THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

THESIS TOPIC :- INTERNATIONAL RESIDENTIAL

SCHOOL (LONAVALA)
THERMAL MASS, INSULATION AND VENTILATION IN
SUSTAINABLE BUILDING

INTRODUCTION:-

Thermal mass acts as a thermal battery. During summer it absorbs heat during the day and releases
it by night to cooling breezes , keeping the house comfortable. In winter the same thermal mass can
store the heat from the sun or heaters to release it at night, helping the building stay warm. Thermal
mass stores and re-releases heat, insulation stops heat flowing into or out of the building. Thermal
mass is particularly beneficial where there is a big difference between day and night outdoor
temperatures.

AIM:-

 To design the school by using thermal mass to make the comfortable environment for the
students.
 To study how use of thermal mass can delay heat flow through the building by as much as
10−12 hours.
 To observe how thermal mass warms the house at night in winter and a cools house during the
day in summer.

OBJECTIVE:-

 To study the ability of a material to absorb and store heat energy.

 Thermal mass is effective in improving building comfort in any place that experiences these
types of daily temperature fluctuations both in winter as well as in summer.
 When thermal mass is used well and combined with passive solar design, thermal mass can
play an important role in major reductions to energy use in active heating and cooling system.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

METHODOLOGY :-

 To design a campus which is energy efficient.

 It will help in cutting the cost of electricity, during summer it absorbs heat during the day and
releases it by night to cooling breezes keeping the building comfortable.
 In winter the same thermal mass can store the heat from the sun or heaters to release it at
night helping the building stay warm.

SCOPE

 Thermal mass helps in investigating passive energy storage and it is focused on how
the thermal properties of materials will influence the following factors :-
1. Energy consumption.
2. Power needs.
3. Thermal comfort.

LIMITATIONS :-

 Thermal mass can be used in some places Using thermal mass every where in the
building may not be advantageous.
 Thermal mass can only be created by using restricted material like concrete floor slab,
adobe walls and by building cavity walls for insulation.
 In some climates building may use more energy if insulation is installed on the wrong
side of the wall.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

1. INTRODUCTION
1.1. CLIMATIC ZONES IN INDIA :-
 The climate in India comprises a wide range of weather conditions across a vast
geographic scale.
 India is home to extraordinary variety of climatic regions, ranging from tropical in the
south to temperate and alpine in the Himalayan north, where elevated regions receives
sustained winter snowfall.
 The nation’s climate is strongly influenced by the Himalayas and the thar desert.
 The country follows the international standards of four climatic zones with some
local adjustments.
1. Hot and Dry climate.
2. Hot and Humid climate.
3. Composite climate.
4. Tropical climate.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

HOT AND DRY CLIMATE :-

 Hot-dry desert and semi-desert climates are characterized by very hot, dry air and dry
ground.
 Day-time air temperatures may range between 27 and 49°C (normally higher than the
31 to 34°C skin temperature), but at night it may fall as much as 22°C Humidity is
continuously moderate to low.
 There is little or no cloud cover to reduce the high intensity of direct solar radiation.
 The clear skies do, however, permit a considerable amount of heat to be reradiated to
outer space at night.
 The dry air, low humidity and minimal rainfall discourage plant life, and the dry,
dusty ground reflects the strong sunlight, producing an uncomfortable ground glare.
 Local thermal winds often carry dust and sand.
 Most of the rainfall occurs in this season and the rain can cause severe floods. The sun
is often occluded during the monsoon season.
 Though mostly dry, it is desserted in the north-west, and wet in the southern districts
due to a heavy monsoon season.

HOT AND HUMID CLIMATE :-

 The most prominent characteristics of this climate are the hot, sticky conditions and
the continual presence of dampness.
 Air temperature remains moderately high, between 21 and 32°C, with little variation
between day and night. It seldom exceeds normal skin temperature.
 Humidity is high during all seasons.
 Heavy cloud and water vapour in the air act as a filter to direct solar radiation; it is
thus reduced and mostly diffused – but clouds also prevent reradiating from the earth
at night.
 Moisture in the air combined with moderate heat and high rainfall is favorable to the
growth of vegetation.
 The plant cover of the ground reduces reflected radiation, and lessens the heating up
of the ground surface.
 Winds are generally of low speed, variable in speed, but almost constant in direction.

COMPOSITE CLIMATE :-
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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

 The composite zone covers the central part of india.

 Composite climate displays the characteristics of hot and dry, warm and humid as
well as cold climate.
 This region receives strong winds during monsoons from the south-east and dry cold
winds from the north –east.
 In summer the winds are hot and dusty.
 The intensity of solar radiation is very high in summer with diffuse radiation
amounting to a small fraction of the total.
 In monsoon, the intensity is low with predominantly diffuse radiation.
 The presence of high humidity during monsoon months is one of the reasons why
places like New Delhi and Nagpur are grouped under the composite climate.

MODERATE CLIMATE :-

 THE TEMPERATE CLIMATE HAS MILD TO WARM SUMMERS AND COOL WINTERS.
 The need for winter home heating is greater than the need for summer cooling.
 It is a relatively comfortable climate, especially near the coast, where summers are cooler
and winters are warmer.
 The temperature ia neither too hot nor too cold, in summers the temperature reaches 30 –
340 c during the day and 17 – 240c at night.
 In winters the maximum temperature is between 27 – 330c during the day and 16 – 180c at
night.
 The relative humidity is low in winters and summers, varying from 20 – 55 % and going upto
55 – 90 % during monsoon.
 The total rainfall usually exceeds 1000mm per year.
 Winters are dry in this zone, winds are generally high during summer their speed and
direction mainly depends on the topography.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

1.2. WHAT IS THERMAL MASS :-

 Thermal mass is the ability of a material to absorb and store heat energy. A lot of heat
energy is required to change the temperature of high density materials like concrete,
bricks and tiles.
 They are therefore said to have high thermal mass.
 Lightweight materials such as timber have low thermal mass.
 Appropriate use of thermal mass throughout your home can make a big difference to
comfort and heating and cooling bills.
 Thermal mass can store solar energy during the day and releases it at night.
 Thermal mass, moderates internal temperatures by averaging out day−night extremes.
This increases comfort and reduces energy costs.
 Poor use of thermal mass can results in the worst extremes of the climate and can be a
huge energy and comfort liability. It can radiate heat to you all night as you attempt to
sleep during a summer heat wave or absorb all the heat you produce on a winter night.
 Thermal mass must be integrated with sound passive design techniques. This means
having appropriate areas of glazing facing appropriate directions with appropriate
levels of shading, ventilation, insulation .

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

1.3. HOW THERMAL MASS WORKS :-

 Thermal mass acts as a thermal battery.

During summer it absorbs heat during the day
and releases it by night to cooling breezes or
clear night skies, keeping the house
comfortable. In winter the same thermal mass
can store the heat from the sun or heaters to
release it at night, helping the home stay
warm.
 Thermal mass is not a substitute for
insulation. Thermal mass stores and re-
releases heat; insulation stops heat flowing
into or out of the building. A high thermal
mass material is not generally a good thermal
insulator (see Rammed earth).
 Thermal mass is particularly beneficial where there is a big difference between day
and night outdoor temperatures.
 A high mass building needs to gain or lose a large amount of energy to change its
internal temperature, whereas a lightweight building requires only a small energy gain
or loss to change the air temperature. This is an important factor to consider when
choosing construction systems and assessing climate change adaptation.
 A high mass building needs to gain or lose a large amount of energy to change its
internal temperature, whereas a lightweight building requires only a small energy gain
or loss to change the air temperature. This is an important factor to consider when
choosing construction systems and assessing climate change adaptation.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

1.4. MATERIALS COMMONLY USED FOR THERMAL

MASS
 A material that had thermal mass is one that has the capacity to absorb, store and release the
sun’s heat energy.
 Its density and levels of conductivity help to keep the internal temperature of building stable.
 Objects that have thermal mass have inherent qualities for both heating and cooling.
 Materials with thermal mass are typically used in the floor or inside walls of passive solar
structure and located near the solar glazing ( south facing windows ) to allow the sun’s energy
to shine to directly on them. In this manner, they can store and release the sun’s heat energy.

They are generally dense materials such as:-

1. Concrete.
2. Stone.
3. Brick.
4. Adobe.
5. Ceramic tile.
6. Water.

1. CONCRETE :-
 Concrete, clay bricks and other forms of masonry
the thermal conductivity of concrete depends on
its composition and curing technique. Concretes
with stones are more thermally conductive than
concretes with ash, perlite, fibers, and other
insulating aggregates.
 Insulated concrete panels consist of an inner layer of concrete to provide the thermal
 mass factor. This is insulated from the outside by a conventional foam insulation and then
covered again with an outer layer of concrete. The effect is a highly efficient building
insulation envelope.
 Insulating concrete forms are commonly used to provide thermal mass to building
structures. Insulating concrete forms provide the specific heat capacity and mass of
concrete. Thermal inertia of the structure is very high because the mass is insulated on both
sides.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

2. ADOBE BRICK OR RAMMED EARTH :-

 Earth AND mud heat capacity depends on its
density, moisture content, particle shape,
temperature, and composition. Early settlers to
Nebraska built houses with thick walls made of
dirt and sod because wood, stone, and other
building materials were scarce.

