Life Cycle Assessment (LCA) of the No Footprint House (NFH) by A-01 (A Company / A Foundation)

Life Cycle Assessment (LCA) of the No Footprint House (NFH) by A-01

Elaborated by: Pablo Mora Marín

October, 2019

Abstract The main goal of this study is to perform a cradle-to-grave life-cycle assessment to estimate total material-related emissions of the No Footprint House in Ojochal (NFH Ojochal). By completing this assessment, key design drivers for lower embodied emission design will be outlined and the zero emission building potential of the NFH Ojochal will be evaluated. The conclusions and key findings of this study are: •

In terms of embodied emissions, NFH Ojochal has a reduction of 20% when compared to a baseline case and the upcoming prototype, the NFH v2., has a reduction of 60% when compared to the baseline case.

•

When comparing total CO2 emissions, NFH Ojochal has a reduction of 40% and NFH v2. has a reduction of 60% from the total emissions of the Base Case.

•

Operational-related emissions represent 50% of the total emissions of the Base Case, 35% of the total emissions of the NFH Ojochal and 50% of the total emissions of the NFH v2.

•

Achieving net-zero emissions in the NFH Ojochal can be accomplished by implementing PV systems to generate on-site renewable energy. The area of PVs required depends on the ZEB ambition level and the efficiency of the PVs. This area varies between 7.2m2 and 132.7m2.

•

For the NFH v2. the area varies between 6.7m2 and 95.0m2.

Contents 1

INTRODUCTION ........................................................................................................................ 1 1.1

BACKGROUND ........................................................................................................................ 1

1.2

GOAL AND SCOPE .................................................................................................................. 2

1.3

TOOL AND METHODS ............................................................................................................. 3

1.4

ZEB DEFINITION AND AMBITION LEVELS ............................................................................. 4

1.5

ABOUT THE REPORT............................................................................................................... 5

BUILDING DESCRIPTION ....................................................................................................... 6 2.1

NFH OJOCHAL ....................................................................................................................... 6

2.2

BASE CASE ............................................................................................................................. 9

2.3

NFH V2. ............................................................................................................................... 11

2.4

ENERGY AND WATER........................................................................................................... 13

2.4.1

Energy Supply Systems .................................................................................................... 13

2.4.2

Water Supply Systems ...................................................................................................... 14

ENERGY AND WATER MODELING.................................................................................... 16 3.1

ENERGY SIMULATION .......................................................................................................... 16

3.1.1

Model Description ........................................................................................................... 16

3.1.2

Energy Budget ................................................................................................................. 16

3.1.3

Operational Energy Use .................................................................................................. 18

3.2

WATER SIMULATION............................................................................................................ 19

3.2.1

Water Budget ................................................................................................................... 19

3.2.2

Operational Water Use ................................................................................................... 20

III

LIFE CYCLE ASSESSMENT .................................................................................................. 22 4.1 4.1.1

Functional Unit ............................................................................................................... 22

4.1.2

Enclosed conditioned gross floor area ............................................................................ 22

4.1.3

Reference Study Period ................................................................................................... 22

4.1.4

System Boundary ............................................................................................................. 22

4.1.5

Structure of the analysis .................................................................................................. 23

4.2

METHODOLOGY ................................................................................................................... 23

4.3

EMBODIED EMISSIONS RESULTS .......................................................................................... 26

4.3.1

Base Case ........................................................................................................................ 26

4.3.2

NFH Ojochal ................................................................................................................... 30

4.3.3

NFH v2. ........................................................................................................................... 34

4.4 5

GOAL AND SCOPE ................................................................................................................ 22

TOTAL EMISSIONS RESULTS ................................................................................................ 38

ZEB BALANCE.......................................................................................................................... 40 5.1

PHOTOVOLTAIC ENERGY PRODUCTION ............................................................................... 40

5.2

ZEB TARGETS, LEVELS AND BALANCE ............................................................................... 41

DISCUSSION .............................................................................................................................. 43 6.1

IDENTIFYING THE HOTSPOTS ............................................................................................... 43

6.2

ACHIEVING NET-ZERO EMISSIONS ...................................................................................... 46

CONCLUSION ........................................................................................................................... 48

FURTHER WORK .................................................................................................................... 48

REFERENCES .................................................................................................................................... 49

List of Figures Figure 2-1 The NFH in Ojochal. Source: (Alda, 2019). ......................................................................... 6 Figure 2-2 Floor plan of the NFH Ojochal. ............................................................................................. 7 Figure 2-3 The NFH in Ojochal. Source: (A-01, 2019). ......................................................................... 9 Figure 2-4 Schematic section of the Base Case. ................................................................................... 10 Figure 3-1 Site energy by energy component and for different building cases. ................................... 17 Figure 4-1 Embodied CO2-eq emissions from materials used in the Base Case by life cycle stage. ..... 27 Figure 4-2 Embodied CO2-eq emissions from materials used in the Base Case by building component. ...................................................................................................................................................... 29 Figure 4-3 Embodied CO2-eq emissions from materials used in the Base Case by building material. .. 30 Figure 4-4 Embodied CO2-eq emissions from materials used in the NFH Ojochal by life cycle stage. 31 Figure 4-5 Embodied CO2-eq emissions from materials used in the NFH Ojochal by building component. ................................................................................................................................... 33 Figure 4-6 Embodied CO2-eq emissions from materials used in the NFH Ojochal by building material. ...................................................................................................................................................... 34 Figure 4-7 Embodied CO2-eq emissions from materials used in the NFH v2. by life cycle stage. ........ 35 Figure 4-8 Embodied CO2-eq emissions from materials used in the NFH v2. by building component. 36 Figure 4-9 Embodied CO2-eq emissions from materials used in the NFH v2. by building material...... 37 Figure 4-10 Total CO2-eq emissions of the Base Case, the NFH Ojochal and the NFH v2. by life cycle stage. ............................................................................................................................................. 39 Figure 6-1 Embodied Emissions per building component comparative between the Base Case, the NFH Ojochal and the NFH v2. ..................................................................................................... 45

Figure 6-2 Embodied emissions (kg CO2eq/m2/year) of the materials used in the Base Case (blue), in the NFH Ojochal (orange) and in the NFH v2. (gray). ................................................................ 46

List of Tables Table 1-1 Stages of a building life cycle as of EN-15978:2011 ............................................................. 4 Table 1-2 Scope of the ZEB ambition levels. ......................................................................................... 5 Table 2-1 Material inventory of building components of the NFH Ojochal. .......................................... 8 Table 2-2 Material inventory of building components of the Base Case. ............................................. 11 Table 2-3 Material inventory of building components of the NFH v2. ................................................ 13 Table 2-4 Carbon emission factor of the electricity mix in Costa Rica. Adapted from (IMN, 2016) .. 14 Table 3-1 Site energy by energy component and for different building cases. ..................................... 17 Table 3-2 Annual emissions and costs per unit of gross floor area for the operational energy use of the Base Case...................................................................................................................................... 18 Table 3-3 Annual emissions and costs per unit of gross floor area for the operational energy use of the NFH Ojochal. ............................................................................................................................... 18 Table 3-4 Annual emissions and costs per unit of gross floor area for the operational energy use of the NFH v2. ........................................................................................................................................ 19 Table 3-5 Potable water consumption of the Base Case. ...................................................................... 20 Table 3-6 Potable water consumption of the NFH Ojochal and NFH v2. ............................................ 20 Table 3-7 Annual emissions and costs per unit of gross floor area for the operational water use ........ 21 Table 4-1 System boundaries with respect to life cycle stages covered in the present LCA according to (CEN, 2011). ................................................................................................................................ 23 Table 4-2 Embodied CO2-eq emissions from materials used in the Base Case by life cycle stage. ....... 27 Table 4-3 Embodied CO2-eq emissions from materials used in the Base Case by building component 28

Table 4-4 Embodied CO2-eq emissions from materials used in the NFH Ojochal by life cycle stage. .. 31 Table 4-5 Embodied CO2-eq emissions from materials used in the NFH Ojochal by building component .................................................................................................................................... 32 Table 4-6 Embodied CO2-eq emissions from materials used in the NFH v2. by life cycle stage. ......... 34 Table 4-7 Embodied CO2-eq emissions from materials used in the NFH v2. by building component .. 36 Table 4-8 Total CO2-eq emissions of the Base Case, the NFH Ojochal and the NFH v2. by life cycle stage. ............................................................................................................................................. 38 Table 5-1 Monthly and yearly PV production rates for surface area of installed PV modules with different efficiencies. .................................................................................................................... 40 Table 5-2 Monthly and annual solar electricity emissions offset of 1m2 of installed PV (depends on PV module efficiency). Results extracted from energy simulations ............................................ 42 Table 5-3 ZEB Balance of the NFH Ojochal. ....................................................................................... 42 Table 5-4 ZEB Balance of the NFH v2. ................................................................................................ 42 Table 6-1 Embodied Emissions per building component comparative between the Base Case, the NFH Ojochal and the NFH v2. .............................................................................................................. 45

VII

1 Introduction 1.1 Background The built environment imposes a tremendous stress on the planet, creating the opportunity for developers, designers, contractors, facility managers, final users and stakeholders in general, to rethink the ways buildings are designed, constructed and operated. Buildings account for more than 40% of global energy use, and approximately 30% of energyrelated greenhouse gas (GHG) emissions (Polesello and Johnson, 2016). In 2010, buildings accounted for 32% (24% for residential and 8% for commercial buildings) of total global final energy use and 19% of energy-related GHG emissions Change (2015). This impact could decrease significantly if the existing best practices and technologies are widely diffused, simultaneously supporting the transition to low-carbon cities (Polesello and Johnson, 2016). Striving to design, construct and operate zero emission buildings could help decrease this impact. In 2010, the government of Costa Rica launched a program for the country to achieve Carbon Neutrality by 2021. This action created the need for institutions and companies to evaluate and assess their environmental impact and gave birth to the development of standards (INTE-1201-06:2011) and certification tools (C-Neutral) for an organizational level, leaving aside however, the building sector, and specific products and services (Badilla Arroyo et al., 2015). The No Footprint House (NFH) is part of the developers mission to promote a carbon neutral development in Costa Rica. The first prototype was prefabricated in the Great Metropolitan Area (GAM) of Costa Rica and transported approximately for 200Km to Ojochal, Puntarenas in the south pacific coast of Costa Rica. The aim of this report is to account for the embodied material emissions of the NFH in Ojochal and assess its potential of achieving net-zero emissions. This will allow to assess key design drivers that will create possibilities for future NFH prototypes to become zero emission buildings.

In 2016, residential buildings accounted for 40% of the total registered construction projects (CFIA, 2017), representing the most significant building typology being developed. This number is expected to increase with the growth of population in the country, estimated to rise from 4.7 million people in 2011 to 5.5 million by 2025 (Badilla Arroyo et al., 2015). Hence the importance of projects like the NFH which aim to become a baseline case for future residential developments.

