Solar Passive Architecture by noidarocker



         DR. BN COLLEGE OF




         ROLL NO.: 2

                   Completion Certificate

This is to certify that Miss. Anu Om Alreja of Dr. BN College of
Architecture University Exam No.:                   Class: Fourth
Year B.Arch Roll No.: 2 has satisfactorily completed the required
amount of work for the Academic Year:               as laid down
by the University/Institution.

   Head of the              External Examiner   Internal Examiner
   Department                                    Subject Teacher

I would like to take this opportunity to extend my sincere thanks to my guide Ar. Arun Ogale,
Ar. Shekhar Garud, Ar. Anagha Paranjape, Ar. Nachiket Patwardhan and Ar. Vasudha Gokhale
for all help, support and guidance provided to complete my dissertation project.

I would also like to extend my sincere gratitude to our Principal Dr. Anurag Kashyap, Dr.
Bhanuben Nanavati College of Architecture , for being a source of inspiration and support.

Thank you.


Anu Om Alreja

  y The need
  y Importance of energy conservation in buildings
  y Pattern of energy consumption
Solar Passive Techniques
  y Passive heating
     Direct gain
     Indirect gain system
     Direct gain systems
       Glazed Wall
       Glazed Atrium
     Indirect gain systems
         Roof-based air heating system
         Thermal storage wall system (Trombe wall)
         Water wall
         Sun spaces
  y Passive cooling
     Passive cooling systems
         Ventilation & Operable Windows
         Wing Walls
         Thermal Chimney
         Other Ventilation Strategies
         Passive Downdraft Evaporative Cooling (PDEC) System
         Earth berming
         Earth air tunnel (EAT) system
         Cooling Tower / Wind catcher / Wind Tower
         Evaporative cooling
         Roof pond system
Case Studies

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To study different types of solar passive architectural and constructional techniques for
designing different buildings and conclude the results.

y   To promote energy efficient building designs i.e. to minimize energy use and the negative
    environment effects of building.
y   To maximize use of renewable and natural resources in building environment.
y   Building construction with optimum use of solar energy.
y   Other forms of ambient energy in energy management.
y   Thermal comfort for the inhabitants.
y   To reduce maintenance cost.

y   Research on solar passive features.
y   Case studies of buildings in different climatic zones to understand the importance and
    usefulness of solar passive features.
y   Conclusions

Solar Passive Techniques
Solar passive techniques are incorporated in building design to minimise load on conventional
systems (heating, cooling, ventilation and lighting) . Passive systems provide thermal and visual
comfort by using natural energy sources and sinks e.g. solar radiation, outside air, sky, wet
surfaces, vegetation, internal gains etc. Energy flows in these systems are by natural means
such as by radiation, conduction, convection with minimal or no use of mechanical means. The
solar passive systems thus, vary from one climate to the other e.g. in a cold climate an
architect¶s aim would be to design a building in such a way that solar gains are maximised, but
in a hot climate his primary aim would be to reduce solar gains, maximise natural ventilation
and so on. The orientation of the building, site selection, materials and design features allow
the home to collect, store and distribute the sun¶s heat in winter, block the sun during summer,
and provide for air circulation and natural day lighting.

The passive energy system involves collecting, storing, distributing and controlling of thermal
energy flow through the natural principles of heat transfer. Various available options of passive
architectural features like shape and orientation of the building, shading device s, earth
berming, air movements etc., and developed passive concepts like trombe wall, water wall,
wind tower, solar chimney, evaporative cooling etc. can be adopted as per the building

Passive solar systems rules of the thumb:
y The building should be elongated on East ± West axis.
y The building¶s south face should receive sunlight between the hours of 9.        a.m through
     . p.m (sun time) during the heating season.

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                                S lar Passive Techni ues

        Passive cooling                                                                Passive heating

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Passive heating
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        irect gain
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                                                                                                                                          Direct gain application                                    7
direct ain system ses 60 75% f t e sun¶s energy stri ing t e windows. The interior thermal
mass tempers the intensity of heat during the day y absorbing heat. At night, the thermal
mass radiates heat into the li ing space, thus warming the spaces.

Direct gain can be achieved by various forms of openings such as clerestories, skylight
windows, etc. designed for the required heating. Direct gain systems have been used for day-
use rooms by architect Sanjay Prakash in the residence for ohini ullick at Bhowali. The user
is extremely satisfied with the thermal performance of the direct gain system in this residence.

