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Re: [EnergyPlus_Support] using heat recovery with 100% outdoor air
More information is needed to properly answer your question. What type
of heat exchanger is being simulated? What is the outside air system's
maximum air flow rate? What is the heat exchanger's nominal air flow
rate? Is an economizer used?
For a flat plate heat exchanger, if the heat exchanger's economizer
lockout flag is set to Yes and the actual air flow rate through the heat
exchanger is higher (usually when the outside air system is in
economizer mode) than the heat exchanger's nominal air flow rate, the
heat exchanger is turned off. If the air flow rate through the heat
exchanger is at or below the heat exchanger's nominal air flow rate then
the unit is on regardless of the outside air system economizer
operation. This logic will be changed in a future release of EnergyPlus.
If the heat exchanger's economizer lockout flag is set to No, then the
heat exchanger is on.
To operate a flat plate heat exchanger all the time, set the flat plate
heat exchanger nominal supply air flow rate equal to or slightly greater
than the outside air system's maximum air flow rate.
For a generic heat exchanger, if the outside air system is in economizer
mode, then the generic heat exchanger is off. If the outside air system
is not in economizer mode, then the generic heat exchanger is on.
See the IO reference manual for further explanation of economizer mode
for each type of heat exchanger.
Zhen Tian wrote:
> Hi, all:
>
> I encountered a problem for using the heat exchanger object. First, I
> add a heat recovery unit to a VAV system. I use "proportional minimum
> outdoor air. It seems that the heat recovery unit works.
> But when I change the VAV system to a constant air flow system, I
> found the the heat recovery never works. In this constant air flow
> system, I use 100% outside air by seting " proportional minimum, with
> maximum and minimum outdoor air flow as the same".
>
> So could somebody tell me what is the problem or how to set up 100%
> outdoor air with heat recovery?
>
> Thanks a lot.
>
> Regards,
>
> Zhen
>
>
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University of Central Florida
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