 The extreme thickness of the walls provided some

insulation, but mainly served as thermal mass,
absorbing thermal energy during the day and releasing it during the night. Nowadays, people
sometimes use earth sheltering around their homes for the same effect.

 In earth sheltering, the thermal mass comes not only from the walls of the building, but from
the surrounding earth that is in physical contact with the building.

 Rammed earth: rammed earth provides excellent thermal mass because of its high density,
and the high specific heat capacity of the soil used in its construction.

3. WATER :-
 Water has the highest volumetric heat capacity of all
commonly used material. Typically, it is placed in
large container(s), acrylic tubes for example, in an area
with direct sunlight. It may also be used to saturate
other types material such as soil to increase heat
capacity.

4. WOOD :-
 wood are used as a building material to create the
exterior, and perhaps also the interior, walls of homes.
wood homes differ from some other construction
materials listed above because solid wood has both
moderate R-value (insulation) and also significant
thermal mass. In contrast, water, earth, rocks, and
concrete all have low R-values. This thermal mass allows
a log home to hold heat better in colder weather, and to
better retain its cooler temperature in hotter weather.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

1.5. THERMAL MASS IN WINTER SEASON :-

 Allow thermal mass to absorb heat during the day from direct sunlight or from radiant
heaters. It re-radiates this warmth back into the home throughout the night.
 In winters thermal mass works like a heater, it absorbs radiant heat from the sun
through north, east and west facing windows and also stores heat from mechanical
heating.
 The thermal mas will slowly releases the heat which reduces the need for heating.
 The house will stay warmer for longer time

THERMAL MASS IN SUMMERS :-

 Allow cool night breezes and to pass over the thermal mass, drawing out all the
stored energy.
 During the day protect the thermal mass from excess summer sun with shading and
insulation if required.
 Materials such as concrete and brick are cooler in summer than the surrounding air
temperature, so they are able to absorb heat, which consequently lowers the room
temperature and the need for additional cooling.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

1.6. PROPERTIES OF THERMAL MASS :-

The following characteristics determine thermal mass performance.

HIGH DENSITY:-
 The more dense the material the higher its thermal mass.
 For example, concrete has high thermal mass, aerated concrete (AAC) blocks have
moderate to low thermal mass, and insulation has almost none.

GOOD THERMAL CONDUCTIVITY: -

 To be effective in most climates, thermal mass should have the capacity to absorb and
close to its full heat storage capacity in a single day – night cycle.
 If conductivity is too low, passive heating can escape from building before being
absorbed.
 If conductivity is too high stored heat is re-released before it is most needed in the
colder part of the night.
 The same applies to passive cooling only in day−night reverse.
For example, rubber has high density but is a poor conductor of heat. Brick and
concrete have high density and are reasonably good conductors.

APPROPRIATE THERMAL LAG :-

 The rate at which heat is absorbed and re-released by insulated material is referred to
as thermal lag.
 Lag is dependent on conductivity, thickness, insulation levels and temperature
differences either side of the wall.
 Consideration of lag times is important when designing thermal mass, especially with
thick uninsulated external wall systems like rammed earth, mud brick or rock.
 In moderate climates, a 24 hour lag cycle is ideal. In colder climates subject to long
cloudy periods, lags of up to seven days can be useful, providing there is additional
solar exposed glazing to ‘charge it’ in sunny weather .

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

THE TABLE INDICATES LAG TIMES FOR COMMON MATERIALS

MATERIAL THICKNESS (MM) TIME LAG (HOURS)

Double brick (250) 6.2

Concrete (250) 6.9

Autoclaved aerated concrete (200) 7.0

Mud brick / adobe (250) 9.2

Rammed earth (250) 10.3

Compressed earth blocks (250) 10.5

Sandy loam (1000) 30days

 Thermal lag influences internal−external heat flow through walls. Rammed earth,
rock and mud brick have a low insulation value and rely on thicknesses of 300mm or
more to increase thermal lag.
 While this is often adequate in mild climates, these systems require external insulation
in cool and cold climates where lag times are reduced by increased internal−external
temperature differences .

Low reflectivity:-

 Dark, matt or textured surfaces absorb and re-radiate more energy than light, smooth,
reflective surfaces (if there is considerable thermal mass in the walls, a more
reflective floor will distribute heat to the walls).

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

1.7. HIGH VOLUMETRIC HEAT CAPACITY (VHC): -

 The amount of useful thermal storage is calculated by multiplying the VHC by the
total accessible volume of the material, i.e. the volume of material that has its surface
exposed to a source of heating or cooling.
 Water has the highest VHC of any common material. The table tells us that it takes
4186KJ of energy to raise the temperature of one cubic metre of water by one degree
C, whereas it takes only 2060KJ to raise the temperature of an equal volume of
concrete by the same amount. In other words, water has around twice the heat storage
capacity of concrete.
 The VHC of rock usually ranges between brick and concrete depending on density.
 The VHC of any material is reduced or even eliminated if the material is covered with
linings such as carpets, plasterboard, timber.

THERMAL MASS FOR VARIOUS MATERIALS

MATERIALS THERMAL MASS (VOLUMETRIC

HEAT CAPACITY, KJ/m3.k )

Water 4186

Sandstone 1800

Compressed earth blocks 1740

Rammed earth 1673

Fibre cement sheet 1530

Brick 1360

Earth wall ( adobe ) 1300

Autoclaved aerated concrete 550

Concrete 2060

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 Some thermal mass materials, such as concrete and brick, have high embodied energy
when used in the quantities required.
 Consider the lifetime energy impact of thermal mass materials: will the savings in
heating and cooling energy be greater than the energy content over the life of the
building.
 In addition, poor design of thermal mass may result in increased heating and cooling
energy use on top of the energy content.

1.8. WHERE TO LOCATE THERMAL MASS :-

 To determine the best location for thermal mass you need to know if your greatest energy
consumption is the result of summer cooling or winter heating.
Heating: - Locate thermal mass in areas that receive direct sunlight or radiant heat from
heaters.
Heating and cooling: - Locate thermal mass inside the building on the ground floor for
ideal summer and winter efficiency. The floor is usually the most economical place to locate
heavy materials, and earth coupling gives additional thermal stabilisation in both summer and
winter in these climates.
 Locate thermal mass in north-facing rooms with good solar access, exposure to cooling night
breezes in summer, and additional sources of heating or cooling (heaters or evaporative
coolers).
 Locate additional thermal mass near the centre of the building, particularly if a heater or
cooler is positioned there. Feature brick walls, slabs, water features and large earth or water-
filled pots can be used.
 Cooling:- Protect thermal mass from summer sun with shading and insulation if required.
Allow cool night breezes and air currents to pass over the thermal mass, drawing out all the
stored energy.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

WHERE NOT TO LOCATE THERMAL MASS :-

 Avoid use in rooms and buildings with poor insulation from external temperature extremes
and rooms with minimal exposure to winter sun or cooling summer breezes.
 Thermal mass can increase energy use when used in rooms where auxiliary heating or cooling
is the only means of adjusting the temperature because it slows the response times.
 Careful design is required if locating thermal mass on the upper levels of multi-storey housing
in all but cold climates, especially if these are bedroom areas.
 Natural convection creates higher upstairs room temperatures and upper level thermal mass
absorbs this energy. On hot nights upper level thermal mass can be slow to cool, causing
discomfort. The reverse is true in winter.

1.9. TYPICAL APPLICATION FOR THERMAL MASS :-

 In rooms with good access to winter sun it is useful to connect the thermal mass to the earth.
The most common example is slab-on-ground construction. Less common examples are brick
or earthen floors, earth-covered housing or green roofs (see Construction systems).
 A slab-on-ground is preferable to a suspended slab in most climates because it has greater
thermal mass due to direct contact with the ground. This is known as earth coupling. Deeper,
more stable ground temperatures rise beneath the house because its insulating properties
prevent heat loss. The slab assumes this higher temperature which can range from 16° to
19°C.
 In summer, the earth has the capacity to ‘wick’ away substantial heat loads. It also provides a
cool surface for occupants to radiate heat to (or conduct to, with bare feet). This increases
both psychological and physiological comfort.
 In winter, the slab maintains thermal comfort at a much higher temperature with no heat
input. The addition of passive solar or mechanical heating is then more effective due to the
lower temperature increase required to achieve comfortable temperatures.
 Use surfaces such as quarry tiles or simply polish the concrete slab. Do not cover areas of the
slab exposed to winter sun with carpet, cork, wood or other insulating materials: use rugs
instead.
 The vertical edges of a slab-on-ground are required to be insulated in Zone 8 (cold climate) or
when in-slab heating or cooling is installed within the slab.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

 Insulate slab edges in cold climates or where

in-slab heating or cooling is installed within
the slab.
 The whole slab must be insulated from earth
contact in cold climates and regions with
low earth temperatures at 3m depth (e.g.
Tasmania) or hot, humid climates with high
earth temperatures (e.g. Darwin).
 Consider termite proofing when designing
slab edge insulation. Take care to ensure
that the type of termite management system
selected is compatible with the slab edge
insulation.
 Masonry walls also provide good thermal mass. Recycled materials can be used. Avoid
finishing masonry walls with plasterboard as this insulates the thermal mass from the interior
and significantly reduces its capacity to absorb and re-release heat.
 Reverse brick veneer is an example of good thermal mass practice for external walls because
the mass is on the inside and externally insulated. In traditional brick veneer, the mass of the
brick makes no contribution to thermal storage because it is insulated from the inside and not
the outside.

