GREEN RETROFITS
TO MAKE BUILDINGS ENERGY EFFICIENT
“THE COLOR OF GREEN IS WHITE”
Research Paper 2016-2017
GUIDE: SONALI ROY CHANDRA
Submitted byAMAN JOT SINGH
IV-A
Chapter 1
1.1 Introduction
1.2 Scope
1.3 Objectives
1.4 Methodology
1.5 Limitations
1.6 Research Questions
1.1 INTRODUCTION
 NEED FOR STUDY
In today’s time, the terms Green building, Green design and Energy conservation are
so important in designing buildings that for the sake of environment, one has to
design a building which is energy efficient. From the last 15-20 years architects of
the world are designing Green buildings in order to reduce the carbon footprint. The
major issue of the world today is the increase in carbon footprint. The building sector
consumes roughly 1/3rd of the final energy used in most countries and it absorbs an
even more significant share of electricity. In developing countries (such as India),
buildings account for 38% of the electricity consumed.
The green buildings are somewhat contributing to the reduction of carbon footprint.
But what about the other 90% buildings which are not green? How are those
buildings contributing in the reduction of carbon footprint? Prior to creating green
buildings, isn't it better to make the existing buildings green?
How can we reduce the energy consumption of existing buildings? Opportunities to
reduce energy use in an existing building differ markedly from those in the design of
new buildings. In the existing buildings most of the major determinants in the
physical aspect of the building are already. These aspects include the building
configuration and orientation, its materials and construction, its mechanical systems
and controls, and its specific location. Most of these are difficult if not impossible to
modify. But the design assumptions of the occupancy, space utilization and
environmental standards are subject to change over a period of time. Hence these
can be effectively controlled to increase the energy efficiency of the building. But
what is the solution to this problem?
TO RETROFIT MEANS TO MODIFY AN EXISTING BUILDING FOR ENERGY
EFFICIENCY
Retrofit measures are actions we can take to upgrade a building, enabling it to
respond positively to climate change. Reducing the property’s carbon footprint is one
of the key objectives of retrofit. Other important considerations include increasing the
comfort of the building for its occupants and reducing the incidence of fuel poverty –
that is, when heating a home adequately becomes unaffordable for the household.
But why is it important to retrofit? Is it the only solution to the problem? Is it cost
effective?
Many of the today’s multi-storey buildings were built prior to the recognition of what
we call now the energy crisis. They were designed and built during a time when
energy utilization was seldom even on a list of design constraints. The energy was
plentiful and more significantly inexpensive, relative to other designing and building
costs. The carefree days are past, but inefficient buildings remain as a legacy.
Thus these buildings consume energy beyond anyone’s definition of reasonable. To
be competitive in the world the owner user has to resort to less energy hungry way of
life of existence- he must retrofit!
1.2 SCOPE
In this research paper we will be talking about how a residential building can be
retrofitted to achieve the highest energy efficiency in that building. The scope will be
limited to the interventions of the building on the building envelop only i.e. the roof
and the façade. The scope of the materials chosen for study will be limited to the
analysis of their property to reflect sunlight. Though retrofitting deals with the wide
range of activities, this research paper will focus more on the architectural approach
on the retrofit strategy.
FIGURE: SCOPE OF STUDY
*The literature study will be based on non-residential buildings for defining only the types of retrofits as the case studies of
residential building is not available at the time of research.
1.3 OBJECTIVE
The objective of this study is to find to ways for making any residential building green
to an extent and to explore different techniques and materials for building envelop to
reduce energy consumption of the building. Facade and roof retrofit represents a
cost-effective alternative for improving the energy performance of a building. Part of
this goal is to explore the energy reductions of a building by the change of different
facade and roof materiality.
1.4 METHODOLOGY
Initially green retrofits will be understood as a whole concept with the basics of
retrofits and different types of retrofits used in building regardless of type of the use
of building to get the general idea of what exactly are green retrofits. The focus of the
study will then be shifted to Façade and Roof only followed by analysis and
conclusion based on the case study and the data acquired by literature study.
FIGURE: METHODOLOGY OF STUDY
A qualitative approach is used for the literature study because of the lack of data.
The literature study will focus on basics of retrofits and benefits of retrofits for any
existing building. Typologies of retrofits are studied in various buildings found in
various case studies. The focus will be shifted towards façade retrofits and roof
retrofits. The data of various retrofits will be acquired based on parameters of SRI,
applications, electricity consumed, cost. The literature of existing cases of retrofitted
buildings is part of the qualitative approach. It provides an idea of the “state of the
art” of façade and roof retrofit. After that, the particular case study will be the object
of simulations and quantitative analysis where those concepts derived from the
literature study will be applied. After that the survey will be done on residences for
identifying the issues related to the building and where the retrofit can be applied.
Through literature and case study best retrofit measures will then be stated in the
end of the paper.
1.5 LIMITATIONS OF THE STUDY
 The literature available on the topic was limited. Whatever was available were



just the examples of how it has been done up till now. Therefore, the opinions
and remarks expressed depend upon the discussion with the guide and other
people who were approached during the process.
This study does not analyse the works done in the field of GREEN RETROFITS
on the basis of structural stability.
Only a few materials and their process and applications could be studied in depth
in thus study. A lot more options are available which have not been discussed in
detail due to various constraints and obstacles faced during the course of writing
the research paper.
The study has been done mainly according to the context of Delhi and cannot be
applicable in exactly the same way, everywhere.
1.6 RESEARCH QUESTIONS
The main focus of the study will be to answer these questions:




