[TRNSYS-users] Heat Pump- type 941/917

[David BRADLEY via TRNSYS-users]

Antonio,

  Both Types941 and 917 are constant speed device models. This means 
that they are either on or off and cannot modulate internally to seek a 
desired outlet temperature. If you want a device that has some internal 
modulation to seek and provide a constant outlet temperature as the 
inlet temperature changes then you need to use a different model. I have 
written a number of variable speed compressor device models (various 
configurations of heat pumps). They are challenging because it is very 
difficult to get equipment manufacturers to talk about how the devices 
are controlled.

kind regards,

  David



On 06/16/2017 01:43, Antonio T via TRNSYS-users wrote:
>
> Hi there users!
>
> I have a quick question! Has anybody used type 941 or 917 to model an 
> air to wáter heat pump? And if so, do you know if there is a way to 
> determine the exiting fluid temperatura no matter the inlet flow rate 
> and fluid temperature? Just like in most of the boiler types. It is 
> pretty tricky to obtain the desired outlet tempereature from the type 
> 941, since every time a fan coil is switched off the return 
> temperature increases but the flowrate remains the same so the outlet 
> temperature increases as well over values it shouldn’t, and trnsys 
> spends ages in each iteration and convergence takes up a ridicoulus 
> amount of time, making a yearly simulation unfeasible.
>
> If anybody offers any help I would be ver thankful!
>
> Cheers,
>
> Antonio
>
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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