air-water heat pump - any good experiences / recommendations?

[ajn9000]

Worcester has got me interested in finding out more about an air-water heat pump. Needs to be suitable for a property with 200m2 total floor area. Does anyone out there have any good experiences or recommendations?

 

[Leesparkykent]

Worcester has got me interested in finding out more about an air-water heat pump. Needs to be suitable for a property with 200m2 total floor area. Does anyone out there have any good experiences or recommendations?

do you have UFH?

 

[Chris Watkins]

Do you have a modern well insulated house, if not forget it would be my advice.

How is it heated at the moment ?

 

[ajn9000]

Do you have a modern well insulated house, if not forget it would be my advice.

How is it heated at the moment ?

It is an old stone cottage. Extension is well insulated and will have UFH (3 rooms). Currently heated by an old oil Rayburn at one end, a coal/wood burner at the other end, plus electric rads when required. So bit of a mixed bag

 

[Worcester]

@ajn9000 you'll probably get more of a response from here: Renewable Energy

Heat pumps work best on a low flow temperature (hence ufh a good option), they are practically limited on output in a domestic situation because of the load on the electricity supply, so in general the maximum size would be 12-18kW at A-3/W40 (beware MOST air source heatpumps are quote at A7/W30 - a completely different output).

Bearing in mind the maximum practical output, to heat a full house that will have to be very well insulated, so rules are:
1) Insulate
2) Insulate
3) Insulate

This will also of course bring your running costs down, and insulation is the cheapest form of heating that you can get (if that makes sense )

We've got a project going on at the moment which is a whole house refurb (black and white, breathable walls..) downstairs UFH, upstairs, correctly sized rads (4.3 x larger than for an oil boiler) Total area 230m2, (average 67W/m2) 15.8kW + 1 kW dhw = 16.8 kW so we're putting in 2 x 9kW heat pumps cascaded, one will do DHW as a priority and the other the Heating exclusively.

The key to a successful heat pump installation, is 1) good design and 2) quality of installation workmanship.
As part of the process you chosen supplier should do full room by room heat loss calculations to assist with the sizing and design.

 

[Chris Watkins]

As a matter of interest Worcester any idea what the likely running costs of that system is likely to be ? We will bare in mind that you don't know what the levels of 1) 2) & 3) :wink_smile: are but from your experience.

I am not convinced that with the higher cost of electrically (let alone the generation carbon & transportation losses) that it makes sense with such poor COP, especially on refries.

Maybe have a look at a thermal store with multiple heat sources input (wool burner + modern condensing oil boiler + ?)

 

[Worcester]

We will only install if we can get a SCoP of at least 3, i.e a maximum flow temp of 45°, the defining factor then becomes heat loss rates and radiator sizing.

Both the MCS website and the manufacturers are behind the curve on calculating SCoP's

Quote from MCS "*The SCOP/SPER calculators are for the use of the Certification Bodies only. They will use the calculators and inform MCS of the data produced, who in turn will upload it to the product search page."

However, despite the options 'may commence working in accordance with this update from 06/05/2015 shall commence working in accordance with this update from 26/03/2016' we have yet to be able to find any data avilable, so they've got their work cut out over the next few weeks