What are the outcomes of the green retrofits used in the existing buildings?
Are green retrofits the solution for the energy efficiency of the buildings?
Can the same retrofits can be implemented to the residential sectors?
What measures can be taken to make the home more efficient in terms of energy
consumption?
Chapter 2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.10
What are green retrofits?
General Terminology
Benefits
Typologies
Façade retrofits
Roof retrofits
Solar reflective index (SRI)
Case study
Rating systems
CSE ANALYSIS OF DELHI'S POWER CONSUMPTION
2.1 What are Green Retrofits?
The term retrofit has not been well defined. The dictionary definition of retrofitting is
“to modify something or install new parts, which were not available when the thing
was fabricated” (Encarta World English Dictionary 2016). Another definition is to “add
(a component or accessory) to something that did not have it when manufactured”
and “provide (something) with a component or accessory not fitted to it during
manufacture” (Oxford University Press 2016). In buildings, Green retrofits refers to
any kind of upgrades to the existing building stock, which is entirely occupied or
moderately occupied to improve the energy performance of the building and quality
of space inside the building in terms of air, natural light, noise and everything is done
with a payback period to the owner so that it is also financially beneficial to the
owner. Today the green development is not limited to the new building stock, but
through the technology it is expanding towards the existing building stock on earth.
So people are moving towards green retrofits for making the existing building stock
green, creating whole lot of new market and job opportunities for the people.
Green retrofits are becoming more popular than new green construction. They are a
less risky investment because there is no cost to build the main components of the
building. Green retrofits are also more efficient in that they use minimal to no new
natural resources to construct the components of the building.
2.2 General Terminology
Keywords: Reconstruction, Restoration, Renovation, Repair, Refurbishment
There are some terms that because of their nature are independent from the energy
aspect of the facade of a building, such as reconstruction and restoration. In
reconstruction no parts of the original building remain and it constitutes a new
building. Restoration means to restore a building to its original form, restorer does
whatever is necessary to return the object’s appearance to that period. These two
terms lay on interventions to which, main goal is the reconstitution of building itself
more than building performance.
Renovation simply means to make an object look like new in which only modifying
parts can be understood as a retrofit in a minor scale. Repairs is limited to the
replacement or repair of defective building components, which can be related to the
term retrofit since it contemplates a failure in one or several buildings’ systems.
Refurbishment simply means returning the building or its systems to their original
condition, when the product is being disuse. Refurbishment contrasts with
conversion because “refurbishment does not involve any major changes to the load
bearing structure or interior layout”, which could be possible in whole buildings’
conversion.
2.3 BENEFITS OF GREEN RETROFITS
Lower cost of operating buildings; improved quality of spaces, for example, through
natural lighting; gain in floor area (in some instances) due to the replacement of
bulky mechanical equipment and building materials with thin variety; improved
corporate image in social responsibility; tax credits and government incentives;
lessened impact on infrastructure; efficient use of natural resources; and lessened
ecological impact.
2.4 TYPOLOGIES OF GREEN RETROFITS
At the time of research four types of retrofits are available in markets:
HVAC RETROFITS
FAÇADE RETROFITS
LIGHT RETROFITS
ROOF RETROFITS
As the scope of the research is limited to façade and roof retrofits, so only these two
retrofits will be studied in detailed for further analysis.
2.5 FAÇADE RETROFITS
Façade retrofits are the upgrade to the façade systems of the building in terms of
fenestrations, material, structure behaviour. Facade is a primary system and a particular
focus in high performance buildings. Most of the buildings standing today will be the part of
the building stock in coming future, this means that these buildings will require extensive
renovation, including façade retrofit, to meet further energy and carbon performance goals in
the building sector. Building energy retrofit in general and façade retrofit in particular, are
relatively new areas of practice and research as most of the buildings are ageing and energy
prices and concerns are increasing. In fact, only 17% of the retrofits undertaken by energy
saving companies include envelop upgrade. For this study, façade retrofit will be understood
as any modification in the façade or any addition to the building envelop for energy efficiency
in the building.
5 Typologies are defined in this research paper
1)
2)
3)
4)
5)
Replacing existing windows for double, triple or quadruple glass
Adding interior and exterior insulation
Adding overhangs and fins to fenestrations
Re-skinning with more glazed area, and
Attaching a double glazed skin to the existing original facade.
TYPE
DESCRIPTION
SINGLE SKIN
The original facade is
maintained, but some
components or all of them are
upgraded or replaced.
SUNSHADES
OVER-CLADDING
RE-CLADDING
DOUBLE SKIN
The facade is maintained, but
external elements are
incorporated with the goal to
control solar heat gain in the
building.
Layers are added to the
existing facade configuration
The original facade is turned
down and a totally new skin is
built.
An additional glazed skin is
added to the original façade. It
can be closed or allowed to
receive ventilation.
INTERVENTION IN FACADE
- Window replacement
- Different low-e films
incorporation to glass
- Seals and infiltration
controls.
- Overhangs
- Fins
- combination
- Internal and external
insulation
- Addition of new cladding
materials to the façade.
- Full glazed skin
- Glazing replacing opaque
spandrels
- Multi-storey double skin
- Full height Double skin
2.6 ROOF RETROFITS
Roof retrofits are the upgrades to the roof systems for the energy efficiency of the
building. Most of the heat gain of the building is through the roof of the building
because of the direct solar gain of roof by the sun. Therefore the upgrade require
something with high reflectance, which can reflect the sun rays back to the space or
some other upgrade which can stop the sun rays at the roof level only . As on now
only two types of retrofits are known during the study. For this study, roof retrofit will
be understood as any modification in the roof or any addition to the roof level for
energy efficiency in the building.
2 Typologies are defined in this research paper:
1) Green Roof
2) Cool Roof
Green roof
The process of building construction may involve destruction of green cover.
Vegetative roofs, or rooftops with green cover, replace this destroyed vegetated
footprint. Vegetative roof systems typically comprise of a lightweight growing
medium, plants, and a root repellent layer in addition to the regular components of a
roof. The additional components and thickness of the growing medium provides
thermal insulation, while the green cover lowers ambient temperatures through
evapo-transpiration. However, green roofs may require regular maintenance and
involve high first costs. There are three distinct types of green roofs - intensive,
extensive, and modular block.
Intensive vegetative roof systems feel and function like gardens – and may be
accessible as parks or as a building amenity. Such systems add a considerable load
to the structure of the roof requiring a minimum soil depth of 300mm. Small trees,
shrubs, and other landscape features may 2 add up to an additional load of 400 to