1.2 Goal and Scope The main goal of this study is to perform a cradle-to-grave life-cycle assessment to estimate total material-related emissions of the No Footprint House in Ojochal (NFH Ojochal). By completing this assessment, key design drivers for lower embodied emission design will be outlined and the zero emission building potential of the NFH Ojochal will be evaluated. The ZEB definition and ambition levels are defined as by the ZEB Centre (Kristjansdottir et al., 2014). A Life-Cycle Assessment (LCA) is carried out to estimate total material-related embodied emissions of the NFH Ojochal. Energy simulations and calculations are carried out to estimate the total operational energy related emissions of the building. These analyses are also performed on a Base Case and on an upcoming prototype of the NFH Ojochal, the NFH v2. The Base Case has the same gross floor area as the NFH Ojochal, similar form, the same orientation, and it is considered to have construction materials and products used for conventional single-family houses in Costa Rica. The NFH v2 is also similar in area, form and orientation to the original version however, has some variations on the material selection of the building envelope. The outcome of this study will result in understanding and revealing which are the energy systems and the construction materials with the highest impact (hotspots analysis) of the NFH, creating the possibility to increase the efficiency of the energy systems to decrease demands and creating also, the possibility of trading the highest impact materials for others with lower impact. 2

1.3 Tool and Methods Zero emission building definition and ambition levels are defined as by the ZEB Centre (Kristjansdottir et al., 2014). A Life Cycle Assessment (LCA) will be carried out to estimate the embodied emissions of the materials used in the NFH Ojochal, the Base Case and the NFH v2, as well as the operational energy-related emissions of the buildings. The scope of the LCA will follow the product-life stages and system boundaries as stated in the European Standard EN-15978:2011 “Sustainability of construction works. Assessment of environmental performance of buildings. Calculation method.” (CEN, 2011). The LCA calculations will be structured in Microsoft Office Excel according to NS 3451 Table of Building Elements (Norge, 2009), covering different components, sub-components, and materials from the building envelope. To calculate these building components, a material inventory will be generated based on the NFH Ojochal, the Base Case and the NFH v2 construction documents, schematic diagrams, and manual calculations. To perform the LCA calculations, generic life cycle data will be accessed from local data (Badilla Arroyo et al., 2015), Ökobilanzdatenbank 2016, The Inventory of Carbon and Energy and EcoInvent version 3. When possible, specific life cycle data will be accessed from international EPDs. Operational energy-related emissions will be estimated using the local electricity mix emission factor (IMN, 2016) while the operational water-related emissions will be estimated using a Norwegian water supply emission factor (DNB, 2016). A detailed explanation of this methodology and selection of data will be described later on this report. Energy simulations will be carried out using the EDGE Buildings Software. EDGE uses quasisteady-state methods to perform energy simulations and serves as a good initial approximation (IFC, 2016a). Water simulations will be performed using local data (AyA, 2010) to assess the building water demand. SIMIEN will be used to estimate the solar energy potential for on-site renewable production.

A ZEB Balance and on-site solar energy generation potential estimations are made for the NFH Ojochal and the NFH v2. Final discussions, conclusions and recommendations are presented based on the results of the analyses.

1.4 ZEB Definition and Ambition Levels A zero-emission building can be defined as a highly energy-efficient building where on-site renewable energy production compensates for CO2 emissions from the building operations (Kristjansdottir et al., 2014). The European Standard EN-15978:2011 “Sustainability of construction works. Assessment of environmental performance of buildings. Calculation method.” (CEN, 2011) is used to define the different ambition levels based upon the different stages of the life cycle of a building defined in the standard which are shown in Table 1-1. Table 1-1 Stages of a building life cycle as of EN-15978:2011 Building Assessment Information Supplementary Information Beyond the Building Life Cycle

Refurbishing

Disposal

Replacement (including transport)

Waste Processing

Transport

De-construction/Demolition

Operarional Water Use

Operarional Energy Use

Repair

C1-C4 End-of-Life Stage

Maintenance (including transport)

Manufacturing

B1-B7 Use Stage

Use

Construction Installation Process

Transport

Raw material supply

A4-A5 Construction Process Stage A4 A5

Transport

A1-A3 Product Stage

D Benefits and loads beyond the system boundary -

Reuse-Recovery-Recycling-potential

Building Life Cycle Information

The ambition levels defined in the ZEB Project report 17-2014 (Kristjansdottir, 2014) are: i. ii. iii.

ZEB-O÷EQ: Emissions related to all operational energy use (O) without considering the energy used for technical equipment and appliances (EQ) need to be compensated with on-site renewable energy generation. Evaluate module B6 from the Use Stage. ZEB-O: Emissions related to all operational energy use (O) including the energy used by equipment and appliances (EQ) need to be compensated with on-site renewable energy generation. Evaluate module B6 from the Use Stage. ZEB-OM: Emissions related to all operational energy use (O) including the energy used by equipment and appliances (EQ) plus the embodied emissions from the materials and 4

iv. v.

technical installations (M) need to be compensated with on-site renewable energy generation. Evaluate at least, modules A1 to A3 and modules B4, B6 from the Use Stage. ZEB-COM: The same as ZEB-OM but taking into account emissions related to the construction process (add modules A4 and A5). ZEB-COME: The same as ZEB-COM but including emissions from the end-of-life phase (add modules C1-C4 to the analysis).

Table 1-2 shows the stages of the building life cycle that need to be evaluated at each level of ambition. Module B7 from the Use Stage is incorporated in the analyses even though is not required to be evaluated as part of the previous ambition levels definition. Table 1-2 Scope of the ZEB ambition levels. Building Assessment Information Supplementary Information Beyond the Building Life Cycle

De-construction/Demolition

Transport

Waste Processing

Disposal

D Benefits and loads beyond the system boundary -

Reuse-Recovery-Recycling-potential

Operarional Water Use

Operarional Energy Use

Refurbishing

Replacement (including transport)

Manufacturing

Repair

Transport

C1-C4 End-of-Life Stage

Maintenance (including transport)

B1-B7 Use Stage

Use

Construction Installation Process

A4-A5 Construction Process Stage A4 A5

Transport

A1-A3 Product Stage

Raw material supply

ZEB Ambition Level

Building Life Cycle Information

ZEB-O÷EQ ZEB-O ZEB-OM ZEB-COM ZEB-COME

1.5 About the Report Chapter 1 of the report is the introductory one. Chapter 2 describes the buildings being evaluated. Chapter 3 deals with the energy and water simulations for each building case. Chapter 4 is dedicated to exhibiting the results of the Life Cycle Assessments from each building case. Chapter 5 presents the ZEB balance for the NFH Ojochal and NFH v2. Chapter 6 discusses the results of the analyses. Chapter 7 presents the conclusions and Chapter 8 the recommendations for further work.

2 Building Description 2.1 NFH Ojochal The NFH is located in Ojochal, Puntarenas in the south pacific coast of Costa Rica immerse in a humid tropical climate. Tropical climates are characterized by year-long hot and moist weather with significant rainfall and humidity. They are located along the equator and experience limited to no seasonal variation, except seasonal precipitation levels, in some cases (Hootman, 2012). In a climate like this, the primary concern is to reduce the cooling loads with passive strategies (Hootman, 2012). The NFH Ojochal combines several passive design strategies to provide comfort for its occupants. Cross-ventilation and an inclined double-skin façade composed of louvers and operable folding doors (see Figure 2-1) provides natural ventilation and minimizes exposure to direct radiation and rain.

Figure 2-1 The NFH in Ojochal. Source: (Alda, 2019).

Active design strategies used in the NFH Ojochal comprise the use of a solar thermal collector system to meet the domestic hot water (DHW) demands, high-performance ceiling fans, efficient LED lighting systems, and energy-efficient rated home appliances. 6

The NFH Ojochal has a gross floor area of 108 m2 and its floor plan is shown in Figure 2-2 Figure 2-1. The floor plan is 9m width by 12m length and is made up of a grid of 3m x 3m, which makes possible to adjust the size of other NFH prototypes either by adding or subtracting area.

5 A LAS BRISAS

T EN

TO RT UG A

VENTANAS

RIO

A BALLENA

2.25 2.85

TERRAZA

2.25 2.85

NPT 0 +0.00 m Q. LAJAS

DORMITORIO

OCEANO PACIFICO

NPT 0 +0.00 m

2.25 2.85

TORTUGA ABAJO

2.25 2.85

LOTE

A PUERTO CORTEZ

COCINA

2.25 2.85

BAÑO

TERRAZA

A TORTUGA ARR

NA DIA LU

RIO ME

UBICACION GEOGRAFICA

NPT 0 +0.00 m

HOJA CORONADO

ESCALA 1: 30

BAÑO

2.25 2.85

MA MA

NPT 0 +0.00 m

DORMITORIO

2.25 2.85

NPT 0 +0.00 m

FIN DE CALLE

TERRAZA

S.A

9.0

NPT 0 +0.00 m 11,93

EP LL CA

baja

.00

A LIC

2.25 2.85

MAR DEL 5,93

NCAS

CALLE PUBLICA

A FI

VESTIBULO

2.25 2.85

LOM

8,96

A FINCAS

Casa de habitación

N NPT 0 - 0.60 m

LOCALIZACION

ESCALA 1:1500

PLANTA DE DISTRIBUCION ARQUITECTONICA ESCALA 1:50

ACABADOS GENERALES

NOTAS GENERALES 1 - LA RESISTENCIA MINIMA DEL CONCRETO SERA DE 210 Kg/cm2

8 - TODO ELEMENTO DE CONCRETO DEBERA DE MANTENERSE EN CURA CONSTAN-

PISOS

TODOS LOS PISOS SERAN EN MADERA

TE DURANTE 15 DIAS MINIMO

Figure 2-2 Floor plan of the NFH Ojochal. 2 - NO DEBERA DE VACIARSE CONCRETO A UNA ALTURA SUPERIOR DE 2,00 m

9- ANTES DE CHORREAR,SE DEBE DE LIMPIAR LAS FORMALETAS CON COMPRE-

3 - EL RECUBRIMIENTO MINIMO DEL ACERO SERA DE 2,5 cm Y 5 cm EN ES-

10- TODAS LAS COTAS RIGEN SOBRE LA ESCALA

SOR DE AIRE

PAREDES

LAS PAREDES SERAN EN MADERA Y EN GYPSUM SEGUN INDICAC

CUBIERTA

LA CUBIERTA SERA EN LAMINA RECTANGULAR ESMALTADA

CIELOS

TRUCTURAS EN CONTACTO CON EL SUELO 11- EL ACERO SERA GRADO 40 ( 2800 Kg/cm ) 4 - TODAS LAS TUBERIAS TENDRAN UNA PENDIENTE MINIMA DEL 2%

TODOS LOS CIELOS SERAN EN MADERA

PRECINTAS

LAS PRECINTAS SERAN EN GYPSUM MR DE 8mm DE ESPESOR

CANOAS

LAS CANOAS SERAN EN HG N° 26

The building components included in the analyses of the NFH Ojochal are described as follows: 12- SE PERMITIRA DESFORMALETAJES A LAS 24 HORAS DE CHORREADO EN ES-

TRUCTURAS VERTICALES, LOS FONDOS DE VIGAS SERAN DESFORMALETADOS

5 - TODAS LAS DIMENSIONES DEBEN DE VERIFICARSE EN OBRA

15 DIAS DESPUES DE SER COLOCADOS

6 - EL DISEÑO DEL CIMIENTO SERA CON UNA CAPACIDAD EN EL SUELO DE 15 Ton/m.

VIGAS

LAS VIGAS SERAN EN TUBO ESTRUCTURAL RECTANGULAR

13- ANTES DE COLOCARSE EL ARMADO DE LAS PLACAS DEBERA DE CHORREARSE UNA LOSA DE 5cm DE CONCRETO POBRE PARA DAR NIVEL DE DESPLANTE CON RESISTENCIA MINIMA DE 105kg/cm2

•

Groundwork and Foundations: isolated reinforced concrete foundations.

