The HPs used on boats use seawater...Joeboy wrote: ↑Tue Apr 15, 2025 2:44 pmAgreed, we have at least one WSHP owner on the forum via a stream and by all accounts it provides a consistent supply of heat with minimal variance. As to WBS and heat pump combo we personally have found it to be a very effective marriage of techs. How popular are ashp's Stateside?MikeNovack wrote: ↑Tue Apr 15, 2025 2:34 pm I was not trying to be condescending But it isn't possible for folks to understand misleading "hype" and manufacturer's claims about ASHP without basic Physics. Or why, IF GSHPs or WSHPs are practical alternatives at your location, they can perform better than ASHPs.
Take "average" COP as advertised for an ASHP. That can be very misleading (disappointing electric consumption over the heating season) if based on "average air temperature" over the heating season. WHY? Because when the outside air temperature is higher, less heat is required for the house. And when the outside air temperature is lower, more heat is required. The heat pump is pumping less heat when the COP is high and more when the COP is low. So the correctly figured "average" has to be weighted by the heat moved at each COP and then that averaged.
Look, this began with my suggestion that IF the log burner was left installed after ASHP put in, an effective use of the log burner would be during cold snaps when the air temperature unusually low (and so the COP of the ASHP unusually low). That is when it most pays to reduce the amount of heat the ASHP is pumping because the COP unfavorable (it doesn't have to pump the heat that the log burner supplied)
I ask as they are a firm established technology here in Turkey under the guise of inverter aircon systems whereas air source water systems are still seen with some scepticism in large sections of the UK.
Does anyone know of a successful marine HP installation or estuary based?
The problem with GSHPs and WSHPs is that the piperuns generally make it cost-prohibitive. I know a guy who paid £20k for the borehole that his GSHP utilises. I don't think he'll see a retun on that investment in 100 years! Sure you get marginally better efficiency from a GSHP vs ASHP on the very coldest days but at what cost? Nowty was "lucky" to find a stream running beneath his house so pipe runs were modest in his case, and he DIYd it for fun so that did away with the additional labour cost too.
I'm also very supportive of fitting an undersized HP and augmenting it with a WBS or SH or whatever for the very coldest conditions. But you're not permitted to do that if you want to receive the grant...