750 kg/m for the building. Such systems are employed for their environmental
benefits as well as aesthetic appeal.
Figure: Exploded view of green roof components
Extensive roof systems are primarily built for environmental benefits. They require a
soil depth of 25 to 125 mm and may contain a modest green cover comprising of
succulents, thick grasses, and hardy plants that are drought-resistant. Additional
loads to a building are between 75 and 250 kg/m2 for the extensive system.
The modular block system is made up of portable units are arranged on a rooftop.
The blocks are self-contained, and are typically made of a heavy gauge metal with
100 mm soil depth and a low-growing plant species. A sheet or pad fastened to the
underside of the container regulates the flow of water from the unit. Such systems
weigh 60 to 90 kg/ m2.
Cool Roof
For this research paper Cool roofs will be studied in depth. A cool roof is one that
reflects most of the incident sunlight and efficiently emits some of the absorbed
radiation back into the atmosphere, instead of conducting it to the building below. As
a result the roof literally stays cooler, with lower surface temperatures, keeping the
building at a cooler and more constant temperature. The term, 'cool roof' refers to the
outer layer or exterior surface of the roof which acts as the key reflective surface.
These roofs have higher solar reflectance than a typical roof surface. The term 'cool
roof' encompasses an extensive array of roof types, colours, textures, paints,
coatings, and slope applications.
PROPERTIES
The two primary thermal properties that characterize roofs are solar reflectance and
emittance. Surfaces with low solar reflectance, absorb a high fraction of the incoming
solar energy. A fraction of this absorbed energy is conducted into ground and
buildings, a fraction is reflected back to the ambient air, and a fraction (termed
emissivity) is radiated back to the sky. For equivalent conditions, the lower the
emissivity of a surface, the higher will be its steady-state temperature. Surfaces with
low emissivity cannot effectively radiate to the sky and, therefore, get hot.
BENEFITS OF COOL ROOF
Cool roofs provide numerous benefits at the micro level as well as the community
level. Cool roofs conserve energy and enhance thermal comfort because the interior
of a building is subject to less thermal flux. They assist in mitigating the urban heat
island effect, and when installed comprehensively, can result in lowered ambient air
temperatures on an urban scale.
During the cooling season, cool roofs reduce heat conduction through the roof during
the day, and hence reduce air-conditioning energy use. During sunny cold winter
days, however, cool roofs may cause a marginal Increase in heating energy
consumption. In Delhi and other composite climate zones, potential heating penalties
are a small fraction of cooling-energy savings due to the long cooling seasons and
short heating seasons. Moreover, buildings require cooling during the summer
season, especially during daytime when the incident solar radiation is intense (and
therefore when cool roofs are most effective), while heating is needed during the
early morning hours during winters when there is little or no solar radiation present
(and therefore when cool roofs are marginally effective or ineffective). Thus, cool
roofs are very effective in reducing the summer electricity use with minimal impact on
winter heating. In general, savings in annual net utility costs can be expected for
most buildings.
FIGURE: Effect of roof construction on Indoor temperature
2.7 Solar Reflectance Index (SRI)
Though most roofing materials have a fairly high thermal emittance, in order to
accurately determine a roofing product’s 'coolness', or its ability to shield the building
beneath it from heat, both solar reflectance and thermal emittance must be
measured. It is important to note that it is possible for a roofing material to have a
very high emittance value and a reflectance value ranging from low to very low, or
vice versa, although such materials would typically not be considered cool roofs. A
high emittance value alone will not result in a cool roof nor will a high reflectance
value alone. The Solar Reflectance Index (SRI), which incorporates both solar
reflectance and emittance in a single value, quantifies how hot a surface would get
relative to standard black and standard white surfaces. The Solar Reflective Index
(SRI) is a measure of the ability of the constructed surface to reflect solar heat, as
shown by a small temperature rise. It is defined so that a standard black.
2.8 CASE STUDY
A demonstration to quantify and record the benefits of cool roofs was conducted at
two office buildings in Hyderabad. The study team included the International Institute
of Information Technology (IIIT) led by Dr Vishal Garg, and Lawrence Berkeley
National Laboratory (LBNL – comprising of Dr Hashem Akbari, Dr Jayant Sathaye,
Mr Craig Wray , Dr Tengfang Xu, and Dr Haider Taha), supported by USAID
(United States Agency for International Development) and SPM Thermoshield.
BUILDING PARAMETRES
The complex houses two near-identical buildings – this facilitated the study through
ensuring identical parametric values for floor area, number of floors, roofing material
and system, occupancy and schedules, and cooling systems. This is a two-storey
building with a roof area of 700m2. The roof of one building was coloured black while
a white reflective cool roof coating was applied to the roof of the other building.
FIRST COATING
OF COOL ROOF
CONVENTIONAL
GREY ROOF
FIGURE: The first coat of cool roof coating is being applied to a grey surface
MONITORED DATA
Weather towers, temperature sensors, current transducers, and data-loggers
continuously monitored the weather, energy-use, and temperature data for the two
buildings. The data points monitored weather conditions, building temperatures, and
energy use:
Weather
• Outdoor temperature
• Relative humidity
Energy Use
• Whole building electricity use
• Cooling energy use
Building temperatures
• Surface temperature
• Heat flux through roof
• Roof underside temperature
• Indoor air temperature
CONCLUSION
The average summertime daily roof surface temperature was reduced by 20 C
degrees (Graph 1). Cooling energy savings due to cool roofing (from grey concrete
to white roof coating) can vary largely, for example, ranging from approximately 15%
to 20% during hot summer days (Graph 2).
Graph 1: Comparison of surface and under-surface temperatures of roof assembly before and after the application of
cool roof coating
Graph 2: Graph illustrating drop in heat flux and cooling energy-use after the application of cool roof coating
2.9 UNDERSTANDING RATING SYSTEM OF GREEN
BUILDINGS
LEED®
LEED® (Leadership in Energy and Environmental Design)
It is the most popular GREEN BUILDING CERTIFICATION programs used
worldwide. Developed by the non-profit U.S. Green Building Council (USGBC) it
includes a set of rating systems for the design, construction, operation, and
maintenance of green buildings, homes, and neighbourhood’s, that aims to help
building owners and operators be environmentally responsible and use resources
efficiently.
LEED® has grown since 1998 to more precisely imply and incorporate emerging
green building technologies. The pilot version, LEED® New Construction (NC) v1.0,
led to LEED NCv2.0, LEED® NCv2.2 in 2005, and LEED® 2009 (previously named
LEED v3) in 2009. LEED® v4 was introduced in November, 2013. Until October 31,
2016, new projects may choose between LEED® 2009 and LEED® v4. New projects
registering after October 31, 2016 must use LEED® v4.
LEED projects earn points across nine basic areas that address key aspects of
green buildings.
1. INTEGRATIVE PROCESS
2. LOCATION AND TRANSPORTATION
3. SUSTAINABLE SITES
4. WATER EFFICIENCY
5. ENERGY AND ATMOSPHERE
6. MATERIALS AND RESOURCES
7. INDOOR ENVIRONMENTAL QUALITY
8. INNOVATION
9. REGIONAL PRIORITY
Based on the number of points achieved, a project earns one of four LEED
rating levels:




