Percentage savings in in an actual building in India.

Sunday, December 23, 2007



"Most commercial buildings have (an) Energy Performance Index (EPI) of 200 to 400 kWhr/sqm/year in India."

"The average energy use for a typical commercial building is 200 kwh/square metre/year. Mandatory enforcement of the ECBC can reduce this to 120-160 kwh/sqm a year (a saving of 30-40 per cent)."


A typical office building: (Gurgaon)

Base EPI: = 186 kWhr/sqm/annum

After envelope optimisation: 165 kWhr/sqm/annum
After lighting optimisation: 120 kWr/sqm/annum
After HVAC optimisation: 98 kWhr/sqm/annum
After HVAC controls: 92 kWhr/sqm/annum
After daylight integration: 86 kWhr/sqm/annum

Reduction over base building due to envelope: = 11.3% (186-165)/186
Reduction over base building due to lighting: = 24.2% (165-120)/186
Reduction over base building due to HVAC: = 13.3% (120-98)/186
Reduction over base building due to HVAC controls: = 3.2% (98-92)/186
Reduction over base building due to Daylighting: = 3,2% (92-86)/186

That would mean a reduction in HVAC of 11.3% + 13.3% + 3.2% = 27.8%

and that for lighting; 24.2% + 3.2% = 27.4%

Total savings on account of HVAC and lighting alone: 27.8% + 27.4% = 55.2%.


Personal opinion:

That does seem rather high. Maybe that's because the base building itself had a thin wall, uninsulated roof, and extensive single glazing poorly oriented in the first place.

Considering the fact that around 57% of the energy in a typical Indian building is consumed by the HVAC system, and 16% by the lighting, seems that the envelope optimisation (which finally contributes to the HVAC load) could have been further optimised.


Or, the equipment load was very high :)

End of Post

Posted by Kaks at 1:11 PM  


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