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THOUGHTFUL COOLING A TOT Workshop on Cooling Interiors Efficiently and Sustainably

Rachana Sansad’s Institute of Environmental Architecture The Fairconditioning Program | The Indian Institute of Architects, Brihan Mumbai Center

Rachana Sansad Auditorium 278 Shankar Ghanekar Marg

Prabhadevi, Mumbai - 400037

9 – 11 January 2015

THOUGHTFUL COOLING | RACHANA SANSAD’S INSTITUTE OF ENVIRONMENTAL ARCHITECTURE

THOUGHTFUL COOLING A TOT Workshop on Cooling Interiors Efficiently and Sustainably

Rachana Sansad’s Institute of Environmental Architecture The Fairconditioning Program | The Indian Institute of Architects, Brihan Mumbai Center

Rachana Sansad Auditorium 278 Shankar Ghanekar Marg

Prabhadevi, Mumbai - 400037

9 – 11 January 2015


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Table of Contents

List of Figures ............................................................................................................................................... iii

Preface ......................................................................................................................................................... 1

1.1 The Environmental Challenge ....................................................................................................... 3

1.1.1 Ozone Depletion .................................................................................................................... 3

1.1.1.1 The Montreal Protocol On Substances That Deplete The Ozone Layer .............. 7

1.1.1.2 The F-Gas Regulation ................................................................................................... 9

1.1.2 Climate Change ..................................................................................................................... 9

1.1.2.1 Definition ......................................................................................................................... 9

1.1.2.2 Evidence ........................................................................................................................ 10

1.1.2.3 Causes............................................................................................................................ 10

1.1.2.4 Impacts........................................................................................................................... 11

1.1.2.5 Kyoto Protocol .............................................................................................................. 11

1.2 Role Of Cooling Systems In Climate Change And Ozone Depletion ................................. 12

2.1 Building Energy Performance In India ...................................................................................... 18

2.2 Government Policies And Regulations ...................................................................................... 19

2.2.1 National Action Plan On Climate Change (NAPCC) ..................................................... 19

2.2.2 Leadership In Energy And Environmental Design (LEED) ............................................... 20

2.2.3 Indian Green Building Council (IGBC) .............................................................................. 21

2.2.4 Green Rating For Integrated Habitat Assessment (GRIHA) ......................................... 22

2.2.5 Energy Conservation Building Code (ECBC) ................................................................... 23

2.3 Thermal Comfort ........................................................................................................................... 24

2.3.1 Personal Parameters ........................................................................................................... 24

2.3.1.1 Activity (Human Metabolic Rate) .............................................................................. 24

2.3.1.2 Clothing Insulation ........................................................................................................ 24

2.3.2 Environmental Parameters .................................................................................................. 25

2.3.2.1 Physics Of Heat: Heat And Temperature ................................................................ 25

2.3.2.2 Physics Of Heat: Heat Flow ....................................................................................... 25

2.3.2.3 Air Temperature .......................................................................................................... 26

2.3.2.4 Mean Radiant Temperature ...................................................................................... 26

2.3.2.5 Air Speed ...................................................................................................................... 26

2.3.2.6 Humidity ........................................................................................................................ 27

2.3.3 Psychrometric Chart ............................................................................................................. 27

2.3.4 Thermal Comfort Indices And Zones ................................................................................. 28


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2.3.5 Other Factors ........................................................................................................................ 29

3.1 Passive Cooling Technologies ..................................................................................................... 30

3.1.2 Appropriate Orientation .................................................................................................... 31

3.1.3 Shading Devices Design ...................................................................................................... 32

3.1.4 Thermal Mass ........................................................................................................................ 32

3.2 Active Cooling Techniques .......................................................................................................... 34

3.2.1 Hvac System Level Design .................................................................................................. 34

3.2.2 Efficient Cooling- Natural Refrigerant Hvac Systems ................................................... 35

3.2.3 Efficient Cooling- Direct & Indirect Evaporative Cooling Systems .............................. 37

3.2.4 Efficient Cooling- Vapour Absorption .............................................................................. 38

3.2.5 Efficient Cooling- Radiant Cooling ................................................................................... 40

References .................................................................................................................................................. 43


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List of Figures

Fig 1: The Oxygen-Ozone Cycle (Wikipedia) --------------------------------------------------------- 4

Fig 2: Concentration of Ozone in Atmosphere (IPCC; TEAP) ----------------------------------------- 4

Fig 3: Ozone as a UV filter and IR blocker (IPCC; TEAP) -------------------------------------------- 4

Fig 4: Projected Ozone concentration based on depletion rate of 1970s (NASA) --------------- 5

Fig 5: Schematic representation of emissions due to the refrigerant industry (IPCC; TEAP) ----- 5

Fig 6: Vertical Ozone profiles measured by ozonesondes at South Pole station, Antarctica

(IPCC; TEAP) ------------------------------------------------------------------------------------------------ 6

Fig 7: Top: Time-series of de-seasonalised global mean. Bottom: Ozone concentration at

Antarctica (IPCC; TEAP) ----------------------------------------------------------------------------------- 6

Fig 8: CFCs Production/Consumption Reduction Schedule (UNEP) ----------------------------------- 7

Fig 9: Worldwide emissions of ozone-depleting substances (ODS) and HFCs (A), global

emissions of CO2 and HFCs (B), and HFC consumption for the period 2000-2050 (C), CFC

data include all the main ODS in the Montreal Protocol except HCFCs. Emissions from different

gas types are multiplied by their respective global warming potential to calculate emissions in

GtCO2/year. (Velders, Fahey and Daniel) ------------------------------------------------------------ 8

Fig 10: Global HFC Consumption. (Bose) --------------------------------------------------------------- 9

Fig 11: The anthropogenic nature of climate change (US EPA) -------------------------------------- 9

Fig 12: Increase in greenhouse gas (GHG) concentrations in the atmosphere over the last

2,000 years. Increases in concentrations of these gases since 1750 are due to human activities

in the industrial era. (US EPA) ---------------------------------------------------------------------------- 9

Fig 13: Global Average Temperature (US EPA)----------------------------------------------------- 11

Fig 14: High Global Warming Potential of Select ODSs and HFCs (Environment and Energy

Study Institute) -------------------------------------------------------------------------------------------- 13

Fig 15: Trends in CO2eq emissions of CFCs, HCFCs, and HFCs since 1950 and projected to

2050. (UNEP) --------------------------------------------------------------------------------------------- 13

Fig 16: Global consumption (in kilotonnes per year) of ozone depleting CFCs and HCFCs.

(UNEP) ----------------------------------------------------------------------------------------------------- 13

Fig 17: HFC emissions in carbon dioxide equivalents. (greenpeace.org) ------------------------ 14

Fig 18: Map of countries with existing HFC regulations. (Zaelke, Borgford-Parnell and

Grabiel) --------------------------------------------------------------------------------------------------- 15

Fig 19: ‘Global average atmospheric abundances of four major HFCs used as ODS

replacements (HFC-134a, HFC-143a, HFC-125 and HFC-152a) since 1990. (UNEP) --------- 16

Fig 20: Flammability and GWP of alternatives. (Deol) -------------------------------------------- 16

Fig 21: Comparative analysis of challenges posed by various probable refrigerants. (Dalang)

------------------------------------------------------------------------------------------------------------- 17

Fig 22: The floor area break up of non-residential built spaces in India (noe21; cBalance

Solutions Hub) -------------------------------------------------------------------------------------------- 18

Fig 23: The floor area break up of built space in India. (noe21; cBalance Solutions Hub) ---- 18


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Fig 24: GHG emissions due to various sectors. (noe21; cBalance Solutions Hub) --------------- 19

Fig 25: Evolving landscape of sustainable habitats in India: genesis of GRIHA. (ADaRSH) --- 22

Fig 26: Energy savings in different cities due ECBC compliance. (ECO-III USAID | India; BEE) 24

Fig 27: Metabolic rate per activity. (ECO-III USAID | India; BEE) -------------------------------- 24

Fig 28: Insulation values for various kinds of clothing. (ECO-III USAID | India; BEE) ----------- 25

Fig 29: Conductivity of porous, fibrous cement board. (Szokolay) -------------------------------- 25

Fig 30: Example wall section: C and U and resistances which are additive. (Szokolay) ------ 25

Fig 31: Suitable wind speeds to achieve thermal comfort at various combinations of

temperature and humidity. (ECO-III USAID | India; BEE) ------------------------------------------- 26

Fig 32: Psychrometric Chart. ---------------------------------------------------------------------------- 27

Fig 33: Basic relationship expressed by the Psychrometric chart. (ECO-III USAID | India; BEE)

------------------------------------------------------------------------------------------------------------- 28

Fig 34: Representation of various air properties on the Psychrometric chart. ------------------- 28

Fig 35: Olgyay's bioclimatic chart, converted to metric, modified for warm climates. --------- 28

Fig 36: ASHRAE Summer and Winter Comfort Zones. (ECO-III USAID | India; BEE) ------------ 29

Fig 37: Comfort zone for warm and humid climate on Psychrometric chart. (ECO-III USAID |

India; BEE) ------------------------------------------------------------------------------------------------- 29

Fig 38: Five climatic zones of India. (ECO-III USAID | India; BEE)--------------------------------- 29

Fig 39: Heat exchange through building envelope. (ECO-III USAID | India; BEE) -------------- 31