•

Superstructure: structural steel (cold formed) with anticorrosive finish.

•

Outer Walls (Façade): structural steel (cold formed), steel plates, anticorrosive finish, radiata pine louvers and folding doors (with electric engines), windows with 6mm single-pane glass and aluminum cladding, and plastic mesh for natural ventilation and mosquito-control.

•

Inner Walls: steel framing with plastered drywall and melamine panels, windows and doors with 6mm single-pane glass and aluminum cladding, and plastic mesh for natural ventilation and mosquito-control. 7

•

Floor Structure: structural steel (cold formed) with anticorrosive finish and radiata pine floor finish.

•

Outer Roof: structural steel (cold formed), corrugated and coated steel sheets as a roof deck and coated steel gutters and flashings, gypsumboard ceiling with aluminumpolyethylene foam insulation.

•

Fixed Inventory: plumbing fixtures, refrigerator, kitchen hob and oven, other.

•

Stairs and Balconies: reinforced concrete strip foundation, structural steel (cold formed) with anticorrosive finish and radiata pine floor finish.

A detailed material inventory of the NFH Ojochal can be found on Table 2-1 while an axonometric diagram showing the building envelope components is shown in Figure 2-3. Table 2-1 Material inventory of building components of the NFH Ojochal. Building Component

Material

Category

Product

Reference

Unit

Quantity

Wood Wood Paints Bindings Metals Aggregates Aggregates Aggregates Textiles Metals Paints Wood Metals Paints Wood Paints Plastics Electronics Electronics Wood Windows Windows Binders Coverings Coverings Sealing Plastics Wood Wood Coverings Windows Windows Metals Paints Wood Paints Metals Metals Paints Coverings Insulation Plastics Wood Metals Metals Coverings Metals Technical Technical Technical Technical Electronics Ceramics Minerals Wood Metals Metals Paints Wood Paints Bindings Metals Aggregates Aggregates

- Plywood, indoor use, generic - Sawn Timber, softwood, generic Dulux: Trade Vinyl Matt White Cement MP/A-28 Ribbed Bars made from reinforcement steel (varilla corrugada #3, #4 y alambre negro) General gravel or crushed rock- virgin (piedra cuarta de río local) General gravel or crushed rock- virgin (arena fina de río local) General gravel or crushed rock- virgin (piedra bola de río local) Non wooven Geotextile Norwegian Steel Association: Cold Formed Welded Structural Hollow Sections CFSHS (average) Dulux: Trade Vinyl Matt Pure Brilliant White Moelven: Standard Glue Laminated Timber Beam excl. Biogenic CO2 Norwegian Steel Association: Cold Formed Welded Structural Hollow Sections CFSHS (average) Dulux: Trade Vinyl Matt Pure Brilliant White Moelven: Standard Glue Laminated Timber Beam excl. Biogenic CO2 Dulux: Trade Vinyl Matt Pure Brilliant White - Polyethylene, low density, generic - Electronic Component, Passive, Unspecified, generic - Cable, Unspecified, generic - Sawn Timber, hardwood, generic Window glass 6mm single pane without cladding Window aluminum cladding Forsand Sandkompani: Ready-mix mortar M5 (standard and fine) Norgips: Steel profile to inner wall series: C68 dB+, C75 dB+, SK70/55, U 68/54,U 75/52 UNILIN: Medium Density Fibreboard (MDF) Division Panels excl. Biogenic CO2 Sika: Sikabond Flooring Adhesive 50, 52, 54, 95 parquet, AT-80, AT-82, T-40 - Polyethylene, low density, generic - Sawn Timber, hardwood, generic Moelven: Standard Glue Laminated Timber Beam excl. Biogenic CO2 Gypsumboard Window glass 6mm single pane without cladding Window aluminum cladding Norwegian Steel Association: Cold Formed Welded Structural Hollow Sections CFSHS (average) Dulux: Trade Vinyl Matt Pure Brilliant White Treindustrien: Structural Pine or Spruce Timber excl. Biogenic CO2 (average) Dulux: Trade Vinyl Matt Pure Brilliant White Ribbed Bars made from reinforcement steel (varilla lisa #6) Norwegian Steel Association: Cold Formed Welded Structural Hollow Sections CFSHS (average) Dulux: Trade Vinyl Matt White Norgips: Steel profile to inner wall series: C68 dB+, C75 dB+, SK70/55, U 68/54,U 75/52 - Expanded Polystyrene (EPS) Rigid Foam Insulation, generic Protan: SE 1.2 Polyvinylchloride PVC Roofing Membrane (1.2mm) Treindustrien: Structural Pine or Spruce Timber excl. Biogenic CO2 (average) Ribbed Bars made from reinforcement steel (varilla lisa #4) Galvanized steel (coil-sheet) Gypsumboard ceiling tiles Galvanized steel (coil-sheet) - Electrolux Fridge freezer ENN2854COW, generic - Electrolux Washing Machine EWF1486ODW, generic - Electrolux Tumble Dryer EDH3987GW3, generic - Electrolux Hob EHL 7640FOK, generic - Electrolux Oven EOB8851VAX, generic - Ceramics: Sanitary, generic Minera Skifer: Natural Stone Slate with sawn edge - Plywood, indoor use, generic Stainless Steel (Kitchen Sink) Norwegian Steel Association: Cold Formed Welded Structural Hollow Sections CFSHS (average) Dulux: Trade Vinyl Matt Pure Brilliant White Treindustrien: Structural Pine or Spruce Timber excl. Biogenic CO2 (average) Dulux: Trade Vinyl Matt Pure Brilliant White Cement MP/A-28 Ribbed Bars made from reinforcement steel (varilla corrugada #3, #4 y alambre negro) General gravel or crushed rock- virgin (piedra cuarta de río local) General gravel or crushed rock- virgin (arena fina de río local)

ecoinvent, v3.1 (2014) ecoinvent, v3.1 (2014) S-P-00550 (2014) PAS 20150 001/2014/UV-P Local Data Inventory of Carbon and Energy- Version 2.0 Inventory of Carbon and Energy- Version 2.0 Inventory of Carbon and Energy- Version 2.0 Inventory of Carbon and Energy- Version 2.0 NEPD nr.: 253E (2014) S-P-00550 (2014) NEPD nr.: 336-222-NO (2015) NEPD nr.: 253E (2014) S-P-00550 (2014) NEPD nr.: 336-222-NO (2015) S-P-00550 (2014) ecoinvent, v3.1 (2014) ecoinvent, v3.1 (2014) ecoinvent, v3.1 (2014) ecoinvent, v3.1 (2014) Local Data Local Data NEPD nr.: 1187-348-NO (2016) NEPD nr.: 171N (2013) rev1 IBU EPD-UNI-20150014-IBA1-EN NEPD nr.: 343-232-EN (2014) ecoinvent, v3.1 (2014) ecoinvent, v3.1 (2014) NEPD nr.: 336-222-NO (2015) Local Data Local Data Local Data NEPD nr.: 253E (2014) S-P-00550 (2014) NEPD nr.: 308-179-NO (2015) S-P-00550 (2014) Local Data NEPD nr.: 253E (2014) S-P-00550 (2014) NEPD nr.: 171N (2013) rev1 ecoinvent, v3.1 (2014) NEPD nr.: 32-203-NO (2015) NEPD nr.: 308-179-NO (2015) Local Data ICE Local Data ICE LCA of enviro declaration (2014) LCA of enviro declaration (2014) LCA of enviro declaration (2014) LCA of enviro declaration (2014) LCA of enviro declaration (2014) ecoinvent, v3.1 (2014) NEPD nr.: 315-192-NO (2015) ecoinvent, v3.1 (2014) ICE NEPD nr.: 253E (2014) S-P-00550 (2014) NEPD nr.: 308-179-NO (2015) S-P-00550 (2014) PAS 20150 001/2014/UV-P Local Data Inventory of Carbon and Energy- Version 2.0 Inventory of Carbon and Energy- Version 2.0

m3 m3 m2 Tonne kg kg kg kg kg kg m2 m3 kg m2 m3 m2 kg kg kg m3 kg kg kg m m3 kg kg m3 m3 kg kg kg kg m2 m3 m2 kg kg m2 m kg m2 m3 kg kg kg kg pc pc pc pc pc kg tonne m3 Kg kg m2 m3 m2 Tonne kg kg kg

0.267912 0.063 39.7425 2.6 699.22 9000 10800 900 32.48 494.56 237.6 6.255 1045.43 459.0455275 5.2246 79.09764753 11.0506 0 60 0.171 0 0 531.5 390.4 5.3671704 6.2 3.344 0.294 2.8715 178.1275195 0 0 0 0 6.615 264.6 214.56 0 25 0 112.8 188 11.95 178.8 0 0 251.7110194 1 0 0 1 1 120 0 0 4.5 135.31 59.41426047 0.049856 0.754793155 0.75 0 2700 1800

Total Embodied Emissions (kg 2

CO2eq/m /yr) Groundworks and Foundations Formwork Groundworks and Foundations Formwork Groundworks and Foundations Paints, sealants, etc. Groundworks and Foundations Cement Groundworks and Foundations Rebar Groundworks and Foundations Aggregates Groundworks and Foundations Aggregates Groundworks and Foundations Aggregates Groundworks and Foundations Geosynthetics Superstructure Structural Steel Superstructure Paints, sealants, etc. Superstructure Wood Outer Walls (Façade) Structural Steel Outer Walls (Façade) Paints, sealants, etc. Outer Walls (Façade) Wood Outer Walls (Façade) Paints, sealants, etc. Outer Walls (Façade) Plastic Mesh Outer Walls (Façade) Engine System Outer Walls (Façade) Steel wire Outer Walls (Façade) Wood Outer Walls (Façade) Glass (window pane) Outer Walls (Façade) Aluminum (window frame) Inner Walls Cement Inner Walls Steel framing Inner Walls Melamine Inner Walls Paints, sealants, etc. Inner Walls Plastic Mesh Inner Walls Wood Inner Walls Wood Inner Walls Drywall Inner Walls Glass (window pane) Inner Walls Aluminum (window frame) Floor Structure Structural Steel Floor Structure Paints, sealants, etc. Floor Structure Wood Floor Structure Paints, sealants, etc. Floor Structure Rebar Outer Roof Structural Steel Outer Roof Paints, sealants, etc. Outer Roof Steel framing Outer Roof Insulation Outer Roof Waterproofing membrane Outer Roof Wood Outer Roof Rebar Outer Roof Galvanized steel Outer Roof Drywall Outer Roof Galvanized steel Fixed Inventory Refrigerator Fixed Inventory Washing machine Fixed Inventory Tumble Dryer Fixed Inventory Kitchen Fixed Inventory Kitchen Fixed Inventory Ceramics (Sanitary) Fixed Inventory Countertop Fixed Inventory Wood Fixed Inventory Kitchen Sink Stairs and Balconies Structural Steel Stairs and Balconies Paints, sealants, etc. Stairs and Balconies Wood Stairs and Balconies Paints, sealants, etc. Stairs and Balconies Cement Stairs and Balconies Rebar Stairs and Balconies Aggregates Stairs and Balconies Aggregates

Total Embodied Emissions (kg CO2eq/m2/yr)

0.02 0.00 0.01 0.35 0.28 0.08 0.09 0.01 0.01 0.03 0.10 0.13 0.06 0.19 0.10 0.03 0.00 0.00 0.11 0.00 0.00 0.00 0.02 0.11 0.64 0.02 0.01 0.00 0.05 0.06 0.00 0.00 0.00 0.00 0.08 0.11 0.09 0.00 0.01 0.00 0.01 0.23 0.13 0.07 0.00 0.00 0.18 0.08 0.00 0.00 0.02 0.07 0.12 0.00 0.00 0.00 0.01 0.02 0.00 0.00 0.09 0.00 0.02 0.02 3.88

2.4 Energy and Water 2.4.1 Energy Supply Systems The energy supply system of the NFH Ojochal is based on electricity from the grid to power electrical demands and a 200L thermal collector to cover DHW demands. Electrical installations have been planned for future installation of photovoltaic arrays to generate on-site electrical energy. For the Base Case, only electricity from the grid is considered to cover the electrical demands whereas for the NFH v2. the same considerations as the NFH Ojochal are being taken into account.