                                                                 Direct gain systems have some
                                                                 limitations. They cause large
                                                                 temperature savings typically 10
                                                                 ° because of large variations in
                                                                 input of solar energy. Strong
                                                                 sunlight, glare, and ultraviolet
                                                                 degradation of the house material
                                                                 are some disadvantages of direct
                                                                 gain systems.       owever, being
                                                                 relatively simple to construct and
                                                                 inexpensive, they are by far the
                                                                 most common systems used
The direct gain system of the Bhowali house. The picture
highlights the fully glazed walls for the day use rooms
from inside.

Indirect gain system
In an indirect gain system, thermal mass is located between the sun and the living space. The
thermal mass absorbs the sunlight that strikes it and transfers it to the living space. The indirect
gain system uses 30-45% of the sun¶s energy striking the glass adjoining the thermal mass.

  irect gain systems

The direct gain strategy is that sunlight enters the building
through a large south-facing window the collector) in the
  orthern hemisphere) and is incident upon the floor and
walls of the structure. The effectiveness of direct solar gain
systems is significantly enhanced by insulative e.g. double
glazing), spectrally-selective glazing low-e), or movable
window insulation window quilts, bifold interior insulation
shutters, shades, etc.). enerally, Equator-facing windows
should not employ glazing coatings that inhibit solar gain.
Selection of different spectrally-selective window coating
depends on the ratio of heating versus cooling degree
days for the design location. Direct-gain systems are more
dependent on double or triple glazing to reduce heat loss.
In cold regions thermal glazing should be equivalent to or
higher than, double glazing. Windows and roof lights                  Typical double glazed
                                                                       aluminium window
provides direct path for admitting daylight.

Depending on climate, the total direct gain glass should not exceed about 12% of the house's
floor area. Beyond that, problems with glare or fading of fabrics are likely to occur, and it
becomes more difficult to provide enough thermal mass for year -round comfort.

Glazed      all
Buildings with rectangular floor plans are elongated on an east -west axis and have a glazed
south-facing wall; a thermal storage media exposed to the solar radiation which penetrates the
south-facing glazing in winters.
There is storage of solar energy in
thermal mass followed by the natural
distribution of this stored solar
energy back to the living space,
when       required,   through     the
mechanisms of natural convection
and radiation. verhangs or other
shading devices sufficiently shade
the south-facing glazing from the
summer sun. There are windows on
the east and west walls, and
preferably none on the north walls.

  isadvantages: Some glazed wall
variants may still be at a
disadvantage in cloudy or very cold
climate.                                                        Glazed Wall

Glazed     trium

This is a northern climate variant of the open courtyard -a building form with a long
architectural tradition in most parts of the world. The addition of roof glazing provides protection
                                                       from rain and wind, and a moderate
                                                       resistance to heat flow. sually located
                                                       centrally within a building, with the glazing
                                                       mainly confined to its roof. The large area
                                                       of glazing on the envelope of these
                                                       structures entails the admission of
                                                       considerable amounts of solar. The atrium
                                                       temperature is higher than those of the
                                                       adjoining indoor spaces but within the
                                                       comfort range; heat can flow naturally to
                                                       adjoining rooms by opening doors or
                                                       windows. Where the parent building is
                                                       mechanically heated such heat flow can be
                                                       expected to displace conventional heating
                                                       thus saving energy.
                  Glazed Atrium

Indirect gain systems
Roof-based air heating system

In this technique, incident solar radiation is trapped by the roof and is used for heating interior
spaces. In the orthern emisphere, the system usually consists of an inclined south-facing
glazing and a north-sloping insulated surface on the roof. Between the roof and the insulation,
an air pocket is formed, which is heated by solar radiation. A moveable insulation can be used
to reduce heat loss through glazed panes during nights. There can be vari ations in the detailing
of the roof air heating systems. In the imachal Pradesh State ooperative Bank building, the
south glazing is in the form of solar collectors warming the air and a blower fan circulating the
air to the interior spaces.

y It can have better exposure to sun and thus collect more energy.
y It does not interfere with elevations of the building.

  lazed wall and roof space collector are ingenious device for capturing incident solar radiation
that would otherwise be lost, without exposing indoor space to temperature and sunshine

                                       Roof space collector

Thermal storage wall system (Trombe wall)

