impact on the emission savings than the ones from saving construction material.

On the example of student housing it was possible to demonstrate the large space saving potential that exists in private rooms. The space need of

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an average student room could get reduced by nearly five times without losing any needed functions. Furthermore, the results state that the buildings size has not always to be reduced to have fewer emissions. By only shifting private space to the common areas of an accommodation the material demand could decrease strongly and consequently the emissions.

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