Rating System

LEED BD+C: New Construction, LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.0, v2 - LEED 2.2

Inquiry

The peak Air Conditioning Load of Green Business Centre Building is as follows: S.No. Description A/C Tonnage 1 Permanent Technology Centre 26.6 2 Seminar Hall 21.8 3 2 Nos. Meeting Rooms 6.3 4 Offices 9.8 TOTALDiversity @ 95 % 64.5 60 TR On the basis of above calculated load, 60 TR chilling machine has been selected which meets the ASHRAE guidelines of COP criteria as well as use of non-CFC refrigerant. However, at the review meeting with the Client, it has been felt that the building is expected to have varied hours of operation and all areas shall not be occupied simultaneously. Therefore use of the 60 TR Machine will result in waste of energy and compromise on part load efficiency. In view of above, it is opinion of the Owners, Architects and Consultants that 3 Nos. 25 TR Chiller shall be more suitable for the project. However, after carrying out a thorough search for CFC- free chillers of 25 TR capacity, which meets COP criteria of 4.5 as given by ASHRAE, we find that presently no manufacturer is offering such Chiller which meets both the criterias. The best selection of chiller available from M/s. Trane uses R-134a refrigerant (which is non-CFC) and has a COP of approximately 4 (less than 4.45 required by ASHRAE). In view of above, we request you to kindly clarify if our project qualifies for relaxation in the norms and the Credit can be achieved. Further to above, it has been mentioned in the LEED reference guide 2.0 page 126, para 4 that the EMP (energy modeling protocol) makes an exception to computer modeling rule applicable to Buildings with equipment with less than 150 TR of cooling capacity. It states that the base line condensor cooling source can be defined to be air, which encourages use of more efficient water based cooling over air cooling in smaller equipment sizes. In view of the same, equipment specification of equivalent air cooled chillers have been sourced from the equipment manufacturer. It has been found that the best CoP available for equivalent air cooled chiller is 2.53. Subject to agreement on use of 25 TR Chillers with CoP of approximately 4, we would request you to kindly let us know if the Base Building could be modeled with air cooled chiller with CoP of 2.53 ( in place of ASHRAE 90.1 - 2001 specified Norm of CoP 2.8 for air cooled chiller).