Thermal mass walls and floor slab Thermal mass floor and light weight frame

CASE STUDIES

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

2. Case studies:-

2.1. JIGSAW HOUSING , CURTIN , AUSTRALIA

Project details :-

Designer and builder :- jigsaw builders.

Site area :- 825 m2.

Buit up area :- 250 m2.

About project :-

 A renovation has transformed a dark and cold house into a liveable and family-friendly home
that is more energy efficient and responsive to the environment. The clever renovation has
also made the house more adaptable to fit the long-term needs of its occupants.
 When the family of four moved into the poorly designed two-storey brick and weatherboard
house they faced some tough questions about what to do to improve it should they knock it
down and start again, remove the top storey and extend outwards or build a bungalow at the
back.
 Environmental considerations and cost made them settle on an extensive retrofit of the
existing house, making it far more habitable and suitable to the climate while keeping an eye
on the family’s future requirements.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

ABOUT SITE LOCATION AND CLIMATE :-

 The house in Curtin, an inner suburb of Canberra, has good access to bike paths, parkland and
public transport

 The house was built as a single-storey dwelling by previous owners in the 1960s; a pitched
roof ‘Cape Cod’ second storey was added in the 1980s.

DESIGN RESPONSE :-

 The worst element of the old house was the central staircase, which allowed heat to escape up
the stairs and left the ground floor bitterly cold in winter. It also divided the living areas of the
house and made family interaction difficult.
 In the renovation the old staircase was demolished and a new one built at the east side of the
house so that the house could effectively function as a two-apartment residence in the future.
 A new laundry and garage are also in the home’s eastern end. The once small and pokey
laundry was in the way as people passed through the house to the backyard. Now, it is tucked
underneath the staircase and clothes can be dried under cover in the garage.
 The kitchen, once in the south-east corner, is now part of a large kitchen–dining area in a
central, north facing position. Double glazed doors bring light deeply into the area, making it
a warm, social family space.
 The lounge, where the kitchen once was, faces south to the backyard, with a double glazed
sliding door allowing easy access to the garden and beyond.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

 Upstairs, the three bedrooms and living area

were left largely as is, though a terraced garden
was constructed on the roof of the garage to
provide more outdoor space.
 A crucial aim of the renovation was to ensure
the home was well sealed in a tight building
envelope, with no unnecessary ceiling
penetrations and few gaps in the house through
which heat could pass. This would ensure that
passive heating and cooling could be most
effective.
 Study nooks and a purple glass splashback were additional design features used to bring a
sense of life and character to the house.

SUSTANIBILTY FEATURES :-

 Evacuated tube solar hot water system

 Double glazed windows and doors
 Hydronic heating
 Light emitting diode (LED) lighting
 North facing design
 Effectively sealed building with minimal gaps
 Rainwater tanks
 Reconstituted timber cladding
 Bamboo flooring

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

SOLAR HOT WATER AND SOLAR PHOTOVOLTAIC (PV) SYSTEMS

 The owners installed an evacuated tube solar hot water system, north facing at a 55-degree
pitch, to replace the old electric hot water service.
 The efficiency of the new system has meant the family rarely uses its electric booster.
 The steep, Cape Cod pitched roof made the installation of solar panels difficult. The owners
decided against a solar power system, instead focusing on improving the home’s overall
energy efficiency to reduce heating and cooling costs.

PASSIVE HEATING AND COOLING :-

 Good window design and location maximise natural lighting. Bright, naturally lit homes
promote health and well-being and reduce the need for electric lighting.
 To maximise the effectiveness of passive heating in this house, north facing double glazed
windows and doors were installed.
 All windows and doors are tilt and turn with flexible opening mechanisms assisting natural
cross-ventilation for cooling.
 The windows and glazed door frames are made from lead-free uPVC, a material with good
insulating properties similar to timber.

ACTIVE HEATING AND COOLING :-

 Canberra’s cold winters mean a form of active heating is a must.

 In this house, an energy-efficient hydronic heating system works through a gas-fired boiler
and radiator panels.
 The hydronic heating has replaced an inefficient heater downstairs and a reverse cycle split
system upstairs. Energy-efficient ceiling fans provide the only form of active cooling in the
house.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

BUILDING MATERIALS AND INSULATION :-

 In parts where bricks were removed, reconstituted timber weatherboards have been used as
cladding. Timber cladding has low embodied energy and generally low environmental impact.
 Insulation acts as a barrier to heat flow and is essential to keep a home warm in winter and
cool in summer.
 In Canberra’s cool temperate climate, the main priority of insulation is to reduce heat loss.
 As part of the renovation, the existing walls were insulated with R3 rated recycled
polystyrene and the timber floors with R2 polyester batts; the ceiling was topped up to R5+
with wool cell insulation.

ENERGY-EFFICIENT LIGHTING :-

 Efficient light emitting diode (LED) lighting has been fitted throughout, sourced from an
electrician and a local lighting store. The owners made creative use of a range of LED lights,
in strips for pelmet lighting, wall-recessed hall and stair lights, and unvented/airtight
downlights that give excellent light while using just 8W.

Strips of energy efficient LED lighting is used

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

DRAUGHT SEALING :-

 Draught sealing around doors and windows can save up to 25% of heat loss and gain. The
owners paid close attention to keeping as much heat in as possible through the installation of
tightly sealing windows and doors. All exhaust fans in the house were fitted with effective
dampers.

Ground floor plan

First floor plan

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

2.2. THOMPSON SUSTAINABLE HOMES

PROJECT DETAILS :-
Architect :- Tim Christopher

Site area :- 1100 m2

Buit up area :- 325 m2

ABOUT PROJECT :-

 This Sunshine Coast display home is designed to meet the highest energy rating .

 A local building company, specialising in sustainable small lot homes, set out to produce a
modern, affordable energy saving home to suit the property market.

 The home’s net zero energy use is a key selling point, appealing to home buyers looking to
cut energy bills.

 The dwelling, part of a housing development display village, showcases the benefits of
energy-efficient design to a broad range of consumers. The builder has aimed to meet the
market’s needs, deliberately blending the home in with the 20 others on show

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LOCATION AND CLIMATE :-

 The architect found an ideal site in the Bells Reach Display Village at Caloundra West, 90km
north of Brisbane in the midst of the Sunshine Coast. It’s an urban area close to the beach
with a temperate year-round climate averaging around 21°C in the winter months.
 Most days are warm and humid especially in summer with hot averages around 28°C. The
temperature can drop on winter nights to around 10°C and rainfall peaks in summer.
 Thermal mass would work well in the home, storing heat on winter days and releasing it on
cool nights.
 The site was picked for its almost north–south aspect conducive to good passive design.
 It was determined that a 10 star house could be built on the block. However, designing for
small lots requires overcoming several restrictions, width being one of them.
 The lot is only 10m wide x 32m deep with houses sitting tightly on either side. Once
essentials such as a garage and entrance are placed at the front of the block, the layout still
needs to address passive design principles, flow-through ventilation and optimisation of the
aspect.

DESIGN RESPONSE :-

 The contemporary design is for a small family home with three bedrooms, two bathrooms and
a single lock-up garage, all on a narrow block. It has tiled living areas and epoxy finished
bedroom floors.
 The master bedroom features a large en suite, and minor bedrooms are in a separate wing with
their own bathroom. The north facing living area is open plan and opens to a rear alfresco
area that faces the yard. The 2.55m ceilings add to a feeling of spaciousness.

 Mains water use is kept to a minimum with all taps having a high WELS (Water Efficiency
Labelling and Standards) rating.

 A 10 star house energy rating was secured with good northern orientation, high levels of
thermal mass, ceiling and wall insulation, and careful consideration of window size and
position. These elements were adjusted in the design until the target rating was achieved with
house energy rating software.

