AFAIK with heat pumps, higher temperature output means lower coefficient of performance?
I remember enough heat engine theory to have a sneaking suspicion its a bit more complicated than that and depends on the working fluid. But not enough to give chapter and verse, sadly.
hmmmmm
Or it could simply be a resistive electric heater to warm up the incoming air or to "top up" the temperature of the output water?
either way, it does sound like the electrical power requirements will be higher. Once you add in electric cars amd change the gas cooker to electric cookers, your 100A supply is inadequate and the electricity supplier will make hay charging you for an upgrade to 3 phase supplies...
See
but limiting factor is still the ideal Carnot cycle where CoP goes down as difference between input and output temperatures goes up?
COP=Khot/(Khot - Kcold)
Kinda telling that there?s no mention of COP anywhere in the info for this heat pump. I guess they?re hoping that people won?t notice that it?s gonna be even more expensive than gas heating or a ?regular? ASHP until too late.
Tim
They have homes that are incredibly well insulated though to begin with.
There is no free lunch. The higher the temperature difference required the lower the overall efficiency/coefficient of performance becomes.
That is why heat pump designs typically go for large area low temperature underfloor heating and/or huge lower temperature radiators.
Twice as much heat pump hardware to go wrong and twice as much electricity used compared to a single heat pump.
The other big snag is that you have no heating at all if the electricity goes off as it tends to do round here in mid-winter storms. A situation made much worse recently by that pissup in a brewery Northern Powergrid. At least NEDL used to do some preventative maintenance in summer.
That would be madness. Hydrogen fuel cell combined heat and power is a more attractive proposition if you can get enough hydrogen.
There seem to be contradictory statements.
"The developers claim their product is not a ?one-size-fits-all solution? for everywhere in the country, but it could be the most effective solution to low-carbon heating in rural and suburban areas."
But then
? 'The high-temperature heat pump solution is innovative, simple to install and could be the solution to help decarbonise homes in the UK that are heated using traditional gas boiler,' said Mark Anderson, the commercial and development director at Vattenfall Heat UK."
Chris
Chris J Dixon quoted:
Can't see much on the Vattenfall website, plus it seems to hate firefox (or adblockers) but the Feenstra site (with google translation from Dutch so beware of hovercraft) seems to talk about a hybrid gas boiler + ASHP.
They're using CO2 (R744) as the refrigerant instead of the common R32. COP of 3 'over an entire season':
Theo
Mine works quite well, with domestic water set at 44C.
there are two stage heatpumps and heatpumps with auxiliary immersion heaters
Does this mean that your fridge is basically a hole in the ground so you can make use of the heat extraction for the home grin. Brian
And as one might expect from the Guardian, the piece is essentially about insulating homes; it's mentioned in more than half the article.
Well it is of course, except that all the cold that you pump into it eventually leaks out into the house.
OH NO NOT CO2, WHAT HAPPENS IF IT LEAKS OUT :-)
Perfect temperature for Legionella to thrive in the hot water tank.
I installed an AS heatpump in 2005, a prefilled self-fit split unit with outside and inside parts linked by pipework and a cable. Somewhat to my surprise, almost 17 years later, it's still working fine and has never needed any maintenance, except for pulling out any weeds that start growing into the outdoor part.
I bought it for cooling in the summer, but it only gets used a few days a year for that. It's mostly used for heating. As I've been a home worker since then, I use it to heat just my main dining/living room where I also work, rather than using the central heating to heat the whole house during the day when I'm working. The first year, I ran it through a power meter and it only cost something like £10 to provide the heating through 3 months of winter (although that was when electricity prices were less than a quarter of what they are today). It also turned out to be really easy to link to my home automation, because its state (on/off, mode, temperature and fan settings, etc) are stored in the remote control, rather than in the unit itself, and I just needed to decode the remote control signal to be able to drive it from home automation instead.
I had previously bought and installed one at my parents' house, and was sufficiently impressed to get one for myself too. They were about £400 from B&Q at the time. A shame B&Q no longer sell them. The one at my parents' house stopped working during building work, and I suspect someone probably hit some part of it with a scaffold pole or plank. I still have it with a vague intention of getting it repaired and reusing it one day.
Andrew
I have a vague recollection of reading somewhere that low temperature tanks, fed from heat-pumps, are supposed to be heated to a higher temperature every so often (a week?) to prevent legionella problems.
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