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Re: [EnergyPlus_Support] DX Cooling and heating Coil Inputs



The rated conditions for the DX Cooling Coil is 26.67 C (80 F) inlet air 
dry-bulb temperature and 19.44 C (67 F) inlet air wet-bulb temperature 
with 35 C (95 F) air temperature entering the condenser. The rated inlet 
air conditions are used to determine the rated air mass flow rate 
through the DX cooling coil which is in turn used to calculate a rated 
bypass factor (approach) for the coil at the "Rated SHR" specified by 
the user. If you knew the Rated SHR for the DX cooling coil at this 
condition (26.67 C Entering DryBulb, 19.44 C EWetBulb, 35 C OutdoorDB) 
you should be able to enter that value along with the your performance 
information (Capacity, COP, rated air volume flow rate, and normalized 
performance curves giving a value of 1.0 at your rating point). There 
are limitations on rated air volume flow rate per watt of rated total 
cooling capacity (0.00004027 - 0.00006041 m3/s or 300 - 450 cfm/ton) so 
you would want to at least be near the rating point. Since the SHR of a 
DX heating coil is 1.0, the bypass factor is not required and you should 
be able to input DX heating coil performance information at your rating 
point (the only check made on a DX heating coil is the flow per watt 
test and there are less stringent air volume flow rate per watt of total 
heating capacity requirements for a DX heating coil).

Since EnergyPlus specifies the rating point, this is the only 
work-around available when using off-design performance information. 
Manufacturers typically provide the performance information at the 
rating point specified above which is why that particular rating point 
is used.

dan_grunbaum wrote:

> Hi there,
>
> Some of the inputs for DX heating and cooling coils include Capacity,
> rated COP and rated air volume flow rate. The InputOutputReference
> document states that these inputs must be at particular rated
> conditions.
>
> What if the specifications I have are taken at different rated
> conditions ?  Is there any way i can adjust for this in EnergyPlus ?
>
> Thanks,
>
> Dan
>
>
>
>
> The primary EnergyPlus web site is found at:
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>
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>
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-- 
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
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The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
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