Certified: 40–49 points
Silver: 50–59 points
Gold: 60–79 points
Platinum: 80 points and above
IGBC®
The Indian Green Building Council (IGBC®), part of Confederation of Indian Industry
(CII) was formed in the year 2001. The vision of the council is to usher in a green
building movement in India and facilitate India to become one of the global leaders in
green buildings by 2010. IGBC® Green Homes is the first rating programme
developed in India, exclusively for the residential sector. It is based on accepted
energy and environmental principles and strikes a balance between known
established practices and emerging concepts. The system is designed to be
comprehensive in scope, yet simple in operation. IGBC Green Homes® Rating
System is a voluntary and consensus based programme. The rating system has
been developed based on materials and technologies that are presently available.
The objective of IGBC Green Homes® is to facilitate the effective use of site
resources, water conservation, energy efficiency, and handling of house-hold waste,
optimum material utilization and design for healthy, comfortable & environmentally
friendly homes.
The rating system evaluates certain mandatory requirements & credit points using a
prescriptive approach and others on a performance based approach. The rating
system is evolved so as to be comprehensive and at the same time user-friendly.
The programme is fundamentally designed to address national priorities and the
quality of life for occupants. The rating programme uses well accepted National
standards and wherever local or National standards are not available, appropriate
international benchmarks have been considered.
Certification Levels
Different levels of green building certification are awarded based on the total credits
earned. However, every Green Home should meet certain mandatory requirements,
which are non-negotiable.
The threshold criteria for certification/pre-certification levels are as under:
Certification Level
Individual Units
Multi-dwelling Units
Recognition
Certified
38 - 44
50 - 59
Best Practices
Silver
45 - 51
60 - 69
Outstanding Performance
Gold
52 - 59
70 - 79
National Excellence
Platinum
60 - 75
80 - 89
Global Leadership
2.10 CSE ANALYSIS OF DELHI'S POWER CONSUMPTION
The CSE analysis of electricity consumption of summer tries to understand the
trends and nature of demand in the city and the likely impacts of the growing
dependence on air conditiosning to escape the heat. The key highlights are as
follows:

