DESIGN ANALYSIS & RECOMMENDATIONS - cbalance.in · As per design 60% As per design As per SVA GRIHA...

DESIGN ANALYSIS & RECOMMENDATIONS

Project: Hiranandani Bungalow, Khandala

2

Contents

• Project Introduction

• Methodology

• Climate Analysis

• Benchmarking

• Passive Strategies

• HVAC Strategies

• Envelope Design Analysis

• Envelope Performance Evaluation

• Heat Gain Analysis

• ECBC – R Benchmarking

• Summary of Approved Passive Design and Active System Measures

PROJECT INTRODUCTION

4

Project Brief:

• The proposed bungalow is a residential

project at Khandala

Location: Khandala, Maharashtra

Latitude: 18.7692° N

Longitude: 73.3768° E

Climate: Temperate

Building configuration:

Lower floor + Stilt + 1st floor+ 2nd floor

Score of Work:

• To analyse building design and thermal

performance

• Identify climate appropriate passive and

sustainable cooling strategies to achieve

thermal comfort.

ENTITY DETAILS

State Maharashtra

City Khandala

Building Type Residential Bungalow

Building Orientation Predominantly oriented

towards south east

Construction Type Proposed, New Building

Carpet Area 5500 sq.ft (550 sq.m)

Ceiling Height (ft) 10 ft

Window to wall ratio 30 to 40%

Occupancy 6 people

Operating Schedule 365 days a year

Built up sqm/capita

thresholds

85 sq.m(SVA GRIHA: 12.5 sqm < x < 50 sqm)

METHODOLOGY

7

Understand project brief:

Understand building functional and occupancy detailsStep 1

Step 4

Step 2Climate analysis

Identify accurate climate zone and suitable passive design features

This is for building envelope

Reduce thermal loads through use of efficient form, orientation, massing and

materials

Step 3Benchmarks for thermal comfort and energy performance

Propose ECBC guidelines for building performance

Step 5

Feasible sustainable cooling technologies:

Propose energy efficient HVAC systems that use natural refrigerants

Step 6

Finalise Energy Conservation Measures (ECMs):

Analyse building performance by combining and comparing passive strategies

through energy modeling

8

Project Brief Analysis

Climate Analysis

Benchmarking Passive Strategy

Analysis

HVAC Strategy Analysis

Strategy Finalisation

CLIMATE ANALYSIS

Climatic Zone of Khandala: Temperate

Khandala falls in the Warm and Humid zone as per NBC 2005. However, microclimatic analysis indicates

that climate conditions are similar to moderate/temperate climate (similar to Bangalore)

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Khandala

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Khandala Climate Data

Source: MNRE

Source: WikipediaTemperature: Temperature peaks in March, April, May at ~ 35C. Average monthly maximum temperature is 29.9C.

Precipitation: Heavy monsoons are seen from June to August. Intermittent rainfall seen during September and October.

Cloud Cover and Humidity

Temperature and Rainfall

Humidity: Maximum humidity in June, July, August, September – 75%. Average humidity ~60%.

Climatic Zone Classification

Classification: Khandala falls in Moderate/Temperate climatic conditions.

12

THERMAL COMFORT ANALYSIS

Using Climate Consultant software, cooling design strategies for Bangalore were studied (Khandala weather file is unavailable – and Bangalore is considered representative of Moderate/Temperate climate). It was found that out of total 8760 hours of a year only 18% of them are in thermal comfort zone (ASHRAE 55)

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PASSIVE COOLING POTENTIAL

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Thermal comfort conditions can be reached for approximately 46% of the year using passive design and cooling strategies such as:

• Sun Shading Windows (30%)

• High Thermal Mass Night Flushed (11.3%)

• Internal Heat Gain (13%)• Passive Solar Direct Heat

Gain (10.9%)• Natural Ventilation

BENCHMARKING

• Benchmarks were identified for envelope elements including – roof,

walls, fenestrations

• Benchmarks prescribed by GRIHA 2015, SVA GRIHA, ECBC 2017

and ECBC R were evaluated

• Specifications for buildings in Temperate/Moderate climate were

evaluated for residential buildings under 2500sq.m (as available)

• Benchmarks for the projects were selected to achieve maximum

performance

15

PRESCRIPTIVE BENCHMARKS

16

Parameters Specification GRIHA Building V3 ECBC 2017 (for ECBC Compliant Building)

ECBC R (for all projects greater than 250m2)

SVA GRIHA

Roof

Maximum Assembly U-factor (W/m2.K)

0.409 W/m2.k (as per ECBC 2007) 0.33 W/m2.k 1.2 W/m2.k NA

Provide cool roof to terrace area which are not covered under services

For Slopes < 20OC; Solar Reflectance ≥ 0.70; Solar Emmitance ≥ 0.75 (as per ECBC 2007)

For Slopes < 20OC; Solar Reflectance ≥ 0.60; Solar Emmitance ≥ 0.90

NA NA

SRI = 82 (as per ECBC 2007) SRI = 72 NA NA

Window

Max WWR60% 40% NA 60%

SRR 5% 5% NA NA


6.9 W/m2.k 3 W/m2.kAs per Residential Envelope Transmittance Value (RETV)

NA

Max SHGC Non-North 0.45 (for moderate/temperate climate)

0.27 NA

Max SHGC North > 15N 0.5 NA

Minimum allowable VLT 0.16 (for WWR 50% - as per ECBC 2007)

0.27WWR ≤ 20% = ≥75% VLT20%<WWR≤30% = ≥50% VLT30%<WWR≤35% = ≥40% VLT

0.40 (for WW 40%)

Shading Design

All windows (Ac and Non-AC) to be completely shaded from 10AM to 3PM from 1st April to 30th September

NA NA

Reduce the overall insolation through thefenestration by 60% or more over the base case

Daylighting

Min Daylighting25% of living space is daylit. Achieve appropriate Daylight Factors.

45% of above grade floor area shall meet or exceed

UDI requirementNA

25% of living space is daylit. Achieve appropriate Daylight Factors.

Max daylighting75% of living space is daylit. Achieve appropriate Daylight Factors.

NA NA75% of living space is daylit. Achieve appropriate Daylight Factors.

