[TRNSYS-users] type 927

[Jeff Thornton]

Gabriela,

1 - In real world practice, it’s sometimes difficult to match the heat output from the heat pumps with a varying load and this often leads to heat pumps chattering or shutting off on high limit control.  The same happens inside TRNSYS.  Good practice is to have the heat pumps charge a storage tank and have the fan coils draw from the storage tanks.  That way their varying requirements don’t need to match up instantly.

2 - please use a different tank model than Type 60.  We have archived that model as it can lead to strange results.

3 - use small timesteps (~ 1-minute) and pipes to help control a quickly changing system.  Large timesteps lead to a multitude of problems in TRNSYS.

Jeff - TESS 
Sent from my iPhone

> On May 2, 2020, at 12:58 PM, gabriela vlad via TRNSYS-users <trnsys-users at lists.onebuilding.org> wrote:
> 
> 
> Dear TRNSYS users,
> 
> I'm trying to model a ground source heat pump system used to heat a building.
> My GSHP consists of: a heat pump (type 927), a vertical U tube ground heat exchanger (type 557), a storage tank with 2 inlets and 2 outlets and no auxiliary heating elements(type 60c) and fan coils(type 928)
> I noticed greater air temperature in the rooms after connecting the HP with the building ( so the system is working, I have significant heat transfer rates on both sides of the HP and a COP of 2.5) but a have problems with load temperatures of the HP. 
> I don't understand why the load temperature at the inlet/outlet of the HP is about 100oC/105oC. My real GSHP  must provide water with 65 oC (in this case the return water temperature must be 58oC).
> 
> Please tell me how I can get this temperature of  65oC. 
> 
> Thank you,
> 
> Gabriela
> 
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