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

Alessandro schrieb:

I don’t understand that, because if the heat pump is set for a temperature difference of 5 K, but the underfloor heating only delivers 3 K, then the heat pump automatically reduces the flow rate, right?

In your case, probably yes. And that makes it less efficient.

I meant to skip the buffer tank and go directly into the underfloor heating with a 3-degree temperature difference. Then with a high flow rate (usually around 30°C in and 26°C out in new houses).

The heat pump would still downregulate anyway, regardless of whether I connect it directly to the underfloor heating or to the buffer tank, right!?

Alessandro schrieb:

The heat pump would still reduce its output, regardless of whether I feed directly into the underfloor heating or into the buffer tank, right!?

But the control variable would then be the return flow from the underfloor heating and not the return flow from the buffer tank. This makes the control more effective and the system more efficient. You save energy by running one less circulation pump and avoid energy losses in or through the buffer tank.

Why do you keep focusing on the values of the temperature difference and the flow rate?

Only three values really determine efficiency:

Achieved room temperature
Achieved supply temperature
Achieved runtime within a smaller range

Example:
If you reach the desired room temperature with a temperature difference of 2°C (3.6°F), the lowest supply temperature, and the longest runtime, then that is the best value.

If you can only reach those values with a temperature difference of 7°C (13°F) and shorter runtime, then that is the best value.

There is no single best temperature difference.

I currently have a temperature difference of 4.8K. At 0 degrees Celsius (32°F), the difference is 6K. Run times are fine. Compressor starts are also okay. I would prefer a smaller temperature difference, but the energy consumption is acceptable, and that is the most important thing. Nothing else matters to me, especially since no one is celebrating 😎

Alessandro schrieb:

The heat pump would throttle down anyway, whether I connect directly to the underfloor heating or to the buffer tank, right?!

So? Then the heat pump just throttles down. But as others have also mentioned, ONLY the heat pump. No buffer tank, no second pump, no secondary circuit. Everything is straightforward to control.

Basically, it’s the same as with any other device. Almost everywhere, there’s just one motor driving a system. Whether it’s in the stove, car, refrigerator, or air conditioner. As soon as you have system A, and system B builds on that to deliver output C, it becomes a) inefficient and b) more complex to regulate. You can see that in your setup.