Daylight Factors / UDIDF: Kitchen-2.5, Living Room -0.625, Study Room - 1.9, Circulation - 0.313

UDI: NA DF for WWR 40% - 2.8, VLT - 0.40

Opaque External Wall


0.431 W/m2.k (as per ECBC 2007) 0.55 W/m2.kAs per Residential Envelope Transmittance Value (RETV)

NA

Maximum Insulation R-Value (m2.k/W)

R-180 m2.C/W (as per ECBC 2007)

NA NA NA

Internal Wall u Value of internal wall (W/m2.K) NA NA NA NA

Door u Value of door (W/m2.K) NA NA NA NA

Window : Floor Area Minimum Window to Floor Area NA NA 12.50% NA

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Project Prescriptive Benchmarks

Parameters Base Case Design Case Benchmarks Proposed case Reference Guides

Roof

2.1 W/m2.k 0.4 W/m2.k 0.4 W/m2.k As per GRIHA v3

NAFor Slopes < 20;

Solar Reflectance ≥ 0.60; Solar Emmitance ≥ 0.90

For Slopes < 20; Solar Reflectance ≥ 0.60; Solar Emmitance ≥ 0.90 As per ECBC 2017 (commercial)

NA SRI = 72 SRI = 72

Window

As per design 60% As per design As per SVA GRIHA

Not applicable Not Applicable Not Applicable Not Applicable

5.6 W/m2.k 3 W/m2.k 2.8 W/m2.k As per ECBC 2017 (commercial)

0.65 0.27 0.44 As per ECBC 2017 (commercial)0.65 0.5 0.44 As per ECBC 2017 (commercial)

0.65 0.4 0.45 As per SVA GRIHA

As per design As per design As per design As per GRIHA v3

Daylighting

As per design

75% of living space to meet room specific daylight factors

As per design As per GRIHA v3As per design

As per design

Opaque External Wall2.9 W/m2.k 0.55 W/m2.k 0.55 W/m2.k As per ECBC 2017 (commercial)

NA NA NA NA

Internal Wall 3.2 W/m2.k 3.2 W/m2.k 3.2 W/m2.k As per design

Door 2.1 W/m2.k 2.1 W/m2.k 2.1 W/m2.k As per design

Window to Floor Area As per design 12.50% As per design As per SVA GRIHA

• Performance benchmarks prescribed by GRIHA 2015, SVA GRIHA,

ECBC 2017 and ECBC R were evaluated

• Relevant performance benchmarks include Energy Performance

Index (EPI) and Envelope Peak Heat Gain factors

• Both benchmarks can be evaluated for the project in order to

maintain focus on implementing energy saving measures as well as

installing energy and low-carbon HVAC systems

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PERFORMANCE BENCHMARKS

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Project Performance Benchmarks

PERFORMANCE BENCHMARKS

Specification GRIHA Building V3 ECBC 2017 (for ECBC Compliant Building)

ECBC R (for all projects greater than 250m2)

SVA GRIHA

1Building Envelope Peak Heat Gain factor (only for non-residential AC buildings)

30 W/sqm NA NA NA

2Max Building Envelope Peak Heat Gain factor - For residential building types under 2500 m2

NA NA NA Pune 1: 125 W/sq.m

NA NA NA Pune 2: 100 W/sq.m

NA NA NA Bengaluru 1: 135 W/sq.m

NA NA NA Bengaluru 2: 115 W/sq.m

3Maximum Residential Envelope Transmittance Value (RETV) -Excludes Roof

NA NA 15 W/m2 NA

4Energy Performance Index (for all buildings in Moderate climate) – For residential buildings

85 kwh/m2/year NA NA NA

5Energy Performance Index Ratio (EPI Ratio) – For hotels in composite climate

NA1 (ECBC), 0.9 (ECBC+),

0.80 (Super ECBC)NA NA

* Solar energy potential for site can also be evaluated with EPI to understand net-zero energy potential for project

PASSIVE STRATEGIES

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PASSIVE STRATEGIES

Design

Form and Orientation

Zoning and Space Planning

Optimized Openings

Shading Strategies

Envelope

Low Conductivity

Low SHGC

High Thermal Mass / Sunken

Floors

High Solar Reflective Index

Insulation / Cavity Walls

Air Tightedness

Passive Cooling

PDEC

Stack Ventilation

Wind Towers

Earth Air Tunnel

Radiative Cooling

Earth BurmConstruction

Night Purging

Sun Spaces

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DESIGN MEASURES

Form and Orientation:

• Major changes to form and

orientation are not suggested at

this project stage.

• Orientation of building

considering a +/- 10 degree

rotation are evaluated.

• It is to be noted that longest

façade of the building is oriented

towards South - West.

First Floor Plan

23

Zoning and Space Planning:

• Major changes to zoning are not

suggested at this project stage.

• The bedrooms are located on the second

floor (top floor). These rooms will have

maximum heat gain through the roof. As

these will be largely evening / night time

spaces care should be taken for night time

cooling – to allow heat to escape.

• The daytime spaces (living room, dining

area, kitchen) are located on the first floor.

These will receive maximum heat gain

through windows – necessary to shade

appropriately.

• The buffer spaces (toilets, staircase,

storerooms) are located on all facades –

predominantly on North –East. Preferable

to have buffer spaces on E and W façade. First Floor Plan

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Optimised Openings:

• Opening are evaluated for

–Window to Wall Ratio

–Shading

–Cross Ventilation

–Optimal Daylighting

–Thermal Performance

• Maximum glazing is towards South

and South-East. These windows can

be well-shaded by horizontal

overhangs.

• Windows in North-West are

obstructed by stone wall – these

windows will receive less daylighting

and will have obstructed views.

• Windows are not completely shaded

by chajjas as the chajjas do not have

uniform depth.First Floor Plan

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WINDOW TO WALL RATIO (WWR)

FloorNomenclature

of space

Window

Length in m

Window

height in m

Window

Area in

mt2 (LXB)

Wall Area in

mt2 (of the

respective

orientation)

WWR

1st floor

Living Hall 12.65 2.25 28.4625

326.16 37.80

Dining Hall 12.73 2.4 30.552

Bedroom 9.57 2.4 22.968

Room 8.53 2.4 20.472

Guest Room 3.65 2.25 8.2125

Kitchen 2 2.4 4.8

Dry Yard 2.47 2.4 5.928

Service toilet 0.8 1.18 0.944

Attached toilet 0.8 1.18 0.944

Total 123.283 326.16 37.80

2nd Floor floor

Bedroom-1 9.57 2.4 22.968

340.05 31.41

Bedroom-2 9.72 2.4 23.328

Room 6.87 2.25 15.4575

Master Bedroom 9.84 2.4 23.616

Passage 7.75 2.4 18.6

Toilet 1 0.8 1.18 0.944

Toilet 2 0.8 1.18 0.944

Toilet 3 0.8 1.18 0.944

Total 106.8015 340.05 31.41

Window to Wall ratio is below maximum measure of 60%.

The SHGC of window is calculated –

• The SHGC is affected by material properties – SHGC of 0.8 is used for single glazed

windows.

• Shading reduces the SHGC of the window assembly. Designed shading is considered.

