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CS-v4 EAc2:Optimize energy performance

District Cooling Confirmation for Path 1 & Path 2

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Anand k
LEEDuser Basic Member
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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:

  1. 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.
  2. 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.

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Thu, 03/19/2026 - 18:58

  1. For DES Path 1 the chilled water should be modeled as purchased chilled water with no efficiency applied in both the Baseline and Proposed models. The efficiencies are inherent in the purchased chilled water rate itself.
  2. For DES Path 2 the actual cooling plant efficiency can be modeled instead of the default value, but must account for all distribution losses and energy use within the plant. These can be determined using monitored data, engineering analysis, or default values. Additional guidance is provided in the LEED Reference Guide.

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