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)
5
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
13
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
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PRESCRIPTIVE BENCHMARKS
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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
Maximum Assembly U-factor (W/m2.K)
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
Maximum Assembly U-factor (W/m2.K)
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
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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
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Stilt Floor – Bedroom 1
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
Orientation
of windowRemark
Bedroom 1 Conditioned North East Good shading
Horizontal Overhang
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Stilt Floor – Bedroom 2
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
Orientation
of windowRemark
Bedroom 2 Conditioned North East Good shading
Horizontal Overhang
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First Floor – Living Hall
Source: http://susdesign.com/overhang_annual/
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
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Spaces
Orientation
of windowRemark
Dining Hall Conditioned South East Good shading
Horizontal Overhang
34
First Floor - Bedroom
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
Orientation
of windowRemark
Bedroom Conditioned North East Average
shading
Horizontal Overhang
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First Floor -Kitchen
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
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
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First Floor - Room
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Spaces
Orientation
of windowRemark
Room Conditioned North EastAverage
shading
Horizontal Overhang
37
First Floor – Room
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Spaces
Orientation
of windowRemark
Room Conditioned North West Bad shading
Horizontal Overhang
38
First Floor – Guest Room
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Spaces
Orientation
of windowRemark
Guest Room Conditioned South West Bad shading
Horizontal Overhang
39
Second Floor – Master Bedroom
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
Orientation
of windowRemark
Master
BedroomConditioned South East Bad shading
Horizontal Overhang
40
Second Floor – Bedroom 1
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
Orientation
of windowRemark
Bedroom 1 Conditioned South East Average
shading
Horizontal Overhang
41
Second Floor – Bedroom 2
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
Orientation
of windowRemark
Bedroom 2 Conditioned North East Bad shading
Horizontal Overhang
42
Second Floor – Family Room
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
Orientation
of windowRemark
Family Room Conditioned NorthEast Bad shading
Horizontal Overhang
43
Second Floor - Room
Source: http://susdesign.com/overhang_annual/
Nomenclature
of spaceType of Space
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
• Material Selection:
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
• Material Selection:
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
• Material Selection:
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
• Material Selection:
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
Cement plaster (15mm)+Concrete Block-25/50 (150mm)+Brick
Burnt Red clay (150mm)+ Rockwool (75)+Cement plaster
(20mm)+ Ceramic(20mm)
0.4 W/m2K -
Rigid
Insulation
Cement plaster (15mm)+Concrete Block-25/50 (150mm)+Brick
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
• Material Selection:
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 Reflect incident solar radiation
o Reduce solar heat gain by roof
• Material Selection:
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:
o Reflect incident solar radiation
o Reduce solar heat gain by roof
• Material Selection:
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-
25/50 (150mm)+Brick Burnt Red clay
(150mm)+ EPC (75)+Cement plaster
(20mm)+ Ceramic(20mm) + aluminum foil
lamination (0.009mm) + Attic/Interior
3
Cool roof +
Structural
Cooling of roof
High Albedo Paint Exterior Coaling
+Cement plaster (15mm)+Concrete Block-
25/50 (150mm)+Brick Burnt Red clay
(150mm)+ EPC (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. 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
Vision Window Openable
Ceiling Vent Window
Combination:
Vision Window Fixed
Vision Window Openable
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)
Proposed Case: SGU_DGU Windows +
Wall Insulation (0.40)
Proposed Case: SGU_DGU Windows +
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
Maximum Assembly U-factor (W/m2.K)
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% -
Maximum Assembly U-factor (W/m2.K)
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
Maximum Assembly U-factor (W/m2.K)
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
Architect - Material Selection Stage
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
Architect - Material Selection Stage
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.
Architect - Material Selection Stage
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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