Heat pump / inverter DIY

mikedain

Does anyone know where I can get a plugin timeswitch for a round pin plug such as this:

http://www.tlc-direct.co.uk/Manufacturers/Telco_White/Plug_Tops_2/

richardc1983

Mike

You would be better off putting that in a different forum such as the I WANT forum.

mikedain

you are correct, will do

paceinternet

The COP is also dependant on the outside air temperature it is using and the temperature it is aiming to achieve inside the unit.
I can't see if they state the conditions under which it achieves those values.

With some units, you will see a graph of COP from around "2" at -15 degC outside > 50 degC refridgerant inside the unit, to over "5" when the differential is much narrower.

stevehead

I joined imeasure.org.uk last week (thanks to MSE for that) and got my first energy usage stats:

• £3.29 on gas
• £16.44 on electricity

Breaking that down a bit... and as we all know it's the coldest start to winter in 30 years:

The gas is used for
All Hot water inc Showers
Cooking except microwave

The Electric is used for ASHP Heating (£7.00)
Everything else a family home does (£9.44)

(Family of 4 / energy inefficient kids / end terrace / work from home / SW England)

That £9.44 sounds a bit high, but imeasure use 12p/KWh and I'm paying Click Energy 6 prices so that's really £8.50.
Still, I'm paying more to run all the other stuff than I am for heating.

It also highlights the complete waste of money solar water heaters would be. I have an old Brittony instant hot water heater, and even though it kicks enough heat out of the flue to seriously burn your hand it after these results I'm hanging on to it.

stevehead

Heat Output
You can test what sort of capacity you require by using/blagging a few fan heaters and plugin energy monitors. Find out just how much heat you need by placing the fan heaters around the home and alter their output until you're comfortable. You can 'pretend' these are ASHP's as they deliver heat in a similar way - stick 'em temporarily on the wall if you can be bothered to gain accuracy.
You will then be able to see how many KW and KWh your home needs.
Then select ASHP's that have a similar output on LOW output.

eg if you are comfortable with 2 X 2KW fan heaters on all the time, then get 2 x ASHP's that deliver 5kw(nominal) max heat. These will then run mainly on low power so very little noise from the inside or outside units as they're not working hard.
You'll find that a 5kw unit can pump 6-7kw in 'Turbo' mode if you come home to a house that's freezing, which will very quickly get the place warm.
This is unlike underfloor which is unable to provide rapid heat.

Type
A lot of ASHP's are designed for cooling only - don't buy these(!).
A lot of ASHP's are designed for cooling, and heating is just bunged in as an afterthought. Look for the cooling/heating performance. If it provides better Kw cooling than heating - don't buy these.
Look at the COP value; aim for 5 or above in heating mode and you're quids in. I won't go into the various technologies as the COP value is all that matters.

Noise
You and your neighbours have to live with this. Check the manufacturers db rating for both indoor and outdoor units. In the 20's for the indoor and 30's for the outdoor is unobtrusive.

Tat
Who can believe vendors/manufacturers claims anyway? Pay a bit more for brands that are trustworthy and forget the Ebay rubbish if you don't want to be disappointed.

Best advise... insulate first, then carry out your requirement tests.

Pold

Cardew wrote: »

Pold,

Can you say what sort of water temperature these achieve? and a typical range of COP?

As has been already stated up to 55 degrees to you're heating system be it rads or underfloor, up to 80 degrees hot water although 55+ is electric heated.

Yes 1/3 bigger radiators too, but ive seen newer 2 bed houses with a mix single and double rads, 200L tank cost 80p per day in electric.

They can be difficult to retro fit in older houses but not impossible, flow out, return in much the same as normal boilers and a three way valve to divert to the tank to heat the water.

http://www.daikin-altherma.co.uk/page_howalthermaworks.htm

paceinternet

The refridgerant type used in the system limits the max temperature. I am told some can exceed 55 deg C but it would be helpful to find some more details on refridgerants.

thechippy

mikedain wrote: »

I have been reading this forum with interest and am looking at saving money while heating our room at night. We have the following air con unit in the bedroom and I am considering using this for night heating instead of gas central heating the whole house unnecessarily. Could anyone tell me if this air con unit is capable of producing the equivalent of 3x or 5x the heat from 1 unit of electricity (we have the slightly more powerful KFR32-GW/NJ1F unit):

http://www.mgr-ac.co.uk/productView.asp?productID=5&categoryID=2

Thank you!

Hi Mike,

Yes it will, no problem.

Garry

anthonykeates

I got a question (probably a stupid one!).

If a unit's specs say it's got 4.6kW of heating capacity (for example the link below) is that the maximum it can achieve? Or will it achieve the 4.6kW times the COP (which will vary with outside temp), say 3 times 4.6 = 13.8kW? Or will it always have a capacity of 4.6kW, just that the higher the COP achieved the less electric used to get the rated heating capacity? Hope that makes sense!

http://www.orionairsales.co.uk/mitsubishi-heavy-industrial-srk20zgx-s-28-kw--9000-btu-hyper-inverter-air-conditioning-220-p.asp