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SHGC CALCULATION

Source: Shading Equivalent Factor Calculation, ECBC 2017

Shading Equivalent Factor (𝑺𝑬𝑭) = (𝐶3×𝑃𝐹^3)+ (𝐶2

×𝑃𝐹^2)+(𝐶1× 𝑃𝐹)+𝐶0

Table – Calculation of Equivalent and Maximum allowable SHGC after shading with various overhang sizes

Projection Factor (PF) = Overhand Depth / Window Height

ApaceOrienta

tionC3 C2 C1 C0

Horizontal

Shading

Dimensions

in m

Proje

ction

factor

- PF

SEF =

(C3XPF3)+(C2

XPF2)+(C1XP

F)+C0

Default

SHGC of

single

glazed glass

(without

shading)

Equivalent

SHGC of

single

glazed

glass (with

shading)

ECBC

recomme

nded

SHGC

Living

Hall

South

East

-

0.9

3 1.370.760.990.62 2.25 0.28 1.28 0.8 0.62 0.45

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Equivalent SHGC

Source: Shading Equivalent Factor Calculation, ECBC 2017

Table – Calculation of Equivalent and Maximum allowable SHGC after shading with various overhang sizes

Floor

Nomenclat

ure of

space

Type of

Spaces

(Air

conditione

d / non air

conditione

d)

Orientatio

n of

window

Window

Length in

m

Windo

w

height

in m

C3 C2 C1 C0Horizontal Shading Dimensions

in m

Projecti

on

factor -

PF

SEF =

(C3XPF3)+(C2XPF2

)+(C1XPF)+C0

Default SHGC of

single glazed

glass (without

shading)

Equivalent

SHGC of single

glazed glass

(with shading)

1st floor

Living HallConditione

dSouth East

12.652.25

-0.93 1.37 0.76 0.99 0.62 2.25 0.28 0.28 1.28 0.8 0.62

Dining HallConditione

dSouth East

12.732.4

-0.93 1.37 0.76 0.99 0.87 2.65 0.33 0.33 1.35 0.8 0.59

BedroomConditione

dNorth East

9.572.4

2.19-3.78 2.62 0.72

0.96 2.4 0.4 0.40 1.30 0.8 0.61

RoomConditione

dNorth East

8.532.4

-0.02-0.1 0.43 0.99

0.45 2.4 0.19 0.19 1.07 0.8 0.75

RoomConditione

d

North

West 8.532.4

1.52 -2.51 2.3 0.76 0.45 2.4 0.19 0.19 1.11 0.8 0.72

Guest

Room

Conditione

d

South

west 4.872.25

-4.09 8.14 -0.73 1.32 0.45 2.25 0.20 0.36 1.94 0.8 0.41

KitchenUncondition

edNorth East

22.4

-0.03-0.23 1.09 0.99

1.05 2.85 0.37 0.33 1.33 0.8 0.60

2nd floor

Bedroom-1Conditione

dSouth East 9.57 2.4

-0.93 1.37 0.76 0.99 0.54 2.7 0.20 0.20 1.19 0.8 0.67

Bedroom-2Conditione

dNorth East 9.72 2.4

2.19-3.78 2.62 0.72

0.35 2.7 0.13 0.13 1.00 0.8 0.80

RoomConditione

d

North

West 6.87 2.25

2.19-3.78 2.62 0.72

0.45 2.25 0.2 0.20 1.11 0.8 0.72

Master

Bedroom

Conditione

dSouth East 9.84 2.4 2.67 -4.99 5.68 0.32 0.8

2.4 0.33 0.79 3.01 0.8 0.27

Stilt Level

Bedroom-1Conditione

dSouth East 7.18 2.4

2.19-3.78 2.62 0.72

1.35 2.85 0.47 0.47 1.35 0.8 0.59

Bedroom-2Conditione

dNorth East 7.18 2.4

-0.93 1.37 0.76 0.99 1.35 2.85 0.47 0.47 1.56 0.8 0.51

Media

Room

Conditione

dSouth

west 8.36 2.4

-1.01 1.91 0.24 1.12 7.02 2.4 2.93 2.93 -7.11 0.8 -0.11

Windows do not meet the SHGC requirement of 0.45 using single glazed glass with existing shading.

Floor Nomenclature of space100% Shading from

April to September

Rate of shading

Bad/Avr/Good

Stilt Level

Bedroom-1 NO Good

Bedroom-2 YES Good

Media Room YES Good

1st floor

Living Hall NO Good

Dining Hall NO Good

Bedroom NO Avr

Room NO Avr

Room NO Bad

Guest Room NO Bad

Kitchen YES Good

2nd Floor floor

Bedroom-1 NO Average

Bedroom-2 NO Bad

Room NO Good

Family Room NO Bad

Master Bedroom NO Bad

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SHADING ANALYSIS

Windows are not shaded for 100% of the time from 10AM – 3PM from April to September

29

Stilt Floor – Media Room

Source: http://susdesign.com/overhang_annual/

Nomenclature

of spaceType of Space

Orientation

of windowRemark

Media Room Conditioned North East Good shading

Horizontal Overhang

30

Stilt Floor – Bedroom 1


Nomenclature


Orientation

of windowRemark

Bedroom 1 Conditioned North East Good shading

Horizontal Overhang

31

Stilt Floor – Bedroom 2


Nomenclature


Orientation

of windowRemark

Bedroom 2 Conditioned North East Good shading

Horizontal Overhang

32

First Floor – Living Hall


Horizontal Overhang

Nomenclature

of spaceType of Spaces

Orientation

of windowRemark

Living Hall Conditioned South East Good shading

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First Floor – Dining Hall


Nomenclature


Orientation

of windowRemark

Dining Hall Conditioned South East Good shading

Horizontal Overhang

34

First Floor - Bedroom


Nomenclature


Orientation

of windowRemark

Bedroom Conditioned North East Average

shading

Horizontal Overhang

35

First Floor -Kitchen


Nomenclature


Orientation

of windowRemark

Kitchen Conditioned North East Average

shading

Horizontal Overhang Note: Kitchen area does not have

projection. However, deck of 2nd floor

will act as the shading device

36

First Floor - Room


Nomenclature


Orientation

of windowRemark

Room Conditioned North EastAverage

shading

Horizontal Overhang

37

First Floor – Room


Nomenclature


Orientation

of windowRemark

Room Conditioned North West Bad shading

Horizontal Overhang

38

First Floor – Guest Room


Nomenclature


Orientation

of windowRemark

Guest Room Conditioned South West Bad shading

Horizontal Overhang

39

Second Floor – Master Bedroom


Nomenclature


Orientation

of windowRemark

Master

BedroomConditioned South East Bad shading

Horizontal Overhang

40

Second Floor – Bedroom 1


Nomenclature


Orientation

of windowRemark

Bedroom 1 Conditioned South East Average

shading

Horizontal Overhang

41

Second Floor – Bedroom 2


Nomenclature


Orientation

of windowRemark

Bedroom 2 Conditioned North East Bad shading

Horizontal Overhang

42

Second Floor – Family Room


Nomenclature


Orientation

of windowRemark

Family Room Conditioned NorthEast Bad shading

Horizontal Overhang

43

Second Floor - Room


Nomenclature


Orientation

of windowRemark

Room Conditioned North West Good shading

Horizontal Overhang

44

DOUBLE GLAZED WINDOWS• Recommendation:

o Replace single glazed windows with double glazed units

• Benefits:

o Reduce the U value of window

o Reduce solar heat gain

• Material Selection:

o Select on the basis of U factor < 3 W/m2K, SHGC <0.45 and VLT>0.27

Note: 1. Considering the designed projection and SHGC for single glass, Griha requirement is not meeting. Therefore, double glazing window is suggested.

