[TRNSYS-users] Type 941 AWHP exiting fluid temperature

[Jeff Thornton]

Laszlo,

This same phenomenon would likely occur in the real world as well.  You have a heating device that heats up quickly in form of the heat pump and a heating source that heats up slowly in the form of the floor slab.  This imbalance causes the heat pump loop to increase quickly in temperature as the slab heat transfer slowly ramps up to match the heat pump output.  But there is an easy, and common, solution.  Have the heat pump instead heat a storage tank to your desired temperature.  Then have the floor slab draw from the tank when it needs heat.  The tank will act as the ideal buffer between the supply and demand.

Jeff 

Sent from my iPhone

> On Sep 9, 2021, at 7:57 AM, Gergely László Zsolt via TRNSYS-users <trnsys-users at lists.onebuilding.org> wrote:
> 
> 
> Dear All,
> 
> I am using the Type 941 AWHP for floor heating (and slab cooling). I am facing the challenge that the exiting fluid temperature does not come as anticipated - with a temperature difference of 5 K I would like the system to work as 35/30°C (inlet and outlet of the floor heating) in order to have high COP values for the HP. However, the HP delivers a significantly higher exiting fluid temperature (at aroungd 55°C), worsening the COP. Are there any means to control the exiting fluid temperature of the HP properly? (Shall I write a function ordering the HP to deliver the exiting fluid temperature depending on the outside temperature, or the actual heat loss of the heatied zone?)
> 
> Any suggestions?
> Thanks in advance,
> 
> László GERGELY
> PhD student, Building Energy Engineering
> Budapest University of Technology and Economics
> <Outlook-lhhwajrg.png>
> <AWHP_V2_H&C_08.26.b18>
> <Multizone_AWHP_V2_H&C_09.01.tpf>
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