High temperature heat pumps

alphabeta · 2022-09-04T07:55:02Z

Hi all, We've just had 8kw of solar installed, a Givenergy 5kw hybrid inverter and 19.5kw of batteries. I'm now looking at my heating which is currently an oil boiler. I'd like to replace it with a high temperature air source heat pump - I've seen Daikin's one which looks pretty good. Property is around 3000sq ft and based in Perthshire. Can anyone give me any tips/pointers? Guess it'd be good to understand A) is this likely to be cost effective B) how I can calculate/convert my oil usage per year into KW per year C) if any other brands worth looking at beyond daikin D) how to find decent installers near me Thanks in advance!

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Air Source Heat Pumps (ASHPs)

Last Post by Mars 3 years ago

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Derek M

(@derek-m)

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Joined: 5 years ago

Posts: 4427

06/09/2022 6:34 pm

Posted by: @alphabeta

Hi Derek,

Yes, we're very fortunate in that we have a big 'swiss style' roof that faces directly south and is at 30 degrees so absolutely ideal for solar panels - so our generation seems to be a decent chunk above any estimates (today was 30kw+ despite it raining for the first half of the day and being cloudy for the second chunk).

We've got a Givenergy 5kw hybrid inverter and 2 X Givenergy 9.5kw batteries - yes our system can cover power cuts also, haven't set that up but is equipped for it. Let me know if you need any other details and happy to share!

Good shout re diverter - I've got an Eddi on order, so this will take solar excess and heat water, just not sure how much it'll need and may need to divert as you describe.

The other option is I have home assistant running all my devices across the house - so could likely do it without a diverter and do it smart (ie take energy generation, subtract battery max and level and then smart select other devices to run to use up excess - eg underfloor if temp under 16C, air con if temp over 23C, car battery if level below X% etc etc)

Definitely keen to get another inverter though as this would unlock our maximum draw to a more comprehensive level.

Will look at A2A though, that seems sensible addition.

Likewise will have a nose at powerpod too! Ta for tips!

The power diverter will have a Current Transformer (CT) with which it monitors your electricity supply from the grid. If it senses that you are exporting power, then it can divert the excess to a designated load, normally up to a maximum of 3kW. If your solar PV is producing say 5.5kW, and your normal house load at the time is 0.5kW, then the diverter could send 3kW to say your immersion heater, which would leave 2kW being exported back to the grid.

If you now switch on a 3kW kettle, 3kW would go to the kettle, but only 2kW to the immersion heater. When the kettle is switched off it would revert back to the above example.

Dependent upon the power rating of your electric UFH, you could have it as a second load connected to your diverter, so the diverter would heat the water first then supply UFH. Alternative you could have your control system monitor the power flow, and when there is sufficient excess generation it could switch on your UFH as a direct feed and allow any excess up to 3kW to be diverted to your immersion heater. In that way you could heat both your water and your home at the same time.

I hope that my explanation makes sense.

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Mars

(@editor)

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Joined: 5 years ago

Posts: 3416

07/09/2022 7:58 am

@kev-m, currently over £2 per litre. When the market is ‘normal’ it’s around £1/litre, when kerosene is around 50p. The excess is down to government levies and duties.

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