CBECC EnergyPlus Error in the Baseline, "Rated air volume flow rate per watt of rated total cooling capacity is out of range"

asked 2016-05-05 12:05:33 -0500

xchen

929 ●1 ●7

I'm getting this error when running a T-24 compliance calculation. All these errors are in the Baseline Case. How am I supposed to fix these? Any thoughts? Is it because i did something in the Proposed Case? Thanks.

*2016-May-05 09:51:45 - EnergyPlus Severe Error(s) (24): 2016-May-05 09:51:45 - 1: Sizing: Coil:Cooling:DX:TwoSpeed "BASESYS12A COILCLG": Rated air volume flow rate per watt of rated total cooling capacity is out of range. Min Rated Vol Flow Per Watt=[4.027E-005], Rated Vol Flow Per Watt=[3.757E-005], Max Rated Vol Flow Per Watt=[6.041E-005]. See Input Output Reference Manual for valid range.

answered 2016-05-05 13:16:40 -0500

xchen

929 ●1 ●7

ok i made some test runs and here's what i found in case anyone experience the same problem.

BaseSys12 is the computer room unit per T-24 baseline system map. In the Design Case we have split system heat pump serving those electrical rooms. In the Design Case, the heat pump heating coil was input as "none". I changed it to heat pump, then put a heating capacity of 1. When I rerun the model, the error is gone.

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Comments

I think heating is required in the Ruleset and that is why you can't have 0 heating capacity. The Standards have to not only account for how a building is used now but also how it may be used in the future. Thus you may not need heating now but if the building is used differently, say under a new owner, they may need heating and Title 24 wants the efficiency of the building to be up to snuff even in that future case. Another way to think of it is that if people could claim they don't need heating (or cooling) then we would end up with seemingly efficient buildings that really aren't.