                                      A trombe wall is a thermally massive wall with vents
                                      provided at the top and bottom. It may be made of
                                      concrete, masonry, adobe, and is usually located on the
                                      southern side (in the northern hemisphere) of a building
                                      in order to maximize solar gains. The outer surface of the
                                      wall is usually painted black for maximizing absorption
                                      and the wall is directly placed behind glazing with an air
                                      gap in between. Solar radiation is absorbed by the wall
                                      during the day and stored as sensible heat. The air in the
                                      space between the glazing and the wall gets heated up
                                      and enters the living spaces by convection through the
                                      vents. Cool air from the rooms replaces this air, thus
                                      setting up convection current. The vents are closed
                                      during night, and heat stored in the wall during the day
                                      heats up the living space by conduction and radiation.
                                      Trombe walls have been extensi vely used in the cold
                                      regions of Leh. Various forms of Trombe walls have been
                                      tried and tested in the Ledeg hostel at Leh. It is
noteworthy that in buildings with thermal storage walls, indoor temperature can be maintained
at about     C when the outside temperature is as low as - oC. Generally, thickness of the
storage wall is between      mm and        mm, the air gap between the wall and glazing is      -
    mm, and the total area of each row of vent is about % of the storage wall area. The
trombe wall should be adequately shaded for reducing summer gains.

Water wall

Water walls are based on the same principle as that for trombe walls, except that they employ
water as the thermal storage material. A water wall is a thermal storage wall made up of drums
of water stacked up behind glazing. It is usually painted black to increase heat absorption. It is
more effective in reducing temperature swings, but the time lag is less. eat transfer through
water walls is much faster than that for trombe walls. Therefore, distribution of heat needs to be
controlled if it is not immediately required for heating the building. Buildings that work during
the daytime, such as schools and offices, benefit from the rapid heat transfer in the water wall.
  verheating during summer may be prevented by using suitable shading devices.

Sun spaces

A sun space or solarium is the combination of direct and indirect gain systems. The solar
radiation heats up the sun space directly, which in turn heats up the living space separated
from the sun space by a mass wall) by convection and conduction through the mass wall. In
the northern hemisphere, the basic requirements of buildings heated by sun space are a) a
                                              glazed south facing collector space attached yet
                                              separated from the building and b) living space
                                              separated from the sun space by a thermal
                                              storage wall. Sunspaces may be used as winter
                                              gardens adjacent to the living space. The
                                                imurja building in Shimla has well designed
                                              solarium as integral part of south wall to
                                              maximise solar gain.

                                                          Sun Space


Transwall is a thermal storage wall that is semitransparent in nature. It partly absorbs and
partly transmits the solar radiation. The transmitted radiation causes direct heating and
illumination of the living space. The absorbed heat is transferred to the living space at a later
time. eat loss through the glazing is low, as much of the heat is deposited at the centre of the
transwall ensuring that its exterior surface does not become too hot. Thus, the system
combines the attractive features of both direct gain and Trombe wall systems.

   transwall has three main components:
‡ ontainer made of parallel glass walls set in metal frame
‡ Thermal storage liquid, which is generally water
‡ A partially absorbing plate set at the centre of the transwall, parallel to the glass walls

It is installed on the south side of the building in the northern hemisphere), located directly
behind double glazing. To prevent the growth of micro -organisms in the storage, an inhibiting
agent may be added.

Passive cooling
In this type of cooling solar thermal energy is not used directly to create a cold environment or
drive any direct cooling processes. Instead, passive solar building design aims at slowing the
rate of heat transfer into a building in the summer, and improving the removal of unwanted
heat. There are many design specifics involved in passive solar cooling. It is a primary element
of designing a zero energy building in a hot climate.

Passive cooling systems rely on natural heat-sinks to remove heat from the building. They
derive cooling directly from evaporation, convection and radiation without using any
intermediate electrical devices. All passive cooling strategies rely on daily changes in
temperature and relative humidity. The applicability of each system depends on the climatic

The relatively simple techniques that can be adopted to provide natural cooling in the building
are reduction of solar and connective heat import by :
   y orientation of building
   y shading by adjoining building
   y landscaping
   y window shading devices
   y surface finishes

 eduction of heat transmission in the building by :
  y thermal insulation
  y air cavities

Passive cooling systems
Ventilation &      perable      indows

A primary strategy for cooling buildings without mechanical assistance passive cooling) in hot
humid climates is to employ natural ventilation. In the Austin area, prevailing summer breezes
are from the south and southeast. This matches nicely with the increased glazing on the south
side needed for passive heating, making it possible to achieve helpful solar gain and ventilation
with the following strategies:
    y Place operable windows on the south exposure.
    y    asement windows offer the best airflow. Awning or hopper) windows should be fully
       opened or air will be directed to ceiling. Awning windows offer the best rain protection
       and perform better than double hung windows.
    y If a room can have windows on only one side, use two widely spaced windows instead
       of one window.