The energy supply system in Costa Rica is managed exclusively by the Instituto Costarricense de Electricidad (ICE), which covers around 99.4% of the country with its distribution grid, being the second with the highest coverage in Latin America (ICE, 2015). The energy generation is based on five main renewable sources, which are, in terms of volume: hydraulic, geothermal, wind, solar and biomass. Fossil-fuels are relied as a complementary or back-up energy source (ICE, 2015). During the year 2015, 98.99% of the total energy production came from renewable sources while in 2016, the total was of 98.21% coming from renewable sources (ICE, 2016). Due to this energy matrix of Costa Rica and the total contribution of renewable sources, the carbon emissions due to the electricity mix vary from year to year. Carbon emission factors for the electricity mix in the last nine years are shown in Table 2-4.Error! Reference source not found. Table 2-4 Carbon emission factor of the electricity mix in Costa Rica. Adapted from (IMN, 2016)

Year 2010 2011 2012 2013 2014 2015 2016 2017 2018 Average

E.F. (kg CO2eq /kWh) 0.0570 0.0824 0.0771 0.1300 0.1170 0.0381 0.0557 0.0754 0.0395 0.0747

In this study and to estimate the total operational energy-emissions, the average emission factor of 0.0747 kg CO2eq/kWh will be used in the calculations.

2.4.2 Water Supply Systems In Costa Rica, the potable water supply and wastewater treatment systems are managed by the Instituto Costarricense de Acueductos y Alcantarillados (AyA) which has the legal authority to manage, set policies, establish and apply regulations, promote the planning, financing and 14

development of potable water and wastewater treatment systems (AyA, 2011). This includes the legal authority to consent licenses for Municipalities, private companies, organizations and cooperatives to manage the supply and treatment systems for different communities. Potable water at the NFH Ojochal is provided by AyA, whereas wastewater treatment is handled on-site with a septic and infiltration system. The same conditions are considered for the Base Case and NFH v2. Currently, there is no information regarding a water supply carbon emission factor in Costa Rica. Therefore, to estimate the operational water-related carbon emissions, a Norwegian water supply emission factor of 0.344 kg CO2eq/m3 is used (DNB, 2016). This assumption is based on the fact that Norway and Costa Rica share similar energy grid schemes. The Norwegian electricity carbon emission factor is around 10 kg CO2eq/kwh to 15 g CO2eq/kwh when considered as an isolated energy system and around 100 g CO2eq/kWh when taking into account the Nord Pool spot market (Fufa et al., 2016). Moreover, the current electricity carbon emission factor used for Norway by the ZEB Centre is of 132 g CO2eq/kwh (Kristjansdottir et al., 2014). In Costa Rica, the electricity carbon emission factor has varied from 38.1 g CO2eq/kwh to 130 g CO2eq/kwh in the last nine years, averaging 74.7 g CO2eq/kwh (see Error! Reference source not found.).

3 Energy and Water Modeling 3.1 Energy Simulation This section describes the methodology used to estimate the energy demands of the NFH Ojochal, the Base Case and the NFH v2. It also exhibits the results from the energy calculations and calculates the total operational energy-related carbon emissions of the different cases.

3.1.1 Model Description The EDGE Buildings Software Tool is being used to estimate the energy demands of the building cases. The EDGE Software Tool is an online, public-available software that can be used as a design tool and is part of the EDGE Certification System. EDGE uses a monthly quasi-steady calculation method based on the European CEN and ISO 13790 standards to assess annual energy use for heating and cooling of a residential or non-residential buildings (IFC, 2016a). For domestic hot water (DHW) requirements and energy consumption, EDGE broadly uses EN 15316-3. For calculating the lighting demands of the building, EDGE uses the EN 15193 standard. Quasi-steady-state methods calculate the heat balance over a sufficiently long time (typically a month or a whole season), which enables one to take dynamic effects into account by an empirically determined gain and/or loss utilization factor. On the other hand, dynamic methods calculate the heat balance with short times (typically one hour) taking into account the heat stored in, and released from, the mass of the building (ISO, 2008).

3.1.2 Energy Budget Historically, detached single-family houses and low-rise residential buildings in Costa Rica do not include the use of HVAC systems and rely exclusively in natural ventilation for cooling purposes (Barrantes Quirós, 2017). However, due to climatic conditions, theoretically there will be a significant cooling demand in a building located within this climatic zone.

Whether this cooling demand is completely satisfied by means of natural ventilation or not, in the performed energy simulations, theoretical cooling demands for occupants’ comfort have been estimated. The results from the energy simulation for the three building cases are shown in Table 3-1 and Figure 3-1. These results define the energy budget of each building. Table 3-1 Site energy by energy component and for different building cases. Base Case Component

Site Energy (kWh/m2 /yr)

Space Cooling Fan Energy Home Appliances (Tech. Equipment) Lighting Domestic Hot Water Total

140,00

38 1 28 16 39 122

NFH Ojochal Site Energy

(kWh/m2 /yr)

31% 1% 23% 13% 32% 100%

2 5 26 10 4 47

% 4% 11% 55% 21% 9% 100%

NFH v2 Site Energy (kWh/m2 /yr)

2 5 26 10 2 45

Base Case

Energy kWh/m2/yr

120,00 100,00 80,00

NFH Ojochal

60,00

NFH v2

40,00 20,00 0,00 Space Cooling

Fan Energy

Home Appliances (Tech. Equipment)

Lighting

Domestic Hot Water Figure 3-1 Site energy by energy component and for different building cases.

% 4% 11% 58% 22% 4% 100%

Energy simulation results show that both NFH Ojochal and NFH v2. have an increase energy performance when compared to the baseline case, with more than 60% reduction of the energy demands of the Base Case. While in the Base Case an HVAC system will most likely be required to meet the cooling demands, in the NFH Ojochal and NFH v2. cooling demands are met by the implementation of passive strategies that allow natural ventilation through cross-ventilation, protection from direct sunlight with shading devices in the building envelope and added high-performance ceiling fans in every room. Domestic hot water (DHW) needs are most commonly met with an electric resistance water heater in the conventional single-family houses while in the NFH Ojochal and NFH v2. between 90% to 95% of the needs are met with the implementation of solar thermal collectors.

3.1.3 Operational Energy Use The operational energy-related emissions and costs (by gross floor area of conditioned space and at an annual basis) of the Base Case, NFH Ojochal and NFH v2. are shown in Table 3-2, Table 3-3 and Table 3-4 respectively. Table 3-2 Annual emissions and costs per unit of gross floor area for the operational energy use of the Base Case. Base Case Component

Emission Factor (kg CO2eq/kWh)

Cost (USD/kWh)

Energy Consumption

Total Emissions (kg

Annual Costs

kWh/m2 /year

CO2eq/m2 /year)- B6

(USD/m2 /year)

Operational Energy (without Tech. Eq.)

0.0747

0.16

7.02

14.94

Operational Energy (including Tech. Eq.)

0.0747

0.16

122

9.11

19.39

Table 3-3 Annual emissions and costs per unit of gross floor area for the operational energy use of the NFH Ojochal. NFH Ojochal Component

Emission Factor (kg CO2eq/kWh)

Cost (USD/kWh)

Energy Consumption

Total Emissions (kg

Annual Costs

kWh/m2 /year

CO2eq/m2 /year)- B6

(USD/m2 /year)

Operational Energy (without Tech. Eq.)

0.0747

0.16

1.57

3.34

Operational Energy (including Tech. Eq.)

0.0747

0.16

3.51

7.47

Table 3-4 Annual emissions and costs per unit of gross floor area for the operational energy use of the NFH v2. NFH v2. Component

Emission Factor (kg CO2eq/kWh)

Cost (USD/kWh)

Energy Consumption

Total Emissions (kg

Annual Costs

kWh/m2 /year

CO2eq/m2 /year)- B6

(USD/m2 /year)

Operational Energy (without Tech. Eq.)

0.0747

0.16

1.42

3.02

Operational Energy (including Tech. Eq.)

0.0747

0.16

3.36

7.15

The operational energy use emissions and costs (with and without the technical equipment contribution) include both cooling demands and DHW demands impact. When these loads can be covered by means of passive strategies and active strategies both emissions and costs will decrease considerably. Reducing consumptions related with lighting and technical equipment will also be of critical importance to reach a desired level of ZEB ambition in the NFH. Both NFH Ojochal and NFH v2. will have an approximate 80% reduction of total emissions and annual costs from the operational energy (without Technical Equipment demands) of the Base Case and an approximate 60% reduction of total emissions and annual costs from the operational energy (including Technical Equipment demands) of the Base Case.

3.2 Water Simulation As mentioned before, operational water usage is addressed for the three building cases evaluated as part of the LCA and ZEB Balance.

3.2.1 Water Budget According to national regulations, the daily operational potable water use in a typical singlefamily house is of 180 L/person (AyA, 2010). This reference value allow the opportunity to perform a quick calculation. Assuming the Base Case model will be occupied by four persons, the daily potable water consumption of the building will be of 720 L, the weekly consumption will be of 5040 L, the monthly consumption will be of 21960 L (20 m3) and the annual consumption will be of 262800 L (242 m3). Detailed calculations are shown in Table 3-5.

Table 3-5 Potable water consumption of the Base Case.

Fixture-Fitting Shower Washbasin Sink Kitchen Sink Water Closet Washing Machine Other

Fitting Flow Daily Use Number of (L/min)- CIHSE* (min/person), person 2011 (flush/person) for 12 6 4 6 4 4 8 5 4 10 3 4 8 1 4 6 1 4 Daily Flow Weekly Flow Monthly Flow Yearly Flow

Flow (L/day)

Flow (m3/day)

288 96 160 120 32 24 720 5040 21960 262800

0.29 0.10 0.16 0.12 0.03 0.02 0.72 5.04 21.96 262.80

With the implementation of higher efficiency plumbing fixtures, potable water consumption can be reduced for the NFH Ojochal and NFH v2. as shown in Table 3-6. Table 3-6 Potable water consumption of the NFH Ojochal and NFH v2.

Fixture-Fitting Shower Washbasin Sink Kitchen Sink Water Closet Washing Machine Other (e.g. Irrigation)

Efficient Fittings Flow (L/min)

Daily Use Number of (min/person), person (flush/person) for 6 4 4 4 5 4 3 4 1 4 1 4

8 6 6 4 8 6 Daily Flow Weekly Flow Monthly Flow Yearly Flow

Flow (L/day)

Flow (m3/day)

192 96 120 48 32 24 512 3584 15626.24 186880

0.19 0.10 0.12 0.05 0.03 0.02 0.51 3.58 15.63 186.88

3.2.2 Operational Water Use When transforming the annual potable water consumption of the Base Case of 262 m3 to a gross floor area-dependent value (taking 108 m2 as the total gross floor area), the total potable water consumption is of 2.43 m3/m2-year. For both NFH Ojochal and NFH v2. this potable water consumption represents 1.73 m3/m2-year.

