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Cooling Capacity PTAC

asked 2023-04-21 03:20:02 -0500

budich's avatar

updated 2023-04-21 12:08:57 -0500

Hi,

I have an error for one conditioned space: "Gross Rated Total Cooling Capacity [W] will be limited by the maximum rated volume flow per rated total capacity ratio".

The error is

** Warning ** SizeDXCoil Coil:Cooling:DX:SingleSpeed KAMAR TIDUR UTAMA PTAC COOLING COIL
**   ~~~   ** ...Gross Rated Total Cooling Capacity [W] will be limited by the maximum rated volume flow per rated total capacity ratio.
**   ~~~   ** ...DX coil volume flow rate ( m3/s ) = 5.633887E-002
**   ~~~   ** ...Requested capacity ( W ) = 925.606
**   ~~~   ** ...Requested flow/capacity ratio ( m3/s/W ) = 6.086E-005
**   ~~~   ** ...Maximum flow/capacity ratio ( m3/s/W ) = 6.041E-005
**   ~~~   ** ...Adjusted capacity ( W ) = 932.608

Hot to fix this issue? would you please find the idf file (master.idf) in the gdrive https://drive.google.com/drive/folder...

thank you very much in advance regards, Budijanto Chandra

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answered 2023-04-21 12:24:08 -0500

@budich, you can correct this issue by adjusting the supply air temperature in the Sizing:Zone object. From the warning message, the air flow rate with respect to the cooling capacity is not that far off. If you reduce the supply air temperature slightly (increasing the coil delta T) in the Sizing:Zone object you will get a lower zone air flow rate during zone sizing. This should eliminate the warning but may require a few iterations.

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Yes Richard, you are correct, the error is not appear when I reduce the supply air temperature thank you very much

budich's avatar budich  ( 2023-04-22 19:33:01 -0500 )edit

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Asked: 2023-04-21 03:20:02 -0500

Seen: 78 times

Last updated: Apr 22 '23