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Difference of cooling capacity between cooling coil total cooling rate + fan and VRF heat pump total cooling rate

asked 2018-10-01 22:06:51 -0500

Alexis gravatar image

updated 2018-10-02 19:46:57 -0500

I am trying to do a simple simulation to understand the link between all the output in Energy plus. I have used a HVAC templates system / zone VRF. No ventilation. No sizing factor. One thermal zone.
When I check the output, I have a difference of cooling capacity (in W) between : cooling coil total cooling rate + fan electric power is different than VRF heat pump total cooling rate.
I have : 16802.43 + 119.89 is not equal to 17763.99.
I have tried many simulations by changing some parameters but I always have a difference. Its not a lot but I would like to understand before extending my model.
What did I forget ? Or what is the reason of this difference ?
Thank for your help

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answered 2018-10-03 08:14:35 -0500

Without seeing your input file the other influence I can think of at the moment is piping losses (see report variable: VRF Heat Pump Indoor Unit Piping Correction for Cooling). However 5% does seem large so if this doesn't resolve the difference then update the numbers and I'll check again.

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I dont have this report variable. I checked and double checked in my rdd file. Nothing about piping loss.
But it seems to be that because when I set the lenght and the height at 1 m, my cooling coil total cooling rate + fan electric power + piping loss is almost equal to VRF heat pump total cooling rate.
I am using E+ v8.7, perhaps this output is arrived after this version ?

Alexis gravatar image Alexis  ( 2018-10-03 20:22:01 -0500 )edit
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The piping correction report is only for AirConditioner:VariableRefrigerantFlow:FluidTemperatureControl. At least you now know why there is a difference in the reports. Good job on figuring that out.

rraustad gravatar image rraustad  ( 2018-10-04 07:51:10 -0500 )edit

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Asked: 2018-10-01 22:06:51 -0500

Seen: 119 times

Last updated: Oct 03 '18