Hello,
we are planning to build soon, and I am currently looking into the heating system.
I have tried to estimate how much electricity our air-to-water heat pump might consume.
Am I correct in understanding that the final energy demand is the amount of energy I need to put into the house for heating and hot water?
And this can be provided by oil, gas, or a heat pump?
If so, how does the COP work in this context?
I am trying to explain it with a very simple, hypothetical example:
A house with 200 sqm (2153 sq ft) and a calculated final energy demand of 10 kWh/sqm/year.
I understand this to mean that 2000 kWh of heating energy is needed annually.
An air-to-water heat pump with a theoretical COP of 2 converts 1 kW of electricity to 2 kW of heat.
Does that mean that with such a heat pump, only 1000 kWh of electricity is needed for heating and hot water?
I hope I am not making too many mistakes, but primary energy, final energy, COP, efficiency, and performance are all new and quite confusing to me.
Thanks in advance
Anja
we are planning to build soon, and I am currently looking into the heating system.
I have tried to estimate how much electricity our air-to-water heat pump might consume.
Am I correct in understanding that the final energy demand is the amount of energy I need to put into the house for heating and hot water?
And this can be provided by oil, gas, or a heat pump?
If so, how does the COP work in this context?
I am trying to explain it with a very simple, hypothetical example:
A house with 200 sqm (2153 sq ft) and a calculated final energy demand of 10 kWh/sqm/year.
I understand this to mean that 2000 kWh of heating energy is needed annually.
An air-to-water heat pump with a theoretical COP of 2 converts 1 kW of electricity to 2 kW of heat.
Does that mean that with such a heat pump, only 1000 kWh of electricity is needed for heating and hot water?
I hope I am not making too many mistakes, but primary energy, final energy, COP, efficiency, and performance are all new and quite confusing to me.
Thanks in advance
Anja
By the way, my final energy demand in the certificate was calculated using an annual performance factor of 3 (air-to-water heat pump). This should be taken into account, as the energy demand in new buildings is likely to be lower than indicated in the certificate for this reason alone.
Apolyxo schrieb:
By the way, my final energy demand in the certificate was calculated using an annual performance factor of 3. (air-to-water heat pump) This value, unlike the primary energy factor, is not defined by building energy regulations, but is calculated individually for each case. The system data of the heat pump used and the design temperature of the heating surfaces are taken into account. Essentially, it is similar to the annual performance factor calculator from the German Heat Pump Association. If no or insufficient data is available, assumptions can, of course, be made; however, reading the heat pump’s nameplate and just a few seconds of research should be reasonable for everyone.
R
Radfahrer2 Oct 2023 11:00dertill schrieb:
The primary energy factor (fP) is regularly reassessed by the Federal Environment Agency and is also influenced by political decisions (lower fP for heat pump electricity, higher fP when accounting for electricity generated by combined heat and power plants). In 2004, the fP for electricity was simply much higher than today, apparently around 3.5.
Today, the fP for grid electricity according to the Building Energy Act is 1.8. In fact, it was just above 1.4 in 2022. As mentioned, this is politically influenced. Ah, OK, so the fP is just adjusted now and then.
So I go from 17,000 kWh/year
to a consumption of about 2,900 * 1.8 = 5,220 kWh/year
primary energy demand.
OK, I consume somewhat less than probably generously calculated, but still.
dertill schrieb:
Unlike the primary energy factor, this value is not defined by the building energy regulations but is calculated for each individual case. Just checked: performance factor 0.3 = annual coefficient of performance 3.33. So it’s not that extreme. And yes: they were lazy here and played it safe. Also: 5% electric heating (probably according to the standard?) is not applicable. I disabled it. I only need it below -20°C (−4°F).
R
Radfahrer2 Oct 2023 13:06Apolyxo schrieb:
Also: 5% electric heating (probably according to the standard?)I could imagine that your ventilation system also requires electricity. Maybe that accounts for the 5%?
Radfahrer schrieb:
I could imagine that your ventilation also needs electricity. Maybe the 5%?No, the ventilation is billed separately. Just like the hot water, where the 3.33 annual performance factor exactly matches. The 5% is probably just the electric heating element.
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