Tuning performance of Dakin 8kw Altherma 3

[toadhall (Alun Hawkins)]

@Terry247

so the question is what is the incremental cost that @ebyard is paying for his 18l/m and is it proportional or a bargain?

This thread goes into it in great detail …

Optimizing flow rate for ideal COP

Having an oversized heat pump, I recently wondered whether the high flow rate pump that goes along with it might also just be too much. Typically, everyone wants a high flow rate but at some point the electricity consumption of the pump will also become significant…the question is when. To find this optimum, let’s have a look at what goes into it. We have our design heat loss P_heat and our radiators (or generally emitters) are chosen so they deliver this power into the house when they are at a…

To summarise, if pump energy was free, then an infinite flow rate would be optimal. This reduces the dT to nothing, but the important point is that it minimises the flow temperature, and the lower the flow temperature the higher the heat pump efficiency.