Manufacturer SeriesWith Shading (0.5m)

U ValueSHGC VLT

Baseline Window Single Glazing 0.68 0.65 5.6 W/m2K

Saint Gobain*

Sparkling Ice

ST 167Double Glazing 0.55 0.59 2.8 W/m2K

Table: Sample calculation of reduction in thermal properties of window assembly on application of Double Glazed Unit

Source: Shading Equivalent Factor Calculation, ECBC 2017* Performance Sheet Saint Gobain

45

SUMMARY: WINDOW STRATEGY

Recommendation Construction (Outer to Inner) Remarks

ShadingProvide uniform depth shading where

possible

Ensure full window is uniformly

shaded

Double glazed

windows

Sparkling Ice – Antelio Plus

ST 160

6 mm Coated Glass (coatingface 2) – 12 mm

air gap – 6 mm clear glass

Double glass is recommended

as curved windows are

designed facing almost in all

directions

• Recommendation:

o Apply insulation on walls

• Benefits:

o Reduce solar heat transfer across walls


o Thermal Resistance (R) of insulation material > 2.10 m2K/W (ECBC recommended)

o Maximum U-value of assembly < 0.40 W/m2k (ECBC Recommended)

o Take into consideration the effects of weather changes on material properties

46

WALL INSULATION

Construction Construction Details (From outer to inner) U factor of assembly

Internal Wall Insulation

Cement Plaster (12mm) + Brick (115mm) + Glasswool (100mm) + Cement Plaster (12mm) 0.4 W/m2K

Cement Plaster (12mm) + Brick (230mm) + Glasswool (100mm) + Cement Plaster (12mm) 0.4 W.m2K

Cement Plaster (12mm) + Brick (115mm) + EPS (75mm) + Cement Plaster (12mm) 0.4 W/m2K

Cement Plaster (12mm) + Brick (230mm) + EPS (75mm) + Cement Plaster (12mm) 0.4 W/m2K

Cement Plaster (12mm) + AAC block (200mm) + Glasswool (50mm) + Cement Plaster (12mm) 0.3 W/m2K

Cement Plaster (12mm) + AAC block (200mm) + EPS (50mm) + Cement Plaster (12mm) 0.4 W/m2K

External Wall Insulation

Exterior Thermal Insulation and Composite Systems (ETICS) Brick (115mm) + EPS (75mm) + Mortar (10mm)

0.4 W/m2K

Exterior Thermal Insulation and Composite Systems (ETICS)Brick (230mm) + EPS (75mm) + Mortar (10mm)

0.4 W/m2K

Table – Rigid and fibrous wall insulation material performance and cost comparison

Source: CARBSE – Roof and Wall assembly U-factor Calculator

Note: External wall insulation with only fiberglass or EPS isn’t suggested as they wither with weather

47

Proposed Case for External Wall with Internal Insulation

48

ETICS offers better weather proofing. It reduces the temperature fluctuation that leads to crack formation in walls. Moreover, the insulation boards are made up of hydrophobic polymer which repels water and moisture.

Proposed Case for External Wall with External Insulation

ETICS: Exterior Thermal Insulation and Composite Systems

49

Summary of Wall Insulation Recommendation

Entity Strategy Assembly

U value

Layers

External Wall

Insulation

Exterior Thermal Insulation and

Composite Systems (ETICS)

Cement Plaster (18mm) + AAC (150mm)

+ EPS (50mm) + Cement Plaster (15mm)

0.4 W/m2K

• Recommendation:

o Apply high Solar Reflective Index (SRI) or high albedo

coatings on exterior wall

• Benefits:

o Reduce urban heat island effect

o Reduce internal solar heat gain


o SRI is measured on a scale of 0 to 100. Select materials

with SRI max 100*

o Paints with higher SRI (>100) can be too bright for eyes.

50

HEAT REFLECTIVE PAINT ON EXTERNAL WALL

Table - Examples of heat reflective paint and coatings manufacturers (not exhaustive list)

Source: BEE Cool Roof Manual, GRIHA directory on building materials and service providers

Cool Roof

Material

Manufacturer Product Specification SRI ApproxCost

(INR/ft2)

High Albedo

(Reflectance)

Paints

Dolphin Floats Pvt Ltd, India Modified acrylis waterproofing coatings

[Seal-n-Cool]100 15

Sun Sheetal High Albedo Paint 108 8

Star Shield Technologies Star Cool Series 130 13.5

Indian Insulation and

Engineering

Cool Roof122 30

* SRI value is recommended as per the ECBC 2017. It is required to look for paint having low emitance

51

SRI value of different wall colors

SRI-70

SRI-95

SRI-75

SRI-80

SRI-89

SRI-81

SRI-51

SRI-48

SRI-53

SRI-18

SRI-45

SRI-42

SRI-71

SRI-47

SRI-45

SRI-22

SRI-70

SRI-92

SRI-70

• Recommendation:

o Use light coloured paints in interior wall

surface

• Benefits:

o Increase internal dispersion of natural light

o Reduce the need of artificial lights


o Darkest black has Light Reflectance Value

(LRV) – 5% (or 0.05) and whitest white has LRV

– 85% (or 0.85)

o Minimum LRV of interior colour should be 50%

52

LIGHT INTERIOR PAINT ON INTERNAL WALL

Low LRV interior paint

High LRV interior paint

Source: http://thelandofcolor.com/lrv-light-reflectance-value-of-paint-colors/

53

SUMMARY: WALL STRATEGY

Sr. No. RecommendationConstruction

(Outer to Inner)Remarks

1

ETICS: Exterior

Thermal Insulation

and Composite

Systems

Exterior Thermal

Insulation and Composite

Systems (ETICS)

1. It is an external insulation with better weather proofing

properties than conventional wall insulation

2. 20-25 years of life

3. Cost is similar to conventional wall insulation

4. Most effective when external and internal temperature

difference is high

5. Doesn’t required additional locating of heat reflective paint

2

Albedo Paint on

External Wall +

Internal Wall

Insulation + Light

Interior Paint

Exterior Wall Paint (SRI

70-100) +

Cement Plaster (18mm) +

AAC (150mm) + EPS

(50mm) + Cement Plaster

(15mm)

1. Incident solar heat is firstly reflected from the surface.

Albedo paints will help reflect the incident solar heat. Paints

with high SRI (>100) can be too bright to eyes. Any light

color shade will be helpful in reducing the solar heat gain.

2. Absorbed heat will be blocked by the insulation from entering

the building. Rigid board insulation preferable to fibrous

insulation as lesser thickness is required and is better for

water resistance.