Lack of energy-efficiency measures is making Delhi an energy
guzzler: According to the newly released report of the Central Electricity
Authority on Load Generation Balance Report 2015-16, Delhi is consuming
more electricity than the states of Himachal Pradesh, Jammu & Kashmir,
Uttarakhand, Chhattisgarh, Goa, Kerala, Bihar, Jharkhand, Odisha, Sikkim
and all states of North-east. It also uses more power than all the other metros
put together. Already, in Delhi, the household electricity consumption per
capita is about 43 units per month against a national average of 25. Currently,
domestic power tariff in Delhi is the lowest amongst all metros.

Excessive peak demand: Delhi’s peak demand has doubled in the last 10
years, growing faster than the population of the city. Delhi registered an alltime high peak demand in June last year at 6,006 MW. This demand was
higher than the combined highest ever peaks of Mumbai, Kolkata and
Chandigarh! CEA projects Delhi’s peak will cross 6,300 MW this year and
12,000 MW by 2021.

Nearly the same peak demand for electricity noticed during day and
night this summer indicating enormous impact of air conditioners in
middle class homes: CSE has analysed the trend in demand for electricity
during night and day. It notes that the day peak builds up late in the afternoon
around 3:30 PM and the second peak hits around midnight. There was barely
any difference between night and day peaks during the month of May. For
example, on May 24, while the day peak demand was 4667 MW the night
peak demand was 5091 MW: the night demand was either higher or had a
very small difference in the range of 1-4 per cent. It is the air conditioners in
homes that skew the demand at night. This trend is starkly opposed to the
trend in most other metros when demand during the night is lower than
daytime as power-intensive sectors like industries, shops, offices and malls
are closed.”

Growing reliance on air conditioning upsets the energy balance in the
city: In Delhi, air conditioning now accounts for the highest consumption of
electricity during the hottest months, accounting for about 28 per cent of the
total monthly electricity consumption. According to an estimate by Bureau of
Energy Efficiency (BEE), ACs contribute to almost 60 per cent of Delhi’s peak
electricity demand.
Chapter 3
3.1
3.2
3.3
3.4
3.5
Paharpur Business Centre
Project Details
Indoor Air Quality
IAQ Foot print
Conclusion
CASE STUDY
3.1 PAHARPUR BUSINESS CENTRE
Paharpur business centre is a living example of a building which had been retrofitted
with various technologies to achieve the lowest GHG footprint in Delhi. PBC is a 25
year old building, located in Nehru Place Greens, built to government design. Its total
built up area is 50,000 sq. It is the first office building in the country to be USGBC
LEED Platinum certified under Existing Buildings (Operations and Maintenance)
category - truly a sustainable building. As per IGBC Research, the Annual Average
Hourly Energy Performance Index (AAhEPI) of commercial buildings ranges from 75150 Wh/hr/sq.mt .The AAhEPI of PBC was 28 Wh/hr/sq.mt when they got BEE 5 Star
Rating, currently they are running at an AAhEPI of 22 Wh/hr/sq.mt and targeted to
operate at 15 KWh/hr/sqm.
TYPES OF RETROFITTING DONE TO THE BUILDING
S. No.
Project
Time frame
Investment
Payback Period
(Months)
2013-14
Medium
18
1
A.
LIGHTING SYSTEM UPGRADATION
Replacement of
36W fluorescent
tube lights with 18
W LED lights
B.
Replacement of
16W CFL with 6W
LED down lighter
2013-14
Low
52
C.
Installation of
Motion Sensors in
Elevators, Lobby
Areas and
Washrooms
2013-14
Low
36
2
Installation of
immersion type
sensor in the
cooling tower sump
and close the loop
for the VFD on the
Cooling tower Fan
motor & the sump
water temperature
sensor.
2013-14
LOW
5
3
Using AHU
condensate water
in Air Washer Unit
2013-14
Low
15
4
Installation of Sky
Lights(Second
Phase)
2012-13
Low
2.5
3.2 PROJECT DETAILS
PROJECT 1: LIGHTING SYSTEM UP GRADATION
A. Scope: Replacement of 1100 36W Fluorescent tube lights with 950 18W LED
lights
Investment: INR 6 Lacs.
Features of New System:



LED lights with Wattage of 18W in place of Florescent Lights of 36W.
Equal Lux Level as compared to the normal tube lights.
Less heat dissipation as compared to normal tube lights, hence less load on
HVAC.
Benefits:


Saving in Electricity Consumption: 11.68KW/hr and 39,485units/year which
amounts to INR 0.428 million /year.
50-55% Energy Saving compared to old system
B. Scope: Replacement of CFL down Lighters with LED down Lighters.
Investment: INR 9.0 Lacs
Features of New System:



LED lights with wattage of 6W in place of 16W CFL.
Improved Lux Levels as compared to the CFLS.
Less Heat Dissipation as compared to CFL, Hence less load on HVAC.
Benefits:


Saving in Electricity Consumption: 5.6KW/hr and 18,928units/year which
amounts to INR 0.20 million /year.
60-62% Energy Saving compared to old system
C. Scope: Installation of 25 MOTION SENSORS in Elevators, Lobby Areas, Air
Curtains and Washrooms.
Investment: INR 23000
Benefits:
 Saving in Electricity Consumption: 0.5 KW/hr and 681units/year = INR 0.205
million/year.
 60-62% Energy Saving compared to old system.
PROJECT 2: USE OF NATURAL SKYLIGHTS IN GREEN HOUSE-SECOND
PHASE
Scope: Replacement of Tube lights with Natural Skylights in Green House
Features of New skylight:
 Zero watt, sunlight harnessing
 Full natural light spectrum, best for plants
 Easy retrofit solution
Benefits:


Reduced Energy consumption by 15KW/day with 12 Hours of Operation with a
payback period of less than 5 years
Reduced Maximum Demand
PROJECT 3: IN-HOUSE RESEARCH & DEVELOPMENT ON ENERGY
EFFICIENCY PRACTICES

Light Colored Tiles on Roof, Light Reflecting Paint (High Albedo paint) and cool
Wall Paints are used to reduce the heat gain.

