High Performance Commercial Buildings in India: Adopting Low-cost Alternative Passive Strategies for Energy Saving

Case Study

General Information:

City: Chennai
Climate: Warm & Humid
Operational schedule ? 8 hours, 5 working days in a week
Area of the building: 10800m� (out of which 9417 m� - conditioned area, 1383 m� - non-conditioned area)

Function: Office Space

Existing Building Design Features

Building Envelope

Walls 230mm brick wall with 30mm plaster on exterior side and 20mm on interior side Roof The U- Value is higher than that of ECBC recommended (0.409W/m2K). This results in high external solar heat gains and increased cooling loads

Window 6mm clear single glazed window in thermally unbroken aluminium frames (SC ? 0.81, U-value of Glass ? 6.14 W/m2K) WWR ? 50% Clear single glazed window and WWR which is more than that of ECBC recommended (40%) increases the external solar heat gains and the cooling loads

Building Lighting
Lighting system 17 % of the total connected load 2 x 36W CFL lamps for work station areas, 11W CFL, 13W CFL and 18W CFL for corridors, 40W fluorescent tube lights for other locations The CFL lamps have electronic ballast Manual controls are used The LPD 20 W/m2 is double than that of max ECBC recommended (10.8 W/m2) for office space which has high energy consuming potential Lighting energy consumption: 7%	HVAC system Design 3 roof top air cooled screw chillers of 340TR each The COP of the chillers is 3.2 (rated) / ECBC recommended is 3.05 Rated Sqft/TR ? 99
HVAC controls Temperature of AC space maintained by variable air volumes and 2-way valve controls in the chilled water line All the work station AHUs provided with manual variable speed drives
Energy Performance of the Building Lighting Energy Performance of the Building Annual Consumption (lighting) ? 21% Lighting Performance Index ? 37 KWh/Sqmt/annum Space Conditioning Energy Performance of the Building Annual Consumption (A/C) ? 79% of the total HVAC Performance Index ? 263 KWh/Sqmt/annum
Annual energy consumption due to lighting & air conditioning (kWh): 3618504 Energy Performance Index of the building (KWh/sq.mts of built up area/annum): 335

Conventional Building, Chennai

Existing Building Design Features

Building Envelope

Walls

Roof

Window

Building Lighting

Lighting system

HVAC system Design

HVAC controls

Energy Performance of the Building

Lighting Energy Performance of the Building

Space Conditioning Energy Performance of the Building