 The site’s near north–south aspect was advantageous, offering perfect orientation for a 10 star
home. The dining and living areas have a northern aspect for best solar access and natural
light; and the low pitch roof helps efficient operation of the solar photovoltaic system to
achieve a zero net energy goal

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

 The home was initially designed using the builder’s regular construction methods, with more
thermally efficient materials added to achieve the 10 star rating only where needed. Reverse
brick veneer was specified for the northern living room wall to increase thermal mass not a
first choice by the builder due to its added expense. In addition, masonry block walls, some
painted and others coloured and honed during manufacture, were used elsewhere to provide
additional thermal mass while acting as a feature wall in the main living area.

Dinning and living area have a northern aspect for

best solar access and natural light

 Other features essential for gaining a 10 star rating and thermal efficiency include light-
coloured exterior walls to reduce heat gain, weather strips for draught proofing, ceiling fans to
ensure good airflow and low-e glass to reflect radiant heat.
 Waste was kept to a minimum by altering the design where needed to optimise material size.
Changing the size of a room by 100mm could save an entire sheet of construction material,
such as external cladding, with the builder implementing this during the design and following
through during construction (see Waste minimisation).
 The house is built with new materials that contain recycled materials as well as materials that
can be recycled. Most of the house can be broken down or reused at the end of its life,
including insulation made from recycled glass bottles and cladding made partially from
pinewood pulp. The steel roofing contains up to 25% recycled materials and can be
completely recycled again at the end of its service life. The concrete slab is recyclable as is
the plasterboard and numerous other components.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

Mains water use is kept to a minimum with all taps having a

high WELLS (Water Efficiency Labelling and Standards) rating.

 A renewable energy system was essential to achieve the net zero energy use goal. The home
was independently assessed for its energy efficiency to determine what size solar photovoltaic
system would generate more electricity than the household would consume in a year. The
display home is not carbon neutral for greenhouse gas emissions as it has a gas hot water
system, but anyone buying this home can elect to have a solar hot water system installed (see
Renewable energy).
 Indoor air quality was important to sustainability goals, with low VOC (volatile organic
compound) paints and laminates used throughout, reducing greenhouse gas emissions and
being healthier for residents.

MATERIALS USED :-

1. Concrete slab :-
 The right combination of horizontal and vertical mass was needed to achieve a 10 star rating,
with a concrete slab providing horizontal thermal mass.

 The concrete sits on and around a series of waffle pods, thus the slab is mostly resting above
the ground and is less susceptible to changes in ground temperature.

 The air pockets created by the pods form an insulating layer between the structure and the
ground .

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

2. REVERSE BRICK VEENER :-

 Reverse brick veneer provides vertical mass in the north and west facing living area to
achieve the 10 star rating.

 A layer of brickwork facing into the living area on the internal wall absorbs and releases
heat.

 Next to it is a thick layer of insulation designed to minimise heat intrusion from the
outside or heat loss from the inside, thus stabilising the internal temperature.

 The external cladding is painted in a light colour to assist in reducing heat absorption
through the outside wall.

Reverse brick veneer was specified for the northern

living room wall to increase thermal mass.

INSULATION :-

 High levels of wall and ceiling insulation were needed to achieve a 10 star house energy
rating. The ceiling has thick R3 batts as well as a layer of R1.5 glasswool roofing blanket
underneath the actual metal roof sheeting.

 The external walls have R1 sisalation wrap on the outside with R2 batts in the wall cavity .

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

2.3. SUZLON ONE EARTH (PUNE)

PROJECT DETAIL :-

Location :- Hadapsar (Pune)

Site area :- 453920 sqm.

Built up area :- 70365 sqm.

ABOUT PROJECT :-

Suzlon is India’s largest and one of the world’s biggest producers of “clean” wind energy. In keeping
with their Green image they wanted to build a Head-Quarters (HQ) building that reflected their global
and “Sustainable” status. Spread over 10 acres of land and with a built-up area of 820,000 sq.ft., in
Hadapsar, Pune, India, Suzlon’s aptly named “One Earth” corporate HQ houses all their functions and
global verticals in a functional, aesthetic and Green campus.

The name “One Earth” signifies recognition of the Earth as a unique eco-system whose resources
must be managed responsibly. It also signifies the effort made to create such an environmentally
responsible corporate home. In keeping with the theme, the corporate buildings at One Earth have
been named after the key elements of nature as Aqua, Tree, Sky and Sun.

Designed by the Pune-based Christopher Charles Benninger Architects and executed by Synefra, One
Earth puts into practice the concept of an “Office in the Garden” rather than merely creating another
concrete and metal eyesore.

One Earth is one of only five buildings in India

to be LEED rated and the first in the state of
Maharashtra. It is also the only building in India
with the highest ratings from LEED (Platinum
rating with 57 points which it obtained in 2010)
and GRIHA (Five Star rating with 96 points).

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

PLANNING AND DESIGN :-

Sustainability principles have been scrupulously adhered to, right from site selection and
design to engineering, construction, materials and operations. This includes usage of native
flora, minimizing both environmental impact and reducing the need for landscaping water,
low-energy/green materials, appropriate orientation of the building facades that ensures
adequate day lighting and minimizes glare etc.

SITE PLAN OF CAMPUS

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

ENERGY EFFICIENCY :-

A hybrid wind (80%) – solar (20%; through

photovoltaic panels) energy system located on-
site and off-site generates 155 kW of power,
making One Earth India’s first 100% renewable
energy campus. Smart solutions like
motion/occupancy sensors, Low-E glass for the
buildings, low energy LED lighting, aluminium
louvers that shade the interiors while providing ample natural illumination, HVAC systems
that filter and cool air before resupplying them to ACs to reduce the load on ACs etc.,
optimize energy consumption.

EFFICIENT LIGHTING DESIGN :-

 Dimmable ballasts in conjunction with daylight sensors are used throughout the open
office space.
 General lighting at 350 Lux.
 The artificial lights dimmed up and dimmed down from 0% to 100% depending on
the adequacy of available daylight to meet the 350lux requirement.
 The task lights have an intelligent built-in occupancy sensor in conjunction with a
continuous dimmer.
 Lighting of individual offices is controlled by combined daylight and occupancy
sensors.
 90% of the luminaries in the office space are with dimmable ballasts and are either
connected to occulux sensors or occuswitch sensors.
 The installed lighting of office spaces has been designed at 0.8W/sq.ft, 0.75 W/sq.ft.
for cores 0.23 W/sq.ft. for basement parking. Overall L.P.D by whole building area
method is 0.8 W/sq.ft.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

ENERGY EFFICIENT HVAC SYSTEM :-

 SYSTEM FLEXIBILITY OF VARIABLE REFRIGERANT VOLUME SYSTEM :-

the indoor unit’s cooling operation can be controlled to maintain desired temperature
in any location in the premises according to end user’s needs and preferences.
 Pre – cooling and heat recovery at T.F.A.s.
 A sensible heat exchanger is used as pre-cooler to sink the temperature of incoming
air to approx. 27.66oc.
 Direct and indirect evaporative cooling.
 Sensible cooling of approx. 130% of fresh air in an efficient heat exchanger, using
pre-cooled water.
 Further cooling of air and simultaneous cooling of water in direct evaporative cooling
section of the unit. Air required for cooling tower part this section is drawn from the
outlet of the same section. This air is termed commonly as “scavenger air”.

WATER EFFICIENT:-
 100% rainwater is harvested, 100% of grey water is recycled via an on-site sewage
treatment plant into flushing, air-cooling and landscaping systems attesting to One
Earth’s water-efficiency.
 Water fixtures including low flow fixtures that reduce in-building water consumption
by 65% and touch less urinals with hytronic sensors all help reduce water
consumption and make One Earth water efficient.

OTHER ENERGY EFFICIENT :-

 Carpooling.
 E-charging points.
 Environmental education.
 Offsite green power.
 Zero waste management policy.
 Construction on renewable energy.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3. DATA COLLECTION
3.1. DESIGN FOR DIFFERENT CLIMATES :-
 Design for climate requires that homes to be designed or modified to ensure that the
occupants remain thermally comfortable with minimal auxiliary heating or cooling in
the climate where they are built. Passive design working with the climate, not against
it is an important component, as are energy efficient heating and cooling systems, and
smart behaviour by the occupants.
 Approximately 40% of household energy is used for heating and cooling to achieve
thermal comfort. This rate could be cut to almost zero in new housing through sound
climate responsive design and, indeed, should be our aspirational goal. Taking into
account current consumer preferences and industry practices, halving the rate to 20%
is a highly achievable in the short term.
 The 40% of household energy used for heating and cooling to achieve thermal
comfort could be cut to almost zero in new housing through sound climate responsive
design.
 Reducing or eliminating heating and cooling needs in existing homes is a significant
challenge, particularly those designed and built before building energy efficiency
standards were introduced, when appliances were effective but inefficient. Based on
1.5% annual renewal rates, at least 50% of our current housing stock will still be in
service in 30 years’ time.
 New homes built now will be in service in future times when we expect to see
significant changes in the climate. Designing for today’s climate is important;
ensuring that those designs can be just as efficient after 30 years of climate change
would certainly be desirable.
 Affordability is often cited as the main barrier to greater efficiency but increasing
energy costs are rapidly shifting the affordability focus from initial or upfront cost to
ongoing or operational cost. With this shift, high levels of thermal performance are
becoming increasingly valuable and the payback or amortisation period for thermal
performance upgrades is diminishing rapidly.