Study by Lawrence Berkeley National Laboratory estimates worldwide energy
savings of $27 billion/ year with White Painted Roofs. . Chart below shows drop
in surface temperatures using cool materials and paints (deg c) on a typical April
day.
The above listed projects are amongst the few of many projects that PBC had dealt to
improve their GHG emission. In this research paper the information of only few projects
had been provided, but this doesn’t change the conclusion that the green retrofitted
building can save energy. PBC provided us with their analysis reports they published.
Summary of Greenhouse Gas Emissions
Year
Annual Energy
Emission of CO2
CO2 Emission Factor
Consumption (KWh) (tonnes)
(Kg of GHG/KWh)
2007
1,073,292
1009
0.94
2008
902,736
849
0.94
2009
713,660
671
0.94
2010
888,928
836
0.94
2011
871,274
819
0.94
2012
661,554
622
0.94
2013
601,982
566
0.94
2014
558,564
525
0.94
The reduction in GHG emission in the year 2014 due the BSES Grid
power consumption is 7% as compared to the year 2013
MONTHLY ENERGY CONSUMPTION FROM DIRECT ENERGY SOURCE
Monthly Energy Consumption Data from Direct Energy Source – BSES (Grid Power – Primary Energy Source)
Month
Data of 2013
Data of 2014
Occupancy Occupied
Total
BSES
occupancy Occupied Total KWH BSES KWH
Total
Area in
KWH per KWH
Total Area Area in
per
area
Sqft
occupied
%
Sqft
occupied
%
Sqft
Sqft
January
30.77%
14913.91 2.88
42924
30.34%
14705.49
2.61
38352
February
29.13%
14119.02 1.94
27420
32.04%
15529.47
1.74
27036
March
27.98%
13561.63 3.06
41448
34.96%
16944.76
2.19
37092
April
28.21%
13673.10 3.99
54540
32.56%
15781.51
2.93
46284
May
31.36%
15199.88 4.43
67308
29.11%
14109.33
4.10
57840
June
32.58%
15791.20 4.41
69648
27.54%
13348.36
4.51
60144
July
33.52%
16246.81 4.38
71208
27.32%
13241.73
4.77
63168
August
34.95%
16939.92 3.45
58368
26.18%
12689.18
4.26
54084
September 37.35%
18103.17 3.09
55872
28.73%
13925.14
4.16
57948
October
36.87%
17870.52 2.71
48504
30.04%
14560.09
2.96
43044
November
33.23%
16106.00 1.99
32004
30.02%
14550.39
2.42
35244
December
30.12%
14598.86 2.07
30200
32.11%
15563.40
2.60
40404
The total energy consumed in the year 2013 is 599,444
The total energy consumed in the year 2014
KWH
is 560, 640 KWH
The Reduction in total consumption of Energy (KWH) in the year 2014 as compared to the total
consumption of Energy (KWH) in the year 2013 is 7%
SOME OTHER MEASURES:

Greenhouse on the rooftop.
Figure: Front view of the building depicting the windows
are covered by green mesh.
By green mesh

Green mesh & heat reflective film is put on the southwest side of the building in
summers to block the direct sun heat into the building.