Fig 40: Examples of heat transfer through the envelope during the day time and the night

time. (ECO-III USAID | India; BEE) --------------------------------------------------------------------- 31

Fig 41: Use of shading devices to control the sunlight during different seasons. (ECO-III USAID

| India; BEE) ---------------------------------------------------------------------------------------------- 32

Fig 42: Appropriate orientation. (ECO-III USAID | India; BEE) ------------------------------------ 32

Fig 43: Types of shading devices. (ECO-III USAID | India; BEE) ---------------------------------- 32

Fig 44: Use of thermal mass to produce time lag. (ECO-III USAID | India; BEE) ---------------- 33

Fig 45: Diagram representing the standard HVAC function. --------------------------------------- 34

Fig 46: Power consumption comparison in Watts ---------------------------------------------------- 36

Fig 47: Energy efficiency ratio comparison (kW cooling/kW Power) ---------------------------- 36

Fig 48: Direct Evaporative Air Cooling. --------------------------------------------------------------- 38

Fig 49: Working of Indirect Evaporative Cooling. -------------------------------------------------- 38

Fig 50: Vapour Absorption Cycle. --------------------------------------------------------------------- 39

Fig 51: Functioning of radiant cooling ---------------------------------------------------------------- 40

Fig 52: Radiant cooling from ceiling ------------------------------------------------------------------ 41


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PREFACE

The cooling and refrigeration needs in India are one of the significant sources of energy

demand throughout the country, and these needs and demands are rising at the similar rapid

pace as the economic development. The amount of energy (and related GHG emissions)

necessary to cool Indian building interiors in the years ahead will depend on how they are

designed and built today and in the coming years, the technology used for cooling, as well as

the behaviour and operation of the equipment by occupants of air conditioned spaces.

The proposed workshop series is a ‘beginning-of-pipe’ opportunity for achieving the goal of

cooling India’s building interiors more efficiently and sustainably. The proposed ‘Train-the-

Trainer’ workshop targets fourth year building services architecture faculty and practicing

architectures across Maharashtra. Experienced personnel from industry and academia will

share their knowledge, tools and case studies through presentations and modelling workshops

to empower and promote efficient and effective cooling. Sessions conducted during the

workshop will prepare and educate the participants with the insight and impact of

conventional cooling techniques and introduce them to various methods through which efficient

and sustainable cooling can be achieved. The workshop is designed to facilitate the following

two-way processes of learning:

o Dissemination of state-of-the-art information related to Energy Efficient Building Design

methodologies and relevant codes (ECBC etc.) which improve the Energy Performance

Index (EPI) of commercial and residential buildings

o Introduction to modelling techniques and educational content (toolkits and other

instructional material) developed in-house as well as drawn from other national efforts

related to Building Energy Efficiency (e.g. the BEEP project’s output products for

educational purposes)

o Site visits to reinforce learnings and obtain a design-based understanding of sustainable

cooling technologies and energy efficient building design

o Harnessing the didactic experience and curricula knowledge of teachers and professors

attending the workshop to devise a implementable detailed action plan for carrying the

program further to the ground-level in the shape of 3 to 4 day certificate programs for

students in the Architecture colleges

o Creating a curricula integration plan in conjunction with participating professors and

academicians to work towards formal curricula integration at the State Level for

Sustainable Cooling Technologies and ECBC code related education.

This workshop is part of the State of Geneva Funded ‘Fairconditioning’ programme’s

Academic Ambassador Vehicle. This is a vehicle where Fairconditioning’s implementation team

and advisory board members (which include domain experts in the field of climate change,

HVAC technology, and energy efficiency) engage with educational institutions to stimulate

learning, impart knowledge related to sustainable cooling technologies, natural refrigerant AC

systems and demand-side-management through advancing knowledge related to Energy


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Conservation Building Codes and their practical implementation in building design and

construction processes. Academic Ambassadors disseminate information using projects,

workshops and certification programmes that complement academic programme curricula in

the fields of energy studies, climate change studies, architecture,

mechanical/electrical/plumbing services (MEP) courses etc. Academic Ambassadors establish

collegiate steering committees that provide highly localised input and intelligence to tailor-

made certificate programs that seamlessly complement existing knowledge on the issue,

organise knowledge transfer and help to build capacity for teachers. In addition, the

Ambassadors engage with the student community to organise behavioural change campaigns

centred on appropriate thermostat settings for ACs.


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1. Climate Change, Ozone Depletion and Cooling

Systems

1.1 THE ENVIRONMENTAL CHALLENGE

Human kind has proven its unfortunate ability to affect the natural systems of Earth at the

planetary scale since scientists first observed the phenomena of Ozone depletion in 1970s. It

was one of the first phenomena that threatened the current human lifestyle and was caused by

anthropogenic emissions. Even though the depletion has been controlled through an aggressive

and cooperative international effort, there already is a permanent damage to the Ozone

layer which is hard to get back to pre-depletion levels (IPCC; TEAP). This serves as warning

for the human kind to be mindful of its actions. Similar to, but of a greater consequence is the

phenomenon of Climate Change that the world is facing today. Similar to Ozone depletion it

is of anthropogenic origin, but poses a greater threat to almost all the systems on Earth. The

major cause of these anthropogenic phenomena is an extraordinary amount of emissions

caused by resource consumption of human beings. One of the major group of resources

blamed to be responsible for causing Climate Change is that of carbon based compounds.

The resource consumption will only increase in future given the increasing living standards of

people world-wide. This will mean an exponential growth in emissions. With regards to cooling

systems, which were majorly responsible for releasing Ozone Depleting Substances (ODS)

earlier and now substances with high Global Warming Potential (GWP), their usage will

similarly increase with increased living standards. Considering India, with more than a billion

people with rising standards of livings, the enormous expansion in the air conditioning

requirements would not only mean rising emissions of high GWP refrigerants but also an

increased strain on the electricity grid. This in turn would require increase fuel import and

consumption, accelerating the global warming impacts (NRDC). In the following sections the

environmental challenges would be discussed in detail.

1.1.1 OZONE DEPLETION

The Ozone layer is the region in Earth’s atmosphere that consists around the stratosphere layer

of the atmosphere and is recognised by a higher concentration of the compound Ozone (O3),

relative to the other parts of the atmosphere. The Ozone layer is responsible for absorption of

most (~97%) of the Ultra Violet (UV) radiation coming out of the Sun (NASA). It is mainly

present in the lower portion of the stratosphere, at about 25 km above the Earth’s surface,

however the thickness varies from place to place and also around the year. It not only absorbs

UV radiation (and warming stratosphere) but also is greenhouse gas, warming the

troposphere. Therefore, Ozone plays a key role in regulating Earth’s climate (IPCC; TEAP).

In the late 1970s, it was observed that there is a significant decrease in concentration of

Ozone in the atmosphere. The decrease was steady with a rate of decline of about 3%. A

major depletion was observed over Polar Regions. The largest declines have been observed

over Antarctica during the spring season and is popularly known as the ‘Ozone Hole’. Here,

the declines have been up to 40-50% below the pre-depletion values. The Arctic region also

shows high yearly variations, with cold winters showing a dip of about 30% (IPCC; TEAP).


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Fig 1: The Oxygen-Ozone Cycle (Wikipedia)

Fig 2: Concentration of Ozone in Atmosphere (IPCC; TEAP)

Fig 3: Ozone as a UV filter and IR blocker (IPCC; TEAP)

The major anthropogenic ODSs have been identified as chlorofluorocarbons (CFCs), hydro-

chlorofluorocarbons (HCFCs) and halons (IPCC; TEAP). The refrigerant industry is the major

source of these substances. These ODSs are leaked in the atmosphere throughout their life


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cycle including production, usage and discarding. These chemicals travel up the atmosphere to

the stratosphere and break down the Ozone molecules (Environment and Energy Study

Institute).

Fig 5: Schematic representation of emissions due to the refrigerant industry (IPCC; TEAP)

The gases in red- CFCs, HCFCs,

Halons etc in the Fig 5,

contribute to Ozone depletion

as well as have global warming

potential. These are also the

gases that are controlled

through Montreal Protocol.

Whereas the gases in the same

figure shown in green are non-

Ozone depleting substances but

have high global warming

potential and contribute to

climate change. These gases are

included under the UNFCCC and

its Kyoto Protocol (IPCC; TEAP).

The presence of ideal amount of

Ozone in the atmosphere is

necessary for the human race as

well as several other species.

Weak Ozone concentrations

affect the amount of UV

radiation reaching Earth’s

surface and consequently results in various harmful effects. These effects include a higher

Fig 4: Projected Ozone concentration based on depletion rate of 1970s (NASA)


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chances of various types of skin cancers, cataract anomalies etc in human beings (de Gruijl)

(West, Duncan and Munoz). Along with human beings, rise in UV radiation also affects other

species, mostly as skin damages among them (Abbie). Additionally, rise in UV radiation also

affects major crops by affecting the leguminous bacteria present in their root systems (Sinha,

Singh and Hader). Hence, once the depletion was observed, it had become increasingly

important to control the emissions of ODSs.

Fig 7: Top: Time-series of de-seasonalised global mean. Bottom: Ozone concentration at Antarctica (IPCC; TEAP)

Fig 6: Vertical Ozone profiles measured by ozonesondes at South Pole station, Antarctica (IPCC; TEAP)


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1.1.1.1 The Montreal Protocol on Substances that Deplete the Ozone Layer

‘The Montreal Protocol on Substances that Deplete the Ozone Layer was

designed to reduce the production and consumption of ozone depleting

substances in order to reduce their abundance in the atmosphere, and thereby

protect the earth’s fragile ozone Layer. The original Montreal Protocol was

agreed on 16 September 1987 and entered into force on 1 January 1989.’

