Designing Low Energy Residential Buildings in Singapore

Tan Tian ChongDeputy Managing Director, Built Environment Research and

Innovation Institute, Building and Construction Authority, Singapore

LETCHI I 25-26 June 2019 I Kuala Lumpur, Malaysia 1

LETCHI International CollaborationLOW ENERGY IN TROPICAL CLIMATES FOR HOUSING INNOVATION

Designing Low Energy Residential Buildings in Singapore

25-26 June 2019Kuala Lumpur, Malaysia

Contents

2LETCHI I 25-26 June 2019 I Kuala Lumpur, Malaysia

2 Designing Low Energy Residential Buildings withGreen Mark (RB) 2016

Tools, Codes, Standards and Guides

Deployment –Policies and Measures

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1 Factors Affecting Sustainable Development of Buildings in Singapore

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25 to 35 Degrees Celsius, 80% -100% R H

Annual Rainfall -2,340 mm

High-Rise, High-Density

Small Island City State ( 720 sq km, Pop of 5.6 m)

City in A Garden

No Natural Resources

• Urban Heat Island (UHI)

• High Rise Buildings

• Biodiversity, Greenery and Waterscape

• Rain (Wind-driven)

• Noise

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Design Considerations

Singapore Electricity Consumption Landscape

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Households: 60% of GFA, 20% of total energy consumption

0%

10%

20%

30%

40%

50%

60%

70%

Commercial Industry Households TertiaryInstitutions

GFA

0

50

100

150

200

250

300

350

Commercial Industry(Aircon)

Industry (NV) Households TertiaryInstitutions

EEI[k

Wh/

m2/

yr]

6

Average Month Household Electricity Consumption by Dwelling Types

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36%

10%12%

16%

5% 5%

10%6%

0%

5%

10%

15%

20%

25%

30%

35%

40%

Air-conditio

ner

Lightin

g

Television

Refrigerator

Microwave oven

Washing machine

Water heater

Others

Air-conditioner Lighting Television RefrigeratorMicrowave oven Washing machine Water heater Others

4-Room HDB Apartment

Electricity Bill by Appliance for Public Housing

Greener Nation, Happier Life

2005 2010 2019 2020 2030

>39%Green Buildings

> 13%Green Buildings

>50%Green Buildings

>80%Green Buildings

< 0.1%Green Buildings

> 3600Green Mark Projects

~ 110million m2 green GFA

Green Mark Try Again Certified Gold Gold Plus PlatinumScore 0 49 50 74 75 84 85 89 90 100

Estimated Energy Savings> 30%25% to 30%15% to 25%10% to 15%

5 Key Assessment Criteria

1. Energy Efficiency

2. Water Efficiency

3. Environmental Protection

4. Indoor Env. Quality

5. Other Green Features

BCA Green Mark Assessment

Drive Towards a Green Nation

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Green Mark for Residential Building 2016

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Section 1: Climatic Responsive Design 35 Points

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Section 2: Building Energy Performance 25 Points

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Section 3: Resource Stewardship 35 Points

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Section 4: Smart & Healthy Building 25 Points

Section 5: Advanced Green Efforts 20 Points

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Climatic Responsive DesignP1 -Enhancing Biodivesity

Lush Greenery, Preserving Trees and Sustainable Landscape and Waterscape Management

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Green Plot Ratio (GnPR) Points2.5 to < 3.0 1.0

3.0 to < 3.5 1.5

3.5 to < 4.0 2.0

4.0 to < 4.5 2.5

≥ 4.5 3.0

Climatic Responsive DesignP1 -Enhancing Biodivesity

Enhance Tropical facade performance to minimize heat gain thus reducing the overall cooling load when required

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Climatic Responsive DesignP2-Overall Envelop Thermal Performance

Level of Award Maximum RETV (Residential Envelope Transmittance Value)

Gold 25W/m2

GoldPlus 22W/m2

Platinum 20W/m2

As determined in accordance with the formula set out in the “Code on Envelope Thermal Performance for Buildings”, the RETV shall not exceed maximum RETV of 25W/m2

