Heat rejection end use for cooling towers

asked 2015-09-16 18:03:49 -0600

bryane
171 ●2

In Openstudio, when you set up a chiller plant from a template and simulate, there is a quantity for heat rejection in the EnergyPlus output report. I assume this is heat rejection from the cooling tower.

If you use a similar cooling tower with say a series of water side heat pumps on the same building, a value of zero is in this end use category (heat rejection) in the output reports for EnergyPlus. Is this correct?

answered 2015-09-17 09:37:00 -0600

Archmage

7185 ●3 ●11

I believe the Heat Rejection heat transfer you are seeing in the first case was reported by the chiller and it represents the heat rejected to the condenser loop by the chiller.

Unfortunately "EnergyTransfer" metering is not really comprehensive, there are so many different heat flows going on inside it gets to be too much to try and report everything.

You can always check the meter definitions ".mtd" file for a description of what is really on each meter and this is more important for heat transfer meters.

In looking at the source code I don't find anyplace where the cooling towers are reporting EnergyTransfer as HeatRejection. They do put all the electricity consumed by the towers on the Heat Rejection end use but the towers don't appear to report the amount of heat transferred. Nor do I find any of the water to air coils reporting this.