The Torrent Research Centre in Ahmedabad, India is a complex of research laboratories that uses passive downdraft evaporative cooling to provide human comfort without mechanical HVAC systems. A system of inlets, outlets, and ventilation towers creates air movement through the building by using the thermal buoyancy effect without electricity. Field tests showed interior temperatures up to 12°C cooler than exterior temperatures of 44°C, demonstrating the effectiveness of this passive cooling approach. The additional construction costs of around 12-13% provide energy savings that result in a payback period of less than 1 year for the additional costs.

1. TORRENT RESEARCH CENTRE BUILDING...
Location: GIDC Bhat, Bhat, Ahmedabad, Gujarat,India.
Architect and interior consultants:Nimish Patel and parul Zaveri, Abhikram, Ahmedabad.
Total built-uparea -19700sqm
Project period :1994-1999
 The Torrent Research Centre (Gujarat, India) is a complex of research laboratories with
supporting facilities and infrastructures, locates on the outskirts of Ahmedabad. This
building uses passive downdraft evaporative cooling for a large-scale office building and
demonstratesthatit is possible to achieve humancomforts in dry hot regionswithout using
regular HVAC system and without compromising the cost of construction.
 This complex of research laboratorieswas designed to provide human comfort within the
building, with minimum use of electrical energy or mechanical appliances.
 A technique, basedon passive ventilationand evaporative cooling, was developed and
tested with a pilot laboratorybefore being applied to the ensemble. The resultis the
dramatic ventilation towers which are the project's distinctive feature.
 Passive Downdraft Evaporative Cooling (PDEC) was attempted through a system of
designated inlets and outlet shafts which as a consequence of their locations, sizes and
heights, and through their complex but simulated and in-depth researched configuration,
generate the required movement of air in different spaces without using any mechanical or
electrical energy.
 India s largest PassiveCooled Buildingfor the past 14 years, with its energy consumptionat
1/9thof India s highend consumptionand1/4thofenergy benchmarkrecommended by TERI
& GRIHA.
 Torrent Research Centre is a complex of pharmaceutical research laboratories, with its
supportive and ancillary facilities and infrastructure.

2. Design :
 The design of the building facilitates generatingan air draft,assumingstillair conditions.
 The air heats up in the peripheral shafts,risesand escape throughtheopenings at the top.
 The air in the volumegets replaced from the usablespaces,which in turnreceives its own
replacement throughttheconcourse area,on top of which the air inlets are located.
 The enteringair is sprinkled with a fine spray of water mist at the inlets,duringhot
temperatureoutside.
 At each floor levels,setsof hopperwindows designed to catch the descending flow,can be
used to divert some of the cooled air into adjacent space having passedthroughthe
space,the air thenexits via high level glass louversopening with connect directly to the
perimeter exhaustshaft towers thatsuck the air and design create a circulation across the
building insuringthe displacement of fresh air alongthe day.
SITE PLAN
 During the warm humid monsoon when the
use of the sprayed water would be
inappropriate,theceling are broughtinto
operation to provide additional air
movement in the office and laboratories.
 In the cooler seasonthe operating
strategyis designed to control the
ventilation,particularlyat night,to
minimise heat loss this is done simply by
the usersadjusting the hooper windows
and opening in their individual spaces to
suit their requirments.
 Overallcontrol of the solarheat gain is
achieved by design of the glazing.

3.  The fixed windows are the only decided quantumand shaded
externally,notonly in the horizontalplane by overhangs,but
also in the vertical one by the air exhausttower which project
from the façade.
 The buildingare thermally massive-the reinforced concrete
constructionframed structurehascavity brick infill
walls,plasteredinside and out,andthe hollow concrete
 blocks filling the roof coffers, also plasteredinside with
vermiculite usedas an insulatingmaterials on both roof and walls.externalsurfave are white
the wall painted the roof usinga china mosaic finish.
PROCESS:
Cool season strategy
(october-february)
Hot seasonstrategy
(march-june)
Monsoonseasons startegy
(july-september)
 Minimize ventilationsrates.  Passive evaporative
cooling.
 Maximize ventilationrate
with micronisers.
 Intels closed by shutters.  Micronisers provided a
downdraft of cool air.
 Ceiling and wall fans to
induce air movement in
the same direction as
naturalflow.
 Exhautsalso closed by
shutter.
 Ambient temperature 41℃
to 43℃.
 Air speed upper limit
1.5mt/sec.
 Insulatedwalls and roof
reduces heat losses.
 Insulatedbuilding mass
and roof.
 Possibly close all exhauts
in the afternoon.
 Encourage ventilation
duringthe day.
 High air change rates
achievable(6-9).
 Close inlets and exhausts at
night .
 Micronisers to be
controlledby reference
to ambient temperature
and relative humidity.

4. PASSIVE DOWN DRAUGHT COOLING:
 Evapourationcooling has beenised for many centuries
in partsof the middle esat,notably iran and turley.
 In this system, wind catchers guidesoutside air over
water-filled pots,including evaporationand causing a
significant drop in temperature before the air enters
the interiors.
 Such wind catchers become primary elements of the
architecturalform also.
 Passive downdraughtevaporationcooling is
particularlyeffective in hot and dry climates.its has
been used to effectively cool the Torrent research
Centre in Ahmedabad.
CONSEQUENCES:
 The consequencesof this major experiment have been
underobservation since the first occupation of the
building andwill continue to be carried for the coming
years.
 In the summers,theinside temperaturehave generally
not exceeded 31℃ to 32℃,when the outside
temperaturehave risen upto44℃,a 12℃ -13℃ drop.
 The temperaturefluctuationinside the building have
rarely exceeded beyond 3℃ to4℃ over any 24 hour
period,when the temperature flucatuationsoutside
were as much as 14℃ to 17℃.
 The economic viablity of the project is demonstrated
by the following indicators,which are computed for the
totalproject, on the basis of the resultsfrom the
building underobservation.
 Additonalcivil works cost of the project including
insulationetc.works out to about 12%to13%of the
conventionalbuilding.
 200M.tonnesof amountenergy is saved from Air-
conditioning plant.
 The cumulativecapital cost of the civil works and the
A.C.plantworks out of approx 50lakhsmore thenthe
conventionallydesigned buildings.

5.  The annualsavingin the electrical consumption
including the savingon account of less use of artifical
lightingduring the day is approximately 60lakhs.
 The pay back period of the additional capacity
cost,from the saving of the electrical consumption
alone,worksout to a little less than 1 year.
 The pay-back period for the cost of the construction
of the entire complex,from the savings if the electrical
consumptionas well as plantreplacement costs,work
out at around15 years.