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

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

Don' know if it makes much difference, but it's an air-to-water 
heater for a centralized system...

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "anarui.oliveira" 
<anarui.oliveira@...> wrote:
>
> 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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