(UNEP)

The Montreal Protocol was a global agreement for the phase-out of production of ODSs. It

was signed and agreed upon by all major emitters, it has now been ratified by 196 countries.

The treaty required to restore the Ozone concentration by ending all production of ODSs and

employing substitute substances through a planned phase-out. It listed both, the first

generation1 and the second generation2 ODSs in the phase out plans. It handled each of the

recognised ODSs with a specific phase out plan. The phase out plan of CFCs is shown in the

figure (Fig 8) below as an example.

Fig 8: CFCs Production/Consumption Reduction Schedule (UNEP)

However, the phasing out of above mentioned ODSs gave rise to the usage of chlorine-less

Hydro-Fluoro-Carbons (HFCs). The HFCs are substances that do not cause Ozone depletion,

but have a high Global Warming Potential (GWP). This was still a problem since the world

has been facing another anthropogenic problem of global warming, and adding more gases

having high GWP to the atmosphere certainly does not seem desirable. The ODSs are

regulated under the Montreal Protocol, but the HFCs are not. The HFCs are currently included

among the group of Green House Gases (GHGs) that are regulated under the Kyoto Protocol

1 Halons, CFCs, carbon tetrachloride, hydrobromofluorocarbons (HBFCs), methyl chloroform, chlorobromomethane and methyl bromide

2 HCFCs


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to the United Nations Framework Convention on Climate Change (UNFCCC). The HFCs

emerged as the popular choice for coolants once the Montreal Protocol regulated a phase

down of other Ozone depleting coolants. The HFCs are majorly produced in developed

countries, and have replaced CFCs and HCFCs as per Montreal Protocol. There is a continuing

debate about how to regulate these HFCs. Whether they should be included in Montreal

Protocol or should they be addresses by Kyoto Protocol. Developed nations are in the favour

of HFCs being monitored by Montreal Protocol since it is this protocol that phased out CFCs

and HCFCs, and HFCs being a consequence of that. However, the developing nations like

India, China and Brazil want the emission and regulation of all GHGs to fall under the purview

of UNFCCCs and HFCs already are included in the basket of six GHGs (Bose).

The Montreal Protocol, however, has been very effective in curbing the usage of ozone

depleting substances. The world is free of CFCs, including the developing countries by 2010. In

1990, during the fourth meeting of Montreal Protocol, the developed countries pledged to

freeze the production and consumption of HCFCs too, by 2004 and completely phase them

out by 2020. The developing nations pledged the same but freezing by the year 2013 and

completely phasing out by 2030 (Bose). The consumption of HFCs has been rising ever since.

Fig 9: Worldwide emissions of ozone-depleting substances (ODS) and HFCs (A), global emissions of CO2 and HFCs (B), and HFC consumption for the period 2000-2050 (C), CFC data include all the main ODS in the Montreal Protocol except HCFCs. Emissions from different gas types are multiplied by their respective global warming potential to calculate emissions in GtCO2/year. (Velders, Fahey and Daniel)


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Fig 10: Global HFC Consumption. (Bose)

1.1.1.2 The F-gas Regulation

The European Union, unlike many other developed nations, has a legislation to regulate and

control the use of HFCs and is called the Fluorinated Gases Regulation or the F-gas Regulation

(Bose). The F-gases are a group of man-made gases that are used in various industrial

applications. These gases do not cause any harm to the Ozone layer and hence are increasing

replacing the ODSs. However, the F-gases are powerful greenhouse gases and have global

warming effect that is about 23,000 times more than carbon dioxide (European Commission).

The groups of F-gases that are being regulated are HFCs, perfluorocarbons (PFCs) and

sulphur hexafluorides (SF6).

The first regulation, adopted in 2006, succeeded in stabilising the F-gas emissions in EU at

2010 levels. The new & the latest regulation will be followed from 1st of January 2015. It

requires EU to cut the F-Gas emissions to two-thirds of 2014 levels by the year 2030. This is

in-line with EUs goal of cutting its overall GHG emissions by 80-95% of 1990 levels by the

year 2050. The expected cumulative emissions saving by 2030 is 1.5 G Tonnes of CO2e by

the year 2030 (European Commission).

1.1.2 CLIMATE CHANGE

1.1.2.1 Definition

Climate Change is a phenomenon where there is a change in the state of climate which can be

identified statistically. The changes occur in the mean and/or variability is observed in the

properties of climate (like temperature, precipitation, wind patterns etc), and this persists for

decades or longer. The changes in the climate over time can be due to natural reasons or

man-made reasons. However, the UNFCCC uses the term climate change in references to

changes in the climate that are directly or indirectly the results of human activities, which

change the properties of global atmosphere

Fig 11: The anthropogenic nature of climate change (US EPA)

Fig 12: Increase in greenhouse gas (GHG) concentrations in the atmosphere over the last 2,000 years. Increases in concentrations of these gases since 1750 are due to human activities in the industrial era. (US EPA)


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in addition to the expected natural climate variability (IPCC).

1.1.2.2 Evidence

It has been proven by various sources that the Earth’s climate is changing. The records already

show a rise in global average temperature by 1.40F in the last century, and is expected to

rise further by 2 to 11.50F by next century. This small rise in average temperature means huge

variations in the climate system of the planet and can result in catastrophic climate shifts and

weather events. The impacts of slight change in the global average temperature can already

be seen around the world. Many regions have seen a shift in rainfall patterns in recent years,

resulting in droughts, heavy rains and also frequent, and more severe, heat waves. The planet

also has also undergone some major changes in oceans and glaciers. The polar ice is getting

thinner and can be seen as receding every year in the recorded satellite images. The sea

levels are showing a rise due to increased glacial melting. Oceans have also become warmer

and more acidic (due to increase in absorption of carbon dioxide, concentration of which is

rising in the atmosphere). All these, and more, give a definite evidence of Earth moving

forward towards a Climate Change. (US EPA)

1.1.2.3 Causes

The Earth’s temperature is largely regulated by the greenhouse gases (GHGs) present in the

atmosphere (the amount of insolation3, and reflectivity of Earth’s surface/atmosphere being

two other major regulators). These gases are some specific compounds that allow the solar

radiation to come inside the atmosphere but do not allow the reflected radiation to go back

to the space. This happens because these compounds do not interfere with shorter wavelength

radiation that comes from sun but they block the longer wavelength (infra-red) radiation. This

phenomenon is known as ‘Green House Effect’. This phenomenon is necessary to support life on

Earth. However, during recent years, especially since the start of industrial revolution around

1750, concentrations of these GHGs have risen unprecedentedly due to various human

activities. The main activities that cause release of these GHGs are burning of fossil fuels,

deforestation, industrial processes and some agricultural practices. The recent increase in

global average temperature can only be explained by the sudden increase of GHG

concentrations in the atmosphere due to human activities, and not due to any natural

phenomena (US EPA).Fig 13: Global Average Temperature Fig 13 gives a clear

representation of the increasing global average temperature and if compared with Fig 12,

gives a definite relationship between increasing GHG concentrations in the atmosphere and

the rising temperature.

3 Insolation: Incoming Solar Radiation.


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Fig 13: Global Average Temperature (US EPA)

1.1.2.4 Impacts

The impacts of Climate Change have already started to be felt across the world. The impacts

being studied can be divided across various sectors including agriculture, coasts, ecosystems,

energy, forests, human health, international, society, transportation and water resources (US

EPA). A few of the extreme weather events have increased in frequency as well as intensity in

the recent decades, and are expected to further increase in the years to come. There would

also be increased risk to human health due to decreased air quality and diseases transmitted

by insects, food and water. Damages to infrastructure due to sea level rise, heavy

precipitation, extreme heat etc are projected to increase due to climate change. The ocean

waters are getting warmer and more acidic, affecting the oceanic systems. The disruptions to

agriculture are being noted and are projected to further increase in the future. Climate

change also poses risk to water resources, which can in turn result into conflicts (National

Climatic Data Centre, NOAA). “Climate-related impacts are occurring across regions of the

country and across many sectors of our economy. Many state and local governments are

already preparing for the impacts of climate change through "adaptation," which is planning

for the changes that are expected to occur.” (US EPA)

1.1.2.5 Kyoto Protocol

The Kyoto Protocol is an international agreement under UNFCCC. The Parties that commit to it

are bound by set emission targets. The protocol operates under “common but differentiated

responsibilities” principle; and puts a greater burden on the developed countries as it


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recognises the principal responsibility of these for the current high levels of GHG emissions in

the atmosphere as a result their industrial activities for past about 150 years. (UNFCCC)

“The Kyoto Protocol was adopted in Kyoto, Japan, on 11 December 1997 and

entered into force on 16 February 2005. The detailed rules for the implementation of

the Protocol were adopted at COP 7 in Marrakesh, Morocco, in 2001, and are

referred to as the "Marrakesh Accords." Its first commitment period started in 2008

and ended in 2012.” (UNFCCC)

An amendment was adopted in the protocol on 8th December 2012, in Doha, Qatar known as

“Doha Amendment to Kyoto Protocol”. The amendment assigned new commitments, revised the

list of GHGs, and amended several articles as per the new commitment period. The first

commitment period saw 37 industrialised countries and European community commit to reduce

their GHG emissions by 5% of 1990 levels. The second commitment period required a

reduction of 18% to the GHG emission, below 1990 levels during an eight year period of

2013 to 2020. The Parties to second commitment, however, are different than the first

commitment. (UNFCCC)

The UNFCC, under Kyoto protocol has identified six GHGs as the major contributors to the

greenhouse effect of atmosphere- carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O),

hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulphur hexafluoride (SF6). The HFCs

and PFCs have global warming potential thousands of time higher than CO2.

