ᐅ Setting a Heat Pump Correctly

Created on: 26 Jan 2014 12:19
J
James
J
James
26 Jan 2014 12:19
Hello dear forum community,

We have been living in our single-family house (150 m² (1,615 sq ft) living area) for several months now. We have underfloor heating everywhere and heat with a brine-water heat pump (supported by heat recovery from the exhaust air system).

Since we have a photovoltaic system on the roof, we decided against a second meter (peak/off-peak) and have the heating run through the "normal" meter to make the most of our self-generated electricity.
Therefore, I don’t have an exact overview of the heating consumption. With the current subzero temperatures (-10 to -12°C (14 to 10°F)), our daily total consumption is about 30 kWh.

With this in mind, I would like to know if I can optimize the heat pump settings to possibly reduce consumption.
A hydraulic balancing was done after commissioning, and each room has thermostatic valves (scale: 1-5).
The heat pump has an outdoor sensor; I can adjust the heating curve and the so-called parallel shift.

Initial values were: room temperature 20°C (68°F), heating curve 30°C (86°F).

There are instructions online for these settings that say: open all thermostatic valves fully (to exclude disturbances) and flatten the heating curve only until the desired temperature is reached.

But: should room thermostats always be set to the highest level? Then I wouldn’t be able to increase the temperature further if I want to!

What room temperature should ideally be reached at setting 3? 20°C (68°F)? Then the heating curve at 30°C (86°F) would probably be quite correct. But then the actuators must constantly close the valves and “regulate down” because it would otherwise become too warm—and in this way, the generated heat is not used optimally? So would it be better to lower the heating curve and open the thermostats wide (5 in the bathroom, 4 in living areas)?

I appreciate any tips!

Best regards
James
€uro
27 Jan 2014 12:48
Hello,
James schrieb:
....There are instructions online for adjustment. They say: Fully open all thermostats (to exclude interference factors) and flatten the heating curve just enough to reach the desired temperature...
You should be cautious with such generalized advice. Usually, these "recipes" come from anonymous sources without any guarantee or warranty, not from professionals!
Someone just repeats what others have preached None of them have formal training! Sometimes it is even recommended to remove the individual room controllers (IRC) at the manifold! Furthermore, this violates or circumvents the energy saving regulations/KfW standards!!!
James schrieb:
...But: Should room thermostats always be set at the highest level? Then I wouldn’t be able to adjust upwards if I want to!?
Correct, that is just a fact! After all, it is called IRC (individual room control) for a reason! The next issue arises during the transition phase, for example, when a living room has large south-facing windows that capture solar gains!
James schrieb:
...What room temperature should ideally be reached at level 3? 20°C (68°F)? Then a heating curve at 30°C (86°F) would probably be about right...
Correct. Hopefully, you have a precise and proper planning/design for the system. The heating load calculation takes your desired room temperature (RT) into account => Form V! This is accordingly considered in the heating surface dimensioning.
Nevertheless, you can still allow temporarily varying RTs from this by using the IRC afterwards!
James schrieb:
...But then the actuators must constantly close the valves....
No, they respond to the desired RT! In solid construction and underfloor heating (wet system), the thermal storage capacity of the entire system means simple IRC is fully sufficient.
In lightweight constructions and less energy-efficient dry underfloor heating systems, PI controllers would be more appropriate!

Best regards
€uro
30 Jan 2014 06:31
HausbauBlog schrieb:
...
Choose a reference room. For us, it was the bathroom, as recommended by the technician. That makes sense, since people usually want it warm there after showering or bathing. Set the thermostat to maximum in this room. The rest of the heating then adjusts according to this room....
A somewhat odd recommendation

Best regards

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