Discussion ... ASHP(Air/Air) with Solar pv ....

gabitzul

Don't know why. Maybe it can get complex pretty quickly? Have you looked on eBay? There are ASHPs fully fitted.
Seriously considering a second purchase, for downstairs (living room). The existing one is upstairs, in the hallway, heating all rooms quite efficiently - I am really impressed with it.

I am also on Octopus Go and I also have batteries (2x 2.4 KWh Pylontechs) which at the moment I am charging at night to 90% at 5p/KWh and the ASHP is on during the day, mopping most of the solar from the 4KW array.

EVandPV

I read somewhere that air to air pumps don't qualify for RHI payments.
Is that correct ?

ASavvyBuyer

EVandPV said:

I read somewhere that air to air pumps don't qualify for RHI payments.
Is that correct ?

Yes, because they can also be used for cooling.

However, I believe that there may be some that can only be used for heating and can't reverse for cooling.

They may qualify.

EVandPV

Been discussing this with the wife and one concern she has is how dry the air gets.
Is this more of an issue with air to air systems compared to radiator heating ?

ASavvyBuyer

EVandPV said:

Been discussing this with the wife and one concern she has is how dry the air gets.
Is this more of an issue with air to air systems compared to radiator heating ?

We don't find it makes any difference, unless you put it on the dry setting. Which can be useful if you are drying clothes inside and want it to dehumidify the air. As the "heat" is not from an element, it does not "use" the oxygen in the air.

Coastalwatch

EVandPV said:

Been discussing this with the wife and one concern she has is how dry the air gets.
Is this more of an issue with air to air systems compared to radiator heating ?

That maybe, but she'll love it to dry damp clothes on, at least mine does. Plus of course it has the bonus of raising humidity a tads, if that's an issue.

joefizz

ASavvyBuyer said:

EVandPV said:

Been discussing this with the wife and one concern she has is how dry the air gets.
Is this more of an issue with air to air systems compared to radiator heating ?

We don't find it makes any difference, unless you put it on the dry setting. Which can be useful if you are drying clothes inside and want it to dehumidify the air. As the "heat" is not from an element, it does not "use" the oxygen in the air.

I sometimes use it as a dehumdifier but the cool air input system dries the air more than the ashp does.

deantrina

Your knowledge / thoughts on this would be welcome .Just had big refurb works done on house basically a new house top to bottom so i went for ASHP & 8 PV panels (generate 2.56KW/Y looks like) . expecting PV to power ASHP & expecting costs of approx £30/ M electric . Just had smart meter fitted ( 1 week ago) & its saying im using £13/day on electric ie: £390/Month . Tarrif with Bulb is £0.1610p / KWh . I have questioned if this is right as its 6 times more than im expecting , i have queried if smart meter is faulty currently awaiting it being tested . meter says used 450KWh in one week . 4 bed house , can that fiqure be right or is it just so far off the mark something is definalty not right . Thanks 

matelodave

You need to understand how a heatpump works and how solar panels work. The heatpump runs most of the time in the winter when its cold, the days are short and the sun doesn't shine very much and so it's use of leccy is at a maximum. Conversely solar panels generate very little in the winter and most in the summer when the heatpump is using least. So they don't really help all that much.

Have a look at this calculator, use the map to find out where you live, fill in a couple of the details in the table on the right (size of your array, orientation of the panels and slope and see what the monthly prediction for solar generation looks like - https://re.jrc.ec.europa.eu/pvg_tools/en/#PVP

Secondly are you using the heatpump correctly or are you trying to use like a gas boiler in short bursts for a couple of hours in the mornings and evenings and with high flow temperatures because thats also uses more energy than when they run at low temperatures for longer periods. (I'm making an assumption that you've got an Air to Water system rather than an Air-to- Air) or ground source

It's quite possible that you could be using 400+kwh in a week when it's very cold outside. The efficiency of a heatpump drops when its very cold (which it has been recently) and if you've got high flow temperatures. Even more so if you have very hot water. Anything above about 50-55 might cause the boost heater to kick in which will increase the running costs dramatically.

What sort of system have you got, make, model size. What heat emitters have you got (radiators, underfloor, fan coils). Wha size hot water tank. What is your flow temperature, what is your hot water temperature, when do you run it and what room temperatures have you set.

I've got an 11kw heatpump which runs most of the time (we are at home all day) and we got through around 1400kwh in January and 1050kwh in February (this was a bit more than usual because it's been colder than usual - 1150 & 960) but around the sort of consumption that I'd expect for this time of year.
In fact this is what my consumption has been over the past ten years. You can see how this January has used a lot more than most previous years. I haven't added Feb yet but it was around 1050kwh. My annual average is around 7200kwh

This is how a solar array would perform where I live in the East of England (the predictions are for a 1kwhp array, so multiply it by whatever size you've got )but you see that it doesn't do much to help run a heatpump until March or April and it drops off around October

deantrina

Matelodave thanks very much for your informed answer , i will dig out the info & post tomorrow , interested in your thoughts