1.2 ROLE OF COOLING SYSTEMS IN CLIMATE CHANGE AND OZONE DEPLETION

The usage of cooling systems around the world is increasing, especially in the warmer parts. In

India there the cities are expanding and so is the market share of air conditioners. As the

income levels and living standards of the people rise, the usage of cooling systems is also

projected to rise. This will in turn result in a higher energy consumption, thus resulting in a

higher fossil fuel consumption and rising CO2 emissions. The emissions of HFCs would also rise.

The current usage of HCFCs, which are ozone depleting, is being phased down as per the

Montreal Protocol. However, the HCFCs are increasingly being replaced by HFCs, which would

further exaggerate the HFCs emissions. The HFCs are listed under the basket of GHGs that

are to be regulated through the Kyoto Protocol and have a very high global warming

potential. The phasing down of HCFCs, and the growing market of room and vehicle air

conditioning will lead to expansion of HFCs emissions quite significantly. This will accelerate

the global warming and hence the climate change. (NRDC)


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Fig 15: Trends in CO2eq emissions of CFCs, HCFCs, and HFCs since 1950 and projected to 2050. The HFC emissions scenarios are from (Velders, Fahey and Daniel) and (Gschrey, Schwarz and Elsner). The low-GWP HFC line represents the equivalent HFC emissions for a scenario where the current mix of emissions (with an average lifetime of HFCs of 15 years and an average GWP of 1600) was replaced by a mix of low GWP HFCs (with an average lifetime of less than 2 months or GWPs less than 20). (UNEP)

Fig 14: High Global Warming Potential of Select ODSs and HFCs (Environment and Energy Study Institute)

The governments around the world are struggling to control GHG emissions. The increase in

the usage of a small group of very powerful GHGs, if unchecked threaten to undo the efforts.

These gases are man-made fluorinated gases, popularly known as F-gases, and are mostly

used in refrigeration and air-conditioning. By the year 2005, these gases were responsible for

about 17% of climate change impacts (greenpeace.org). Even though the present contribution

of HFCs in climate forcing4 is less than 1% of all other GHGs combined, they are increasing

rapidly. The CO2e emissions of HFCs (except HFC-23) increased by approximately 8% p.a.

4 ‘A metric that accounts for climate effects caused by the use of a product, such as increased energy consumption .’ (UNEP)

Fig 16: Global consumption (in kilotonnes per year) of ozone depleting CFCs and HCFCs. The phasing in of HFCs as replacements for CFCs is evident from the decrease in CFC usage concomitant with the increasing usage of HFCs. Use of HCFCs also increased with the decreasing use of CFCs. HCFCs are being replaced in part by HFCs as the 2007 Adjustment to the Montreal Protocol on HCFCs continues to be implemented. Thus, HFCs are increasing primarily because they are replacing CFCs and HCFCs. (UNEP)


14 | P a g e

between 2004 and 2008 (UNEP). Further, by the year 2050, the annual emissions of HFCs

are projected to increase to about 3.5 to 8.8 Gt CO2eq. These are projected to be equivalent

to 7 to 19% of the CO2 emissions in 2050 based on IPCC’s SRES5, and equivalent to 18 to

45% of CO2 emissions based on IPCC’s 450

ppm CO2 emissions pathway scenario (UNEP).

Considering the high potential of the F-gases,

it becomes highly important to regulate the

usage. The refrigeration industry will have to

play a very decisive role. Some of the

developed countries already have a phasing

down of F-gases planned. The F-gas

regulation of the EU has already been

described previously. ‘The EU is currently

strengthening its broader f-gas regulations, with

a particular focus on HFCs As part of its

regulatory regime to control f-gases, the

European Directive on mobile air conditioning

systems already bans the use of f-gases with

GWPs higher than 150; new type vehicles are

covered as of 1 January 2013, and all vehicles

sold in the EU will be covered by 2017’ (Zaelke,

Borgford-Parnell and Grabiel). However, as

mentioned earlier it’s the developing countries

that are going to see a massive increase in F-gas consumption, and it is here that lies the

biggest challenge and responsibility for the refrigeration industry. The following figure (Fig

18) shows a map of countries that already have some kind of HFC regulations. As is evident

from the figure, only few countries have regulations for HFCs and there is need to expand it to

rest of the world.

5 Special Reports on Emissions Scenarios

Fig 17: HFC emissions in carbon dioxide equivalents. (greenpeace.org)


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Fig 18: Map of countries with existing HFC regulations. (Zaelke, Borgford-Parnell and Grabiel)

Air conditioning systems have three impacts on the climate. There is direct impact through

emissions of refrigerant GHG (HFCs etc), which has been discussed at length earlier. There are

also indirect impacts when there are emissions due to combustion of fuel to run the air

conditioning systems. The third is impact is due to resource consumption in production,

transportation, service and disposal of the product over its life cycle. The calculation of all the

impacts in a carbon dioxide equivalent metric is called Life Cycle Climate Impact (LCCP)

(NRDC; CEEW; TERI; IGSD). These impacts can be addressed by increasing the efficiency of

the processes as well as switching to low-GWP refrigerants. As identified by a report

published by UNEP on HFCs, there can be various alternative technical options to minimise the

impacts, and these have been divided into following three categories:

1. ‘Alternative methods and processes’: The aim here is to avoid the need of air

conditioners by using building insulations, and efficient building designs. These

alternative methods can either make use of air conditioners completely unnecessary, or

reduce significantly the usage and resource consumption of air conditioners due to

increase in efficiency. (UNEP)

2. ‘Using non-HFC substances with low or zero GWP’: The HFCs with high GWP can be

replaced with substances other than any kind of HFC, which have either zero GWP or

very low GWP. The examples for such substances can be hydrocarbons, ammonia,

CO2, dimethyl ether etc. (UNEP)

3. ‘Using low-GWP HFCs’: The HFCs that are currently used have a varied range of

atmospheric lifetimes and GWPs. Most of these HFCs have high GWP and an average

lifetime of about 15 years. However, there are several low GWP HFCs that are now

commercially available and have an atmospheric lifetime less than a few months! These

include HFC-1234ze which is used in foam products, and HFC-1234yf, used for mobile

air-conditioners. (UNEP)


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However, the replacement of ODSs

around the world have generally been

high GWP HFCs. Also, the developing

world that is still to shift from ODSs,

where HCFCs are still being used, will

majorly see a shift to high GWP HFCs as

replacements following the trend in the

developed world. Even though

alternatives to high GWP HFCs are

present, there are various barriers

present in the way of the switch from

high GWP HFCs to the zero of low

GWP alternatives. As per UNEP’s

synthesis report on HFCs, ‘these barriers

include: the need for further technical

developments, risks due to flammability

and toxicity, regulations and standards

that inhibit the use of alternatives,

insufficient supply of components,

investment costs, and lack of relevant skills among technicians’ (UNEP). Nonetheless, the usage of

alternatives in small amounts do portray that these barriers can be overcome. The alternatives

that are currently present have their own specific challenges and are portrayed in the

following figure.

Fig 20: Flammability and GWP of alternatives. (Deol)

Fig 19: ‘Global average atmospheric abundances of four major HFCs used as ODS replacements (HFC-134a, HFC-143a, HFC-125 and HFC-152a) since 1990. This illustrates the rapid growth in atmospheric abundances as a result of rapid increases in their emissions. These increases are attributed to their increased usage in place of CFCs and/or HCFCs. The increase in HFC-23, the second most abundant HFC in the atmosphere, are not shown since it is assumed that the majority of this chemical is produced as a byproduct of HCFC-22 and not because of its use as a replacement for CFCs and HCFCs. The abundance of HFC-23 was 22 ppt in 2008, with an annual growth rate of 0.83 ppt (roughly 4% per year) in that year’. (UNEP)


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Fig 21: Comparative analysis of challenges posed by various probable refrigerants. (Dalang)

As is evident from the figures above (Fig 20 & Fig 21), there is a range of alternatives

available. The challenges posed by these alternatives can easily be managed through

technological advancements. The best non-HFC options as per the comparison comes out to be

hydrocarbons and carbon dioxide. The best low-GWP HFC option can be HFC32 with a GWP

of 650 (Dalang).


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2. Energy Efficiency, Thermal Comfort and Cooling

Systems 2.1 BUILDING ENERGY PERFORMANCE IN INDIA

Buildings are responsible for about 8% of GHG emissions worldwide and 33% of energy

related emissions (United Nations Environment Programme). The energy consumption in India is

quite different than the developed world but is likely to follow them in coming years

(Chaturvedi, Eom and Clarke). In the wake of predicted climate change and India’s voluntary

commitment to reduce its GHG emissions, building sector becomes one of the high priority

sectors. The creation of National Mission on Sustainable Habitat under National Action Plan on

Climate Change (NAPCC) by the Government of India with one of its key part being energy

efficiency in buildings, also highlights its importance. For developing economies, economic

growth is priority and cannot be sacrificed to achieve the required reduction. Increase in the

he energy efficiency (EE) of the current building systems and enforcement of EE on the new

constructions would provide one of the achievable alternatives.

