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

Tolentino schrieb:

As far as I know, buffer tanks are meant to prevent or compensate for too short compressor run times caused by closed ERR. It often happens that the coolant also acts as a lubricant, and if the pump only runs for about 30 seconds at a time, it doesn’t get lubricated enough. The buffer is supposed to ensure lubrication for at least 5 minutes.
I think they mostly deal with customers who use the ERR and then report defective compressors within the warranty period, rather than customers who want to run their heat pump as efficiently as possible as a new hobby.

That’s exactly how Brötje justified it to Heizu.
What’s strange is the size and design of the buffer. A 100-liter (26.4 US gallons) tank where the flows collide and completely mix the contents is, in my opinion, not a buffer but an efficiency killer.
At Heliotherm, which is behind Brötje, such a small buffer is not planned at all. They start at 300 liters (79.3 US gallons). There, the heat pump and underfloor heating supply temperatures will match more closely...
I would prefer a larger buffer, but would I want to sacrifice that much space in the utility room for it?

Alessandro schrieb:

It is quite surprising that the energy saving regulation requires an ERR but does not specify a maximum supply temperature!

My experience with my system is that the supply temperature doesn’t matter to my heat pump at all. Whether the supply temperature is 30°C (86°F) or 35°C (95°F), the heat pump always consumes 2 kWh.

The only factor that makes a difference for me is the outdoor temperature, which forces the heat pump to run longer and/or start earlier.

Zaba12 schrieb:

In my experience with my system, the supply temperature doesn't really matter; the heat pump always uses 2 kWh whether the supply temperature is 30°C (86°F) or 35°C (95°F).

The only factor that makes a difference for me is the outside temperature, which forces the heat pump to run longer and/or start earlier.

That contradicts basic physics and heating technology. Higher supply temperatures significantly increase consumption, especially with a heat pump.

I am mainly referring to this in relation to the spacing of the underfloor heating pipes. You can clearly see the difference when designing for 35°C (95°F) compared to 32°C (90°F). What’s the point of using a weather-compensated control (ERR) to save energy if you still have to operate at a 40°C (104°F) flow temperature to heat the house?

In my case, the heat pump runs most efficiently when the flow rate is kept consistently high. Although this increases compressor performance, it allows the flow temperature to be lowered. I find it hard to believe that your flow temperature does not significantly affect efficiency, @Zaba12.

Alessandro schrieb:

I’m referring more to the spacing of the underfloor heating pipes here.
You can clearly see the difference between designing for 35°C (95°F) or 32°C (90°F).
What’s the point of working with ERR to save energy if I still have to run a supply temperature of 40°C (104°F) to heat the place?

In my system, the heat pump runs most efficiently when the flow rate is consistently high. Although this increases the compressor output, it allows the supply temperature to be lowered.
I can’t quite believe that your supply temperature doesn’t have a significant impact on efficiency @Zaba12

Of course, the supply temperature produced also influences efficiency, which can be seen in the performance charts of heat pumps. These are usually specified for 35°C (95°F) and 55°C (131°F) heating water temperatures. In fact, the COP is lower at 55°C heating water than at 35°C heating water at the same air temperature.
What type of heat pump do you have, @Zaba12? Modulating or fixed-speed?

I believe it was a fixed rate; of course, it’s possible that the minimum output is high enough that 35°C (95°F) is sufficient.