ᐅ Air-to-Water Heat Pump: Current Consumption and Data

Created on: 29 Sep 2020 11:06
B
Bookstar
Hello!
I'll start.
Heated area 200m2 (2,153 sq ft)
KfW 55 standard
Mechanical ventilation with heat recovery
Current outdoor temperature 6°C (43°F)
Heating energy consumption including hot water 35 kWh
Electricity consumption 9 kWh
COP 3.88
A
Alessandro
10 Feb 2021 14:48
Alessandro schrieb:

It's the same for me. I don't know why either...
Within one hour, the return flow drops by 3°C (5.4°F)

So much for: Your screed stores much more energy than your buffer :p :p :p :p :p
H
halmi
10 Feb 2021 14:51
Why are you quoting yourself? Your screed will never cool down by 3K within one hour.
T
T_im_Norden
10 Feb 2021 15:02
If the return flow drops quickly and significantly, the causes may be:
Hydraulics
Buffer tank
The screed has this temperature
Missing insulation
Z
Zaba12
10 Feb 2021 15:03
Bookstar schrieb:

I would say the minus 3 degrees outside temperature 🙂. But you have that as well, so that wouldn’t be an explanation.
Exactly
B
Bookstar
10 Feb 2021 15:06
halmi schrieb:

Is your UV completely closed?

Great point you bring up! According to three different HVAC technicians, it must never be fully closed, because during defrosting the flow rate would not be sufficient. I didn’t believe it at first, but they were right.

I constantly had defrosting issues because the minimum flow rate couldn’t be maintained.
tomtom7910 Feb 2021 15:13
Bookstar schrieb:

Great point you bring up! According to three different HVAC technicians, it should never be fully closed because during defrosting the flow rate would then be insufficient. I didn’t believe it at first, but they were right.

I kept having defrosting issues because the minimum flow rate couldn’t be reached.

Then it’s more likely that your hydraulic settings are incorrect, and a supply temperature of 28°C (82°F) is quite high for a modern house. I use 25°C (77°F) / 21°C (70°F) / 0 for a KfW 70 standard.

That would also explain the rapidly increasing return temperature.