 This introductory overview of key design objectives and responses to creating

thermally comfortable homes in each main climate zone in Australia needs to be

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further refined and customised to your individual site, locality and design brief. Use
this overview, and the references to other articles, to access more detailed information
as you proceed through the various stages of designing, purchasing or altering your
home.

3.2. INDIAN CLIMATE ZONES :-

 The four climate zones are defined by the Building Code .Each climate zone has
distinctly different design and construction requirements. Within each main zone are
many regional sub-zones determined by local geographic features including wind
patterns and height above sea level. Nathers identifies 69 of these sub-zones, which
can be called up by postcode.

 Climate change is likely to alter the characteristics of each zone during the life span of
homes currently being built or renovated

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.3. ORIENTATION :-

 Orientation is the positioning of a building in relation to seasonal variations in the

sun’s path as well as prevailing wind patterns. Good orientation can increase the
energy efficiency of your home, making it more comfortable to live in and cheaper to
run.
 Read about the principles of good orientation in this article in conjunction with
Passive solar heating, Passive cooling and Shading. Identify your climate zone and
develop an understanding of appropriate design responses by referring to Design for
climate.

orientate your home to make best use of sunlight and winds

 When deciding the best orientation for your home, bear in mind that the climate is
warming, and hotter summers with more extreme heat waves will become the norm
during its life span. While passive solar heating is still very desirable in climates that
require heating, the priority will gradually shift from heating to cooling. Additional
attention to shading of windows and walls (particularly west facing) and exposure to
cool breezes and other forms of natural cooling is required in all climate zones.

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3.3.1. PRINCIPLES OF GOOD ORIENTATION :-

 Good orientation, combined with other energy efficiency features, can reduce or even
eliminate the need for auxiliary heating and cooling, resulting in lower energy bills,
reduced greenhouse gas emissions and improved comfort. It takes account of summer
and winter variations in the sun’s path as well as the direction and type of winds, such
as cooling breezes.
 Good orientation can help reduce or even eliminate the need for auxiliary heating and
cooling, resulting in lower energy bills, reduced greenhouse gas emissions and
improved comfort.
 Ideally, choose a site or home with good orientation for your climatic and regional
conditions and build or renovate to maximise the site’s potential for passive heating
and passive cooling, adjusting the focus on each to suit the climate. For those sites
that are not ideally orientated, there are strategies for overcoming some of the
challenges.
 In hot humid climates and hot dry climates with no winter heating requirements, aim
to exclude direct sun by using trees and adjoining buildings to shade every façade
year round while capturing and funnelling cooling breezes

Left: How to calculate sun angles.

Right: Midday sun position north of the tropic of Capricorn.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

 In all other climates a combination of passive solar heating and passive cooling is
desirable. The optimum balance between capturing sunlight (solar access) and
capturing cooling breezes is determined by heating and cooling needs.
 North orientation is generally desirable in climates requiring winter heating, because
the position of the sun in the sky allows you to easily shade northern façades and the
ground near them in summertime with simple horizontal devices such as eaves, while
allowing full sun penetration in winter.
 North-facing walls and windows receive more solar radiation in winter than in
summer. As shown in the diagram, the opposite is true for other directions and why,
in mixed or heating climates, it is beneficial to have the longer walls of a house facing
north to minimise exposure to the sun in summer and maximise it in winter.

AVERAGE DAILY SOLAR RADIATION ON VERTICAL SURFACES

3.3.2. CHOOSING THE BEST ORIENTATION :-

 Prioritise your heating and cooling needs. Are you in a climate that requires mainly
passive heating, passive cooling, or a combination of both?
 Compare your summer and winter energy bills, consult an architect or designer, ask
your local energy authority or refer to local meteorological records.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.3.3. YOUR LOCAL CLIMATE RESEARCH SHOULD STUDY:-

 Temperature ranges, both seasonal and diurnal (day–night)

 Humidity ranges
 Direction of cooling breezes, hot winds, cold winds, wet winds
 Seasonal characteristics, including extremes
 Impact of local geographic features on climatic conditions (see choosing a site)
 Impact of adjacent buildings and existing landscape.

The Indian Bureau of Meteorology provides wind roses for each region in India. They are
based on daytime data and don’t address evening and night breezes that are often the main
source of cooling.

3.3.4. ORIENTATION FOR PASSIVE HEATING:-

 Orientation for passive heating is about using the sun as a source of free home heating
by letting winter sun in and keeping unwanted summer sun out desirable in the
majority of Australian homes. It can be done with relative ease on northern elevations
by using horizontal shading devices to exclude high angle summer sun and admit low
angle winter sun.
 ‘Solar access’ is the term used to describe the amount of useful sunshine striking glass
in the living spaces of a home. The desired amount of solar access varies with climate.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.3.5. SUN MOVEMENT FROM HIGH ANGLE IN SUMMER TO LOW

ANGLE IN WINTER.

 Variations in orientation towards east and west can have advantages in some climates
and for some activities. For example, in cold climates, orientations west of north
increase solar gains in the afternoon when they are most desirable for evening
comfort, but east of north can warm the house more in the mornings, improving
daytime comfort for those who are at home then. In warmer climates, orientations east
of north can allow better capture of cooling breezes
 Poor orientation and lack of appropriate shading can exclude winter sun and cause
overheating in summer by allowing low angle east or west sun to strike glass surfaces
at more direct angles, reducing reflection and increasing solar gains.

3.3.6. ORIENTATION DOES NOT HAVE TO BE PRECISE: THERE

IS A DEGREE OF FLEXIBILITY.

 A range of methods is available for measuring and assessing the amount of solar
access required when designing a new home, renovating an existing home or buying a
unit. The most thorough (and commonly used) method is to have an accredited
thermal performance assessor simulate the home’s thermal performance using house
energy rating software such as accurate, BERS Pro and First Rate. This will identify
both problems and opportunities. Accredited assessors can be contacted through the
Association of Building Sustainability Assessors or the Building Designers.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.3.7. ORIENTATION FOR COOL CLIMATES :-

 Good orientation for passive cooling keeps out unwanted sun and hot winds while
ensuring access to cooling breezes. A degree of passive cooling is required in most
Australian climates but in hot humid climates, orientation should aim to exclude
direct sunlight and radiant heat (from nearby structures) at all times of the year while
maximising access to cooling breezes.

 Cool breezes can come from a range of directions but near the coast are generally
onshore. On the east coast of India they are generally north-easterly to south-easterly
whereas on the west and southern coasts, they are commonly south-westerly. The
predominant cooling breezes are from the north-west in the wet season and the south-
east in the dry season.
 Breeze direction can vary within a few hundred metres due to landforms, vegetation
or other buildings. Talk to your neighbours or spend time on your site in hotter
seasons to establish the direction of your most reliable cooling breezes.
 While many inland areas often receive no regular breezes, cool air currents form as
cooling night air flows down slopes and valleys (just as water would), and in flat
inland regions, thermal currents created by diurnal temperature differences also
provide useful cooling. These are often of short duration and occur later at night or in
early morning and need to be trapped and stored as ‘coolth’ for the following day.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

Prevalling breeze flow pasthouse dense tree planting deflects breeze

through house

Unlike sunlight, breezes can be diverted, so find a way to divert them through your home
using fences, outbuildings, plantings and windows that open widely.

3.3.8. OTHER PASSIVE COOLING OPTIONS :-

1. Night purging of heat from the building to cooler night air is critical for thermal
comfort. Because breezes are often unreliable, alternative means of purging are
recommended. Among the most effective means is a whole-of-house fan that creates
breezes.

2. One way roof insulation uses low emissivity reflective insulation to reduce
daytime heat gains while allowing conduction and convection to allow upward flow of
heat at night. This is only useful in climates with low or no heating needs .

3. Active cooling systems use roof mounted solar panels that heat the home in winter
to cool it in summer by running in reverse drawing heat out of the building and
radiating it to clear night skies and cool night air. Parts of the roof must have
unobstructed solar access for this to work.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.4. SHADING IN BUILDING

Direct sun can generate the same heat as a single bar radiator over each square metre of a
surface, but effective shading can block up to 90% of this heat. By shading a building and its
outdoor spaces we can reduce summer temperatures, improve comfort and save energy. A
variety of shading techniques can help, from fixed or adjustable shades to trees and
vegetation, depending on the building’s orientation as well as climate and latitude.