The total operational water-related carbon emissions and annual costs are shown in Table 3-7 and as it can be seen, a reduction of almost 30% of the total emissions and annual costs have been achieved in the NFH Ojochal and NFH v2. when compared to the Base Case. Table 3-7 Annual emissions and costs per unit of gross floor area for the operational water use Component

Emission Factor (kg CO2eq/m3 )

Cost (USD/m3 )

Water Consumption

Total Emissions (kg

Annual Costs

m3 /year/m2

CO2eq/m2 /year)- B7

(USD/m2 /year)

Base Case

0.344

0.70

2.43

0.84

1.71

NFH Ojochal

0.344

0.70

1.73

0.60

1.21

NFH v2.

0.344

0.70

1.73

0.60

1.21

4 Life Cycle Assessment This section details the life cycle assessment (LCA) performed for the NFH Ojochal, the Base Case and the NFH v2.. This will include the scope and methodology of the calculations and the results for both materials embodied emissions and total operational-related emissions.

4.1 Goal and Scope The goal of this LCA is to estimate the embodied carbon dioxide (global warming potential) emissions of the construction materials and products that take part of the NFH Ojochal, the Base Case and an improved version of the NFH, the NFH v2. This will provide an overview of the building components and materials that contribute the most to the embodied CO2eq emissions’ pool.

4.1.1 Functional Unit The functional unit of the LCA analysis has been defined as the CO2eq emissions per square meter of enclosed conditioned gross floor area per year of operational building lifetime.

4.1.2 Enclosed conditioned gross floor area The enclosed conditioned gross floor area of the NFH Ojochal, Base Case and NFH v2. is of 108 m2, and accounts only for the interior and conditioned spaces of the building. Exterior spaces such as parking spaces, hardscaped and landscaped areas are not included.

4.1.3 Reference Study Period The reference study period (RSP) in this LCA analysis is defined as the building service life which is assumed to be of 60 years.

4.1.4 System Boundary The product-life stages included in this LCA analysis can be seen marked with an “X” in Table 4-1. They comprise the product stage (A1-A3), the construction process stage (A4-A5), the replacement module (B4) including transportation for the embodied emissions of the use stage, 22

and the end-of-life stage (C1-C3, not including C4). Operational-related carbon emissions (modules B6 and B7) previously calculated (see Table 3-2 through Table 3-4 and Table 3-7) will be added to the assessment but do not take part of the embodied emissions analyses. Table 4-1 System boundaries with respect to life cycle stages covered in the present LCA according to (CEN, 2011).

4.1.5 Structure of the analysis The LCA calculations were structured in Microsoft Office Excel according to NS 3451 Table of Building Elements (Norge, 2009), covering different components, sub-components, and materials from the building envelope. To calculate these building components, material inventories were generated based on construction documents, schematic diagrams and by manual calculations. Detailed material inventories can be found in the Annex section.

4.2 Methodology To perform the LCA calculations, generic life cycle data was accessed from: local data (Badilla Arroyo et al., 2015), Ökobilanzdatenbank 2016, The Inventory of Carbon and Energy and EcoInvent version 3. When there is no available generic life cycle data, specific lifecycle data will be accessed from international EPDs. This process of data selection is due to the fact that there are not any generic life cycle databases for construction materials available in Costa Rica. Moreover, the use of software tools like 23

SimaPro or GaBi is not to that accessible in Costa Rica, therefore using generic life cycle databases that are accessible to everyone is an important aspect of the analysis. The use of generic life cycle databases has the limitation that, emission factors for the different construction materials and products available in the local market, could be either higher or lower than they actually are. However, these generic values represent a good approximation. A more detailed methodology process is enlisted, for every product-life stage under evaluation, as follows: •

Product Stage (A1-A3)

The selection process, in order of hierarchy, of the data used in this product-life stage is as follows: i.

Local data- Generic. In this case the local data selected was developed by (Badilla Arroyo et al., 2015) in the reference thesis project “Cálculo de huella de carbon para materiales de construcción en Costa Rica” (Calculation of the carbon footprint of construction materials in Costa Rica).

ii.

Ökobilanzdaten 2016- Generic

iii.

The Inventory of Carbon and Energy- Generic

iv.

EcoInvent version 3- Generic

International EPDs- Specific

Whenever there is no information available at one of the tiers, the procedure was to advance to the next tier. •

Construction Process Stage (A4-A5)

For the A4 module, whenever the data selected for the A1-A3 modules did not include this transportation module declared, transportation emission factors from EcoInvent v3.1 where used. In this case, assuming the transport of the materials from factory gate to project site is going to be done on a 16-32 t EURO4 lorry with an emission factor of 0.000168 kg CO2eq/kg-km. An average distance of 10 km from gate to site was assumed, this is valid since the project site will 24

be in the GAM, therefore having good connectivity with different construction material manufacturers and providers. The transport of the construction equipment is not accounted. For the A5 module, different waste production percentages per total quantity of a specific material (Chavarría Grillo, 2011) were used to estimate the impact of this module. Ground works and landscaping, storage of products, transport of materials within the site, temporary works, on-site product manufacturing, provision of thermal control systems during construction, installation of secondary materials needed, water use for on-site cleaning and waste management including transportation to final disposal facility are not accounted. •

Use Stage (B4)

The B4 module calculations depend on the service life of the construction materials being implemented. The equation to calculate the number of replacements for a product or material is as follows (CEN, 2011): 𝑁𝑅 =

𝑅𝑒𝑞𝑆𝐿 −1 𝐸𝑆𝐿

Where NR represents the number of replacements of a building component, product or material, ReqSL is the requested service life of the building that for the present study is the same as the reference study period of 60 years, and ESL is the estimated service life of the product or material. The result from this equation needs to round up to the next higher integer value. The estimated service life of the products and construction materials included in the LCA, have been selected from different local and international sources and technical data sheets. The carbon emission factor used for these calculations is the same as the used for the material to be replaced in the A1-A3 modules from the product stage. To include the carbon emissions due to the transport of the materials to be replaced, the same procedure explained for the A4 module is being used.

Waste management of the removed components is not accounted in this module. •

End-of-Life Stage (C1-C3)

There exist several limitations to estimate the end-of-life stage for the SFH Base Case since most of the products and materials included in the analysis do not have the modules C1-C4 declared. To estimate the C1 module, a value of 8% of the total A1-A3 module was accounted for (Cole and Rousseau, 1992). For the C2 module, an average of 10 km to the waste processing center were assumed and the embodied emission factor used is of 0.0000846 kg CO2eq/kg-km assuming the transport of the materials from project site to the waste processing center is going to be done on a 32 t EURO4 lorry. This emission factor is again extracted from EcoInvent v3.1 Module C3 is estimated using the emission factor of 0.0414 kg CO2eq/kg from EcoInvent v3.1. Module C4 is not included in the analysis since few generic or specific data was found and no reliable approximations were found either.

4.3 Embodied Emissions Results 4.3.1 Base Case It is imperative to compare the NFH Ojochal with a baseline in order to evaluate its performance and overall material-related embodied emissions. The total embodied emissions of the Base Case are presented in Table 4-2 and based on the functional unit of this study represent a total of 9.39 kg CO2eq/m2-yr. This result is also shown in Figure 4-1.

Table 4-2 Embodied CO2-eq emissions from materials used in the Base Case by life cycle stage. Stage

Module

Product Transport Gate-to- Site Construction Process Recplacement (incl. Transport) Decontruction/Demolition Transport Site-to-Waste Mgmt. Center Waste Processing Total

A1-A3 A4 A5 B4 C1 C2 C3

Embodied Emissions kg CO2-eq

kg CO2-eq/yr

kg CO2-eq/m2

kg CO2-eq/m2/yr

34393.51 2558.86 980.71 12096.06 2514.06 757.95 7519.91 60821.07

573.23 42.65 16.35 201.60 41.90 12.63 125.33 1013.68

318.46 23.69 9.08 112.00 23.28 7.02 69.63 563.16

5.31 0.39 0.15 1.87 0.39 0.12 1.16 9.39

10.00

Embodied emission kgCO2 eq/m 2/yr

9.00

1.16

8.00

0.12

0.39

7.00

1.87 0.15

6.00

0.39 5.00

4.00

3.00

5.31 2.00

1.00

0.00

Base Case A1-A3

Figure 4-1 Embodied CO2-eq emissions from materials used in the Base Case by life cycle stage.

In the Base Case, the embodied emissions from the product stage (A1-A3) represent 57% of the total whereas 20% come from the replacement stage (B4) and waste processing stage (C3) represent 12% of the total embodied emissions. These are the three main contributing modules to the total embodied emissions. The rest of the modules (A4, A5, C1 and C2) contribute in about 11% to the total. These results were expected since, the extraction (A1), the transport of the extracted materials (A2) and the manufacturing of the goods (A3), are regularly the modules with the highest embodied emissions in the life-cycle of a product. The use stage module B4 comes in second because it includes the embodied emissions due to the replacement of different materials and products with a RSL lower than 60 years. Materials such as paintings for instance, 27

have a RSL of 8 years, meaning that replacing the surfaces that are painted needs to be done approximately seven times during the lifetime of the building. The B4 stage includes the emissions due to the product stage of the materials to be used as replacements (modules A1A3) plus the transport of these materials to the project site (same as module A4 in this case). The module C3 is estimated as previously explained, and includes all the processes required prior the final disposal of the waste material. Since it is estimated as explained in the methodology, it is important to address the fact that eventually in the NFH Ojochal or future prototypes, if parts of the building are dismantled or deconstructed and sorted out for reuse or recycling, these processes might have different embodied emissions than other that will require more energy and resource use. In terms of building components, as it can be seen in Table 4-3 and Figure 4-2 the components that drive the highest emissions are the Floor Structure (24%), the Outer Walls (20%), the Superstructure (15%), the Inner Walls (14%) and the Outer Roof (11%). These are the five major sub-components contributing to the total embodied emissions. These building sub-components contain the high quantities of different cementitious materials (concrete, mortars, plaster, bonding mortar, etc.), the highest use of reinforcement steel and include also the highest quantities of internal finishes, which tend to require at least one replacement during the lifetime of the building. On the other hand, the Outer Roof subcomponent comprises a significant use of structural steel (cold formed structural hollow sections) as part of the roof structure and galvanized coated steel roof decking. These materials represent the main drivers of the embodied emissions of the baseline case and therefore can be optimized to reduce overall emissions. Table 4-3 Embodied CO2-eq emissions from materials used in the Base Case by building component Building Sub-Component 21 Groundwork and Foundations 22 Superstructure 23 Outer walls 24 Inner walls 25 Floor Structure 26 Outer Roof 27 Fixed Inventory 28 Stairs and Balconies EE (kg CO2eq/m2/yr)

A1-A3 0.64 1.15 0.87 0.59 1.07 0.79 0.15 0.05 5.31

EE (kg

Building Life Cycle Stage Module A4 A5 B4 C1 C2 0.07 0.02 0.00 0.05 0.02 0.05 0.03 -0.08 0.09 0.01 0.05 0.02 0.76 0.07 0.01 0.07 0.01 0.44 0.05 0.01 0.14 0.03 0.24 0.07 0.06 0.01 0.04 0.15 0.04 0.00 0.00 0.00 0.35 0.01 0.00 0.00 0.00 0.00 0.00 0.00

C3 0.18 0.13 0.08 0.11 0.62 0.02 0.00 0.01

CO2eq/m2/yr) 0.99 1.38 1.86 1.28 2.24 1.05 0.52 0.07

11% 15% 20% 14% 24% 11% 6% 1%

0.39

1.16

9.39

100%

0.15

1.87

0.39

0.12

(%)

2.50 2.25

Embodied emission kgCO2 eq /m2 -yr

2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 0.00 -0.25

21 Groundwork and Foundations

22 Superstructure

23 Outer walls

24 Inner walls

25 Floor Structure

26 Outer Roof

27 Fixed Inventory

28 Stairs and Balconies

0.18

0.13

0.08

0.11

0.62

0.02

0.00

0.01

0.02

0.01

0.06

0.00

0.05

0.09

0.07

0.05

0.07

0.04

0.01

0.00

-0.08

0.76

0.44

0.24

0.15

0.35

0.00

0.02

0.03

0.02

0.01

0.03

0.04

0.00

0.07

0.05

0.07

0.14

0.01

0.00

A1-A3

0.64

1.15

0.87

0.59

1.07

0.79

0.15

0.05

Figure 4-2 Embodied CO2-eq emissions from materials used in the Base Case by building component.

