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[EnergyPlus_Support] Re: Is there any way to simplify DX Unit Model?
Dr. Li,
I am modeling an existing building energy performance,and trying to compared that with detailed field measured data. DX units compressor energy use, condenser fan energy use, outside air/entering air temperature, humidity are going to be measured as well as AHU airflow, in other words, I actually can derived real-time COP for the DX unit and correlate that with a lot parameters.
However, the sad part is that even I have all those measured data, I still can't generate the field-measured curves since I don't exactly know how I can deal with those "CapacityModification Curves" as functions of airflow and wet-bulb temperatures, which should be provided by the manufacture but the unit is 1999 installed McQuay.
Any ideas on how to deal with this situation? Thanks for your help.
Ke
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
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> You do not have to care about those curves, if you are interested only in the heat transfer properties. Keep the PLR values and coil temperature, or what ever the parameters are used in those curves. When you really need to covert the heat transfer property to electrical power, then you would need the conversion. A constant COP and PLR will give you a first approximation to the conversion process. If you are working with LEED certification then you would need al those curves. When you wanted to buy a window air-coditioner, look for the best COP and PLR=0.5. You know it may be less efficient at other PLR values, but who is really to care. Dr. Li
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: xukevin24@...
> Date: Mon, 2 Apr 2012 15:15:31 +0000
> Subject: [EnergyPlus_Support] Is there any way to simplify DX Unit Model?
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> Dear all,
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> Since a single-speed DX coil model stated in E+ engineering reference involves 5 curves (TotCapTempModFac, EIRTempModFac,EIRFlowModFac,PartLoadFrac,ect.), which requires over 20 constant parameters as inputs, but in my case, it is almost impossible to obtain all curves from the manufacture,I am wondering if there is a way that I can avoid all those curves input? or put it in other words, is there a simpler DX model built in E+? for example, a curve directly correlate coil part load ratio to the energy use ratio? and if E+ does allow users to develop such a curve, where can I define it?
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> Thanks in advance.
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> Ke
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