3. High LRV interior paint will help transmit the daylight better

in the room and reduce the requirement of artificial lights.

However, it will not be helpful in dealing with solar heat gain.

3

Albedo Paint on

External Wall +

Internal Wall

Insulation + Light

interior paints

Cement Plaster (15mm) +

AAC (115mm) + Rock

wool (75mm) + Cement

Plaster (15mm) + Internal

paint

• Recommendation:

o Apply insulation to roof

• Benefits:

o Reduce solar heat transfer across roof


o Thermal Resistance of insulation(R) > 2.1 m2K/W (ECBC recommended)

o Maximum U-value of assembly < 0.4 W/m2k (ECBC Recommended)

o Effect of weather changes on material properties

o Flexibility of the material – since it is a curved roof

54

ROOF INSULATION

Table – Rigid and fibrous roof insulation material performance and cost comparison

Source: CARBSE – Roof and Wall assembly U-factor Calculator

Entity- Construction DetailsMaximum U factor

of assembly

Approximate

Cost

Baseline

Cement plaster (15mm)+Concrete Block-25/50 (150mm)+Brick

Burnt Red clay (150mm)+ Cement plaster (20mm)+

Ceramic(20mm)

2.1 W/m2K -

Fibrous

Insulation


Burnt Red clay (150mm)+ Rockwool (75)+Cement plaster

(20mm)+ Ceramic(20mm)

0.4 W/m2K -

Rigid

Insulation


Burnt Red clay (150mm)+ EPC (75)+Cement plaster (20mm)+

Ceramic(20mm)

0.4 W/m2K 1120 INR/m2

55

PROPOSED ROOF ASSEMBLY_OPTION 1

56

PROPOSED ROOF ASSEMBLY_OPTION 2

57

RADIANT BARRIER• Recommendation:

o Install radiant barrier (with inbuilt insulation) under roof

• Benefits:

o Reflect incident solar radiation

o Reduce solar heat gain by roof


o Temperature difference obtained for given thickness. Generally 4mm thick material is sufficient.

o There isn’t any U value for Radiant Barrier

o Air bubble reflector material is preferred for Non RCC roof structure whereas Chemically Crosslinked Polyethylene

foam based radiant barrier is recommended for RCC roof structures

Recommended

ManufacturersSeries Material Thickness

Emissivit

yReflectivity

Temperature

Diff obtained

Approximate

Cost

Goldcoin

IndustriesTHERMbarrier

Chemically Crosslinked

Polyethylene Foam (XLPE

Materials) + single side Aluminum

lamination

8-10 mm - - 10-12°C 148 INR/m2

Goldcoin

IndustriesTHERMbarrier

Chemically Crosslinked

Polyethylene Foam (XLPE

Materials) + both side Aluminum

lamination

8-10 mm - - 10-12°C 184 INR/m2

Goldcoin

IndustriesTHERMbarrier Air Bubble Reflector 8-10 mm - 0.96-0.99 8-9°C 125 INR/m2

Supreme

IndustriesINSUreflector

Polyethylene air bubble film +

aluminum foil lamination4 mm 0.01-0.04 0.96-0.99 5°C 105 INR/m2

Supreme

IndustriesINSUreflector

Polyethylene air bubble film +

aluminum foil lamination8 mm 0.01-0.04 0.96-0.99 6°C 115 INR/m2

Table – Radiant barrier material performance and cost comparison

Note: Any radiant barrier is suitable for the application. Single sided radiant barriers are preferred with structure cooling with reflective surface facing open area

58

Features of Radiant Barrier:

1. It doesn’t require additional layer of insulating material

(Rockwool, EPS etc.)

2. Minimum 0.5 inch gap is recommended between

ceiling and radiant barrier

3. Reflective surface to be faced upwards – towards

ceiling as it will reflect the radiation from ceiling

4. It is held in position with help of criss cross wire

• Recommendation:

o Apply paints or tiles with high reflectance and thermal emittance on roof surface

• Benefits:




o As per ECBC mandate for cool roofs,

▪ Material should have minimum solar reflectance of 0.6 and

▪ Minimum solar emittance of 0.9

▪ Hence materials selected should have SRI ≥ 72 (calculated using http://HeatIsland.LBL.gov)

59

COOL ROOF FINISH

Note: Solar Reflective Index (SRI) is measured on a scale of 0 (reflectance-0.05, emittance-0.9) to 100 (reflectance-0.80, emittance-0.90).

It is possible for some materials to have SRI >100 as it is interpolated based on maximum temperature of the material

ECBC Prescribed Roof Properties Roof SlopeMinimum Solar

Reflectance

Minimum

Solar

Emittance

Equivalent

SRI

All roofs that are not covered by solar photovoltaics, or solar

hot water, or any other renewable energy system, or utilities

and services that render it unsuitable for the purpose, shall

be either cool roofs or vegetated roofs.

<20 degrees 0.60 0.90 72

Table – Rigid and fibrous wall insulation material performance and cost comparison

60

Solar Reflective Index (SRI) for typical roofing material

Source: BEE Cool Roof Design Manual

61

Table - List of cool roof material type and their manufacturers

Entity Manufacturer Product Specification SRI

Approx.

Cost

(INR/ft2)

Remarks

Cool Roof

Tiles – for

flat roof

Ishaan Industries

Thermatek Heat Resistant

Ceramic Tile104 -

Thermatek Heat Resistant

Terrace Tile90.7 -

Thermatek Cool Mortar 92 -

Applicable for all

masonry work, can be

combined with tiles for

better results

Insulla Insulla Cool Roof Tile 96 -

China Mosaic 70-90 - Depends on type of tile

High Albedo

Paints – for

curved

sheet

Thermoshield India Pvt Ltd High Albedo Roof Coating 104 35

Excel Coatings Excel CoolCoat 122 14Reflective + Nano

Insulative Technology

Dolphin Floats Pvt Ltd,

India

Modified acrylis waterproofing

coatings [Seal-n-Cool]100 15

Ishaan IndustriesThermatek Heat Reflective

Paint90.6 40

Sun Sheetal High Albedo Paint 108 8

Star Shield Technologies Star Cool Series 130 14

Indian Insulation and

EngineeringCoolRoof 122 30

Source: GRIHA directory on building materials and service providers

High Albedo Paint on Roof

Cool Roof Tiles – China Mosaic

62

• Recommendation:

o Install collapsible radiant barrier on roof

• Benefits:




63

EXTERNAL COLLAPSIBLE SHADING WITH RADIANT BARRIER

Recommended

ManufacturersSeries Material

Conductivity

(W/m2K)

Density

(kg/m3)Cost

Goldcoin Industires THERMbarrierChemically Crosslinked Polyethylene

Foam (XLPE Materials)0.0383 30-36 125 INR/m2

Supreme Industries INSUboard Extruded Polystyrene 0.028 32-35 385 INR/m2

64

STRUCTURE COOLING ON ROOF

• Recommendation:

o Install structure cooling pipes in roof

o Install structure cooling pipes in balconies and deck + upto 1m offset from balconies

• Benefits:

o Directly drains solar heat load from structure

o Will give approximate energy savings of 18%

Medium Thermal Conductivity (W/mK) Specific Heat Capacity (W/kg.k) Density (kg/m3)

Air 0.03 1.004 1.225

Water 0.6 4.18 1000

Medium Cooling Capacity Flowrate Required Power Required

Air 100 TR ~ 40,000 cfm 22 kW

Water 100 TR ~32 cfm 3.7 kW

Table: Comparison of physical properties of air and water

Table: Comparison of power and flow rate requirement for air and water as medium

65

Structure Cooling on Veer Samarak Auditorium Roof

Step 1: Pump in the insulated,partitioned tank circulates water.

