Thank you for reply Hanno,
That is what i was waiting for i think, I can clearly see it works very well as a bufer for home against the cold water being supplied straight to home. I think i am sold for that solution, on other hand i do not have many defrost cycles, on reverse. there are reverse defrosts only when outdoor temp is below 2.6C, otherwise heat pump is doing passive defrosts i which it does not compressor to defrost.
Thanks a lot for reply
Thats interesting my volumiser is on the return so when the HP goes in to defrost it first pulls from the volumiser before the the radiators/emitters
âŚwhich sounds like it should be the preferred configuration, doesnât it - to maintain the temperature of the emitters during a defrost cycle.
The catch is that means the slug of cold âdefrostâ flow coming from the outdoor unit then goes directly to the emitters and chills them down, while the volumiser stays relatively warm.
If the volumiser is on the flow side instead, the cold flow gets mixed inside the volumiser so the emitters stay warmer. (The same mixing happens with the extra-hot water that often gets dumped into the heating circuit at the end of a DHW cycle, which can be beneficial for UFH systems that donât like such hot water.)
I donât believe it really matters too much and I definitely wouldnât advocate moving a volumiser thatâs already installed, but the Renewable Heating Hub article linked earlier convinced me that itâs generally better to put a volumiser on the flow side, in a new installation.
Would it work to have two smaller volumisers - one on flow, one on return for the best of both worlds?
I expect the best option is a 3 way valve with a sensor in the volumiser so the radators donât get any flow until the volumiser have recovered from a defrost cycle. But that would need integration with heatpump software.