ᐅ Air-to-water heat pump supply temperatures

blackm88 schrieb:

My heat pump actually only runs from 8 a.m. to 5 p.m. and only in one cycle during that time. Currently, outside temperature is 3.1°C (38°F), flow temperature now 24.9°C (76.8°F) at 20L

My wife would definitely tease me about those settings 😀. It would be interesting to know your hysteresis and the entire heating system. It seems to be quite an unusual house after all 🙂

Bookstar schrieb:

My wife would probably think I’m crazy with all these settings 😀. It would be interesting to know your hysteresis and the whole heating system. Sounds like a very unusual house 🙂

Sure, current room temperature in the bathroom is 23°C (73°F) and in the living room 22.8°C (73°F).
The exhaust air temperature in the mechanical ventilation with heat recovery is now 24.3°C (75°F).
It’s quite warm; even the bedroom is between 22–24°C (72–75°F), and the basement around 21–23°C (70–73°F)...

And where does the "energy" come from then? I really can’t imagine achieving 23-24°C (73-75°F) room temperature with a supply temperature of 24.9°C (76.8°F).

Yes, that is physically not really possible. There would either have to be a hot spring under the house or an insulation standard far beyond KfW40+. But he is keeping us in the dark 🙂

lesmue79 schrieb:

Okay, that sounds more interesting. I was just wondering if a supply temperature of about 26°C (79°F) is normal at an indoor temperature of 20-21°C (68-70°F) when it’s around 8°C (46°F) outside. According to the calculations, the system should be able to manage with a maximum supply temperature of 30°C (86°F) at -12°C (10°F) outside, so I was surprised to see 26°C (79°F) supply temperature already when it's not even freezing yet.

What heating curve do you have set, and do you possibly have any offset applied?

halmi schrieb:

What building standard does your house follow? I assume you currently have a cozy 19°C (66°F) inside?

At the moment, I have about 20°C (68°F), which would be fine except for the bathroom, where it can comfortably be between 21-22°C (70-72°F).

KFW 55 air-to-water heat pump with underfloor heating designed for a maximum supply temperature of 30°C (86°F) at an outdoor temperature of -12°C (10°F). The entire underfloor heating system uses VA 10 (stainless steel type 10) piping.

Bookstar schrieb:

That won’t work. You’ll need a higher supply temperature. Where does that assumption come from?

I’m trying to adjust gradually since it’s not cold enough yet to properly balance the underfloor heating system.

If I run the system 24/7, it cycles too often.

Currently, I allow heating for 8 hours during the day (because there’s also photovoltaic on the roof) and I get 3 compressor starts with 7 hours of runtime.

If I let the system run continuously, I get about 15-20 cycles per day.

The heating curve is set at 0.15 with a target temperature of 22°C (72°F).