This is the second new build block of flats with a green heating system that doesn't perform well. Previously it was a solar thermal roof mounted array backed up by a pellet boiler heating 12 key worker flats.
Now my sister in law is in a joint ownership block of 10 apartments converted from a detached Victorian town house, each apartment has a heat meter to proportion costs. There is a communal air source heat pump sitting in the back garden but instead of using under floor loops the architrave has specified radiators as if for a conventional system running at ~80C, apparently the calcs show this and there was little liaison with the company supplying the heat pump. Litigation is on the cards but I'm only pondering a solution. There is little chance of retrofitting radiators or floor loops.
I haven't seen it yet so I don't know the power requirement but my first thought is for a combi gas boiler in the feed from the heat pump, one that can accept a 50C feed.
Mostly I'm wondering about the control algorithm as, presumably, the heat pump will meet demand even with the lower flow temperatures and undersized radiators. The simplest would be to fire the combi whenever the feed water fell below 50C but with the limited heat exchange it would mean the return temperature to the heat pump would be too high so I'm trying to think of some sort of injection circuit that would still allow the heat pump to provide energy much of the time. Any thoughts?
AJH