Step 2: Water picks up heat from theslab

Step 3: Returning water is cooled by afan cooled heat pipe on its way to thetank.

Step 4: Returns to the same tank,closing the loop

Step 5: At night, radiative panel lowerstank temperature by direct radiationto the sky. Cooled water ready for thenext day’s cycle.

66

SUMMARY: ROOF STRATEGY

Sr.

No.

Recommenda

tionConstruction (Outer to Inner) Remarks

1

Cool roof +

Insulation

(Rockwool)

+ Radiant

barrier

High Albedo Paint Exterior Coaling +

Cement plaster (15mm)+Concrete Block-

25/50 (150mm)+Brick Burnt Red clay

(150mm)+ Rockwool (75)+Cement plaster

(20mm)+ Ceramic(20mm)+aluminum foil

lamination (0.009mm) + Attic/Interior

1. Albedo paint to be applied on exterior surface of plaster

2. Cool roof materials – china mosaic tiles, white tiles etc. to be applied on flat roof surface

3. Insulating layer will further block the conductive and convective solar heat gain

4. Radiant barrier material will block the radiant heat gain2

Cool roof +

Insulation

(EPS) +

Radiant barrier

High Albedo Paint Exterior Coaling

+Cement plaster (15mm)+Concrete Block-


(150mm)+ EPC (75)+Cement plaster

(20mm)+ Ceramic(20mm) + aluminum foil


3

Cool roof +

Structural

Cooling of roof

High Albedo Paint Exterior Coaling

+Cement plaster (15mm)+Concrete Block-


(150mm)+ EPC (75)+Cement plaster

(20mm)+ Ceramic(20mm) + aluminum foil


1. Albedo paint to be applied on exterior surface of plaster

2. Cool roof materials – china mosaic tiles, white tiles etc. to be applied on flat roof surface

3. Structural cooling will reduce the heat gain

HVAC STRATEGIES

67

68

TWO TIER COOLING• Recommendation:

o Install a two tiered cooling system in the bungalow

• System Details :

o Install energy efficient DOAS system – DOAS system dehumidifies air and provides fresh air– this handles the fresh air and room latent heat (high humidity in bungalow during monsoon months)

• The dehumidifier provides a mixture of fresh air and room air through outlets near each occupant (air vents provided near seating areas)

• This air is cooled to ~24C

o Install conventional AC system OR IEC system to handle the sensible heat load (to be confirmed)

• The room design dry bulb temperature can be raised to 26-27C – making it more energy efficient

LLDC Auditorium with louvres for natural light and under-seat air vents

• Benefits:

o System takes care of Internal Sensible Load , Internal Latent Load and Fresh Air Requirements

• In addition to solar load, we have sensible, latent and fresh air loads

• In a conventional system, we combine all the loads and design a single unit with adequate cooling capacity, that will supply sufficient air quantity

• However, in a two-tier system each load is handled separately making it possible to save energy

o Enhanced comfort and improved indoor air quality

• Fresh air is provided at point of use – near occupants

• The air from dehumidifier provided near the occupants is cool, dry and rich in oxygen creating a very healthy breathing zone

o Energy savings of upto 30%

• Only dehumidifier can be switched on when the auditorium is not filled to full capacity

• The tonnage of the conventional AC is reduced substantially

• As only a small part of the circulating air has to be chilled, the energy needed for dehumidification is much less

• Supply outlet air temperature can be raised (21C instead of 12C) as there is less difference between source (air duct) and sink (human). This results in almost 40% savings for the same sensible load.

69* Tonnage and system details of system can be evaluated after architect discussion.

ENVELOPE DESIGN ANALYSIS

70

INTENT: To Deliver Visual Comfort

• BENCHMARK:

o Achieve minimum glazing factor of 1 in Bedroom and 2 in Study/Kitchen for 95% of regularly occupied spaces (95% of total house living area) [source: IGBC Green Homes]

o Glazing Factor dependent on floor area, window area and window VLT

o Window openings with angle of obstruction greater than 70 are not considered for daylighting calculations

• ANALYSIS:

o Living Room, Dining Hall, Bedrooms, Kitchen, Study/Office Room are considered to be regularly occupied areas

o Windows in Study/Office Room , Guest Room on 1st Floor and Children’s Room on 2nd Floor are not considered for daylighting calculations as windows are blocked by stone wall

o Required glazing factor is met in 83% of regularly occupied spaces – using single glazed window (VLT – 0.65) as well as double glazed window (VLT – 0.59)

• RECOMMENDATION:

o Convert Family Room on 2nd Floor to Children’s Room

o Required glazing factor will be met in 90% of regularly occupied spaces – using single glazed window (VLT – 0.65) as well as double glazed window (VLT – 0.59)

o Vision windows to have lower VLT (~65%) to reduce glare

71

DAYLIGHTING

72

Floors Name of SpacesRqd. Glazing

FactorBase Case Proposed Case

Floor Area (sq.m)

Floor Area MET (sq.m)

1st floor

Living Hall W1 1 5.35 4.85 51.75 51.75

Dining Hall W1 1 10.79 9.80 28.04 28.04

Bedroom W1 1 12.48 11.33 18.22 18.22

Study/Office Room 2 0.00 0.00 9.31 0

Guest Room 1 0.00 0.00 15.51 0

Kitchen 2 3.52 3.19 13.30 13.30

2nd floor

Bedroom1 1 12.48 11.33 18.23 18.23

Bedroom2 1 12.48 11.33 18.22 18.22

Room / Family Room 1 0.00 8.88 14.99 14.99

Master Bedroom W3 1 8.90 8.08 27.63 27.63

Stilt LevelBedroom1 W1 1 12.48 11.32 18.23 18.23

Bedroom2 W2 1 12.48 11.33 18.22 18.22

TOTAL AREA 251.64 226.82

% TOTAL AREA MET 90%

73

SHADING DESIGNINTENT: To Deliver Thermal Comfort (without air-conditioning)

• BENCHMARK:

o The WWR and SRR to not exceed 60% and 5% respectively AND

o All windows (AC and Non-AC) to be completely shaded from 10AM to 3PM from 1st

April to 30th September OR

o All windows to meet effective SHGC requirements as per ECBC (~0.40 for Moderate

climate) [source: GRIHA v5]

