[EnergyPlus_Support] Re: Minimum Inlet Air Temperature for Heat Pump

["anarui.oliveira" <anarui.oliveira@xxxxxxxxx>]

Thank you.
I understand the technical limitation reasoning, but, other than 
that, is there an associated limit related to numerical programming 
issues, on E+, or is that a "hard value", somewhat arbitrarily 
imposed, based on that technical reasoning, and perhaps there is a 
way around it? Can it be changed?

I'm working on projects (more than one) that rely solely on Heat Pump 
for Heating, in regions where temperatures drop below 5ºC (and even 
below 0ºC), and the selected equipments report COP as a function of 
outdoor temperature for temperatures as low as -5ºC.

Regards,
Ana.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "JV Dirkes II" 
<jvd2pe@...> wrote:
>
> Dear Ana,
> 
> Many heat air-to-air pumps which were made in the last 20-30 years
> cannot provide useful refrigeration effect at temps colder than 
about
> 5C.  In addition, their refrigeration circuit may have operational
> problems at those temps.
> For that reason, systems installed in cold climates used backup
> heating from gas or electricity during the relatively short periods
> with cold temps.
> 
> I suspect that more recent recent heat pump models can operate at
> colder temps, but am not sure about this.  It may be a good choice 
for
> you to add backup electric resistance heating for temps when the 
heat
> pump does not function.
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "anarui.oliveira"
> <anarui.oliveira@> wrote:
> >
> > Hi.
> > 
> > Can anyone tell me why, in the "Heat Pump:Water Heater" model, 
> > the "Minimum Inlet Air Temperature for Heat Pump Compressor 
Operation" 
> > is 5ºC? Couldn't find any mention to it the documentation.
> > 
> > How can I model a HeatPump that is used for heating water for a 
> > climatization system (with Hot Water coils), using outside air, 
in 
> > regions where the outdoor temperature drops below 5ºC?
> > 
> > Regards,
> > Ana Rui.
> >
>



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