In India, the residential and commercial sector consumed 47% of the total final energy

consumption (IEA (International Energy Agency)). The consumption is growing at the rate of 8%

per year (Rawal, Vaidya and Ghatti). India already experiences an electricity shortage of

9.9% and a peak demand shortage of 16.6% (Central Electricity Authority). Moreover, as

projected, 40% of India’s population will stay in urban areas by 2030 (McKinsey Global

Institute). A rapid urbanisation will result in a very high growth rate of the commercial sector

that will have to provide jobs and services to a huge population. As stated by a few research

papers, only 33% of the total floor space area that would exist in 2030, is present currently.

Commercial sector is growing at a tremendous rate of 13% (Mewada, Rawal and Shukla). This

provides the commercial building sector with a huge potential to save energy. If proper

measures are taken, and if Energy Conservation Building Code (ECBC) is followed, a building

can save as much as 40% of its actual energy consumption (Rawal, Vaidya and Ghatti).

In the year 2010, India was estimated to have 4.5 billion square metre (sq.m) of built space,

further, it’s projected to grow 10 folds to 41 billion sq.m by 2030. By 2030, 60% of the

commercial space in India would be air conditioned and 40% of the urban residential area

will have more than one air conditioning units. The number of Window and Split ACs in

operation in India are expected to grow from 4.7 million in 2010 to 48 million in 2030.

(noe21; cBalance Solutions Hub)

Fig 23: The floor area break up of built space in India. (noe21; cBalance Solutions Hub)

Fig 22: The floor area break up of non-residential built spaces in India (noe21; cBalance Solutions Hub)


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India’s commercial building have an Energy Performance Index6 (EPI) that varies between 200

and 400 kWh/sq.m/year. It has also been observed that the EPI of conventional buildings are

generally about 50% higher than the EPI of energy efficient buildings. In a conventional

building lighting would consume about 37-60 kWh/sq.m/year whereas in a low energy

building it would consume about 21-28 kWh/sq.m/year. Similarly, if electricity consumption

due to cooling loads are compared, conventional buildings consume on average 263

kWh/sq.m/year and low energy buildings consume 195 kWh/sq.m/year. (noe21; cBalance

Solutions Hub)

As mentioned earlier, the building sector consume about one third of the total electricity

consumed in India, further, its growth rate is also notable with commercial sector growing at a

rate of 13% and the residential sector growing at 9%. This puts an immense pressure on the

power generation in India, with 2,956 MW in 2012 and projected 22,022 MW in 2031 just

by window and split ACs. It also contributes significantly to India’s Greenhouse Gas Emissions/

Carbon Footprint; the Carbon Footprint of just Window and Split ACs in 2031 will be 187.5

million tonnes of CO2e or the equivalent of 750 million lesser trees. (noe21; cBalance Solutions

Hub)

Fig 24: GHG emissions due to various sectors. (noe21; cBalance Solutions Hub)

2.2 GOVERNMENT POLICIES AND REGULATIONS

2.2.1 NATIONAL ACTION PLAN ON CLIMATE CHANGE (NAPCC)

The birth of NAPCC can be traced back the first meeting of Prime Minister’s Council on

Climate Change on 13th July 2007. In that meeting the council decided that “A National

Document compiling action taken by India for addressing the challenge of Climate Change, and

the action it proposes to take” be prepared (Prime Minister's Council on Climate Change). This

consequently resulted in creation of National Action Plan on Climate Change by the

Government of India. The NAPCC identifies the development goals for India along with

identifying the co-benefits that address the climate change. It recognises specific opportunities

that promote development as well as fulfil objectives related to both adaptation to the

impacts of climate change and mitigation of GHG emissions. The NAPCC also recognises

India’s handicap with necessary financial and technological resources required to meet the

threats from climate change. Hence, it proposes the need to identify and prioritise strategies

6 Energy Performance Index or EPI is the ratio of total annual energy consumption of a building and the total floor area of the building. The general unit for EPI is kWh/sq.m/year.


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that promote development goals, keeping the poor in mind while also serving specific climate

change objectives.

There are a total of eight national missions proposed by the NAPCC:

1. National Solar Mission

This mission is aimed at exploiting vast solar resources that the country possess. India is

a tropical country where solar radiation is available in adequate quantities. The main

aim of the mission is to significantly increase to share of solar energy in the energy mix

of the country.

2. National Mission for Enhanced Energy Efficiency

Implementation of energy efficiency through Bureau of Energy Efficiency (BEE) in the

Central Government and designated agencies in each state, is legally mandated by

The Energy Conservation Act of 2001. This mission directly promotes energy efficiency

in the cooling systems.

3. National Mission on Sustainable Habitat

National Mission on Sustainable Habitat deals directly with increasing efficiency in the

physical infrastructure of human settlements. It aims at improvement of energy

efficiency in buildings, promotion of public transport and management of solid waste.

The aim of improving energy efficiency in buildings directly promotes either designing

buildings that do not require conditioning or using conditioners that are energy

efficient as well as mitigate climate change by controlling GHG emissions.

4. National Water Mission

5. National Mission for Sustaining the Himalayan Ecosystem

6. National Mission for a Green India

7. National Mission for Sustainable Agriculture

8. National Mission on Strategic Knowledge for Climate Change

The implementation is expected to be carried out by institutionalising each of the missions. The

organisation would be through inter-sectoral groups that would include related Ministries,

Ministry of Finance, Planning Commission, and experts from the industry, academia and civil

society. (Prime Minister's Council on Climate Change)

2.2.2 LEADERSHIP IN ENERGY AND ENVIRONMENTAL DESIGN (LEED)7

LEED stands for Leadership in Energy and Environmental Design. It is a voluntary, consensus

based national standard for developing high performance, sustainable buildings. LEED was

created to define ‘Green Building’ by establishing a common standard of measurement for

green buildings. It is supposed to promote integrated, whole-building design practices and

recognize environmental leadership in the building industry. It is also aimed at stimulating a

‘green’ competition in the market. LEED has also successfully raised consumer awareness of

green building benefits. LEED standards and certifications are managed by United Stated

Green Building Council (USGBC) and certifications are available for:

Building Design and Construction (LEED BD+C)

Interior Design and Construction (LEED ID+C)

Existing Building: Building Operation and Maintenance (LEED EB: O+M)

7 Source of the content: (IGBC) & http://in.usgbc.org/certification


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Neighbourhood Development (LEED ND)

LEED Homes

Each of these certifications then award a ‘level’ of certification to the project based on the

degree of compliance to the set guidelines, in terms of points awarded. The certification level

and their respective points are as follows:

Certified: 40-49 Points

Silver: 50-59 Points

Gold: 60-79 Points

Platinum: 80+ Points

LEED in India was mobilised by IGBC, and was the key driver in establishing it. USGBC and

IGBC continue their collaboration in promoting green buildings in India. However, the LEED

projects in India registered after June 2014, would be certified by Green Building

Certification Institute (GBCI). LEED is a voluntary certification program.

2.2.3 INDIAN GREEN BUILDING COUNCIL (IGBC)8

In India, one of the green building rating systems is managed by Indian Green Building

Council (IGBC), which was formed in the year 2001. IGBC is a part of Confederation of

Indian Industry (CII).

‘The vision of the council is, "To enable a sustainable built environment for all

and facilitate India to be one of the global leaders in the sustainable built

environment by 2025".’ (IGBC)

IGBC rating system, like LEED, are voluntary. Initially the certifications given by IGBC were

based on LEED certifications by USGBC. IGBC has now, however, evolved into a more context

specific certification system and has rolled out various new certifications. These certifications

are awarded by. Currently there are nine possible certifications:

IGBC Green New Buildings

IGBC Green Existing Buildings

IGBC Green Homes

IGBC Green Schools

IGBC Green Factory Building

IGBC Green Townships

IGBC Green SEZs

IGBC Green Landscapes

IGBC Green Mass Rapid Transit System

These certification have slightly different criteria for measurements, however the rating are

almost similar for all of them being named as Certified, Silver, Gold and Platinum; Platinum

being the highest rating. The criteria for measurements are generally performance in the

following sectors:

8 Source of the content: (IGBC)


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o Sustainable Site Management

o Water Efficiency

o Energy Efficiency

o Sustainable Material Usage

o Health & Comfort

o Innovation in Design etc.

All these sectors have specific targets, attaining which earns some specific points for the

project. The total points earned by the project is used to give a rating to the project. For

example, in ‘IGBC Green New Buildings’ certification, if a building earns 90-100 points, it

gets super platinum rating; 80-89: platinum rating; 70-79: gold rating; 60-69: silver rating;

and it needs to get at least 50 points to be certified.

2.2.4 GREEN RATING FOR INTEGRATED HABITAT ASSESSMENT (GRIHA)9

GRIHA was adopted as the national rating system for green buildings by the Government of

India in the year 2007. GRIHA is also a voluntary rating system. The Energy and Resource

Institute (TERI) played an important role in converging various initiatives which are effective in

implementation and mainstreaming of sustainable habitat. With decades of experience, TERI

developed GRIHA. GRIHA is tailored to suit the building industry in India. A timeline of

evolution of sustainable habitats in India is shown in the following figure.