• ANALYSIS:

o WWR for existing design is 40%

o All windows are not completely shaded for specified duration

o Windows facing Southeast, South and South West have worst performance

o Windows in Northeast, North and Northwest meet shading requirements

74

SHADING REQUIREMENTS NOT MET

Second Floor: Bedroom Facing Pool

SHADING REQUIREMENTS MET

Second Floor: Family Room

75

• RECOMMENDATION:

o Chajja depth increased or window length decreased such that:

• All bedrooms, living room and dining room to have minimum depth of 0.60m to 0.75m

• Shading can be added to windows in passage area to prevent overheating of common

space (appropriate blinds can be added in case chajja does not meet aesthetic

requirements)

o Window Glazing SHGC to be minimum 0.55 except for

• Windows facing Northeast, North, Northwest (SHGC 0.65)

• Stilt Level Windows

Average Effective SHGC

Glazing SHGC 0.80

Glazing SHGC 0.65

Glazing SHGC 0.60

Glazing SHGC 0.55

N,NE,NW Glazing SHGC 0.65

S,SE, SW Glazing SHGC 0.55

First Floor 0.64 0.54 0.49 0.46 0.48

Second Floor 0.71 0.57 0.53 0.49 0.52

Stilt Level 0.54 0.44 0.40 0.37 0.44

76

SHGC 0.65

SHGC 0.65

SHGC 0.55

SGHC 0.55

SHGC 0.55

77

NATURAL VENTILATIONINTENT: To Aid Thermal Cooling (without air-conditioning)

• BENCHMARK:

o Window to Floor Area Ratio (WFRop) to be minimum 12.5% in Temperate/Moderate

climate per unit[source: ECBC – Residential]

• ANALYSIS:

o WFRop meets requirements for existing design

o 2/3rd of window considered openable for all rooms (except service areas)

– Predominant winds are from South-West during monsoon

• RECOMMENDATION:

o Maintain existing window to floor area ratio

o Windows with varying pane sizes can help ventilation - different panes can be

opened at different times depending on room usage, wind direction, wind

temperature, rain direction

78

As per the WFRop calculation, every room has adequate ventilation.

FloorNomenclature of

spaceFloor Area (sq.m)

Window Area (sq.m)

Operable Area (sq.m)

Window to Floor Ratio per room

WFRop per Floor

1st Floor

Living Hall 51.75 21.29 14.26 27.56

42.31

Dining Hall 28.04 23.28 15.60 55.63

Bedroom 18.22 17.50 11.72 64.34

Study/Office Room 9.31 15.72 10.53 113.16

Guest Room 15.51 8.213 5.50 35.47

Kitchen 13.30 3.6 2.41 18.14

Dry Yard 4.04 2.18 1.46 36.18

Service toilet 2.49 0.71 0.35 14.20

Attached toilet 4.35 0.71 0.35 8.14

Total 147.01 93.19 62.20

2nd Floor

Bedroom-1 18.23 17.50 11.72 64.31

43.08

Bedroom-2 18.22 17.50 11.72 64.34

Room 18.80 11.59 7.76 41.30

Master Bedroom 27.63 18.91 12.67 45.87

Toilet 1 13.69 0.71 0.35 2.59

Toilet 2 4.55 0.71 0.35 7.78

Toilet 3 3.225 0.71 0.35 10.98

Total 104.33 81.49 44.94

Stilt LevelBedroom-1 18.23 17.496 11.72 64.31

64.32Bedroom-2 18.22 17.496 11.72 64.34

Total 36.45 75.22 23.44

WINDOW TO FLOOR AREA RATIO ANALYSIS

79

Combination:

Vision Window Fixed

Vision Window Openable

Floor Vent Window

Combination:

Vision Window Fixed


Ceiling Vent Window

Combination:

Vision Window Fixed


Floor Vent Window

VARYING WINDOW PANE DESIGNS

80

Annual Wind Rose Summer Wind Rose Winter Wind Rose

• Annualy, gentle to moderate breeze

are predominant

• Wind blows from north-west and

south-west direction (52% of all

hourly wind directions)

• During summer time, maximum

gentle to moderate breeze come

from west and south - west direction

(76% of all hourly summer wind

direction)

• Wind temperatures are at ~25C that

can help cooling

• During winter time, wind blows from

east and west

• Wind temperatures are at ~20C to

25C

• Wind is cooler from North-East/East

compared to Northwest/West

Green Building Studio

https://gbs.autodesk.com/GBS/Weather?ProjectId=EB6%2f4MhW9bI%3d

WIND ROSE ANALYSIS

ENVELOPE PERFORMANCE ANALYSIS

81

82

RESIDENTIAL ENVELOPE HEAT TRANSMITTANCE (RETV )

INTENT: To Reduce Heat Gain from Building Envelope

To Aid Thermal Comfort (without air-conditioning)

• BENCHMARK:

o RETV to be minimum 15 w/sq.m in Temperate/Moderate climate [source: ECBC – Residential]

o RETV is dependent on

o WWR

o Wall U-Value

o Glazing U-Value

o Window Frame U-Value

o Glazing SHGC

o Shading Design

o Meeting RETV benchmark results in ~20% energy savings compared to BAU

• ANALYSIS:

o Base case has RETV of 24.84 W/sq.m - Does NOT meet RETV benchmark

83

Base Case

Base Case + Combined SGU_DGU Windows

Base Case + DGU Windows

Base Case + Wall Insulation1

(0.55)

Base Case + Wall Insulation2

(0.40)

Proposed Case: SGU_DGU Windows +

Wall Insulation (0.55)


Wall Insulation (0.40)


Wall Insulation (0.40) +

WWR (-10%)

First Floor

Parameters Value Value Value Value Value Value Value Value

WWR 0.41 0.41 0.41 0.41 0.41 0.41 0.41 0.37

Uopaque W/m²K 2.33 2.33 2.33 0.88 0.74 0.88 0.74 0.72

Unon-opaque W/m²K 5.56 2.32 0.55 5.56 5.56 2.32 2.32 2.32

SHGCeq 0.54 0.48 0.46 0.54 0.54 0.48 0.48 0.48

RETV Value W/m2 26.88 23.68 22.34 22.38 21.94 19.18 18.74 17.21

Second Floor

Uopaque W/m²K 2.27 2.27 2.27 0.80 0.65 0.80 0.65 0.65

Unon-opaque W/m²K 5.56 1.75 0.55 5.56 5.56 1.75 1.75 1.75

SHGCeq 0.57 0.52 0.49 0.57 0.57 0.52 0.52 0.52

RETV Value W/m2 27.00 24.03 22.65 22.28 21.82 19.31 18.85 18.20

Stilt Floor

WWR 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32

Uopaque W/m²K 2.22 2.22 2.22 0.73 0.58 0.73 0.58 0.58

Unon-opaque W/m²K 5.56 5.61 0.55 5.56 5.56 5.61 5.61 5.61

SHGCeq 0.44 0.44 0.37 0.44 0.44 0.44 0.44 0.44

RETV Value W/m2 20.64 20.65 17.39 15.24 14.72 15.26 14.73 14.73

Average RETV 24.84 22.79 20.80 19.97 19.49 17.91 17.44 16.71

84

PROPOSED BUILDING BENCHMARKS

PARAMETERS SPECIFICATION BASE CASE PROPOSED CASE PROPOSED ASSEMBLY

Roof


2.1 W/m2.k 0.4 W/m2.kCement Plaster (15mm)+Concrete 150mm)+Brick Burnt Red Clay (150mm)+ EPS(75mm)+Cement Plaster (20mm)+ Ceramic (20mm)

