I am working on a building that supplies process cooling water (PCW) to lab spaces. The PCW rejects its heat through a heat exchanger to the chilled water system from a district energy plant. Therefore, my proposed design would allow a 4.4 COP for electric consumption by the district energy plant (CHW system) serving my building's PCW system. Because of the system pressures, a CHW pump is not required for the proposed design.
How should I model the PCW energy in the baseline design? Because I essentially have DX equipment in the baseline design, could I reference a type of equipment under ASHRAE 90.1-2007 Table 6.8.1C efficiency requirements? Say "Air cooled, with condenser, electrically operated; All capacities; 2.80 COP"?
Christopher Schaffner
CEO & FounderThe Green Engineer
LEEDuser Expert
963 thumbs up
September 8, 2011 - 10:54 am
It's not clear to me which parts of this system are within your project.
You should take a close look at the latest District Energy System (DES) guidance from the USGBC.
If the PCW loop is cooled from the DES, it should be treated the same as any other building cooling loads. What you compare to depends on your DES modeling approach.