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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
>
>
>
>
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Richard A. Raustad
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[Non-text portions of this message have been removed]
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:
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<*> To unsubscribe from this group, send an email to:
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<*> Your use of Yahoo! Groups is subject to:
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