Solar Reflectance Index NA 72 China Mosaic / High SRI Paint Finish

Window

Max WWR 40% 40% -


5.6 W/m2.kSGU: 5.6 W/m2.kDGU: 2.8 W/m2.k

In E,W,S

DGU with UPVC Frame:U-Value – 2.8 W/m2.KSHGC – 0.55VLT – 0.60

In N

SGU with UPVC Frame:U-Value – 5.6 W/m2.kSHGC – 0.65VLT – 0.65

Max SHGC Non-North(E, W, S)

0.65 0.55

Max SHGC North > 15N (N,NE,NW)

0.65 0.65

Minimum allowable VLT 0.65 0.65

Shading Design (minimum depth)

Varying Varying Provide chajja of min 0.60m on S, SE, SW

Opaque External Wall


2.9 W/m2.k 0.40 W/m2.kCement Plaster (18mm) + AAC (150mm) + EPS (75mm) + Cement Plaster (15mm)

• RECOMMENDATION:

o Improve wall and window specifications for RETV 17.44 W/sq.m

o Reduce WWR along with improved wall and window specifications for RETV 16.71 W/sq.m

o RETV Benchmark NOT MET in proposed cases without further design intervention

85

ECM CAPITAL COST

PARAMETERS AREA RATE AREA TOTAL COST

Roof 75mm EPS Insulation Rs. 660/ sq.m 186 sq.m Rs. 1,22,760

Window

SGU -Toughened Sparkling Ice Antelio

167 (St. Gobain)Rs. 105/ sq.ft 1465 sq.ft Rs. 1,53,825

DGUSparkling Ice Antelio 167 (St.

Gobain)Rs. 240/ sq.ft 1620 sq.ft Rs. 3,88,800

External Wall 75mm EPS Insulation Rs 660/ sq.m 450 sq.m Rs. 2,97,000

TOTAL COST Rs. 9,62,385

HEAT GAIN ANALYSIS

86

87

HEAT GAIN SUMMARY

Base Case Value Unit Value Unit

Stilt Floor54,167

Btu/hr4.5

TR

First Floor1,15,793

Btu/hr9.6

TR

Second Floor86,396

Btu/hr7.2

TR

Total 2,56,356 Btu/hr 21.4 TR

Proposed Case

Value Unit Value Unit

Stilt Floor38,822

Btu/hr3.2

TR

First Floor99,216

Btu/hr8.3

TR

Second Floor50,395

Btu/hr4.2

TR

Total 1,88,433 Btu/hr 15.7 TR

TOTAL HEAT GAIN REDUCTION: 26%

BASE CASE: 192 SFT/TR

PROPOSED CASE: 262 SFT/TR

ECBC – R BENCHMARKING

88

PARAMETERS SPECIFICATION PROPOSED CASE CRITERIA MET/NOT MET

RoofMaximum Assembly U-factor to be

1.2 W/m2.K0.4 W/m2.k MET

RETV Maximum RETV to be 15 W/sq.m

40% -

Window Glazing U Value:SGU: 5.6 W/m2.kDGU: 2.8 W/m2.k

NOT MET

Window Glazing SHGC: SGU: 0.65DGU: 0.55

Window Frame U Value: 5.6 W/m2.k

( UPVC Frames)

Wall Assembly U Value:0.40 W/m2.k

Shading Varying: Chajja min depth 0.60m on S, SE, SW

VLT Maximum VLT for WWR 40% 0.40 MET

WFRop Minimum WFRop of 12.5% 50% MET

89

** Analysis done as per draft ECBC-R. Performance evaluation can be redone on release of final ECBC-R in April 2018.

Summary of Approved Passive Design and

HVAC Measures

90

91

Element Strategy Implementation/ Co-Ordination

Responsibility

Roof Install Structure Cooling System on entire roof slab, entire

2nd floor slab and deck area of first floor slab. The system

will be added on top of the mother slab. Equipment details

will be finalised on appointment of vendor.

Architect, MEP Team, Structural

Consultant, Structure Cooling Team-

Design Stage

Roof finish with high SRI-72 material. Paints or tiles of

appropriate specifications can be used.

Architect - Material Selection Stage

Fenestrations Install double-glazed windows on all facades facing south,

south-west and south-east. This includes all bedrooms, living

room and dining area. Material specifications: (1) For

Frames: UPVC window (2) For Glazing: VLT - 60%, SHGC -

0.55, U-Value - 2.8 W/sq.m-K


Passive Design Strategies

92

Element Strategy Implementation/ Co-Ordination

Responsibility

Fenestrations Install single-glazed windows on all facades facing north,

north-east and north-west. This includes kitchen, office room,

guest bedroom, children's room, family room, media room.

Material specifications: (1) For Frames: UPVC window (2) For

Glazing: VLT - 65%, SHGC - 0.65, U-Value - 5.6 W/sq.mK


Provide chajja of minimum 0.6m on South, South-East and

South-West Facade

Architect - Design Stage

Maintain Window:Wall Ratio (WWR) of 40% or reduce existing

WWR

Architect- Design Stage

Ensure 2/3rd of fenestration area in living spaces (living room,

bedroom, dining room etc) is openable by installing 3-4

shutter windows

Architect - Design Stage, Product

Selection Stage

External Wall Use AAC bocks for external walls with U-Value: 0.67

W/sq.mK

Architect, Structural Consultant - Design,

Material Selection Stage

External wall finish with high SRI-72 material. Paints or tiles of

appropriate specifications can be used.


93

HVAC System Tonnage Requirements

Cooling Capacity and Dehumidify CFM Requirements

Cooling Capacity (Btu/hr) Cooling Capacity (TR) Dehumidify CFM

Stilt Floor 38,822 3 1,360

First Floor 99,216 8 3,077

Second Floor 50,395 4 1,871

Total 1,88,433 16 6,308

Type of HVAC System: Variable Refrigerant Volume (VRV) System

Manufacturer: Daikin

Max. Cooling Capacity: 16 TR

Refrigerant: R410 A*

Note: At the time of purchase we recommend to review the model number and whether a lower GWP

refrigerant , such as R32, has become available in India.

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