ᐅ Determine the electricity consumption of the air-to-water heat pump as a proportion of the total power consumption.
Created on: 2 Jan 2022 13:38
T
Tx-25
Hello, in 2020, we consumed about 6,800 kWh of electricity. Of this, 1,750 kWh was self-consumption from our photovoltaic system. This means our electricity purchase from the grid was 4,062 kWh. Since we have an air-to-water heat pump, the heating also runs on electricity.
How can I now separate the electricity consumption of the air-to-water heat pump from the overall costs?
We have a meter on the electrical distribution board showing 1,294.59 kWh. Additionally, there are two heat meters installed (12,082 and 2,477 MWh).
How can I now separate the electricity consumption of the air-to-water heat pump from the overall costs?
We have a meter on the electrical distribution board showing 1,294.59 kWh. Additionally, there are two heat meters installed (12,082 and 2,477 MWh).
B
Benutzer2002 Jan 2022 22:41Tx-25 schrieb:
Which meter do you mean? The separate meter in the distribution board?The internal meter of the heat pump. That one is a real "rough guy."RotorMotor schrieb:
Almost 7000 kWh for a 150 m² (1600 sq ft) KFW40 house sounds quite high, but that might also include an electric car, sauna, mining farm, etc.
What unit is MVh? Sorry, I made a mistake in the transfer. In post #1, I mentioned that we consumed about 4,000 kWh and had 1,750 kWh of self-consumption from the photovoltaic system. So that’s "only" 5,800 kWh in total.
Also, I should add that I worked 100 percent from home, and my girlfriend about 50 percent. So I think that consumption makes sense, right?
MVh is what is shown on the heat meter. I’ll provide pictures tomorrow.
driver55 schrieb:
With the "refrigerator temperatures" (20°C (68°F)) in the KfW40 house, I would have guessed a maximum of 2000 kWh for the heat pump.
But where are the remaining 4800 kWh being "wasted"?
Or is it just normal household electricity consumption and completely messed up hydraulics/floor heating system?
Maybe the domestic hot water temperature is set to 55…60°C (131…140°F)?
@TE: Your consumption remains a mystery.
We need more input.
I recommend recording all meter readings — with correct units — daily from now on until all the questions are cleared up. The domestic hot water temperature is set at 50°C (122°F). I have done a hydraulic balancing for the underfloor heating. Therefore, it should actually run efficiently. I have disconnected the ERR. The underfloor heating should therefore run smoothly without constantly switching on full power/off/full power, etc.
I calculated about 3000 kWh of household electricity consumption with home office included. This results in an annual performance factor of around 5, including hot water. That would be really excellent for an air-to-water heat pump, but it might still be possible since it looks like you have already optimized everything.
If you really want to know, have a simple submeter installed on the distribution panel. Together with the heat meters, this provides the perfect opportunity for analysis.
If you really want to know, have a simple submeter installed on the distribution panel. Together with the heat meters, this provides the perfect opportunity for analysis.
Joedreck schrieb:
I estimated about 3000 kWh of household electricity consumption including working from home. That results in an annual performance factor of around 5, including domestic hot water. That would be excellent for an air-to-water heat pump, but it might be possible since you have already optimized everything.
If you really want to know, have a simple sub-meter installed on the mains supply. Together with the heat meters, this provides the perfect basis for analysis.How did you calculate the annual performance factor?
By comparing the readings from the heat meters with the remaining kWh?
Joedreck schrieb:
Assuming 2500-3000 kWh household electricity usage, you end up with an annual performance factor of about 2. And with 1000 kWh less total consumption, it would be…
Joedreck schrieb:
I calculated around 3000 kWh household electricity with home office. Then you get an annual performance factor of about 5, including hot water. That calculation doesn’t really add up.
Tx-25 schrieb:
How did you calculate the annual performance factor?
The readings from the heat meters through the remaining kWh? That remains his secret. Yesterday, assuming 3800 kWh instead of now 2800 kWh for heating, the annual performance factor was still about 2; now it’s supposed to be around 5. 🙄
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