Wing Walls

Wing walls are vertical solid panels placed
alongside of windows perpendicular to the wall on
the windward side of the house. Wing walls will
accelerate the natural wind speed due to pressure
differences created by the wing wall.
                                                      Top View of Wing Walls
                                                          Airflow Pattern
Thermal      himney

A thermal chimney employs convective currents to draw air out of a building. By creating a
                                        warm or hot zone with an exterior exhaust outlet,
                                        air can be drawn into the house ventilating the
                                        Sunrooms can be designed to perform this
                                        function. The excessive heat generated in a south
                                        facing sunroom during the summer can be vented
                                        at the top. With the connecting lower vents to the
                                        living space open along with windows on the north
                                        side, air is drawn through the living space to be
                                        exhausted through the sunroom upper vents. The
                                        upper vents from the sunroom to the living space
                                        and any side operable windows must be closed
                                        and the thermal mass wall in the sunroom must
                                        be shaded.)
        Summer Venting Sunroom

Thermal chimneys can be constructed in a
narrow configuration like a chimney) with an
easily heated black metal absorber on the
inside behind a glazed front that can reach
high temperatures and be insulated from the
house. The chimney must terminate above
the roof level. A rotating metal scoop at the
top which opens opposite the wind will allow
heated air to exhaust without being
overcome by the prevailing wind. Thermal
chimney effects can be integrated into the
house with open stairwells and atria.

                                                                  Thermal Chimney
Other Ventilation Strategies
   y      ake the outlet openings slightly larger than the inlet openings.
   y   Place the inlets at low to medium heights to provide airflow at occupant levels in the
   y   Inlets close to a wall result in air ³washing´ along the wall. Be certain to have centrally
       located inlets for air movement in the center areas of the room.
   y   Window insect screens decrease the velocity
       of slow breezes more than stronger breezes.
       Screening a porch will not reduce air speeds
       as much as screening the windows.
   y     igh mass houses can be cooled with night
       ventilation providing that fabric furnishings are
       minimized in the house.
   y   Keep a high mass house closed during the
       day and opened at night.
                                                                  Thermal Chimney Effect
                                                                      Built into Home          14
Passive Downdraft Evaporative Cooling (PDEC) System

                                                            y   A system of inlet and outlet
                                                            y   Locations, sizes and heights :
                                                                generate required air
                                                            y   A fine spray of water cools
                                                                the air at entry.
                                                            y    -9 air change rates per hour
                                                            y   Strategy:
                                                                    o Hot season:
                                                                        evaporative cooling.
                                                                    o Monsoon: cooling off,
                                                                        induce ventilation by
                                                                    o Winter:ventilation
                                                                        closed by shutters)

Design of PDEC System

Ambient hot-dry air is trapped, cooled by evaporation of water and then introduced in the
building. Simple system based on shower spray system developed by B. Givoni . PDEC system
works very well in the summer months. For example, in May, the temperature of cooled air
leaving the tower is about °C while the corresponding ambi ent temperature is about    °C.
Thus, the drop in day-time temperature is significantly high in May, i.e. about °C.

Implications of PDEC system:

Low cost single pass system
Easy to maintain
Entry of birds and pests prevented
 Charcoal tray to filter out dust
Sophisticated water treatment is not required
Single tower serving multiple floors
 Can be used for pre-cooling the building at night

 High humidity
 Noise due to spraying of water

Earth berming

Earth is piled up against exterior walls and packed, sloping down away from the house. The
roof may, or may not be, fully earth covered, and windows/openings may occur on one or more
sides of the shelter. Due to the building being above ground, fewer moist ure problems are
associated with earth berming in comparison to underground/fully recessed construction.

