11 Neeraj Kapoor

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The Relevance of Earth Air Tunnel Heat Exchanger

(EATHE) for School Buildings

Green School Design Conference

presenter: Neeraj Kapoor

for : Sustainable Design Practices for Schools in India

Hanifl Centre for Outdoor Studies, Woodstock School, Mussoorie

date: Saturday, April 17th, 2010

Kalpakrit Sustainable Environments Pvt. Ltd.


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Our Immediate Environment: Comfort in BuildingsAs lifestyle aspirations evolve for the middle class India, we havestarted seeing air conditioning getting installed largely as an additionalfacility. Its usually used only during certain times and that forms

the basis of a mixed mode operational approach.

Ceiling Fans

Nat. Vent. / Night Flushing

Evap. Cooling

Air Conditioning

Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec

AC used for 6 hrs a day for 45 days(270 hrs a year )

Ceiling fans through out summer

Graphic & Source: Ashok Lall Architects office space comfort systems usage pattern, New Delhi


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Changing Expectations in Thermal Comfort

Basic Cool ~ Cold ~Outright Chilly

Source: Ashok B. Lall Architects


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Changing Means to meet Comfort ExpectationsAs India develops economically there is a rising trend toward adoptingrefrigerant based air conditioning for indoor comfort.

Ceiling Fans

Nat. Vent./ Night Flushing

Evap. Cooling

Air Conditioning


Graphic & Source: Adaptation of the graphic to represent contemporary trend in Institutional Buildings in India


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Alternatively, theres . . .The Adaptive comfort model accounts for our physiological capacitiesto adapt to a wider range of temperature and humidity conditions inreal life than those that are assumed to be the idealized limits

established by laboratory experiments or even steady state standards.

Graphic & Source: Acceptable operative temperatureranges for naturally conditioned spaces, ASHRAE 55 - 2004

Adaptive Comfort


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Adaptive Comfort versus Steady State

Adaptive / Reasonable

Hot Dry season (RH < 60%):Not Uncomfortable at 30C.

Warm Humid season (RH = 65% to 70%):Not Uncomfortable at 28C.

Image Source: Ashok B. Lall Architects


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Forced Air Distribution versus Natural StratificationForced Air:

12.5 - 14C

UFAD/ Stratified:

15.5 18.5C

Source: # web #


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Temperature of earth below 4m remains relatively less variantthrough the year. This characteristic is helpful in providingpreconditioned air by passing it through tunnels, thus reducing the

cooling capacity of the primary plant equipment.

Introducing . . . Earth Air Tunnel Heat Exchanger

Each tunnel to be 90m long to handle 12000 CFMapprox. depending on 900mm wide tunnel.

Slow Speed system: Air quantity based on 6 ACH inPeak Summer and 3 ACH in Monsoon & Winter.

Displacement Ventilation for natural stratification ofair column.

Source: Kalpakrit Sustainable Environments


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EATHE must go with Displacement Ventilation

Outside air is first cooled & then let to naturally stratify as it picks up heat.

29C to 33C

25C to 29C

21C to 24C

Source: Nirmal Gupta Consultants; Original Source: # web #


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Relevance vis--vis Schools . . . Air Quality!

Source: # web #


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Health

Comfort

Environmentconducive tobetterperformance

Sense ofaccomplishment,sensitivity and

ownership towardsenvironmentalinitiatives.

For Students

Source: # web #


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Comfort & Energy Efficiency when used with . . . .

Evaporative cooler in

hot dry season

Refrigerant basedcooling hybridized tocondense water outof the air

Thermal EnergyStorage formanaging peak

loads, and differentialutility tariff structures.


Graphic: Adaptation of the graphic to represent use of EATHE

EATHE

Nat. Vent./ Night

Flushing

Evap. Cooling

Air Conditioning


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Energy Efficiency Potential

CASE 1: School, Gurgaon, NCR



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Energy Efficiency Potential

CASE 2: School, Delhi



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Operational Cost Savings Potential

CASE 1: School, Gurgaon, NCR



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Operational Costs Savings Potential

CASE 2: School, Delhi



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Laundry List of Factors Influencing Performance

Housing in the Everglades

Tunnel Material

Tunnel Diameter

Tunnel Location

Tunnel Depth

Earth Temperature

Tunnel Length

Soil Properties

THANK YOU !

11 Neeraj Kapoor

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