When evaluating building materials, concrete accounts for about a quarter of the total materialrelated embodied emissions, followed by rebars used to make reinforced concrete accounting 16% of the total, glass from window panes with 10%, aluminum cladding from window framing with 8%, ceramic tiling used in the flooring and bathroom walls with 7%, concrete masonry with 7% of the total as well, and the galvanized steel roof deck with 6%. These building materials represent almost 80% of the total embodied emissions of the base case (see Figure 4-3). As mentioned before, optimizing the use and selection of these materials will have the highest impact in reducing the total embodied emissions. Even when these main driving materials are optimized to reduce the overall embodied emissions, there are many other materials that can be optimized at every sub-component category and generate important reductions.

Embodied emission kgCO2 eq/m2/yr

2,50

2,28

2,00 1,55 1,50 0,94

1,00 0,71 0,50

0,66

0,62

0,59

0,43

0,49

0,36

0,33 0,10

0,00

0,03

0,00

0,00 0,00

0,00

Al um in um

A (w ggr Ce Ce ind ega ra m ow te s m en ics t a fra m n til es d m e) an or t d sa ar n it Co nc Co ary re nc te re M te as on En Dr ry gin yw Fix e S all ed yst In em ve nt F Ga or ory m lva ni wor z Gl Ge e d k as os ste s ( yn e l w i n t he do tic w s pa ne Pa ) in ts E M P ,s ea ela S la mi St nt ne ee s l( Pl , ot st as he ru tic r ct ur m al, es h fra m Re W i b at ng er , o ar pr th oo er fin ) T g m im em ber br an e

0,00

0,13

0,17

Materials Base Case

Figure 4-3 Embodied CO2-eq emissions from materials used in the Base Case by building material.

With these results it is possible to assess and compare the performance both the NFH Ojochal and NFH v2. in terms of material-related embodied emissions.

4.3.2 NFH Ojochal The total embodied emissions of the NFH Ojochal are presented in Table 4-4 and based on the functional unit of this study represent a total of 7.54 kg CO2eq/m2-yr. This result is also shown in Figure 4-4.

Table 4-4 Embodied CO2-eq emissions from materials used in the NFH Ojochal by life cycle stage. Stage

Module

Product Transport Gate-to- Site Construction Process Recplacement (incl. Transport) Decontruction/Demolition Transport Site-to-Waste Mgmt. Center Waste Processing Total

A1-A3 A4 A5 B4 C1 C2 C3

Embodied Emissions kg CO2-eq

kg CO2-eq/yr

kg CO2-eq/m2

kg CO2-eq/m2/yr

44137.73 1221.68 1075.55 -3552.72 3576.21 234.52 2171.89 48864.85

735.63 20.36 17.93 -59.21 59.60 3.91 36.20 814.41

408.68 11.31 9.96 -32.90 33.11 2.17 20.11 452.45

6.81 0.19 0.17 -0.55 0.55 0.04 0.34 7.54

9.00 0.34

Embodied emission kgCO2 eq/m 2/yr

8.00

0.04

0.55 0.17 0.19

7.00 6.00 5.00 4.00

6.81 3.00 2.00 1.00 0.00

-0.55

-1.00

A1-A3

NFH OJOCHAL A5 B4 C1

Figure 4-4 Embodied CO2-eq emissions from materials used in the NFH Ojochal by life cycle stage.

The majority of the embodied emissions (90%) result from the product stage (A1-A3). It is important to note that replacement stage (B4) has a negative input. This occurs due to the material used for the superstructure and floor structure of the building, which is cold formed welded structural metal hollow sections that with a service life of 100 years (higher than the service life of the study) makes possible to account as negative embodied emissions the replacement stage.

The waste processing stage (C3) in the NFH Ojochal has a reduction of about 70% from the embodied emissions calculated for the Base Case due to the fact that demolition and deconstruction waste from the Base Case is more likely to end up being disposed rather than recycled or reused. The embodied emissions from evaluated end-of-life stage (C1-C3) account a 45% in the NFH Ojochal when compared to the Base Case. Although overall material-related embodied emissions of the NFH Ojochal account a 20% reduction when compared to the Base Case, product stage module (A1-A3) embodied emissions result in an increment of about 30%. This occurs mainly because of the use of additional materials from the double-skin façade which is not a common practice in conventional single-family houses in Costa Rica. However, this strategy aid in improving energy performance significantly as previously showed. In terms of building components, as it can be seen in Table 4-5 and Figure 4-5, the components that drive the highest emissions are the Outer Walls (28%), the Inner Walls (22%), the Outer Roof (21%) and the Groundwork and Foundations (11%). Table 4-5 Embodied CO2-eq emissions from materials used in the NFH Ojochal by building component Building Sub-Component 21 Groundwork and Foundations 22 Superstructure 23 Outer walls 24 Inner walls 25 Floor Structure 26 Outer Roof 27 Fixed Inventory 28 Stairs and Balconies EE (kg CO2eq/m2/yr)

A1-A3 0.58 1.39 1.81 0.80 0.78 1.24 0.08 0.14 6.81

EE (kg

Building Life Cycle Stage Module A4 A5 B4 C1 C2 0.03 0.02 0.00 0.05 0.02 0.02 0.04 -1.25 0.11 0.00 0.04 0.04 0.03 0.15 0.00 0.04 0.02 0.72 0.06 0.00 0.04 0.02 -0.39 0.06 0.00 0.02 0.02 0.17 0.10 0.00 0.00 0.00 0.21 0.01 0.00 0.00 0.00 -0.04 0.01 0.00

C3 0.15 0.02 0.02 0.03 0.03 0.03 0.00 0.03

CO2eq/m2/yr) 0.85 0.33 2.10 1.68 0.55 1.59 0.30 0.15

11% 4% 28% 22% 7% 21% 4% 2%

0.19

0.34

7.54

100%

0.17

-0.55

0.55

0.04

Weight (%)

2.50 2.25 2.00

Embodied emission kgCO2 eq/m 2/yr

1.75 1.50 1.25 1.00 0.75 0.50 0.25 0.00 -0.25 -0.50 -0.75 -1.00 -1.25 -1.50

21 Groundwork and Foundations

22 Superstructure

23 Outer walls

24 Inner walls

25 Floor Structure

26 Outer Roof

27 Fixed Inventory

28 Stairs and Balconies

0.15

0.02

0.03

0.00

0.03

0.02

0.00

0.05

0.11

0.15

0.06

0.10

0.01

0.00

-1.25

0.03

0.72

-0.39

0.17

0.21

-0.04

0.02

0.04

0.02

0.00

0.03

0.02

0.04

0.02

0.00

A1-A3

0.58

1.39

1.81

0.80

0.78

1.24

0.08

0.14

Figure 4-5 Embodied CO2-eq emissions from materials used in the NFH Ojochal by building component.

When evaluating building materials, structural steel used in different building components has the highest emissions and represent 15% of the total, the engine systems from the folding exterior façade doors represent 14% of the total, the galvanized steel roof deck stand for 10% of the total, timber used in the outer walls and floor structure has 9% of the total emissions, melamine from the inner walls comes in with 8%, aluminum cladding from the window framing of the inner walls represents 8% of the total, materials such as paints, sealants and primers represent about 7% while cement and mortars account for 6%. These building materials represent almost 80% of the total embodied emissions; the embodied emissions of the NFH Ojochal by building material can be seen in Figure 4-6. These results allow the comprehension and understanding of which are the main drivers of the material-related embodied emissions of the NFH Ojochal in order to make design decisions to improve upcoming prototypes.

Embodied emission kgCO2 eq/m2/yr

1,40 1,16

1,20 1,04 1,00 0,79

0,80 0,60

0,70

0,64

0,58 0,46

0,51

0,45

0,44

0,40 0,20

0,21

0,20

0,12

0,02

0,00

0,01

0,00

0,01

Al um in um

A (w ggr Ce ind ega m ow tes en f Ce t a ram ra nd e) m ics mor (S tar an Co itar un y) te rto En Dr p gin yw Fix e S all ed yst In em ve nt or F o Ga y r lva mw ni o rk z Gl Ge e d s o as t s ( syn eel w i n t he do tic s w pa ne ) Pa in EP ts M ,s S ea elam la in St n e ts ee l( Pl , oth st as ru tic er ct ur m es al, h fra R m eb W i ng at a er ,o r pr t h oo er ) fin g m Tim em ber br an e

0,00

0,17

Materials NFH Ojochal

Figure 4-6 Embodied CO2-eq emissions from materials used in the NFH Ojochal by building material.

4.3.3 NFH v2. The total embodied emissions of the NFH v2. are presented in Table 4-6 and based on the functional unit of this study represent a total of 3.88 kg CO2eq/m2-yr. This result is also shown in Figure 4-7. Table 4-6 Embodied CO2-eq emissions from materials used in the NFH v2. by life cycle stage. Stage

Module

Product Transport Gate-to- Site Construction Process Recplacement (incl. Transport) Decontruction/Demolition Transport Site-to-Waste Mgmt. Center Waste Processing Total

A1-A3 A4 A5 B4 C1 C2 C3

Embodied Emissions kg CO2-eq

kg CO2-eq/yr

kg CO2-eq/m2

kg CO2-eq/m2/yr

16461.58 784.93 513.23 4038.86 1316.93 183.00 1866.90 25165.43

274.36 13.08 8.55 67.31 21.95 3.05 31.11 419.42

152.42 7.27 4.75 37.40 12.19 1.69 17.29 233.01

2.54 0.12 0.08 0.62 0.20 0.03 0.29 3.88

4.50

4.00

Embodied emission kgCO2 eq/m 2/yr

0.29 3.50

0.20

3.00

0.62

0.03

0.08 0.12

2.50

2.00

1.50 2.54 1.00

0.50

0.00

NFH v2. A1-A3

Figure 4-7 Embodied CO2-eq emissions from materials used in the NFH v2. by life cycle stage.