ETTV/RETV FORMULA

Where

ETTV/RETV: envelope thermal transfer value (W/m2)WWR : window-to-wall ratioUw : thermal transmittance of opaque wall (W/m2 K) Uf : thermal transmittance of fenestration (W/m2 K) CF : Correction factor for solar heat gain through

fenestrationSC : shading coefficients of fenestration

+ Solar radiation glass

Radiationgain

ETTV/RETV = Heat conduction wall + Heat conduction glass

Heat gain

Heat gain

Heat gainWindow

11.9(1-WWR)Uw + 210.9(WWR)(CF)(SC)+ 3.37(WWR)UfETTV =

3.4 (1-WWR)Uw + 58.6(WWR)(CF)(SC)+ 1.3 (WWR)UfRETV =

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Climatic Responsive DesignP3- CFD Ventilation Simulation Modelling and Analysis

• Encourage building design utilizing prevailing wind directions to achieve good natural ventilation and indoor thermal comfort

• Reduce turnaround time by 60%

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Ventilation Performance : To ensure effective building layout design and unit design reduce the needs of using air-conditioning.

Climatic Responsive Design

Singapore Wind Rose Data from Meteorological Service Singapore – Changi Station 1975 - 2006.

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District-level CFD Simulation

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• Provision of either void decks at the ground floor or void spaces in between buildings to encourage air flow through and around buildings

• To encourage macro simulation to check block layout to ensure passive design been considered from the early stage

Climatic Responsive Design

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Dwelling Unit CFD Simulation

Cross Ventilation

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Building Energy PerformanceP6- Air-conditioning system efficiency

• Encourage the use of energy efficient air-conditioners that are certified under the Singapore Energy Labelling Scheme Green Mark Gold- at least 3 ticks

Green Mark Gold Plus- at least 5 ticks

Green Mark Platinum- at least 5 ticks

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Building Energy PerformanceP8-Harnessing Renewable Energy

• Solar Energy Feasibility

• Solar Energy Ready-Structural, Electrical and Spatial

• Renewable Energy Replacement

MOOC guide Green Mark Requirements Tools Codes/standards/guides

Integrated design

Multi-disciplinary team collaboration Integrative design process(1.01b)Environmental credential of project team (1.01c)BIM for building performance analysis (1.01d) User engagement (1.01e)Smart BIM (5.01g)

Revit,ArchiCADBentley

Green Mark for Residential Buildings 2016 (https://www.bca.gov.sg/GreenMark/others/GM_RB_2016_criteria_final.pdf)BCA BIM Essential Guide(https://www.corenet.gov.sg/media/1588649/essential-guide-bim-to-bpa.pdf)

Define VISION• Creating conscious user

behaviour & redefining expectations

• Set Benchmarks & Key Performance Indicators

• Initial Site Assessment• Formulate design guidelines

Climate responsive design brief(1.01a)Environmental impact analysis(1.02a)Urban Heat Island (UHI)(1.02a)Integrated landscape and waterscape (1.02b)Green Plot Ratio (GnPR) (1.02b)

EcotectSTEVE(https://enterprise.nus.edu.sg/technology-commercialisation/for-industry/technology-highlights/steve-tool)

Green Mark Technical Guide and Requirements(https://www.bca.gov.sg/GreenMark/others/GM_RB2016_Technical_Guide_Requirements.pdf)

Ideate CONCEPT• Program & Function

assessment • Zoning & Circulation • Site Design & Planning • Orientation, Form and

Massing

Response to site context (1.02a)Internal space organisation (1.03b)Ventilation performance (1.03c)Passive design strategies (5.01a)

Energy Plus (BCA updated weather file)FLUENTANSYSOpenFOAMSTAR-CCM+GrBEST(https://iopscience.iop.org/article/10.1088/1755-1315/238/1/012077)

Guidelines on ETTV for Buildings (https://www.bca.gov.sg/PerformanceBased/others/ETTV.pdf)

Evaluate ANALYSE & REVIEW • Response to site features. • Response to climate. • Response to program and

function.