This technique is used both for passive cooling as well as heating of buildings, a feat which is
made possible by the earth acting as a massive heat si nk. Summer as well as winter variations
die out rapidly with increasing depth from the earth's surface. This temperature at a depth of a
few meters remains almost stable throughout the year. Thus, the underground or partially sunk
buildings would provide b oth cooling in the summer) and heating in the winter) to the living
space. Besides, load fluctuations are reduced by the addition of earth mass to the thermal
mass of the building. The infiltration of air from outside is reduced.

The earth sheltered stru cture has to be heavier and stronger to withstand the load of the earth
and the vegetation above. Besides, it should be suitably waterproofed and insulated to avoid
ground moisture.

Additional cooling if required can be provided by circulating air throug h ducts built underground
 where the temperature is low). The same ducts can provide some degree of preheating for the
fresh outside air during the cold periods.

                                              Earth berming

                                                          Earth air tunnel E T) system

                                                          Daily     and    annual    temperature
                                                          fluctuations decrease with the increase
                                                          in depth below the ground surface. At
                                                          a depth of about 4 m below ground,
                                                          the temperature inside the earth
                                                          remains nearly constant round the
                                                          year and is nearly equal to the annual
                                                          average temperature of the place. A
                                                          tunnel in the form of a pipe or
                                                          otherwise embedded at a depth of
                                                          about 4 m below the ground, will
                                                          acquire the same temperature as the
                                                          surrounding earth at its surface and
therefore the ambient air ventilated though this tunnel will get cooled in summer and warmed in
winter and this air can be used for cooling in summer and heating in winter. Earth air tunnel
                                                         has been used in the composite climate
                                                         of urgaon in the ETREAT building.
                                                         The living quarters the south block of
                                                         the RETREAT) are maintained at
                                                         comfortable                temperatures
                                                          approximately between 20 ° and 30
                                                         ° ) round the year by the earth air
                                                         tunnel system, supplemented, whenever
                                                         required, with a system of absorption
                                                         chillers powered by         P     during
                                                         monsoons and with an air washer during
                                                         dry summer. owever, the cooler air
                                                         underground needs to be circulated in
                                                         the living space. Each room in the South
                                                         Block has a µsolar chimney¶; warm air
                                                         rises and escapes through the chimney,
                                                         which creates an air current for the
                                                         cooler air from the underground tunnels
                                                         to replace the warm air. Two blowers
                                                         installed in the tunnels speed up the
                                                         process. The same mechanism supplies
                                                         warm air from the tunnel during winter.
                   Earth air tunnel

Cooling Tower / Wind catcher / Wind Tower

This system can work effectively in hot and dry climate, where daily variations in temperatures
are high with high temperature during day time and low temperature during night time. The
openings of the wind catcher are provided in the direction of the wind , and outlets on the side
take advantage of the pressure difference created by wind speed and direction.

The principle of the wind catcher :

‡ ay time
The hot air enters the tower through the openings and cooled when it comes in
contact with the cool tower and thus becomes heavier and turns down.
When an inlets is provided to the rooms with an outlet on other side there is a draft
of cool air. The wind tower becomes warm in the evening, after a whole day of heat

‡Night time
During night the reverse happens: the cooler air comes in contac t with the bottom of
the tower through the rooms; it gets heated up by the warm surface of wind tower
and thus an air flow is maintained in the reverse direction.

A combination of sensible cooling in the ground and evaporative cooling with the flow of
air induced by the wind catcher. Wind towers with indirect evaporative cooling systems have
been integrated with VA system for pre-cooling fresh air.

                                             1. oncepts of wind catcher can work well an
                                             individual units of house and not in multi -storeyed
                                             2.In a dense urban area the wind tower has to be
                                             very high to be able to catch enough air.
                                             3.The surface of the wind tower accumulates dust
                                             and heat transfer from the surface of wind tower
                                             to the air becomes slower.
                                             4.If the wind direction is unpredictable, it is better
                                             made openings of the inlet wind catcher on all
                                             four sides.
    Wind Tower Evaporative Cooling

                                  Evaporative Cooling Tower

Evaporative cooling

Evaporative cooling lowers indoor air temperature by evaporating water. It is effective in hot-
dry climate where the atmospheric humidity is low. In evaporative cooling, the sensible heat of
air is used to evaporate water, thereby cooling the air, which in turn cools the living space of
the building. Increase in contact between water and air increases rate of evaporation. The
presence of a water body such as a pond, lake, sea etc. near the building or a fountain in a
courtyard can provide a cooling effect. The most commonly used system is a desert cooler,
which comprises of water, evaporative pads, a fan, and pump. Evaporative cooling has been
tried as a roof-top installation solar energy centre, urgaon. owever, the system has now
become defunct due to poor water supply in the area.