The majority of the embodied emissions (65%) result from the product stage (A1-A3), the replacement stage (B4) account for 16% of the total and the waste processing module (C3) account for 7%. The rest of the modules account a total of 12% all together. When compared to the NFH Ojochal, all of the embodied emissions form each module have had a significant reduction except the replacement stage module (B4). This improvement is mainly due to the use of locally fabricated glue-laminated timber as a structural material, the use of folding doors with a manual mechanism in the Outer Walls, the removal of glass-window panes and aluminum window framing and the incorporation of a TPO roofing membrane instead of the galvanized coated steel roof. Overall embodied emissions of the NFH v2. experienced a reduction of 60% from the Base Case and of 50% from the NFH Ojochal.

In terms of building components, as it can be seen in Table 4-7 and Figure 4-8, the components that drive the highest emissions are the Inner Walls (23%), Groundwork and Foundations (22%), the Outer Roof (16%), the Outer Walls (13%), and the Fixed Inventory (8%). These five major components account for 82% of the total embodied emissions. Table 4-7 Embodied CO2-eq emissions from materials used in the NFH v2. by building component Building Sub-Component 21 Groundwork and Foundations 22 Superstructure 23 Outer walls 24 Inner walls 25 Floor Structure 26 Outer Roof 27 Fixed Inventory 28 Stairs and Balconies EE (kg CO2eq/m2/yr)

A1-A3 0.58 0.28 0.52 0.45 0.14 0.34 0.08 0.14 2.54

EE (kg

Building Life Cycle Stage Module A4 A5 B4 C1 C2 0.03 0.02 0.00 0.05 0.02 0.01 0.01 -0.10 0.02 0.00 0.01 0.01 -0.12 0.04 0.00 0.04 0.02 0.32 0.04 0.00 0.00 0.00 0.09 0.01 0.00 0.02 0.01 0.23 0.03 0.00 0.00 0.00 0.21 0.01 0.00 0.00 0.00 -0.03 0.01 0.00

C3 0.15 0.02 0.03 0.03 0.02 0.00 0.00 0.03

CO2eq/m2/yr) 0.85 0.26 0.50 0.90 0.28 0.64 0.30 0.16

22% 7% 13% 23% 7% 16% 8% 4%

0.12

0.29

3.88

100%

0.08

0.62

0.20

0.03

Weight (%)

1.00

Total emission kgCO 2 eq/m 2/yr

0.75

0.50

0.25

0.00

-0.25

21 Groundwork and Foundations

22 Superstructure

23 Outer walls

24 Inner walls

25 Floor Structure

26 Outer Roof

27 Fixed Inventory

28 Stairs and Balconies

0.15

0.02

0.03

0.02

0.00

0.03

0.02

0.00

0.05

0.02

0.04

0.01

0.03

0.01

0.00

-0.10

-0.12

0.32

0.09

0.23

0.21

-0.03

0.02

0.01

0.02

0.00

0.01

0.00

0.03

0.01

0.04

0.00

0.02

0.00

A1-A3

0.58

0.28

0.52

0.45

0.14

0.34

0.08

0.14

Figure 4-8 Embodied CO2-eq emissions from materials used in the NFH v2. by building component.

When evaluating building materials (see Figure 4-9), melamine is the material with the highest impact (16%) in total material-related embodied emissions. This will be used as part of the Inner Walls mainly in the furniture of the house. Timber comes out as the second material in terms of total embodied emissions with a total of 13%. This result logical since glue-laminated timber is proposed to be used in the Superstructure, Outer Walls, Inner Walls, Floor Structure and Outer Roof. Paints, sealants and other similar products account for 13% and will be mainly used in the protection and finishes of the glue-laminated timber elements and will require some replacement over the service life of the building. Cement (12%) and reinforcement bars (11%) account for a total of 23% as part of the reinforced concrete as part of the Groundwork and Foundations component. Steel profiles might be used as part of the inner walls in the NFH v2. and might contribute to 8% of the total embodied emissions. The TPO waterproofing membrane will account for about 6% of the total. These seven materials represent 82% of the total embodied emissions of the NFH v2. prototype.

Embodied emission kgCO2 eq/m2/yr

0,70

0,64

0,60 0,50

0,50

0,49

0,46

0,44

0,40 0,31 0,30

0,23

0,21

0,18

0,17

0,20 0,12 0,10 0,00

0,00

0,02

0,01 0,00 0,01

0,01

Al um in um

A (w ggr in eg do at w es fra Ce m e ra m Ce ) ics m (S ent an Co itar un y) te rto En Dr p gin yw Fix e S all ed yst In em ve nt o F Ga or ry lva mw o ni ze rk Gl Ge d s t as os s ( yn eel w t h in do etic w s pa ne ) Pa in EP ts M S ,s ea elam l an i St t s ne ee ,o l( P la the st st ru ic r ct m ur es al, h fra R m eb W i ng a at ,o r er pr th oo er fin Ti ) m gm b em er br an e

0,00

0,06

Materials NFH v2.

Figure 4-9 Embodied CO2-eq emissions from materials used in the NFH v2. by building material.

4.4 Total Emissions Results Total emissions account both material-related embodied emissions and operational-related emissions from modules B6 and B7. The results of the total emissions for the three building cases are shown in Table 4-8 and Figure 4-10. Table 4-8 Total CO2-eq emissions of the Base Case, the NFH Ojochal and the NFH v2. by life cycle stage.

Emissions (kg CO2-eq/m2/yr) Stage

Module Base Case

Product Transport Gate-to- Site Construction Process Replacement (incl. Transport) Operational Energy Use Operational Water Use Decontruction/Demolition Transport Site-to-Waste Mgmt. Center Waste Processing Total

A1-A3 A4 A5 B4 B6 B7 C1 C2 C3

5.31 0.39 0.15 1.87 9.11 0.84 0.39 0.12 1.16 19.34

NFH Ojochal 6.81 0.19 0.17 -0.55 3.51 0.60 0.55 0.04 0.34 11.65

NFH v2 2.54 0.12 0.08 0.62 3.36 0.60 0.20 0.03 0.29 7.84

When taking into account emissions from operational use modules B6 and B7, together they represent approximately 50% of the total emissions of the Base Case, 35% of the total emissions of the NFH Ojochal and 50% of the total emissions of the NFH v2. Hence the importance of the implementation of passive strategies in the NFH Ojochal and NFH v2. in order to improve the energy efficiency of the buildings and thus the overall environmental impact prior attempting to reach any ZEB ambition level. Moreover, NFH Ojochal has a 40% total emission reduction from the Base Case while NFH v2. has a 60% reduction from the Base Case and more than 30% reduction when compared to the NFH Ojochal.

22.00 21.00 20.00

Base Case

19.00 18.00

Emissions kgCO2-eq/m2/yr

17.00 16.00 15.00

NFH Ojochal

14.00 13.00 12.00 11.00 10.00

NFH v2

9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 -1.00

A1-A3

Figure 4-10 Total CO2-eq emissions of the Base Case, the NFH Ojochal and the NFH v2. by life cycle stage.

5 ZEB Balance This section comprises the evaluation of the potential that NFH Ojochal and NFH v2. prototypes have to become zero emission buildings through on-site renewable energy production with the use of photovoltaic systems (PV).

5.1 Photovoltaic Energy Production The use of photovoltaic (PV) systems is encouraged as an important source of renewable energy (solar electricity) for net-zero emission buildings. Although photovoltaics (PVs) are not the answer for all projects, they offer an integration technology and modular design that make them quite versatile and building-friendly plus PVs generate electricity, which is at the heart of their versatility (Hootman, 2012). In Costa Rica, buildings and especially residential units, are mainly designed to be 100 percent electric, making PVs a very complimentary solution. The potential monthly and yearly production rates of PVs installed in San José, Costa Rica, and depending on the efficiency of the PV module is shown in Table 5-1. Table 5-1 Monthly and yearly PV production rates for surface area of installed PV modules with different efficiencies. Monthly Production (kWh/m2) Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sept

Oct

Nov

Dec

Yearly Production

PV Module

Efficiency (%)

(kWh/m2)

High-efficiency

25%

386

Medium-efficiency

20%

309

Low-efficiency

15%

232

This production rates can be used to size a PV system to generate the required on-site electricity to offset both the energy demands and operational-related carbon emissions, with and without considering the technical equipment and home appliances demand. Aspiring to generate 100% of energy demands with a PV system is encouraged in order not only to offset the energy-related carbon emissions towards a net-zero emission building, but also to achieve a net-zero energy building 40

It is of great importance to consider sizing the on-site renewable energy generation system after other cost-effective strategies have been implemented and the total energy consumption of the building has been reduced when compared to the baseline case. This way, the cost of the onsite renewable energy system will be lower and more effective.

5.2 ZEB Targets, Levels and Balance Once having the results of the operational-related carbon emissions and the embodied emissions from the materials, it is possible to calculate the CO2 emission balance that could be reached with the implementation of on-site renewable energy production and revise how to achieve different ZEB ambition levels. To perform a ZEB balance, it is important to first set energy targets for each ambition level. The energy target is defined as the energy use of the building and does not account reduction of site energy due to renewable energy (Hootman, 2012). Even if a zero-emission building requires the implementation of on-site renewables to offset the carbon emissions, it will continue to use and demand energy. It becomes of great importance to assure a high level of energy efficiency and performance prior the sizing of the on-site renewable system. In Costa Rica there are no guidelines which specify required energy performance targets for residential buildings; therefore, in this study the energy target is assumed as the site energy which resulted from the energy simulation. The same is assumed for the operational water use. One more thing is needed to understand the whole process of achieving net-zero emissions: the production potential of the on-site renewables. In this case, PV systems are being analyzed due to their versatility however, other renewable energy sources can be explored for these purposes and as part of further work. As previously stated, there are several types of PV modules with different efficiencies and therefore a distinction of three main efficiencies is specified: low-efficiency modules, representing those with efficiencies ranging from 15% to 19%; medium-efficiency modules ranging between 20% and 24%; and high-efficiency modules with efficiencies higher than 25% (Hootman, 2012).

Potential monthly and annual production rates for 1 m2 of installed PVs depending on their efficiencies were shown in Table 5-1 while potential production offsets (monthly and annual) are shown in Table 5-2. Table 5-2 Monthly and annual solar electricity emissions offset of 1m2 of installed PV (depends on PV module efficiency). Results extracted from energy simulations

Feb

Mar

Apr

May

Jun

Jul

Aug

Sept

Oct

Nov

Dec

Yearly Production Offset

Jan

Monthly Production Offset (kgCO2eq/m2-yr)

Efficiency (%)

High-efficiency

25%

3.0

2.8

3.0

2.8

2.3

2.5

2.6

2.5

2.6

2.4

2.8

32.4

Medium-efficiency

20%

2.4

2.3

2.4

2.2

1.9

2.0

2.1

1.9

2.3

25.9

Low-efficiency

15%

1.8

1.7

1.8

1.7

1.4

1.5

1.6

1.5

1.7

19.4

PV Module

(kgCO2eq/m -yr)

The different energy targets, total CO2 emissions and the total area of installed PV systems required to offset the total emissions of the building to reach a particular ambition level are presented in Table 5-3 for the NFH Ojochal and in Table 5-4 for the NFH v2. These results represent the ZEB Balance for each building case. Table 5-3 ZEB Balance of the NFH Ojochal. Operational Operational Embodied Emissions Total Emissions to Offset PV Installation Required (m2) Energy Water 2/ (kgCO /m yr) (kgCO2eq/m2/yr) 2eq Ambition Site Energy Emissions Emissions Level (kWh/m2 /yr) (kgCO2eq/m2 (kgCO2eq/m2 Low-Eff Med-Eff High-Eff Low-Eff Med-Eff High-Eff Low-Eff Med-Eff High-Eff (15%) (20%) (25%) (15%) (20%) (25%) (15%) (20%) (25%) /yr) /yr)

