Air Source Heat Pumps

Andy_WSM

lomb wrote: »

Fair enough, but perhaps you are retired or work from home? I for one have no interest in paying for heating im not using be that at night or when im out at work during the day. I like the concept of split air for instant heat and digital temperature control as well as superior COPS due to it being a larger market therefore more manufacturer money goes into R+D. In any case I shall bow out of the argument and post back as soon as my splits are up and running to report back on controllability as well as comfort.

I guess different systems suit different people / lifestyles. If we all wanted the same, life would be easy & dull at the same time!

For quick - and cheap heat, I think you are doing absolutely the right thing.

lomb

Cheers, i dont think there is any confusion. ufh =storage heater=comfortable but uneconomical unless heat needed all time powered by gas oil or heat pump. I personally see little to no attraction for GSHP or ASHP in wet systems. Capital+Maintainance costs imho far exceed any saving to be made and there are compromises.

lomb

Andy_WSM wrote: »

I guess different systems suit different people / lifestyles. If we all wanted the same, life would be easy & dull at the same time!

For quick - and cheap heat, I think you are doing absolutely the right thing.

Thanks for the support! Indeed my priority is rapid heat up and control I have spent years fiddling with storage heater input and output and have no interest in that .

albyota

OK I just timed the A2W HP Ecodan go into defrost....the external temperature here in the midlands is 2.6 degrees it is 10pm all the heating is on....lounge and kitchen are at 22.5 rest of house at between 19 and 21 bathrooms at 23.
just forced the thing to defrost by increasing the flow temp from 38 up to 55 defrost cycle lasted for exactly 2 minutes...flow temp dropped to 26 degrees whilst in defrost....Owl energy meter is reading between 15.5 and 23.5 kW (inverter) ( pretty much what it draws when normal running) with a base load of 0.63kW with fridge, freezer TV, Sky, 2 x PC's and a few CFL lamps. my annual bill all electric for 2009 was £837....£69.75/month......with plenty of defrosts and......the power hungry crankcase heater.

hope this helps

Andy_WSM

albyota wrote: »

Owl energy meter is reading between 15.5 and 23.5 kW

Really?! Are those figures right?

I can't get more than ~15Kw from my fuse board if I wanted to as I am limited by a 60A supply. Even if you have a 100A supply you must be right on the limit?

albyota

Andy......no.no, no no no......the Owl thing measures in real time, the heat pump (8.5 kW) draws 23 Amps Max....1.55 kwh to 2.35 kWh I should have said.....equates to 15p to 23p an hour...if it were on for an hour, sorry I was reading the pence per hour screen from where I was....

Therefore output of 8.5 kW / COP 3.6 = 2.36 kW input

Andy_WSM

albyota wrote: »

Andy......no.no, no no no......the Owl thing measures in real time, the heat pump (8.5 kW) draws 23 Amps Max....1.55 kwh to 2.35 kWh I should have said.....equates to 15p to 23p an hour...if it were on for an hour, sorry I was reading the pence per hour screen from where I was....

I was sat here envisioning copper cables going into meltdown each time the unit had to do a defrost

Yes, that makes more sense! My 5KW pump is on a 13A plug, which is convenient for keeping an eye on the running costs as it has it's own energy monitor. I rarely see it drawing much more than 1.5KW (6 amps) of power.

albyota

littletiger82, have you worked out how to programme the time settings yet?

paceinternet

Great info, many thanks albyota.

defrost cycle lasted for exactly 2 minutes...flow temp dropped to 26 degrees whilst in defrost

Flow temp dropped from 55 to 26. So what happened next?
I guess your underfloor mass didn't drop to 26, but how long did it take to recover the flow temp, and was the heat pump on max power during the recovery?

littletiger82

albyota wrote: »

littletiger82, have you worked out how to programme the time settings yet?

I have the HW coming on for an hour from 4-5 every morning as that seems to give me enough hot for the day. CH is now programmed to be on from 5-11 in the morning and 5-11 in the evening as I work shifts and could be coming in or going out at pretty much any time so its difficult to set tight timescales.

I've turned the thermostat on the HW tank down to 55C - is that right?