Roof pond system

This system can provide both heating and cooling. 6 -12 inches of water are contained on a flat
roof, usually stored in large plastic or fiberglass containers covered by glazing. During the
cooling season, an insulated cover is removed at night to expose th e water to cool night air.
The water absorbs heat from below during the day, and radiates it out at night. The
temperature within the space falls as the ceiling acts as a radiant cooling panel for the space,
without increasing indoor humidity levels. During the heating season, the insulated cover is
removed during the day. The water absorbs heat from the sun, and radiates it in to the building
below. In cold climates such as ours, an attic pond beneath pitched glazing is more effective
than a flat roof pond .

The limitation of this technique is that it is confined only to single storey structure with flat,
concrete roof and also the capital cost is quite high. Roof ponds require somewhat elaborate
drainage systems, movable insulation to cover and uncover th e water at appropriate times, and
a structural system to support up to 65lbs/sq ft dead load.

                            Roof pond                       Roof pond
                             cooling                         heating
Principle of the courtyard:
Due to the incident solar radiation in the courtyard, the air in the courtyard
becomes warmer and rises up. To replace it, cool air from the ground level
flows through the openings of the room, thus producing the air flow.
During the night, the process id reversed. The cooled surface air of the
roof sinks down to the court and this cooled air enters the living spaces
through the low level openings and leaves through higher level openings.
This system can work effectively in hot and dry climates, where day time
ventilation is undesirable, as it bring s heat inside and at night the air
temperature becomes cooler and it can ventilate the building.
                                                                                 Model of courtyard
Limitations                                                                      house
1.When the courtyard receive intense solar radiation, much heat will be conducted and
radiated into the rooms as against the induced draft of air which may be problematic.
2.The intense solar radiation can produce glare for the inside room.
The best way is to keep the courtyard shaded and only partially open to sky.
                    Case Studies
                   H.P. STATE CO-OPERATIVE                  ANK      ILDING,
                   SHI LA

                   Location : Shimla, imachal Pradesh
                   Climate : old and loudy

                   Brief description of building :

                   This building is a ground and three -storeyed structure with
                   its longer axis facing the east-west direction. The smaller
                   northern wall faces the prevailing winter winds from the
                   north-eastern direction. The building shares a common
                   east wall with an adjoining structure. Its west façade
                   overlooks a small street from which the building draws its
                   main requirements of ventilation and daylighting. A plan
                   and section of the building showing the various passive
                   techniques incorporated is given below.

Section and plan of H. P. state co-operative bank, Shimla                   20
Energy conscious features:
  y South-facing Trombe wall and sunspace heats up the interior .
  y South-facing solar collectors on the roof provide warm air, which is circulated by means
     of ducts.
  y    orth face is protected by a cavity wall that insulates the building from prevailing winter
  y Western wall is provided with insulation as well as double glazing .
  y Daylighting is enhanced by providing light shelves. Skylight on the terrace also provides
  y Air lock lobbies are provided to reduce air exchange .

Performance of the building:
The predictions of the energy savings of the building component -wise) per
annum, as compared to a conventional building are as follows:
West wall double glazing and insulation) = 43248 kWh
                           Roof insulation = 237 6 kWh
                    Roof top solar collector = 10278 kWh
                               Trombe wall = 73 8 kWh
                                       Total = 84720 kWh


Location : ulbarga, Karnataka
Climate : ot and dry
Brief description of the building:
This building is a ground and two -storeyed structure designed by Kembhavi Architecture
  oundation to house the offices of the Inspector eneral of Police, ulbarga. The building is
constructed using innovative materials. or example, the external walls are composite walls
 i.e. granite blocks on the outer side and rat -trap bond brick walls on the inner side) and the
roof is made of filler slab. The -values of the walls and roof are 1.53 W/m2 -K and 2.15 W/m2-
K respectively. The building is roughly rectangular with the longer axis along the north -south
direction. ost windows face east or west. A layout plan of the building is give n. As the building
is located in a hot and dry climate, evaporative cooling has been used for providing comfort.
   ost of the offices are cooled by passive downdraft evaporative cooling PDE ) tower system.
  igure below shows a photograph of the building as well as a sketch section of a typical PDE
tower to explain its principle.

