Hi,
We seek your confirmation on the correct energy modeling approach for a project served by a District Cooling Plant (DCP) with a coefficient of performance (COP) of 6.2, in accordance with ASHRAE 90.1-2010 and LEED requirements.
The baseline HVAC systems for the project have been selected as System 06 – Packaged VAV with Reheat, based on conditioned floor area, per Appendix G.
We request confirmation on the following two modeling approaches:
- DES Path 1 – ASHRAE 90.1-2010, Option 1 (Simplified DES Approach):
- Under this approach, the baseline building systems are converted from System 06 to System 08 (VAV with Chilled Water Plant).
- The baseline chilled water plant efficiency is modeled using the same district cooling plant efficiency as the proposed case (COP = 6.2).
- The proposed case has been utilized using the actual district cooling plant efficiency of 6.2 COP.
- DES Path 2 – Full DES Performance Accounting:
- Under this approach, the baseline system remains System 06 – Packaged VAV, without district cooling.
- The proposed case is modeled with district cooling network with default DES COP value of 4.4 with 5% losses, as provided in LEED district cooling guideline.
Kindly confirm if the above interpretations and understanding for both DES Path 1 and DES Path 2 are correct, or advise if any revisions are required.
Thank you for your guidance.