ᐅ Is a buffer tank useful for a heat pump?

WilderSueden schrieb:

With daytime temperatures of 13-15°C (55-59°F) and significant solar gains, heating demand is so low that any heat pump cycles on and off.

Currently, there are 3-4 cycles within 24 hours at daytime temperatures of up to 15°C (59°F). This is completely normal for the equipment.

News:
The neighbors, whose heating system runs 5 cycles per day instead of 25 cycles per day like ours, have an annual heating demand that is 2.7 times higher. We have 12,740 kWh, they have 34,480 kWh. It’s no surprise, then, that their heating operates differently from ours. The system size is appropriate for their needs, but not for ours. The heat pump has a modulating capacity of 3–12 kW. A subsequent heating demand calculation for our house showed a requirement of 6.3 kW. This would be a strong argument to completely remove the current unit and install one of the right size. Very frustrating!

It might not help you much, but why do the neighbors need so much more?

Can you still cancel the repair scheduled for Tuesday?

WilderSueden schrieb:

A heating capacity of 4 kW is definitely not enough for the area. He himself mentions a heating requirement of 7-8 kW.

If you had read carefully, the data I had available resulted in a heating load of 5 kW (excluding ventilation). With the controlled residential ventilation system, it would be even less. So a 4 kW heat pump would fit. The first step is to clarify where the 7-8 kW figure comes from.

Sorry, but with a 4kW heat pump, even with controlled ventilation, you won’t manage with a rough estimate of 5kW. Longer periods with double-digit below-zero temperatures don’t occur as often anymore, but when they do, will you then plug in a space heater? For a house of this size, 5kW is also very optimistic.

jx7 schrieb:

- Data
Energy standard: nearly KfW-55
Annual primary energy demand Qp according to energy saving regulations: 34.5 kWh/(m2a)
Specific transmission heat loss H'T: 0.305 W/(m2 K)
Heated building volume: 920 m³ (32,485 ft³)
Living area: 220 m² (2,368 ft²)
Heated living area: 170 m² (1,830 ft²)
Controlled ventilation with heat recovery is installed.

I bet someone just roughly multiplied 220 by 34.5 and came up with something like 7–8. But that doesn’t really have much to do with heat load calculation.

And regarding better energy efficiency: well, you don’t need to be a fortune teller to know that if I install a modern pump according to today’s standards, it will be more efficient than a 7-year-old unit. If the new one is also correctly sized (starting at about 1 kW, not 3 kW), then it will definitely be even more efficient.