                             Layout plan of I.G.P. Complex, Gulbarga                           21
Energy conscious features:
  y Passive downdraft evaporative cooling PDE ) towers for providing comfort.
  y Tinted glasses to reduce glare.
  y Alternative building materials such as composite walls to reduce heat gain and filler slabs to
       reduce the quantity of concrete in the structure.
   y   A central atrium to enhance cross ventilation and provide daylighting.
   y   Solar PV lighting and pumps, rainfall harvesting and water conservation facilities incorporated.

Performance of the PDEC system:
The building is in the final stage of construction. The PDE system¶s design is based on the
³shower tower´ concept developed by ivoni. Preliminary measurements taken in ay and
September, 2005 showed that the temperature of the air exiting from the tower is lower by
about 10° and 4° respectively, compared to that of ambient air. igure below presents the
hourly values of the temperature of air exiting from the tower on a typical day in September.
The corresponding measured values of ambient temperature are also plotted for comparison.
Additionally, the figure shows the theoretically calculated values based on ivoni¶s model of
the shower tower. It is seen that t he measurements agree reasonably well with the predictions.
  igure below shows the estimated performance of a tower in various months during daytime. It
presents the results of exit temperature of air leaving the tower and the corresponding ambient
dry bulb temperature. It is seen from the figure that the performance of the cooling tower is
quite satisfactory in the summer months. The drop in temperature is about 12 - 13 ° in arch,
April and ay. onsidering that the PDE system is used in these months, the predictions of
the energy savings of the building per annum, as compared to an air-conditioned building
maintained at 27.5 ° , are as follows:
Estimated ost of PDE system = Rs. 17,50,000
Estimated savings per annum         = Rs. 3,52,000
Simple payback period               = 5 years approximately)

                      Photographs of IGP Complex, Gulbarga and sketch
                           showing the principle of a PDEC tower                                      22
        Comparison of measured and predicted temperature of air exiting PDEC

          Monthly prediction of the temperature of air exiting the PDEC tower

The RETREAT Resources Efficient TERI Retreat for Environment
Awareness and Training) complex of TERI The Energy and Resources
Institute) at Gurgaon in Haryana

                                            Site Address / Location:        ual Pahari,
                                            Climatic Zone: omposite
                                            Building Type: Institutional
                                            Architect(s): Sanjay Prakash and TERI
                                            Client/ Owner: The Energy and Resources

                                            RETREAT is a part of the 36-hectare TERI
                                            campus at ual Pahari, about 30 km south of
Delhi, in the northern state of Haryana. It is a   -room training hostel with conference facilities
for      people, dining space and a kitchen, recreational area, computer room, and a library .
The basic design process is to minimize energy demand in the building through passive
concepts such as solar orientation, latticework for shading, insulation, and landscaping.

Key Sustainable Features
Orientation, insulation, and design of the building .

   y   Wall insulation with      -mm thick expanded polystyrene and roof insulation using
       vermiculite concrete (vermiculite, a porous material, is mixed with concrete to form a
       homogenous mix) topped with China mosaic for heat reflection.
   y   Building oriented to face south for winter gains; summer gains offset using deciduous
       trees and shading.
   y   South side partially sunk into the ground to reduce heat gains and losses.
   y   East and west walls devoid of openings and are shaded.

Earth air tunnel for the south block
   y   Four tunnels of m length and cm diameter each laid at a depth of m below the ground to
       supply conditioned air to the rooms.
   y   At a depth of m below ground, temperature remains      °C (in Gurgaon) throughout the year.
   y   Four fans of HP each force the air in and solar chimneys force the air out of rooms.
   y   Assisted cooling by air washer in dry summer a nd a   TR dehumidifier in monsoon.

Solar hot water system
   y     solar water heating panels (inclined at        degrees instead of   degrees) integrated
      with parapet wall.
   y Innovative daylighting by means of skylights.

