[TRNSYS-users] (no subject)

[Javier Vega via TRNSYS-users]

Hi TRNSYS users,

I'm experiencing a weird issue. I'm testing a simple system where I have a
heat pump (Type 941) and solar collectors (Type 538) coupled  to a Vertical
Storage Tank *via heat exchangers*, modelled with Type 534. The tank is
connected to a closed loop to a radiant floor.

I have the control system setted this way:

-The collector's circuit works if they can gain energy. ON/OFF strategy
-The Radiant Slab Loop operates if the thermostat of the thermal zone
requires it (ON/OFF strategy)
-The heat pump works if the required temperature for the radiant slab loop
isn't satisfied by the collector's energy gain. The temperature set for
heating is *35 (°C) in the top of the storage tank. *ON/OFF strategy

For some reason, when the heat pump is active its operating temperatures
are *above 60 (°C) *at the heat pump's inlet,* even if the tank is at 35
(°C)*. I've checked and the heat exchanger seems to transfer all the heat
pump's energy to the storage tank. I don't know what is causing the
temperature raise.

Is this what is supposed to happen? Is it a weird simulation unrealistic
error?

My heat pump has a nominal capacityof *9 kW. *The heat load transfered to
the radiant slab is above 7 kW max.

My heat pump's performance map has operating data just to 50 (°C) inlet
water temperature. If I force the heat pump to work below this, the heat
pump operates less often and the system can't supply enough energy to keep
the radiant floor water at 35 (°C).

Here are two pics of the situation. First is the heat pump operating
"naturally" at high temperature. Water inlet in the heat pump is in pink.
Water temperature to the radiant slab is in blue. Heat output in the
radiant slab is in green . Red is for the airnode temperature.

[image: Imágenes integradas 1]

[image: Imágenes integradas 2]

I would appreciate some help, thanks in advance.

King regards,
Javier Vega
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