Occupant comfort (4.01a)Effective daylighting (4.02a)Potential of glare and daylight control(4.02a)Wind driven rain simulation (5.01)

IESVE (GM Pro)DaySIMDIVAOpenFOAMSTAR_CCM+EnergyPlus/OpenStudio

Green Mark Technical Guide and Requirements(https://www.bca.gov.sg/GreenMark/others/GM_RB2016_Technical_Guide_Requirements.pdf)

Develop DESIGN • Site • Structure • Skin • Services • Space

Tropical façade performance (1.03a)Energy efficiency (2.01)Energy effectiveness (2.02)Renewable energy (2.03)Water efficiency (3.01a)Alternative water resources (3.01c)Sustainable construction, CUI (3.02a)Conservation and waste recovery (3.02a)Embodied energy (3.02b, 5.01i)

IESVE (GM Pro)BIM HVACToolPre-Simulated Daylight Autonomy Tables (https://www.bca.gov.sg/GreenMark/others/GM_RB2016_Technical_Guide_Requirements.pdf)Green Mark Energy Performance Points Calculator (https://www.bca.gov.sg/GreenMark/others/BCA_Energy_Performance_Points_Calculator.xlsx )BCA online Embodied Carbon Calculator(https://www.bca.gov.sg/CarbonCalculator/Index.aspx?ReturnUrl=%2fCarbonCalculator)

Guidelines on ETTV for Buildings (https://www.bca.gov.sg/PerformanceBased/others/ETTV.pdf)SS 530 : 2014. Code of practice for energy efficiency standard for building services and equipmentSS 553 : 2016. Code of practice for air-conditioning and mechanical ventilation in buildingsSS 554: 2016. Code of Practice for Indoor air quality for air-conditioned buildingsSS 531-1 - Code of Practice for Lighting of Work Places

Monitor PERFORMANCE • Triple bottom line – People,

profit & planet. • Life cycle assessments.

Energy monitoring (4.3a)Water usage monitoring (3.1b)Smart building operations (5.01k)Cost neutral design (5.02a)Social benefits (5.04a)

IAQ report template (https://www.bca.gov.sg/GreenMark/others/IAQ_report_template.xlsx)POE Survey form (https://www.bca.gov.sg/GreenMark/others/POE_survey_template.xlsx,

Green Mark Technical Guide and Requirements(https://www.bca.gov.sg/GreenMark/others/GM_RB2016_Technical_Guide_Requirements.pdf)SS 554: 2016. Code of Practice for Indoor air quality for air-conditioned buildings

Green Mark standards and online calculator

Green Mark Carbon & Embodied Energy Calculator

BIM Essential Guide

IES-VE’s dedicated tool for Green Mark – GM Pro BIM HVAC Tool’s dedicated tool for Green Mark – ETTV Calculator

29

Integrated Environmental Modeller (IEM)

• Urban microclimatic modelling tool

• Provide wind, shadow, solar

irradiance, thermal & noise mapping

analysis

• Help the town ship or city planning

process to incorporate the Urban

Heat Island (UHI) mitigation or

countermeasure strategies

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GRBEST

• Computational Fluid Dynamics (CFD) airflow modelling and simulation tool

• Coupled with the geometry input from BIM-REVIT

• Reduce the CFD turnaround time and initial capital cost to acquire a CFD license

• Assist to meet the CFD simulation requirements for natural ventilation under the Green Mark scheme

500 lux

300 lux

200 lux

3 different illuminance level

3 ranges of Urban Obstruction Angle

Unobstructed Sky(0 - 11.25 degree

Urban Obstruction)

22.5 Degree Sky Obstruction

(11.25 – 33.75 degree Urban Obstruction)

45 degree Sky Obstruction

(33.5 - 57.25 degree Urban Obstruction)

3 ranges of Shading Overhang

0 degree Shading Overhang

15 degree Shading Overhang

30 degree Shading Overhang

8 Orientations

10 Window-to-wall ratios

6 Glazing types-Visual Transmittance value

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Simplifying Design Workflows- Quick and Easy infoNew Pre-Simulated Daylight Availability Tables

Design Parameters checks:• Average Urban Obstruction

Angle (AUOA)• Horizontal shading depth• Glazing type-visual

transmittance (Tvis)• Orientation • Window-to-Wall ratio (WWR)

Result: ‘Number’ shown in the “square”; use the number multiply by the width of the space obtain area of coverage for that space

Cells with Red/ Pink Background indicate Glare exists more than 10% of the occupied hours; area excluded as meeting requirement

Reading Info from the Matrix Tables

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• Legislation

• Incentives

• Public sector taking the lead

• Capability development

• Tools - codes, standards and guides

• Whole-of-government (WOG)

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Deployment –Policies and Measures