Building management system
   y Monitors building parameters (temperatures, humidity, consumption, etc.)

   y The winter temperature in the rooms heated by solar gains and earth air tunnel systems
      was recorded to be      °C (average night -time condition) when the ambient temperature
      was about      °C.
   y In the dry summer month of May, a room temperature (in the rooms cooled by earth -air
      tunnels combined with evaporative cooling system) of      °C (average daytime condition)
      with     %- % relative humidity was recorded when the am bient temperature and
      relative humidity were    °C and %, respectively.
   y In the humid summer months, a room temperature (in rooms cooled by the earth-air
      tunnel supplemented by ammonia absorption chillers) of            °C and     % relative
      humidity were recorded with the ambient condition being      °C at % relative humidity.
   y The conference rooms cooled by ammonia absorption chillers maintain an average
      temperature of     °C at % relative humidity.
   y The building being only partially loaded as yet now consumes a ma ximum of        units of
      electricity per hour. The PV system generates an average of          units per day on a
      sunny day.

   y   From the above case studies it can be concluded that solar passive techniques are
       really effective in controlling the temperature, day light, etc within a building as per the
       users comfort, location and climate of the area in which the building is located.
   y   Solar passive architecture is a very helpful and a very cost effective technique to control
       the climatic conditions within a building.

   y   Since it uses the non conventional solar energy source, use of solar passive
       architecture can also save the limited conventional energy sources, which are
       traditionally used as energy sources for a building, from getting depleted.
   y   Hence the use of solar passive architecture systems can prove to be a more effective
       method than the conventional methods for temperature control in a building.

Advantages of solar passive architecture:
  1. Environmental friendly
   . Low energy bills
   . Comfortable living conditions
   . Low maintenance
   . Clean and hygienic
   . Durable
   . No operating noise

   y   A maximum saving of       ± % on conventional fuels required for space heating during
       winters and cooling during summers can be achieved.
   y   Large windows and views, sunny interiors, open floor spaces, warmer in winters and
       cooler in summers resulting in comfortable living conditions even during power failures,
       durable reduced operational cost, independent from future rises of fuel costs, clean
       environment to combat growing concern over global warming and ozone depletion are
       the main features.
   y   Winter room temperature:      C (when ambient temperature is about 10 oC)
   y   Summer room temperature:          C and humidity at         ± 0% (when the ambient
       temperature is about 10 C and humidity 0%)

The incorporation of passive solar features in a new house will not normally require extra
expenditure. The houses under consideration can be divided in three main categories:
   1. Houses where choice of proper orientation and site planning and efficient funct ional
      planning is possible, energy efficiency can be achieved at no major extra cost.
    . Houses for which there is less availability of sunlight, less independence in selecting the
      site and orientation, there is an increase of only -10% in cost which may be required for
      greater levels of insulation, special heating and cooling requirements. However, due to
      lesser fuel / electricity consumption year round , this incremental cost can be recovered
      in ± years.
    . Houses which are to be retrofitted with space heat ing solar passive systems like Trombe
      wall, sun space, space for heating of green houses, adding insulations will require extra

Unlike fossil fuels, solar energy is available just about anywhere on earth. And this source of
energy is free, immune to rising energy prices. Solar energy can be used in many ways ± to
provide heat, lighting, mechanical power and electricity.

                                  Passive house

                                  The dark colours on this thermogram of a passive house
                                  (right) show how little heat is escaping compared to a
                                  traditional building (left).

Manual on solar passive architecture: energy systems engineering IIT Delhi and Solar Energy
Centre, Ministry of Non-conventional Energy Sources, Government of India, New Delhi)

Bansal N K, Hauser G, Minke G. Passive building design: A handbook of Natural climatic

Nayak J K, Hazra R. Development of design guidelines by laws.

Thomas A Fisher. 199
AIA, November 199

TERI report 9 RT__ Window design optimisation

Mazria E. 19 9
The Passive Solar Energ y book, Rodale Press, Pennsylvania

Levy M. E., Evans D., and Gardstein C., The Passive Solar Construction Handbook, Rodale
Press, Pennsylvania, 19 ). 0nasser% 003_04/House% 0Plan/Ventilation% 0and% 0c
ooling.pdf 1 -
9/Session% 03/passive% 0solar% 0architecture(J.K.Nayak).pdf 1 -
9/Session% 04/Design% 0guidelines% 0for% 0energy% 0effci ent% 0building(% 0J.A.Praj
apati).pdf -% 0energy% 0eff% 0biuldings.pdf -technologies/Energy/buildings.htm .gif -glazing-glass-options/ -science/solar-architecture/passive-solar-design-

                                                                                        27 com_cstudy&task details&sid       4 .pdf .gif


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