Shading glass reduces unwanted heat gain

 Shading glass is the best way to reduce unwanted heat gain, as unprotected glass is
often the greatest source of heat entering a home. However, fixed shading that is
inappropriately designed can block winter sun, while extensive summer shading can
reduce incoming daylight, increasing the use of artificial lighting. Shading uninsulated
and dark coloured walls can also reduce the heat load on a building.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

 Radiant heat from the sun passes through glass and is absorbed by building elements
and furnishings, which then re-radiate it inside the dwelling. Re-radiated heat has a
longer wavelength and cannot pass back out through the glass as easily. In most
climates, ‘trapping’ radiant heat is desirable for winter heating but must be avoided in
summer.
 Shading of wall and roof surfaces is therefore important to reduce summer heat gain,
particularly if they are dark coloured or heavyweight. Light coloured roofs can reflect
up to 70% of summer heat gain.

Shading requirememts vary according to climate and house orientation as

shown below :-

orientation Suggested shading type

Fixed or adjustable horizontal shading above window and

extending past it each side
North

Fixed or adjustable vertical louvres or blades deep verandas or

pergolas with deciduous vines.
East & west

Adjustable shading or pergolas with deciduous vines to allow

solar heating or verandas to exclude it.
North east & north west

South East & South West Planting trees in cool climates, evergreen in hot climates

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.4.1. GENERAL GUIDELINES FOR ALL CLIMATES:-

 Use external shading devices over openings, such as wider eaves, window awnings
and deep verandas or pergolas. Lighter-coloured shading devices reflect more heat,
and those with light coloured undersides make better use of daylight than dark
coloured. Internal shading does not prevent heat gain unless it is reflective: only shiny
surfaces can reflect short wave radiation back through the glass without absorbing it.
 To reduce unwanted glare and heat gain, use plants to shade the building, particularly
windows. Evergreen plants are recommended for hot humid and some hot dry
climates. For all other climates use deciduous vines or trees to the north, and
deciduous or evergreen trees to the east and west

Within the range of north orientation that allows good passive sun control (20°W and 30°E of
solar north) sun can be excluded in summer and admitted in winter using simple horizontal
devices, including eaves and awnings. For situations where a good northerly orientation
cannot be achieved (e.g. existing house, challenging site) it is still possible to find effective
shading solutions.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.4.2. CALCULATING SUN ANGLES :-

The angle of the sun in the sky at noon can be easily calculated for the solstices and
equinoxes as follows:

 Equinox = 90° — latitude

 Summer solstice = Equinox + 23.5°
 Winter solstice = Equinox — 23.5°

The diagram for Darwin below shows why southern façades must be shaded in tropical
locations to keep out the summer sun buildings need to be able to be shaded all year round

Many designers have computer aided drafting programs that calculate sun angles and
shadows for various locations and topographies based on a digital site survey.

The Geoscience Indian website allows you to find the latitude of more than 250,000 place
names in India and calculate the sun angle at any time of the day, on any day of the year.

Low U-values (best performance) are desirable in cooler climates and hot climates where
windows are kept closed, e.g. because of air conditioning or high external air temperatures .

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.4.3. FIXED SHADING :-

 Fixed shading devices (eaves, awnings, pergolas and louvres) can regulate solar
access on northern elevations throughout the year, without requiring any user effort.
 Summer sun from the north is at a high angle and is easily excluded by fixed
horizontal devices over openings. Winter sun from the north is at a lower angle and
penetrates beneath these devices if correctly designed.

3.4.4. EAVES :-

 Correctly designed eaves are

generally the simplest and least
expensive shading method for
northern elevations and are all that
is required on most single-storey
houses. Some designers may
avoid sizing eaves properly in the
mistaken belief that the process is
complex.
 Precise angles for each latitude
can be calculated using the simple
process above. They only vary the
day and month that sun begins to
strike the glass in autumn and shade it in spring because the movement of the sun is
most noticeable to us around the spring and autumn equinoxes. This is due to the
‘apparent’ movement of the sun slowing as it changes direction at each solstice due to
the earth’s tilted axis as it orbits around the sun.
 The following simple rules of thumb ensure that north-facing glass is fully shaded for
a month either side of the summer solstice and receives full solar access for a month
either side of the winter solstice.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

 As a rule of thumb, eaves width should be 45% of the height from the window sill to
the bottom of the eaves. Aim for consistent sill heights where possible and consider
extending the eaves overhang over full height doors or windows. This allows the 45%
rule to be simply met with the following standard eaves overhangs:

 450mm where height is 900–1200mm

 600mm for a height of 1200–1350mm
 900mm for a height of 1350–2100mm
 1200mm for a height of 2100–2700mm

3.4.5. VARYING THE RULE OF THUMB :-

Variations to the 45% rule of thumb are beneficial for fine-tuning your passive shading to suit
varying heating and cooling requirements determined by regional climate, topography and
house design. For example, reduce the overhang by decreasing the percentage of the height
by up to 3% to extend the heating season:

 at higher altitudes (e.g. eastern highlands, tablelands and alpine regions)

 where cold winds or ocean currents are prevalent (e.g. southern Western Australia and
South Australia)
 in inland areas with hot dry summers and cold winters (e.g. Alice Springs)
 in cold, high latitude areas (e.g. Tasmania and southern Victoria).

Gradually increase the percentage of height as heating requirements decrease in latitudes

north of 27.5°S (Brisbane), to decrease or eliminate the amount of sun reaching glass areas
either side of the equinox:

 For hot dry climates with some heating requirements, gradually increase the overhang
up to 50% of height (full shading).
 For hot humid climates and hot dry climates with no heating requirements, shade the
whole building at all times with eaves overhangs of 50% of height from floor level to
both north and south where possible, and use planting or adjoining buildings where it
is not possible. East and west elevations require different solutions.

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THERMAL MASS INSULATION AND VENTILATION IN SUSTAINABLE BUILDING

3.4.6. FIXED SHADING :-

West-facing glass and walls are a significant source of heat gain in hotter climates. East-
facing glass can be equally problematic because, while the home is cooler in the morning and
heat gains do not cause noticeable discomfort, it is the start of a cumulative process that
causes thermal discomfort in the afternoon and early evening. Both east and west require
shading in hotter climates. In cooler climates, east shading is a lower priority.

Because east and west sun angles are low, vertical shading structures are useful in allowing
light, views and ventilation while excluding sun. Roof overhangs, pergolas and verandas that
incorporate vertical structures such as screens, climber covered lattice and vertical awnings
are also effective.

Pergola with vertical screen to vlock low-angle sun

Vertical timber batten screen attached to the house

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3.5. CLIMATE SPECIFIC RESPONSES :-

In high humidity climates and hot dry climates with warm winters, shade the building and
outdoor living spaces throughout the year. For all other climates, use appropriate passive
solar design principles.

3.5.1. HOT AND HUMID CLIMATE :-

In hot humid climates, it is essential to shade the walls year round and highly advantageous to
shade the whole roof.

 Shade all external openings and walls including those facing south.
 Use covered outdoor living areas such as verandas and deep balconies to shade and
cool incoming air.
 Use shaded skylights to compensate for any resultant loss of natural daylight.
 Choose and position landscaping to provide adequate shade without blocking access
to cooling breezes.
 Use plantings instead of paving to reduce ground temperature and the amount of
reflected heat.
 A ‘fly roof’ can be used to shade the entire building. It protects the core building from
radiant heat and allows cooling breezes to flow beneath it.

A fly roof protects a building from radiant and encourages cooling breezes

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3.5.2. HOT AND DRY CLIMATES :-

 Shade all external openings in regions where no winter heating is required.

 Provide passive solar shading to north-facing openings in regions where winter
heating is required.
 Avoid shading any portion of the glass in winter when winter heating is required use
upward raked eaves to allow full winter solar access, or increase the distance between
the window head and the underside of the eaves.
 Use adjustable shade screens or deep overhangs (or a combination of both) to the east
and west. Deep covered balconies or verandas shade and cool incoming air and
provide pleasant outdoor living spaces.
 Place a shaded courtyard next to the main living areas to act as a cool air well. Tall,
narrow, generously planted courtyards are most effective when positioned so that they
are shaded by the house.
 Use plantings instead of paving to reduce ground temperature and the amount of
reflected heat.

Courtyard pools cool through evaporation

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3.5.3. WARM AND HUMID CLIMATES :-

 Provide passive solar shading to all

north-facing openings, using shade
structures or correctly sized eaves.
 Use adjustable shade screens or deep
overhangs to the east and west.
Adjustable shade screens exclude low
angle sun the most effectively.

This adjustable shade can exclude low

angle sun

3.5.4. COOL CLIMATES :-

 Do not place deep covered balconies to the north as they obstruct winter sun.
Balconies to the east or west can also obstruct winter sun to a lesser extent.
 Avoid shading any portion of the north-facing glass in winter — use upward raked
eaves to allow full winter solar access, or increase the distance between the window
head and the underside of the eaves.
 Use deciduous planting to the east and west. Avoid plantings to the north that would
obstruct solar access.

