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ASHP results
Posted: Wed Jul 26, 2023 8:23 pm
by Stinsy
I know we like Mick in these parts. He’s written a blog post about how his ASHP got on last winter:
https://energy-stats.uk/first-winter-wi ... heat-pump/
Re: ASHP results
Posted: Wed Jul 26, 2023 10:15 pm
by MrPablo
I really respect how much information Mick provides in their articles, especially when it's backed up with very useful data.
Good to see their external installation of the hot water tank has worked well too.
I'm in the middle of a refurb in one of the bedrooms here (soon to become a nursery) and I'm doing a fair bit of work to reduce heat loss, ahead of a likely heat pump next year.
Re: ASHP results
Posted: Thu Jul 27, 2023 12:35 am
by Swwils
Surprised his cop is so low
Re: ASHP results
Posted: Thu Jul 27, 2023 7:06 am
by Oliver90owner
I’m surprised the COP is so high. Does this include energy used to thaw the heat exchangers? Many installations include a resistive heater in the system, for very cold weather assistance, which may not be recorded/included for COP calculations
Calculations on COP are all very well, but while gas is less than a quarter of electrical energy (on standard current normal capped prices, these installations are little better than a good gas boiler system, from an economic POV. The main advantage is that, as renewables and nuclear (not at Hinkley point strike prices) reduce the amount of fossils burned, the CO2 emissions are reduced - good from a climate change POV.
I’m not yet sold on ASHP tecnology.
Re: ASHP results
Posted: Thu Jul 27, 2023 7:43 am
by chris_n
Oliver90owner wrote: ↑Thu Jul 27, 2023 7:06 am
I’m surprised the COP is so high. Does this include energy used to thaw the heat exchangers? Many installations include a resistive heater in the system, for very cold weather assistance, which may not be recorded/included for COP calculations
Calculations on COP are all very well, but while gas is less than a quarter of electrical energy (on standard current normal capped prices, these installations are little better than a good gas boiler system, from an economic POV. The main advantage is that, as renewables and nuclear (not at Hinkley point strike prices) reduce the amount of fossils burned, the CO2 emissions are reduced - good from a climate change POV.
I’m not yet sold on ASHP tecnology.
His heat pump runs in reverse to provide defrost cycles.
Re: ASHP results
Posted: Thu Jul 27, 2023 9:35 am
by Ken
I would say that was a slightly high COP when compared to others we hear about, but remember it was a mild winter and therefore also low gas use.
Re: ASHP results
Posted: Thu Jul 27, 2023 9:58 am
by Stinsy
Ken wrote: ↑Thu Jul 27, 2023 9:35 am
I would say that was a slightly high COP when compared to others we hear about, but remember it was a mild winter and therefore also low gas use.
Let's not forget he doesn't optimise for CoP! Using TRVs to have different rooms at different temperatures and running the HP harder in the cheap period might be beneficial overall but it lowers headline CoP.
Re: ASHP results
Posted: Thu Jul 27, 2023 6:11 pm
by Swwils
Oliver90owner wrote: ↑Thu Jul 27, 2023 7:06 am
I’m surprised the COP is so high. Does this include energy used to thaw the heat exchangers? Many installations include a resistive heater in the system, for very cold weather assistance, which may not be recorded/included for COP calculations
Calculations on COP are all very well, but while gas is less than a quarter of electrical energy (on standard current normal capped prices, these installations are little better than a good gas boiler system, from an economic POV. The main advantage is that, as renewables and nuclear (not at Hinkley point strike prices) reduce the amount of fossils burned, the CO2 emissions are reduced - good from a climate change POV.
I’m not yet sold on ASHP tecnology.
Almost every heat pump in a heating system on the planet is sized for efficiency and not for 100% heat load at the coldest point of the year.
We do the latter in the UK and it's bizzare and silly.
Everywhere else they size the heat pump for use most of the year and then when it gets real cold roll out a secondary heat source.
In general terms this would mean size the pump for 6C rather (heating season average) than -3C in the UK.
You will be sold on heat pumps once the penny clicks that they allow you even when running them on electric from gas to move more heat than the energy in the gas itself contains.
Re: ASHP results
Posted: Thu Jul 27, 2023 6:42 pm
by AE-NMidlands
Swwils wrote: ↑Thu Jul 27, 2023 6:11 pm
You will be sold on heat pumps once the penny clicks that they allow you even when running them on electric from gas to move more heat than the energy in the gas itself contains.
running them on electric from gas? you have CHP?
Maybe cheaper... if you have pv or a TOU tarriff and batteries. My electricity costs over 4 times per kW compared to what gas costs
Re: ASHP results
Posted: Thu Jul 27, 2023 6:43 pm
by AE-NMidlands
AE-NMidlands wrote: ↑Thu Jul 27, 2023 6:42 pm
Swwils wrote: ↑Thu Jul 27, 2023 6:11 pm
You will be sold on heat pumps once the penny clicks that they allow you even when running them on electric from gas to move more heat than the energy in the gas itself contains.
"running them on electric from gas?" you have CHP?
Maybe cheaper... if you have pv or a TOU tarriff and batteries. My electricity costs over 4 times per kW compared to what gas costs