Fig 25: Evolving landscape of sustainable habitats in India: genesis of GRIHA. (ADaRSH)

The GRIHA rating system was developed to help ‘design and evaluate’ new buildings. The

buildings are assessed for their predicted performance over the lifetime. It has identified three

stages of lifetime for the evaluation:

Pre-construction Stage

Building Planning and Construction Stages

9 Source of the content: (ADaRSH)


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Building Operation and Maintenance Stage

The GRIHA rating has 34 different criteria for evaluation, 8 of which are mandatory. It is a

100 point system. The levels of certification are similar to LEED and IGBC, however they are

denoted by number of stars. There are total five levels of certification, with 50 being the

minimum points to earn a certification and get one star. There are currently four different

kinds of certification awarded by GRIHA which include Sva GRIHA Rating for buildings with

built up area (BUA) less than 2,500 sq.m, GRIHA Rating for buildings having more than 2,500

sq.m BUA, GRIHA for Large Development for large townships, and GRIHA Pre-Certification for

all buildings except industrial complexes.

2.2.5 ENERGY CONSERVATION BUILDING CODE (ECBC)

The ECBC is proposed as a mandatory enforcement code which was launched by Ministry of

Power, Government of India in May 2007. It has been developed and improved by Bureau of

Energy Efficiency (BEE) in association with ECO-III Project by USAID. The code expected to

facilitate India to a big leap towards energy efficiency given its considerable potential for

energy saving coupled with fast growing building sector (ECO-III | USAID India). The main

objectives of ECBC as per (ECO-III | USAID India) are as follows:

Provide technical support to BEE to implement the ECBC in a rigorous manner

Develop reference material and documentation to support the Code

Develop ECBC Training material for workshops and training programs

Develop a road map for ECBC implementation

The code is applicable to commercial buildings with a connected electrical load greater than

100 kW or a contract demand greater than 120 kVA. The code is designed keeping in

consideration the five climate zones of the country. It regulates building thermal performance

and energy use, making them efficient. It encourages the use of passive techniques like

increased day-lighting, shading, natural ventilation, solar energy etc. It focuses directly on the

energy performance of the buildings rather than the green building design. (ECO-III USAID |

India; BEE) The mandatory and prescriptive requirements of the code are outlines as energy

performance in the following criteria (ECO-III USAID | India; BEE):

Building Envelope

Heating, Ventilation and Air Conditioning (HVAC)

Service Hot Water and Pumping

Lighting

Electrical Power


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Fig 26: Energy savings in different cities due ECBC compliance. (ECO-III USAID | India; BEE)

2.3 THERMAL COMFORT

The main purpose of a building is to provide shelter with adequate amount of comfort to the

occupant. Thermal comfort for the occupant is one of the necessary objectives. Thermal comfort

is guaranteed by keeping the interior environment within certain limits of air properties like

temperature, humidity etc. Thermal comfort can be defined as ‘that condition of mind which

expresses satisfaction with the thermal environment and is assessed by subjective evaluation’

(ECO-III USAID | India; BEE). The parameters to measure the thermal comfort can be divided

into two kinds: personal parameters influenced by personal choices and environmental

parameters influenced built design- building envelope and HVAC. The personal parameters

consist of activity (human metabolic rate) and clothing; whereas the environmental parameters

consist of air temperature, mean radiant temperature, air speed and humidity.

2.3.1 PERSONAL PARAMETERS

2.3.1.1 Activity (Human Metabolic Rate)

The degree of thermal comfort that

an occupant feels is hugely affected

by her body metabolic rate. The

metabolic rate is the rate of change

of the stored chemical energy in the

human body to heat and mechanical

work. This is usually expressed in

terms unit area of the total body

surface or met units. 1 met is equal

to 58.2 W/sq.m and is equal to

energy produced due to metabolism per unit surface of the body of a person seated at rest.

2.3.1.2 Clothing Insulation

The type and layers of clothing that a person provides insulation to the body and controls the

thermal comfort attained. The unit of measurement for the clothing is ‘clo’. One clo is said to be

equal to 0.155 sq.m-K/W worth of insulation.

Fig 27: Metabolic rate per activity. (ECO-III USAID | India; BEE)


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Fig 28: Insulation values for various kinds of clothing. (ECO-III USAID | India; BEE)

2.3.2 ENVIRONMENTAL PARAMETERS

To understand the environmental parameters it is imperative to understand the physics of heat.

2.3.2.1 Physics of Heat: Heat and Temperature

Heat is a form of energy that is contained in substances owing to the molecular motion, or in

space as electromagnetic radiation. It has same units as that of energy (joule), which is the

ability to do work. Temperature is the measure of heat in a substance. It has various scales,

one of them is Celsius, which is based on the phases of water and the freezing point is

denoted as 00C while the boiling point as 1000C. Another scale is called Kelvin and is based

on absolute zero, and starts at total absence of heat. (Szokolay)

2.3.2.2 Physics of Heat: Heat Flow

Heat due to its properties can flow from one substance with higher heat content to another

with lower heat content. The flow is similar to water flow from a higher position to a lower

position. The transfer of heat happens in the following ways:

Conduction: This happens within a body or when the bodies are directly in contact,

through spread of molecular energy from one part to another.

The conduction of a substance depends on its property called conductivity which is

measured in W/m-K. Material with low conductivity are good insulator. The

conductivity of a porous, fibrous cement insulating board is given in the following

table:

Fig 29: Conductivity of porous, fibrous cement board. (Szokolay)

Conductivity is the property of material regardless of its

shape or size. The property of a physical body, like

window, is called conductance (C) and is measured between

Fig 30: Example wall section: C and U and resistances which are additive. (Szokolay)


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two sides of the body. Transmittance, or U-Value includes the surface effects also and is

the most frequently used measure with W/sq.m-K as the unit. The reciprocal of U-value

is Resistance (R).

Convection: The transfer happens through surface (from solid body to liquid), or within

a substance due to movement of mass (heating of water). The rate of transfer depends

on area of contact, difference of temperature and the convection coefficient which

depends physical properties of the substance.

Radiation: Radiation occurs through space from a warmer surface to the cooler

surface. Thermal radiation is a wavelength band of electromagnetic radiation.

2.3.2.3 Air Temperature

Air temperature is measure of the heat content of air. It is normally measured in degrees

Celsius (0C) or degrees Fahrenheit (0F). The comfort temperature varies depending upon

geographical location, and also the local season, however it mostly varies between 240C to

270C. There are various models to predict the comfort temperature or neutrality temperature

(Szokolay). The neutrality temperature is a subjective term and can change from person to

person, also.

2.3.2.4 Mean Radiant Temperature

It is also important to discuss another term here called Mean Radiant temperature (MRT). ‘It is

the uniform temperature of an imaginary black enclosure in which radiant heat transfer from the

human body equals the radiant heat transfer in the actual non-uniform enclosure’ (ECO-III USAID

| India; BEE). It is the spatial average of weighted surface temperature around the occupant,

weighted by their view factors with respect to the occupants.

2.3.2.5 Air Speed

Air speed is the average speed of air that an occupant experiences. Air speed affects the

thermal comfort of the occupant as it accelerates the convection and changes the surface heat

transfer coefficient of the skin and clothing. It also increases the evaporation from the skin.

Thus, producing cooling effect (Szokolay). The following tables give comfort wind speeds at

various temperatures:

Fig 31: Suitable wind speeds to achieve thermal comfort at various combinations of temperature and humidity. (ECO-III USAID | India; BEE)


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2.3.2.6 Humidity

Humidity represents the moisture content in the air. It is expressed in various terms like relative

humidity, vapour pressure, dew point temperature etc; and it affects the latent cooling load of

the air (ECO-III USAID | India; BEE). “Medium humidities (RH 30% to 65%) do not have much

effect, but high humidities restrict evaporation from the skin and in respiration, and thus kerb the

dissipation mechanism, whilst very low humidities lead to drying out of the mucous membranes

(mouth, throat) as well as the skin, thus causing discomfort.” (Szokolay)

2.3.3 PSYCHROMETRIC CHART

Psychrometric is the study of thermodynamic properties of moisture content of atmospheric air.

In the building industry it is normally taken to be meant for the study of atmospheric moisture

and the way it affects the buildings (ECO-III USAID | India; BEE). The psychrometric chart

represents several atmospheric properties and their relationships that facilitate the study.

Fig 32: Psychrometric Chart.

To understand and read the psychrometric chart, it is important to be familiar with various

terms that represent the properties of atmospheric air. These are explained as follows:

Dry Bulb Temperature: It is the air temperature measured by a simple thermometer. It is

shown on the bottom axis of the psychrometric chart.


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Relative Humidity: It is the ratio of the actual vapour pressure to the vapour pressure of

the saturated air at the same temperature, expressed as percentage. These are curved

lines that move upwards to the left in the psychrometric chart.

Wet Bulb Temperature: It is the air temperature measured with a common mercury

thermometer whose bulb is covered with a moistened wick, with a known air velocity over

it. These are straight lines that slope upwards to the left in the psychrometric chart.

Dew Point: The temperature at which water vapour starts to condense. This temperature is

read by following a horizontal line from the state-point (found earlier) to the saturation

line.

Specific Volume: It is the space occupied by a unit weight of dry air.

Humidity: It is the moisture content of unit weight of air, expressed in weight of water

vapour per unit. The vertical axis on right hand of the psychrometric chart represents

humidity.

Enthalpy: It is the energy

content per unit weight of air.