Covered balconies should allow winter sun acess

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3.6. USING TREES FOR SHADING :-

In addition to providing shade, plants can assist cooling by transpiration. Plants also enhance
the visual environment and create pleasant filtered light (see Landscaping and garden design).

 Deciduous plants allow winter sun through their bare branches and exclude summer
sun with their leaves.
 Trees with high canopies are useful for shading roofs and large portions of the
building structure.
 Shrubs are appropriate for more localised shading of windows.
 Wall vines and ground cover insulate against summer heat and reduce reflected
radiation.

Trees can provide shade and act as windbreakers

SHADING FOR HEALTHIER ENVIRONMENT :-

Appropriate shading practices reduce the chance of exposure to harmful ultraviolet rays.
Planting is a low cost, low energy provider of shade that improves air quality by filtering
pollutants.

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3.7. DAY LIGHTING :-

 Exposed concrete soffits can help to provide good daylight penetration when designed
in unison with the façade.

 The objective is to maximise the daylight within the space without causing excessive
glare and solar gains.

 A high window head allows light to be reflected off the soffit and travel well beyond
the perimeter zone.

 The use of profiled soffits (e.g. coffered) running parallel to the path of daylight can
enhance daylight penetration.

 Slabs can also be angled slightly upwards towards atria or windows to improve
performance.

 In addition to aiding daylighting, profiled slabs can provide a positive visual aspect to
the lighting design by creating areas of contrast which help to define room
geometries. Ideally, a high surface reflectance of at least 70–80% should be achieved,
and a gloss factor of no more than 10% to prevent lamps from becoming visible.

 A simple painted finish using white emulsion is a particularly effective way to

achieve this, and provides a cost-effective solution that has been widely used.

 Another option is to use white cement in the mix to provide a light surface finish that
is largely maintenance free.

 The use of an unpainted soffit made with white cement requires a high standard of
casting to achieve a consistent, fair-faced finish.

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3.8.INSULATION

 Insulation acts as a barrier to heat flow and is essential for keeping your home warm
in winter and cool in summer. A well-insulated and well-designed home provides
year-round comfort, cutting cooling and heating bills by up to half. This, in turn,
reduces greenhouse gas emissions.

 Climatic conditions influence the appropriate level and type of insulation. Establish
whether the insulation is predominantly needed to keep heat out or in (or both).
Insulation must cater for seasonal as well as daily variations in temperature.

 Use passive design techniques in conjunction with insulation. For example, if

insulation is installed but the house is not properly shaded, built-up heat can be kept in
by the insulation, creating an ‘oven’ effect. Draught sealing is also important, as
draughts can account for up to 25% of heat loss from a home in winter.

 Most common construction materials have a low insulating value, but some require
little or no additional insulation. Such materials include aerated concrete blocks,
hollow expanded polystyrene blocks, straw bales and rendered extruded polystyrene
sheets.

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3.8.1. INSULATION TYPES AND THEIR APPLICATIONS

1. BULK INSULATION:-

Bulk insulation mainly resists the transfer

of conducted and convected heat, relying
on pockets of trapped air within its
structure. Its thermal resistance is
essentially the same regardless of the
direction of heat flow through it. Bulk insulation traps air in still layers

Bulk insulation includes materials such as glass wool, wool, cellulose fibre, polyester
and polystyrene. All bulk insulation products come with one material R-value for a
given thickness.

2. REFLECTIVE INSULATION :-

Reflective insulation mainly resists radiant

heat flow due to its high reflectivity and low
emissivity (ability to re-radiate heat). It relies
on the presence of an air layer of at least
25mm next to the shiny surface. The thermal
resistance of reflective insulation varies with
the direction of heat flow through it.

Reflective insulation is usually shiny aluminium foil laminated onto paper or plastic
and is available as sheets (sarking), concertina-type batts and multi-cell batts.
Together these products are known as reflective foil laminates, or RFL.

Dust settling on the reflective surface greatly reduces performance. Face reflective
surfaces downwards or keep them vertical. The anti-glare surface of single sided foil
sarking should always face upwards or outwards.

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3.8.2. ADDING INSULATION TO STRUCTURE :-

 Insulation can be added to buildings with varying effectiveness and cost depending on
the construction type and where the insulation is being placed.

 Ceilings and suspended floors with easy access are relatively simple to insulate post-
construction. Insulation board can be laid beneath floor finishes if there is no under-
floor access.

 Walls and skillion roofs are the hardest to insulate after construction, as the internal or
external lining must be removed. A good time to insulate walls is during recladding or
replastering. Specialised products are available to insulate existing walls: check with
your local building information centre. External insulation or (if local building
regulations permit) cavity fill are often appropriate solutions for cavity brick walls.

 Adding insulation to buildings can greatly increase comfort and reduce energy costs
and greenhouse gas emissions. An ideal time for doing this is during renovations.
Insulation can be retrofitted to various construction types.

CAVITY BRICK WALLS :-

 The total thermal resistance of typical cavity brick wall construction is approximately
R0.5. This is insufficient for most building code compliance or sustainability
requirements and needs to be supplemented with additional insulation.

Cavity brick wall with extruded foam

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 Cavity fill insulation is mainly used to insulate existing cavity brick walls. Check that
local building regulations allow use of cavity fill. It must be treated to be water
repellent.

 Foam boards with reflective surfaces do not perform properly if air gaps are not large
enough or the reflective surfaces get dirty during construction.

 Using cavity fill in double brick walls provides a total R-value of around R1.3.

SOLID WALLS :-

 Solid walls include concrete block, concrete panel, stone, mud brick, rammed earth
and solid brick construction without a cavity.

 The total thermal resistance of solid wall construction without a cavity is

approximately R0.3 to R0.4. This is insufficient for most building code compliance or
sustainability requirements and needs to be supplemented with additional insulation.

 Solid walls can be insulated on the inside or the outside. Do not insulate the inside of
walls whose thermal mass is to be utilised. Insulation isolates the thermal mass from
the interior, wasting its beneficial passive heating potential.

Solid wall with internal foam moisture

barrier :-

Suitable materials include polystyrene boards,

bulk batts, and foil faced foam boards with a
still air layer of at least 25mm each side. For
internal walls, plasterboard products
incorporating polystyrene are also suitable.

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Solid wall with external polystyrene render :-

On external walls, polystyrene can be clad with

an external finish, such as render. No additional
waterproofing is required. Fix bulk batts
between battens and cover with a waterproof
cladding.

FLOOR INSULATION :-

Suspended floors :-

The BCA specifies that a suspended floor, other than an intermediate floor in a building with
more than one storey, must achieve a certain R-value for the downwards direction of heat
flow for the relevant climate zone. In addition, such a suspended floor with an in-slab heating
or cooling system is required to be insulated around the vertical edge of its perimeter and
underneath the slab with insulation having an R-value of not less than 1.0.

Suspended floor with polystyrene

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SLAB ON GROUND :-

The vertical edges of a slab-on-ground must be insulated only if located in climate zone 8
(cold climate) or when in-slab heating or cooling in installed within the slab.

Slab edge insulation is usually sufficient, as approximately 80% of the heat loss occurs
through the edge. Install edge insulation before the slab is poured. Do not install insulation
under concrete edge beams.

Follow the manufacturer’s directions, particularly regarding the placement of the insulation
in relation to the waterproof membrane. In termite prone areas precautions may be needed.
Consult your local building information centre.

Slab edge insulation Slab with polystyrene fin

The fin should extend 1–1.5m and can be laid under external paving. The presence of the fin
affects ground temperature gradients, resulting in more stable ground temperatures below the
slab.

The fin is easy to install and can be done as a retrofit to existing slabs. It does not interfere
with the load carrying capacity of the footings.

Insulate the underside of ground slabs where groundwater is present. This method can also
be used in alpine climates and where slab heating is used, although the ‘fin’ method may be
just as effective. Insulation under slabs must have a high compressive strength and be
resistant to moisture penetration and rotting. If the material is compressed it no longer acts as
an insulator and can even lead to structural failure. Some waffle pods can be used for under-
slab insulation, as long as they meet the above criteria.

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ROOF AND CEILING INSULATION :-

Installing roof and ceiling insulation can save up to 45% on heating and cooling energy.

Pitched roof with flat ceiling :-

This is the most common type of construction and the easiest to insulate. The different
insulation requirements for roofs and ceilings according to the climate zone.