ZEB O÷EQ ZEB O ZEB-OM ZEB-COM ZEB-COME

21 47 47 47 47

1.57 3.51 3.51 3.51 3.51

0.60 0.60 0.60 0.60 0.60

0.00 0.00 18.51 18.87 19.72

0.00 0.00 13.34 13.69 14.54

0.00 0.00 11.25 11.60 12.45

2.16 4.11 22.62 22.98 23.83

2.16 4.11 17.45 17.80 18.65

2.16 4.11 15.36 15.71 16.56

12.0 22.9 125.9 127.9 132.7

9.0 17.1 72.7 74.2 77.7

7.2 13.7 51.3 52.4 55.3

Table 5-4 ZEB Balance of the NFH v2. Operational Operational Embodied Emissions Total Emissions to Offset 2 PV Installation Required (m ) Energy Water 2/ (kgCO /m yr) (kgCO2eq/m2/yr) 2eq Ambition Site Energy Emissions Emissions Level (kWh/m2 /yr) (kgCO2eq/m2 (kgCO2eq/m2 Low-Eff Med-Eff High-Eff Low-Eff Med-Eff High-Eff Low-Eff Med-Eff High-Eff (15%) (20%) (25%) (15%) (20%) (25%) (15%) (20%) (25%) /yr) /yr)

ZEB O÷EQ ZEB O ZEB-OM ZEB-COM ZEB-COME

19 45 45 45 45

1.42 3.36 3.36 3.36 3.36

0.60 0.60 0.60 0.60 0.60

0.00 0.00 12.40 12.60 13.11

0.00 0.00 8.01 8.21 8.69

0.00 0.00 6.58 6.78 7.25

2.01 3.96 16.36 16.56 17.07

2.01 3.96 11.97 12.17 12.65

2.01 3.96 10.54 10.74 11.21

11.2 22.0 91.1 92.2 95.0

8.4 16.5 49.9 50.7 52.7

6.7 13.2 35.2 35.8 37.4

For the ZEB-O÷EQ ambition level, the energy target or site energy is calculated by subtracting the energy demand for technical equipment and appliances to the total site energy demand of (see Table 3-1). For the rest of the ambition levels, the total site energy demand of 47 kWh/m2/yr for the NFH Ojochal and 45 kWh/m2/yr for the NFH v2. are set as the energy targets. Operational-related emission targets are calculated with the same procedure for the energyrelated emissions and as explained before for the water-related (the target is based on the improved water consumption when implementing efficient plumbing fixtures). Embodied emission targets vary depending both on the ambition level and on the efficiency of the PV modules. This is because, when having a higher ambition level, the embodied emissions will cover more modules from the life cycle stages of the building, therefore increasing the embodied emissions. When these embodied emissions increase, the required area of PV installation will also be higher (the lower the efficiency of the modules, the higher the required area of installation). This happens to the ambition levels ZEB-OM, ZEB-COM and ZEBCOME.

6 Discussion 6.1 Identifying the Hotspots The results of the cradle-to-grave LCA performed on the NFH Ojochal show that embodied emissions represent a total of 7.54 kg CO2eq/m2/yr. The majority of these embodied emissions come from the product stage module (A1-A3) at 90% since the replacement module (B4) has a negative input in the overall calculations due to the reference service life (RSL) of one of the materials used in most of the building components (structural steel). The five building components that drive the highest emissions in the NFH Ojochal are the Outer Walls (28%), the Inner Walls (22%), the Outer Roof (21%) and the Groundwork and Foundations (11%). Together they represent 82% of the total embodied emissions. The most significant reduction of embodied emissions in future NFH prototypes can be achieved by identifying the hotspots or main embodied emission drivers in these building components. 43

The materials that were driving the highest emissions were: structural steel (15%), engine systems from the folding exterior façade doors (14%), the galvanized steel roof deck (10%), timber (9%), melamine (8%), aluminum cladding (8%), materials such as paints, sealants and primers (7%) and cementitious materials (6%). These building materials represent almost 80% of the total embodied emissions, optimizing the use and selection of these materials will result in the highest impacts in terms of embodied emission reductions. When compared to the Base Case, the NFH Ojochal has a 20% reduction of the material-related embodied emissions. An upcoming prototype of the NFH was assessed, the NFH v2 which optimizes material selection based on LCA results of the NFH Ojochal and based on market availability of new products and systems. With a total of 3.88 kg CO2eq/m2-yr the NFH v2. has approximately a 60% reduction of the embodied emissions when compared to the Base Case and almost a 50% reduction when compared to the NFH Ojochal. This reduction is attributed mainly to the trade-off of using glue-laminated timber instead of structural steel as the main structural element. The gluelaminated timber to be used is made of teak wood planted and grown in Costa Rica and processed locally to create the structural elements as well as panels that will serve as floor and roof decking to next prototype of the NFH. Additional trade-offs to be made at the NFH v2 are: use of mechanical systems to operate the folding doors instead of engine systems in the folding doors, removal of glass-window panes and aluminum window framing and the selection of a TPO roofing membrane to be installed on top of the glue-laminated timber panels that will serve as a roof deck. Comparison of total embodied emissions from the components of the three building cases are presented in Table 6-1 and Figure 6-1. Moreover, a comparison of the material inventories from the three building cases can be seen in Figure 6-2. When comparing the material inventories, it can be seen that usage of the materials with the highest environmental impact from the Base Case such as ready-mix concrete, reinforcement bars, glass panes, aluminum from window framing and concrete masonry has been reduced

considerably in the NFH Ojochal and NFH v2. Also, the usage of materials with the highest environmental impact from the NFH Ojochal has been reduced or traded in the NFH v2. Table 6-1 Embodied Emissions per building component comparative between the Base Case, the NFH Ojochal and the NFH v2.

EE (kg CO2-eq/m2/yr) NFH Base Case NFH v2 Ojochal 0.99 0.85 0.85 1.38 0.33 0.26 1.86 2.10 0.50 1.28 1.68 0.90 2.24 0.55 0.28 1.05 1.59 0.64 0.52 0.30 0.30 0.07 0.15 0.16

Building Sub-Component Groundwork and Foundations Superstructure Outer walls Inner walls Floor Structure Outer Roof Fixed Inventory Stairs and Balconies 2

9.39

EE (kg CO2eq/m /yr) 10.00

3.88

Base Case

9.00

Embodied emissions kgCO2-eq/m2/yr

7.54

NFH Ojochal

8.00 7.00 6.00

NFH v2

5.00 4.00 3.00 2.00 1.00 0.00

Groundwork and Foundations

Superstructure

Outer walls

Inner walls

Floor Structure

Outer Roof

Fixed Inventory

Stairs and Balconies

Figure 6-1 Embodied Emissions per building component comparative between the Base Case, the NFH Ojochal and the NFH v2.

Al um Embodied emission kgCO 2 2 eq/m -yr in um A (w ggr eg i n C Ce ra em dow ate s m en ics t a fra m til nd e es m ) an or t d sa ar n it Co nc Co ary re nc te re M te as on En Dr ry gin yw Fix e S all ed yst In em ve nt Ga For ory lva mw ni z or Gl Ge e d k as os ste s ( yn e l w i n t he do tic w s pa ne Pa ) in EP ts M ,s ea elam S la St nt ine ee s, l( P st la oth ru s tic er ct m W ura es at l, h er fra R pr oo min eba fin g, r g m oth em er) br an e W oo d

2,50 2,00 1,50 1,00 0,50 0,00

Materials Base Case

NFH Ojochal

NFH v2

Figure 6-2 Embodied emissions (kg CO2eq/m2/year) of the materials used in the Base Case (blue), in the NFH Ojochal (orange) and in the NFH v2. (gray).

When taking into account emissions from operational use modules B6 and B7 (see Table 4-8 and Figure 4-10), together they represent approximately 50% of the total emissions of the Base Case, 35% of the total emissions of the NFH Ojochal and 50% of the total emissions of the NFH v2. Hence the importance of the implementation of passive strategies in the NFH Ojochal and NFH v2. in order to improve the energy efficiency of the buildings and thus the overall environmental impact prior attempting to reach any ZEB ambition level. Moreover, NFH Ojochal has a 40% total emission reduction from the Base Case while NFH v2. has a 60% reduction from the Base Case and more than 30% reduction when compared to the NFH Ojochal.

6.2 Achieving Net-Zero Emissions A particular ambition level of zero emissions can be achieved through on-site renewable energy production. In this case, the analysis is performed for solar energy production due to the versatility of the PV systems and its potential.

The first two ambition levels (ZEB-O÷EQ and ZEB-O) do not take into account the materialrelated embodied emissions; therefore, areas of installed PVs vary between 7.2m2 and 22.9m2 (depending on the system efficiency) to achieve these ambition levels for the NFH in Ojochal and from 6.7m2 and 22m2 (depending on the system efficiency) for the NFH v2. Implementing PV systems for on-site renewable energy generation create an additional input to the overall material-related embodied emissions that was not previously accounted in the LCA of both NFH Ojochal and NFH v2. Due to this, it becomes more ambitious to achieve ZEB levels such as ZEB-OM, ZEB-COM or ZEB-COME. However, areas of installed PVs may vary between 51.3m2 and 132.7m2 (depending on the system efficiency) for the NFH in Ojochal and between 35.2m2 and 95.0m2 (depending on the system efficiency) for the NFH v2, in order to achieve these ambition levels. These results show the importance of reducing operational-related emissions (energy and water consumption) as much as possible in order to achieve a higher performance building and the possibility of achieving ZEB-ambition levels without having to invest in large areas of PV installation systems. Reaching ZEB ambition levels that take into account material-related embodied emissions represent a higher challenge since PV systems will add a significant input to these embodied emissions. Reducing the material-related embodied emissions through design and advancing in new technologies of PVs with higher efficiencies and lower embodied emissions will contribute with the goal of reaching zero-emission buildings.

7 Conclusion The conclusions and key findings of this study are: •

In terms of embodied emissions, NFH Ojochal has a reduction of 20% when compared to a baseline case and the upcoming prototype, the NFH v2., has a reduction of 60% when compared to the baseline case.

•

When comparing total CO2 emissions, NFH Ojochal has a reduction of 40% and NFH v2. has a reduction of 60% from the total emissions of the Base Case.

•

Operational-related emissions represent 50% of the total emissions of the Base Case, 35% of the total emissions of the NFH Ojochal and 50% of the total emissions of the NFH v2.

•

For the NFH v2. the area varies between 6.7m2 and 95.0m2.

8 Further Work Based on the analyses performed and the results presented, further work that can be done is listed as follows: •

Calibrate the energy simulations of the three building cases using a dynamic methodology software that models thermal transmission, heat flow by ventilation, thermal storage and internal and solar heat gains in the building zones.

•

Track and monitor total site energy delivered to the NFH Ojochal and future prototypes to compare actual energy use versus theoretical energy simulations. Furthermore, in future prototypes of the NFH, install submetering devices in order to track and monitor not only the total site energy delivered to the building but also the different energy uses.

•

Explore the possibility and feasibility of different on-site renewable energy production systems (i.e. wind power, ground-source heat pumps, etc.)

•

Investigate the financial feasibility of reaching ZEB ambition levels in the NFH future prototypes. 48

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LIFE CYCLE ASSESSMENT (LCA) OF THE

NO FOOTPRINT HOUSE (NFH) BY

A-01 (A COMPANY / A FOUNDATION)