2.3.4 THERMAL COMFORT INDICES AND ZONES

There is a certain range of

values of atmospheric

properties where occupants

generally feel thermally

comfortable. This range

varies based on geographic

location of the building. This

range is known as the

Comfort Zone. One of the

first attempts of graphically

representing this was made

by Olgyay (1953), his

‘bioclimatic chart’ is shown in

Fig 33: Basic relationship expressed by the Psychrometric chart. (ECO-III USAID | India; BEE)

Fig 34: Representation of various air properties on the Psychrometric chart.

Fig 35: Olgyay's bioclimatic chart, converted to metric, modified for warm climates.


29 | P a g e

the adjacent figure (Szokolay).

The following figures show various other

representations of comfort zone:

A comfort index is an effort to create a single figure that would express the combined effect

of several relevant environmental variables. Over several years, at-least thirty such indices

have been developed based on different studies and having different representations

(Szokolay). Olgyay’s bioclimatic chart is one of them. A couple of the recent and popular

indices are mentioned below:

Predicted Mean Vote (PMV): ‘An index that predicts the mean value of the votes of a large

group of persons on the seven point thermal sensation scale.’ (ECO-III USAID | India; BEE)

Predicted Percentage Dissatisfied (PPD): ‘An index that establishes a quantitative prediction of

the percentage of thermally dissatisfied people determined from PMV.’ (ECO-III USAID | India;

BEE)

2.3.5 OTHER FACTORS

There are several other factors that

influence the thermal comfort of occupants.

These can be classified as external and

internal factors. The external factors

include the climatic parameters like solar

radiation, wind velocity, precipitation,

cloud cover, atmospheric pressure etc. The

solar radiation can be subdivided into

direct solar gain normal solar radiation.

The building can gain heat through direct

or indirect solar radiation. Wind velocity is

governed by differences in atmospheric

pressure, which is caused by difference in

surface characteristic (land, water etc) and

Fig 37: Comfort zone for warm and humid climate on Psychrometric chart. (ECO-III USAID | India; BEE)

Fig 36: ASHRAE Summer and Winter Comfort Zones. (ECO-III USAID | India; BEE)

Fig 38: Five climatic zones of India. (ECO-III USAID | India; BEE)


30 | P a g e

its heating due to solar radiation. The wind velocity affects the indoor comfort conditions by

influencing the convective heat exchanges of building envelope as well as indoor space.

Precipitation includes all forms of water like rain, hail, snow etc. It affects the indoor

environment by cooling the structure and also bringing the local temperature down. Cloud

cover directly regulates the amount of insolation and also the amount of heat that radiates

back to the space from the atmosphere. Atmospheric pressure is the factor that determines the

evaporation rate and in turn the rate of evaporation of sweat from the human body. All these

external factors, and the prevalent atmospheric properties based on the regional climate

have been used to divide the country into five climatic zones. The areas in particular climatic

zone have similar combination of these climatic factors. The five climatic zones of India are hot

& dry, warm & humid, composite, temperate and cold (Fig 38).

The internal factors are those factors that influence the indoor thermal environment from the

inside of the built space. These are known as internal heating/cooling loads. These include

heat generated by the occupants themselves, heat generated by the equipment being

operated inside, number and type of lights etc.

3. Sustainable Cooling Technologies (End-of-Pipe

Solutions) 3.1 PASSIVE COOLING TECHNOLOGIES10

Passive cooling techniques refer to an approach of designing the cooling systems of building

that it requires nil or very low energy consumption. This approach involves either reducing heat

gain from outside or increasing heat loss from inside or both. This is done by using various

design techniques and controlling the building design elements. The heat energy transmission

or exchange in any building happens through the envelope of building. The building envelope

is the external skin of the building that separates the indoor environment from the external

environment.

10 Source of the content: (ECO-III USAID | India; BEE)


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Fig 39: Heat exchange through building envelope. (ECO-III USAID | India; BEE)

Fig 40: Examples of heat transfer through the envelope during the day time and the night time. (ECO-III USAID | India; BEE)

To control the heat transfer through the building envelope there are various techniques that

can be used and are characterized into three main categories: Appropriate Orientation;

Shading Devices Design; Thermal Mass Design.

3.1.2 APPROPRIATE ORIENTATION

Building orientation plays a very important in controlling the

amount of heat gained by the building due to insolation, and

also the ventilation. It also controls the amount of daylight

penetration inside the spaces. All these factors affect the energy

usage by the lighting and HVAC systems in the buildings.

Appropriate orientation can help achieve optimal thermal (and

visual) comfort. The orientation that maximises the Northern and

Southern façades whilst reducing the Eastern and Western

façades, maximises the daylight penetration and also help


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control heat gain due to horizontal sun on the Eastern and Western façades.

3.1.3 SHADING DEVICES DESIGN

Shading devices are mechanism to shade the parts of building

envelope (windows) from natural elements like wind,

precipitation and insolation. These can be aptly designed to control heat gain in the building

and consequently reduce cooling energy use. The shading devices are also used to eliminate

glare and provide enhanced visual comfort.

There are several types of shading

devices and each can be controlled to

increase their efficiency. External shading devices can be

tweaked to maximise the daylight penetration while

controlling the heat gain. The south windows can have horizontal projections the length of

which can be calculated using sunpath diagrams11. The East and West windows can have

vertical projections. Although there is no direct insolation on the North side, shading devices

are needed to control the glare. There are also various internal devices available as passive

techniques, however they have limited abilities and are mostly used as glare control.

3.1.4 THERMAL MASS

Thermal mass is the ability or the capacity of a physical body to store heat and its units are

J/0C or J/K. Thermal mass of a homogenous body is the mass of material multiplied by the

specific heat of the material. Thermal mass provides a storage, and hence a lag, for

temperature gains or fluctuations and is known as Time Lag. Thermal mass of a body can be

used to effectively control heat gains, e.g. absorb heat during the day to keep the interior

cool and release the heat during the night to warm the interior. Traditionally thick walls made

of earth, stone etc have been used as thermal mass.

11 Sunpath diagrams are visual representations of the three dimensional paths that the sun takes with respect to a stationary point on earth, throughout the day and throughout the year.

Fig 42: Appropriate orientation. (ECO-III USAID | India; BEE)

Fig 41: Use of shading devices to control the sunlight during different seasons. (ECO-III USAID | India; BEE)

Fig 43: Types of shading devices. (ECO-III USAID | India; BEE)


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Fig 44: Use of thermal mass to produce time lag. (ECO-III USAID | India; BEE)


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3.2 ACTIVE COOLING TECHNIQUES

3.2.1 HVAC SYSTEM LEVEL DESIGN

Fig 45: Diagram representing the standard HVAC function.

Air-conditioning is the process that allows specific temperature, relative humidity and air purity

conditions to be created and maintained in a closed environment. Independently of the

external climatic conditions, this process ensures, by controlling four variables (temperature,

humidity, air movement and air quality), personal comfort, the correct storage of objects or

mechanisms, and the maintenance of the correct conditions for certain phases in industrial

processing. The main process that air-conditioning is based on is the exchange of heat and

water vapour between the inside environment, the outside environment and the people

present. The various components of a standard HVAC system is shown in the Fig 45. Among all

the components of the HVAC system, the compressor holds the greatest potential for saving

energy.

The role of compressor in a refrigerant circuit: The refrigerant has properties whereby it

evaporates at a low temperature and pressure, absorbing heat, and then gives up this heat

by condensing at a higher temperature and pressure. This procedure requires the contribution

of energy. The compressor is the element that represents the heart of the refrigerant circuit. Its

purpose is to control the circulation of refrigerant inside the circuit, drawing in gas refrigerant

at low pressure and low temperature, and delivering it at a higher pressure and temperature.


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It draws in the superheated gas refrigerant arriving from the evaporator, compress it, and

then deliver it to the condenser, where it will become liquid again. The mechanical operation

of the compressor implies an increase in the heat contained in the vapour. The compression

increases the pressure of the vapour and consequently its temperature. In a refrigeration

system, the refrigerant is used to absorb heat from one area and transfer it to another. As a

result, it is important to optimize the rate of heat transfer. To ensure this, the materials used

must feature good thermal conductivity, such as copper and aluminium.

Types of Compressors

Reciprocating compressors (divided into hermetic, semi-hermetic and open-type) are

mostly used for applications with higher capacity requirements.

Rotary compressors, including scroll, vane and screw compressors (suitable for high

capacity applications, up to 1200 kW) and centrifugal compressors (used for applications

that require higher capacities).

Coefficient of Performance (CoP): To control and measure the efficiency of an HVAC system,

it is important to understand the Coefficient of Performance (CoP) of an HVAC system. The

CoP of a system is the ratio of heating or cooling provided to the electricity consumed by the

system. The CoP of any system is generally below 1 as it is expected that the system will lose

energy to the atmosphere. Higher the CoP, higher is the energy efficiency, and is generally

dependent on external climatic conditions as well as the general status of maintenance.

