What flow temperatures are you currently running?

  • Erstellt am 2021-10-24 10:27:23

OWLer

2021-11-18 17:50:11
  • #1



One more time the question: What does the energy integral and compressor hysteresis mean and how do I influence the efficiency with them?

Mine is running the factory setting:
 

RotorMotor

2021-11-18 18:58:39
  • #2
I would understand it in such a way that the "Vaillant" energy integral influences how much the heat pump overheats to extend the cycles. So, for example, if you increase it to -120, the cycles become longer. An advantage might be a longer lifespan, a disadvantage is a somewhat higher consumption due to increased flow temperature.

The compressor hysteresis also seems to be a temperature differential of the compressor. I think here, a higher value also means longer but somewhat less efficient cycles.
 

lesmue79

2021-11-18 19:21:31
  • #3
I can't fully explain it myself because I haven't completely internalized it yet.

The energy integral is based on the difference between the target supply temperature and the actual supply temperature (sometimes also called degree-minutes).

The compressor/heat pump starts heating at -90 minutes. If the system eventually stops delivering heat because the rooms have reached their temperature, the actual supply temperature rises above the target supply temperature; this difference, let's say 1.5 degrees, is then a so-called degree-minute.

These 1.5° then tick down every minute from the set -90° until, for example, 0° is reached, then the system switches off.
If the reverse situation occurs, the target supply temperature drops below the actual supply temperature and goes in the other direction until at -90 minutes the heating starts again.

Additionally, there is an extra protection called compressor hysteresis, for example 3K, when the actual supply temperature rises quickly. Then the compressor switches off when the actual supply temperature is 3°C above the target supply temperature.

In short:
A high compressor hysteresis leads to a longer running time of the system (mine is set to 15°C or Kelvin).

An increase in compressor start time also leads to a longer running time because it simultaneously takes longer for the system to start and stop working. For me, 120 minutes.

I hope I was able to explain it somewhat; whether it is 100% correct is another matter. I'm not a professional.
 

driver55

2021-11-18 19:24:18
  • #4
Partially correct. Yes, the integral towards -120...-180 extends the cycles. One could also say that the room target temperature is subject to slightly higher fluctuations.

However, this has no effect on the flow temperature, since it is determined solely by the outdoor temperature (of course still dependent on heating curve, room setpoint temperature, but that remains unchanged).

My Vaillant 63/2 from 2008 does not know compressor hysteresis.
 

RotorMotor

2021-11-18 19:31:32
  • #5

If the heat pump runs at minimal power for 2 hours instead of 1 hour, for example, the actual flow temperature naturally increases as well.
So it has slightly less efficiency for fewer heating cycles.
There must be some disadvantage after all.

But you should be careful not to get too theoretical here. ;)
 

driver55

2021-11-18 19:32:26
  • #6
No. The integral is reduced by the delta actual flow / actual return. According to your description, the integral would only count down after the floor is "recharged." But that happens already minutes after the compressor starts.
 

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