ROOF :-

A second layer of RFL (either sarking or foil

batts) beneath the roof increases resistance to
radiant heat. This may be useful in hot climates.
Ensure that there is at least a 25mm gap between
reflective surfaces and other materials. Place RFL
sarking directly under the roofing material
between the battens and the rafters with the shiny
side facing down.
Pitched roof with flat ceiling
CEILING :-

Place ceiling insulation between the joists. Suitable bulk insulation includes batts, loose-fill
and polystyrene boards. In alpine climates two layers of bulk insulation may be installed to
increase thermal performance, one between the joists and the second on top.

There are hazards related to covering ceiling

joists with insulation, e.g. safe places to walk
cannot be identified when accessing the roof
space. If insulation is removed each time the roof
space is accessed it must be reinstalled in
accordance with the Australian Standard.

Suitable reflective insulation includes multi-cell

batts, which should be placed between ceiling
joists. Install insulation strictly in accordance with
manufacturer’s instructions. Failure to do so can significantly reduce insulation values.

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4. LITERATURE REVIEW

Thermal mass insulation and ventilation in sustainable building

Prajit nair, university of kerala

4.1. ABSTRACT

There is a plethora of dynamic Building Performance Simulation (BPS) tools on the market,
that use different methods in terms of how they calculate the effect of thermal mass in
buildings.

This paper analyses the ability of six widely known BPS tools to calculate the thermal mass
potential in whole BPS. The first stage is focused on the analysis of heating and cooling
energy consumption, produced for a single-zone test building. This is done using the IEA
Building Energy Simulation test (BESTEST) diagnostic method. The results are compared
among the different BPS tools in order to examine the extent of variations.

The second stage is a systematic comparison of the tools against some key parameters on the
calculation methods and aims to investigate the implications of the inter-model variability on
the simulation results. The results indicate that there is a divergence in the BPS predictions,
and that the relative differences in the simulation results of the different BPS tools are always
higher for high thermal mass.

Sustainable housing standards are reviewed including the UK 2005 building regulation . the
significance of insulation, orientation, ventilation, thermal mass, occupancy, gains, shading
and climate on predicted energy performance is illustrated. An ESP-r model is then used to
investigate these factors across a range of climates and occupancy / gains scenario. The
investigation covers both heating and cooling energy requirements. The relative importance
of key factors is quantified and a matrix of results presented with conclusion. The role of
simulation in informing design decisions is demonstrated as well as the importance of
considering climate and occupancy / gains patterns.

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4.2. INTRODUCTION :-

Climate change has been the focus of much scientific research over the past decades. The
most direct impact of climate change is the increase of global temperature maxima, which is
also expected to result in significant changes in the weather patterns and increased frequency
of extreme weather events (NHBC, 2012a; DEFRA, 2012). With 36% of the UK total
Greenhouse Gas (GHG) emissions deriving directly from the built environment (McLeod et
al., 2013; NHBC, 2012b), the UK government has set a target to reduce building energy
consumption and CO2 emissions, by focusing on the reduction of fabric heat losses (reduced
infiltration, better insulation etc) and the optimal use of solar gains. Being highly insulated,
low carbon buildings are particularly sensitive to overheating.

The thermal performance of high thermal mass buildings is characterised by dynamic

response to heat transfer, hence when investigating the thermal response of a heavyweight
construction it is important to calculate the heat transfer in transient conditions. In respect to
heat flow in and out of the thermal mass, the prevailing heat transfer mechanism is
conduction. Transient heat conduction is defined by Kossecka and Kosny (1998) as the heat
flow that occurs when the temperature within an object is changing as a function of time.
Nevertheless, when investigating the effects of thermal mass in whole building energy
performance, there are many key influential physical parameters that need to be taken into
consideration.

4.3. METHODOLOGY :-

The research was carried out in three stages. The first was a critical software review to
identify the main features and capabilities of six BPS tools. Focus was placed on the different
calculation methods and solution algorithms used by each of the tools for calculating the
thermal loads of the space and the zone air temperatures.

The method consists of a number of cautiously specified test cases, which progress from very
simple to relatively realistic; it is used for evaluating the modelling capabilities of whole BPS
tools and for diagnosing errors in their source code .

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The bestest method was used in order to minimise the variables in the input data. Two test
suites were selected for the comparison, case 600 (low thermal mass) and case 900thermal
masS. The drycold weather file was used in the simulations, representing a typical
meteorological year (TMY) with cold winter and hot summer dry bulb temperatures.

4.4. RESULTS :-

There is relative consistency in the simulation results given by all six BPS tools for the
annual heating energy consumption, for both the low and high mass case . Tool ‘A’ shows an
increased annual heating demand when compared to the median of all tools, 8% for the low
mass case and 13% for the high mass case.

The general observation from the results for annual heating and cooling energy consumption
is that both heating and cooling demand are decreased by approximately 65% in the high
mass case. The divergence in the results is greater for the annual cooling demand calculation.
The relative differences in the results of all the BPS tools, when compared to the median, are
always higher in the high mass case, hence the results confirm that discrepancies are more
substantial in a high thermal mass building.

Bestest annual energy consumption Bestest annual energy consumption

low mass case 600 high mass case 900

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4.5. DISCUSSION :-

Based on the BESTEST simulation, the larger discrepancies in the results were identified in
the annual cooling energy consumption. Moreover, the maximum deviation in simulation
results was also identified in the annual cooling energy demand. In general, the relative
differences in the results of all BPS tools when compared to the median, were always higher
in the high mass case. This finding is consistent with those from previous studies reported in
the literature review showing that discrepancies are more substantial in a high thermal mass
building.

The analysis showed that the algorithms used to calculate the solar gains distribution within
the internal surfaces of the zone have no impact on the inconsistencies.

4.6. CONCLUSION :-

Whole structure performance simulation is essential in order to assess the energy and thermal
performance of buildings, especially in the case of high thermal mass structures. It has been
shown that there are inconsistencies in the simulation results when modelling an identical
building using different BPS tools. The analysis focused on the comparison of six dynamic
BPS tools, with respect to their ability in calculating the effect of thermal mass. Moreover,
the analysis explored the implications of the inter-model variability and the tools’ inherent
differences on the simulation results.

Regarding the divergence in the calculation of annual heating and cooling energy
consumption, the analysis showed that the relative differences in the results of all BPS tools,
when compared to the median, is always higher for high thermal mass.

The discrepancy on the calculation of thermal mass effect (the difference between low and
high mass results) is more obvious for annual cooling energy consumption, around
10%,while for annual heating demand is less than 5%.

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QUESTIONS FOR ENGINEERS AND ARCHITECTS

1. How does thermal mass works ?

-> Thermal mass works by absorbing heat and re–radiating it as a temperature

drop.

2. which material is a good thermal insulator and why?

-> Polyurethane foam is a good thermal insulator besause it is environmental

friendly and light in weight.

3. Does thermal mass work for heat storage where limited solar energy is
available?

-> no, as thermal mass absorbs the energy from the sun and wind so it can not
work in the such regions.

4. which one is better to place thermal mass in floors or in walls?

-> insulation on walls are more effective because it is exposed to direct sunlight

5. which are other thermal mass options/

-> passive cooling and passive heating are alternate of thermal mass.

6. Best orientation for building?

-> building should be placed in such direction from where it can gain as much
as direct sun light.

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QUESTIONS FOR ENGINEERS AND ARCHITECTS

1. How does thermal mass works ?

-> Thermal mass works for heating and cooling according to the climate.

2. which material is a good thermal insulator and why?

-> Mineral wool and cellulose as both of them are fir resistance and low in cost.

3. Does thermal mass work for heat storage where limited solar energy is
available?

-> yes, thermal mass can absorb the energy which is available.

4. which one is better to place thermal mass in floors or in walls?

-> Thermal mass works on solar energy so it should be installed where direct
sunlight is available.

5. which are other thermal mass options/

-> evaporating cooling is another option

6. Best orientation for building?

-> south east or south west so that walls can gain more solar energy.

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CONCLUSION :-

This study rightly showing the effects of individual building elements like static sunshade,
brick cavity wall with brick projection and hollow roof and their combined effect on indoor
air temperature and thus thermal comfort. Considering the composite climate of the location
in the present study, the building elements that respond to various climate needs.

 Designed static sunshade may be used when it is desirable to raise indoor air
temperature in winter.

 Brick cavity wall with brick projection may be used in summer to lower minimum
indoor air temperature and in winter it raise air temperature.

 Hollow roof may be used in summer when it is desirable to lower indoor air
temperature.

 Brick cavity wall with brick projection and hollow roof may be used in summer to
lower indoor air temperature.

 All the building elements may be used in combination in summer to lower maximum
and minimum indoor air temperature and in winter to raise it in morning and night.

 Hollow roof may be used in summer to lower indoor air temperature throughout the
day. It may also be used to lower maximum, minimum indoor air temperature and
reduce temperature wing.

The structure with designed static sunshade, brick cavity wall with brick projection and
hollow roof lowered indoor air temperature in summers and raised it in winters morning and
nighs. The combined effects of these building elements is thus useful for energy conservation
in building in composite climate as per seasonal needs.

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