Use of BEE 5 star rated appliances only

Light coloured tiles on the roof and cool wall paints are used to decrease
envelope heat gain. Chart below shows drop in surface temperatures using cool
materials and paints (deg c) on a typical April day.
3.3 INDOOR AIR QUALITY
Another factor Paharpur Business Centre had done is making their IAQ index very
low, to breathe fresh air inside the building. They are using a technique called
Hydroponics for growing fresh air inside the building. With the help of plants, the indoor
air is made rich in oxygen, In order to promote health, which results in reduced
absenteeism due to fewer sick days and higher productivity for occupants. The fresh
air load is 0.60 watts per ft2, a reduction of 0.18 watts/ft2. This gives an energy saving
of 30% in fresh air load on HVAC system and hence reduced energy bills.
They are using these 3 plants to grown fresh air inside the building. There are over
1200 plants in the building
Figure : Interiors of PBC
3.4 IAQ FOOTPRINT
With Ambient Air numbers as poor as they are in New Delhi, Indoor Air results are no
better. Table given below shows the average readings of various pollutants in different
commercial buildings in New Delhi. Compared to the Indoor Air Quality guidelines
published by WHO or by ASHRAE, these numbers are very poor. Awareness of Air
Quality and pollution is very low and this needs to become a priority. Indoor Air
pollution is the second highest killer in India after Blood Pressure, 1.3 million people
in India die due to indoor air pollution every year.
Parameter
Measure
ASHRAE Standard
CO2
Ozone
Nitrogen dioxide
Sulphur dioxide
PM 2.5
PM 10
ppm
μg/m3
μg/m3
μg/m3
μg/m3
μg/m3
700 over ambient
100
100
80
15
50
Average of Other
Buildings
1278.45
8.393
68.114
22.16
61.58
103.7
The Indoor Air Quality at PBC is equivalent to being up in the mountains. The
numbers speak for themselves. Table given below outlines the results of Air Quality
monitoring at PBC for the last few years. This is testing done by the dedicated IAQ
team of PBC. Further studies have been done by LBNL and CPCB corroborating the
numbers below. These studies are outlined below.
Paramete
r
CO2
Measure
Carbon
monoxide
Nitrogen
dioxide
Sulphur
dioxide
RSPM
(PM 10)
ppm
Air Quality Parameters Tested at PBC
ASHRAE
2008
2009
2010
Standard
700 over
395
318
477
ambient
9
0.089
BDL#
BDL
μg/m3
100
21
19
μg/m3
80
8.2
μg/m3
50
18
ppm
2011
2012
471
488
BDL
BDL
8
8
40
8.1
7
4.5
34
16
29
27.9
40
3.5 CONCLUSION
Thus from this study we conclude that retrofitting in any means to any building in
Delhi can save energy up to 70% depending upon various factors. The monthly
energy consumption of this building is reduced by 7% yearly. They started from
845KVA and in 1991 there load had reduced to 300KVA approx. i.e. the energy load
had been reduced 3x times which means they are saving 1.5-2.0 cr. approx. per
year.
Similarly, Green Retrofits if applied carefully in the existing stock of residential
buildings it can save a decent amount of energy. From this case study and the
literature study some measures can be taken to solve the issues regarding the
energy efficiency of residential sector.
Chapter 4
4.1
4.2
4.3
4.4
Identification of Issues
Measures to Address Issues
General Measures
Conclusion
4.1 IDENTIFICATION OF ISSUES IN RESIDENCES
A survey was conducted between 100 houses of different zones and different areas
in Delhi. The crowd targeted was architectural students of the college as the survey
was more of architectural based question. From the survey the data was collected
about the Roof and Façade materials, the orientation of the building, the units
consumed by the house, no. of Air conditioners in the house. Most of the heat is
trapped by the building envelop, so the materials on the envelop play a major role in
doing that.
1) SECTION OF ROOF
From the survey it was identified that 93% of the houses have cemented finish on
their roofs.
Figure: Typical section of roof
This type of configuration of roof gains heat through roof and increase the indoor
temperature. Diagram below shows how heat travels through the roof.
Figure: Flow of energy through roof
The typical section shows that only plaster had been applied on the roof, which has a
very low reflectivity i.e. dark colour absorbs energy and transmit it into the interiors.
The hot ceiling continues to heat up the space – during the day and well into the
night - making the spaces unbearably hot throughout the summer season.
TYPICAL PHOTOS OF ROOF FINISH
2) WALL SECTION
From the survey it was identified that 75% of the houses have Paint finish on the
Facade of the house.
Figure: Typical wall section
This figures shows that the major amount of heat is transferred through the wall due
to its poor reflectivity. The images shows on the next page shows the typical
typologies of colour of façade and the type of finish of the façade. (These images was
collected as part of the survey).
Figure: Typical facades
Figure: Transmission of heat through wall
The typical section shows that only plaster and paint finish have been applied on the
wall, which has a very low reflectivity. The heavy mass of the brick stores the heat
and reradiates it to the inside. The hot walls continue to heat up the space – during
the day and well into the night - making the spaces unbearably hot throughout the
summer season.
3) IMPROPER SHADING OF WINDOWS
Most of the houses don’t have sunshades on their windows. Instead they have
placed curtains on the inside of the house to protect the interiors from direct sunlight.
Most of the times heat is trapped between the space of curtains and windows which
is then transferred to the indoor space through radiation. Thus, the cooling load on
the Air – conditioner is increased and a greenhouse effect is created inside the
house.
Figure: Transmission of heat through window
This is a major issues in terms of energy transfer from outside to inside. The heat
energy is coming directly from the sun to the indoors without having any solid
thermal mass in between the two. So, something has to be retrofitted to window so
that the heating coming from the exterior should stay outside of the window.
Windows account for 15 % of the building fabric, making them a weak spot in house
design. An ordinary window (alum framed, clear glass) can conduct around 6.5
W/m2.K (its U-value). So if there’s a 10˚ temperature differential between the inside
and outside, then that’s 65W of energy loss for each m2 of window (typically around
40m2 to 60m2 per house).
4) PLACEMENT OF AIR-CONDITIONERS
The Placement of air conditioners is wrong as they are placed at topmost height of
the room and away from the major cooling areas of the room. Thus, the cooling load
on the room and the Air conditioners is increased.
Figure: Placement of Air conditioner away
from heating load
5) EXTENSIVE USE OF WATER
Excessive use of water not only increases the demand of water of the building but
also increase one’s electricity bill. The volume of water wasted in the entire day
through faucets has to be replenished by the water pump and the pump is running
for extra time just to replenish the waste water in the tank.
4.2 MEASURES TO ADDRESS THE ISSUES

ROOF SECTION
The first issue which was observed in a typical building, was the conventional roof
was grey coloured and the section of roof had no reflecting materials. Concrete
being a thermal mass absorbs a large amount of heat from the sun and radiate the
heat to the interiors of the home.
So, the section should be developed with some high reflectivity material like mosaic
flooring embedded in screed over RCC slab. If the typical grey coloured Roof is
replaced by this, the amount of energy will certainly get reduced to some
percentage. After mosaic if the coating of cool roof white paint is applied the
temperature is decreased by 9-10 degC. (Experiment in literature study).
Figure: Roof section

WALL SECTION
The second most issue which was identified in building envelop of typical building,
façade material was distemper or emulsion paint. That paint is only for aesthetic
purpose having very low reflectivity about 20% of the heat is reflected.
The wall section should be developed such that the aesthetics should not be
compromised and the reflectivity gets increased.
Therefore, HIGH ALBEDO PAINTS are the best option for this purpose. The light
being incident on the wall gets reflected back to the atmosphere making the exterior
walls of the building cool, making an appreciable amount of temperature difference in
the interiors. (MATERIAL DERIVED FROM CASE STUDY)
Figure: Wall section

IMPROPER SHADING OF WINDOW
The third problem which was observed in the typical houses was the use of curtains
was on the indoor side making the window as a greenhouse medium. The curtains
which is use for blocking the sunlight in the interiors and not really serving their
purpose. The trapped heat between the curtains and the windows cannot go outside
so the heat is entering inside the homes through the glass and then energy is
transferred inside the room through radiation. Thus this increase the heating load on
the air conditioners and making it consuming more energy.
So, something has to be placed on the outside of the windows to block the sunlight
from entering the interior space without compromising the view and the aesthetics of
the interior.
Window films can be put on the glass to restrict the heat, UV and Infrared rays in
the interiors.
Green mesh can be put on the façade to restrict the sunlight from entering into the
premises.
Plastic screens can be used on the exterior of the window as low cost option.
Figure: Window films
The above image shows how the film works. The film is self-adhesive easily rolling
onto the window. The film can be put on the interior or on the exterior depending on
the accessibility of window. The image below shows the plastic screens put by
Paharpur Business Centre recently in place of green mesh earlier to prevent sunlight
entering the inside of office.
Figure: Plastic screen