3.2.2 EFFICIENT COOLING- NATURAL REFRIGERANT HVAC SYSTEMS

Natural refrigerants are chemicals which occur in nature’s bio-chemical processes. These can

be used as cooling agents in refrigerators and air conditioners. The natural refrigerant do not

deplete the ozone layer and make negligible contribution to global warming. Natural

refrigerants also provide high efficiency which means lower indirect contribution to global

warming than many standard HVAC systems. Natural refrigerants also deliver on the Montreal

and Kyoto Protocols and have no or very low GWP. These refrigerants can be used in split AC

systems as well as central AC systems. Natural refrigerant can be divided into three

categories:

Hydrocarbons: Propane (R920), Propylene (R1270), R600a

Ammonia

Carbon dioxide


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Fig 46: Power consumption comparison in Watts

Fig 47: Energy efficiency ratio comparison (kW cooling/kW Power)

Applications and Limitations

Ammonia

Application: Large air conditioning systems (chillers), commercial & industrial refrigeration

(storage, food, brewing, heat extraction, ice rinks etc.)

Limitation: Ideal & efficient refrigerant if used in accordance with national safety

standards and codes of practice.

Carbon Dioxide

Application: Static/mobile air conditioning systems, warehousing, commercial refrigeration,

chill cabinets and vending machines, process chilling, low- and ultra-low temperature

applications.

Limitation: Often used as a secondary refrigerant along with ammonia, thereby opening

up applications where ammonia as a single-stage refrigerant would not be applicable.

Hydrocarbon Refrigerants

Applications: Industrial and domestic air conditioning, domestic appliances, commercial and

industrial refrigeration, chill cabinets and vending machines, heat pumps, low- and ultra-

low temperature applications.


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Limitation: Extremely inflammable.

3.2.3 EFFICIENT COOLING- DIRECT & INDIRECT EVAPORATIVE COOLING SYSTEMS

Evaporative cooling systems work on the same principle as perspiration on the human body. As

air passes over the skin evaporation takes place and a cooling effect is felt. Evaporative air

coolers use filter pads as the cooling outer skin and a fan draws air through the water-soaked

pads, evaporating the water and cooling the air that is then blown into the house. A

temperature reduction of as much as 20 degrees can be achieved using this system of cooling.

Evaporative cooling is considered one of the most efficient systems in areas of low humidity.

However, in humid areas these systems do not work very efficiently as the high humidity

content in the air discourages the evaporation, which in turn does not let the air temperature

drop. In dry area, on the other hand, less moisture content facilitates the evaporation and

hence temperature reduction.

Two basic types of evaporative coolers:

Direct Evaporative Coolers– In these coolers, the fan moves the supply air past a wetted

media, adding moisture to the supply air stream to accomplish the evaporative cooling effect.

Indirect Evaporative Coolers– No direct contact between the supply and the room air. Hence,

no added moisture. Indirect evaporative coolers can be used in conjunction with direct

evaporative cooler and/or with refrigerated air coolers. The combination has a higher first

cost, but offers a good mix of energy conservation, comfort and is reliable.

Constraints (Direct Evaporative Cooling)

These systems provide more comfort hours during the humid weeks, yet still are not designed

to maintain comfort. Evaporative cooling systems add moisture to the air, thus may not be

ideal for high humidity regions. Relatively short service life of aspen media pad coolers. Need

for seasonal maintenance. Reduced cooling performance during wet season.

Applications (Evaporative Cooling)

Industries – An energy efficient solution for industry. Provides comfort to staff from hot indoor

climate, thus leading to reduction in errors and increased productivity.

Commercial – Evaporative cooling media can be ordered in customized sizes to fit in any air

handling unit, thus improving the working environment of the businesses.

Residential – The evaporative cooler can be used to fit specific residential requirements.

Poultry Industry –Vital for optimizing the air quality during periods of hot weather. By

maintaining lower air temperatures, heat-stress related problems are reduced.

Horticulture Industry – A consistent air temperature is very important inside a greenhouse.

Evaporative-cooled houses ensure the balance of temperature.


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Fig 48: Direct Evaporative Air Cooling.

Fig 49: Working of Indirect Evaporative Cooling.

3.2.4 EFFICIENT COOLING- VAPOUR ABSORPTION

Vapour Absorption chiller machine (VAM) produces chilled water using a heat source rather

than electrical input as in the case of vapour compression cycle. Its working is explained as

follows: An electric chiller employs a mechanical compressor creating the pressure difference

necessary to circulate the refrigerants whereas the absorption chiller uses a heat source. A

secondary fluid or absorbent is used to circulate the refrigerant. The difference causes an

absorption system to use little to no work input, but energy must be supplied in the form of

heat. This makes the system an attractive option when there is cheap source of heat, such as

solar heat or waste heat from electricity.

Type of Generations (source)

Fossil Fuel (Coal, Gas etc)


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Renewable energy (Solar)

Based on types of driving heat source

Hot water driven

Flue gas driven

Steam driven

Direct Fired

Based on intensity of Input heat

Single effect or Double effect

For applications above 5oC (primary air-conditioning) the cycle uses Lithium Bromide as

the absorbent and water as the refrigerant.

For application below 5oC, an ammonia water cycle is employed with ammonia as the

refrigerant and water as the absorbent.

Fig 50: Vapour Absorption Cycle.

Benefits:

Environment Friendly (No CFC involved).

Low power consumption (Fractional Power for small pumps only).

Part load efficiency is as good as efficiencies at full load.

Meets variety of cooling loads like air-conditioning, process cooling.

Requires negligible maintenance since there are no moving parts.

Absorbent and refrigerant are less costlier unlike refrigerant gas in mechanical chillers.

VAM circuit is subject to lesser operating pressure eliminating chances of leakages

Rigid construction and no fragile-weak extensions

No special foundations and sheds required

Noiseless and Vibration free operation

Fully Automatic micro-processor based operation and/or BMS integration available

Short capital payback period, usually 11 to 38 months


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Constraints:

The major constraint is the absence of true-value accounting or green accounting principles

which exclude the externalities of fossil fuel extraction and use from its market price

This subsidization economy artificially suppresses the cost of conventional fossil fuel based

sources and conversely inflates the cost of renewable sources of energy which do not have

a shadow price unlike fossil fuels

Space requirements for cooling towers, solar heat harvesting makes it suitable for large

applications only

Applications:

For facilities that use lot of thermal energy for their processes

For facilities that have a simultaneous need for heat and power (cogeneration system),

absorption chillers can be utilized

For facilities that have high electrical demand charges. Absorption chillers minimize or

flatten the sharp demand spikes as part of a peak shaving strategy

For facilities where the electrical supply is not robust, expensive, unreliable, or unavailable

For facilities, where the cost of electricity verses fuel oil/gas tips the scale in favour of

fuel/gas

For facilities wanting to use a “natural refrigerant and aspiring for LEED certification as

absorption chillers do not use CFCs or HCFCs.

3.2.5 EFFICIENT COOLING- RADIANT COOLING

Radiant Cooling is based on the physical principle, that bodies with varying temperatures

exchange thermal radiation until an equilibrium is achieved. The principle of Radiant Cooling

has been around in nature, and human beings have been using this principle knowingly or

unknowingly for ages.

Active Radiant Cooling systems rely on air handling units to move heat from the room air and

transfer it to the water. The chilled air is then blown through duct work to the occupied spaces.

Fan coil units move the chilled water closer to the occupied space than air handlers and

attempt to minimize the energy required by fans. Chilled beams require the water to be

cooled by a separate system outside of the space.

Fig 51: Functioning of radiant cooling


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There are three types of chilled beam systems:

Chilled ceiling – They work by means of

convectional heat transfer, and induce air

movement in the room in which they are placed. The

sensible cooling capacity is approximately 24

BTU/hour per suare foot of beam. Chilled ceilings

lack the ability to control the humidity of a room

and must be paired with a ventilation system.

Passive chilled beam – Passive beams use

a pipe surrounded by a coil in order to form a

radiator system, often used in conjuction with an

under-floor air distribution system. The cooling capacity is approximately 400 BTU/hour

per linear foot of beam. These too do not have any method for maintaining the humidity

of a room, and must be paired with a ventilation system.

Active chilled beam – They have a ventilation air ducted through the chilled beam. The

ventilation air must first be de-humidified upstream of the passive chilled beam, to avoid

condensation potential at the chilled beam.

Radiant cooling cools a floor or ceiling by absorbing the heat radiated from the rest of the

room. Cooling the ceiling is usually done in homes with radiant panels. Aluminium panels

suspended from the ceiling, through which chilled water is circulated. Panels must be

maintained at a temperature very near the dew point within the house, and the house must be

kept dehumidified.

Benefits:

Offers lower energy consumption than conventional cooling systems.

Energy savings depend on the climate, but can be estimated to be in the range of 30%

compared to conventional system. These savings can be attributed to:

-Less energy required to transport heat transfer medium (water) compared to

conventional HVAC where air is used.

-Chilled water supply from the chiller is typically at 16o C compared to 7oC for

conventional HVAC. This also leads to additional savings.

It has lower first costs attributed to integration with structure and design elements.

Lower life cycle cost compared to conventional, due to decreased maintenance.

Constraints:

The potential for condensate formation on the cold radiant surface hinders their

application.

The surface temperature should not be equal or below the dew point temperature in the

space.

The use of an additional system, such as dehumidifier, can limit humidity and allow for

increased cooling capacity.

Fig 52: Radiant cooling from ceiling


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Application:

Commercial Area – office spaces, schools, and few applications in hotels.

Residential – in homes, in areas where humidity is less.

Industry- Capillary tubes maybe used for an industrial application, as well as a fire

suppression system

Hospitals and Laboratories – Radiant cooling can be effective to maintain aseptic

environment in hospitals and laboratories. It provides a silent, draft-free, thermally stable

environment for sedentary patients.


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