PLACEMENT OF AIR CONDITIONERS
The placement of air conditioner should not touch the ceiling. The air conditioner
should be placed almost at the height of 7ft, so that the volume of air to be air
conditioned get reduced by some fraction. The air conditioned should be placed
near the heating load, not away from heating load (Heating load refers to things
need to be cooled down in the interior for example, computers, bed etc.). If it is
not placed around the heating load then it has to work more to get its job done.
Figure: Placement of Air- conditioner
 GENERAL MEASURES
 Use of LED lights in place of CFL or incandescent lights.
 The outdoor unit of A/C should be placed in shade to minimise the load on the Air




-conditioner
Use of BEE 5-star rated electrical appliances.
Minimise the Use of water to reduce the electrical consumption of house.
High IAQ can be achieved by using the plants mentioned in the case study of
Paharpur business centre. These plants not only maintains the good air quality
but improves the energy efficiency of the house.
The roof and the façade should be of white colour because of its high reflectivity.
CONCLUSION
Energy consumption in Delhi is increasing and existing homes are consuming most
of the energy in Delhi. The existing building stock in very inefficient in terms of
energy consumption.
This paper looked at what are the major areas where we are losing energy and what
are the measures which one can take to cater it. Most of the energy in the building is
used by the Air conditioners in summers. So, if we can make building cooler than
most of the energy of the home can be saved. Combining the issues Green retrofits
are an apt solution to the problem as we have perceived in the study that many
buildings are retrofitted on the globe and are saving a decent amount of energy,
reducing their per capita energy cost. If every house is retrofitted in the city then it
can save a tremendous amount of energy for the city.
Therefore, Green Retrofits if applied carefully in the existing stock of residential
buildings it can save a decent amount of energy as a whole and can reduce GHG
emission of every building. Not only it reduces energy but introduction of plants in the
indoor space of the building can improve the IAQ of the indoor space which will
improve performance of people, energy consumption of building, reduce eye
irritation, and increase the oxygen levels of the indoor space. Overall, it will benefit
the persons and the building in every manner.
Thus, we can conclude that proper knowledge of Green retrofits can save per capita
energy of an individual, saving a decent amount of money per year.
Notes and References
ARTICLES:
Paharpur business centre “SUSTAINABILITY REPORTS” Volume 1-8.
Features and Benefits of Cool Roofs: The Cool Roof Rating Council Program,
Journal of Green Building
[http://www.coolroofs.org/documents/JGB_V3N2_a02_vanTijen.pdf] Volume 3:
Number 2, Spring 2008.
Akbari, H., T. Xu, H. Taha, C. Wray, J. Sathaye V. Garg (2010). Using Cool Roofs to
Reduce Energy Use, Greenhouse Gas Emissions, and Urban Heat-island Effects:
Findings from an India Experiment. Lawrence Berkeley National Laboratory Final
Report.
Akbari, H. (2008). Evolution of Cool-Roof Standards in the US, volume 2, pages 132, Advances in Building Energy Research
Giebeler, Georg, Rainer Fisch, Harald Krause, Florian Musso, Karl-Heinz Petzinka,
and Alexander Rudolphi. 2005. Refurbishment Manual (Construction Manuals. 1st
ed. Birkhäuser Architecture
Encarta World English Dictionary. 2016. “Dictionary - MSN Encarta.”
http://encarta.msn.com/encnet/features/dictionary/DictionaryResults.aspx?lextype=3
&search=retrofit.
ARUP. 2009. “Existing Buildings Survival Strategies
U.S. Green Building Council. 2012. “Certified Project Directory.”
http://www.usgbc.org/LEED/Project/CertifiedProjectList.aspx.
BEE, “DESIGN GUIDELINES FOR MULTISTOREY RESIDENTIAL BUILDINGS”
(2014)
TERI, (2013 )“ROADMAP FOR INCORPORTATIN ENERGY EFFICIENT
RETROFITS IN EXISTING BUILDINGS”
Centre for Sustainable Buildings and Construction (2010), “EXISTING BUILDING
RETROFITS”
Central Electrical Authority of India (2015), “POWER GENERATION REPORT”
Centre for science and environment (2015), “ANALYSIS OF POWER GENERATION
REPORT”
INDIAN GREEN BUILDING COUNCIL,”BENEFITS OF GREEN HOMES”
Green Roof Blocks (2012)
http://greenroofblocks.com/products/green-roof-blocks/
Lawrence Berkeley National laboratory (2008),” Cool Materials”
Cool Roof Rating Council, “By Laws”
California Energy Commission (2005),”Building Façade” page 3-1 to 3-86
USGBC (2016), “LEED CERTIFICATION”
http://leed.usgbc.org/leed.html?gclid=CNys-o-Dt88CFdGGaAodJ_sPGQ
Jones Lang LaSalle (2012), Advance Retrofitting in India’s central business districts
National Resource Defence Council (2013), Energy-Efficiency Retrofit of the Godrej
Bhavan Building in Mumbai
Building and construction authority Singapore (2012), Retrofitting of existing
buildings
Geoffrey Shen (2014), Literature review of green retrofit design for commercial
Buildings with BIM implication,SASBE