Air Source Heat Pumps

eugeneg

How do you measure the COP ? The input side is straight forward, but I don't see how the output is quantified. Is it from the units themselves ?

paceinternet

Presumably you recognise the "up to" bit of the spec as also in the previous reply.
So, is the issue about "how do I achieve the maximum quoted COP"?

Did they discuss the output temperature settings with you? They must be able to say that at ground temperature of x and hot water inlet or outlet temperature of y, it will give you COP 4. If so, have you run it under those conditions?

You must know that if you are running it at less than x and more than y, the COP will not be as good.

They have specifically agreed that the 800m loop installation is acceptable?

bludger

I've been reading about central heating using fanned convection heaters. These use very low volumes of water which need to be heated to a lesser degree than normal radiators because of the fanned air distribution.

If I've got it right, they are supposed to be as efficient and as economical as underfloor heating. This would make them excellent for an ASHP installation.

Has anyone any experience or knowledge of these units, please?

albyota

yes bludger, finned fan coils do work very well with lower water temps, and you can get good efficiencies with them, however they are a bit on the bulky size if you require anything bigger that a couple of kW's. the fan coils can be high level wall or low level floor mounted, cassette type, and underslung type, the bigger ones (more output, are rather like the old school hall type but have been smartened up a bit. ideal for churches and large areas.

richardc1983

bludger wrote: »

I've been reading about central heating using fanned convection heaters. These use very low volumes of water which need to be heated to a lesser degree than normal radiators because of the fanned air distribution.

If I've got it right, they are supposed to be as efficient and as economical as underfloor heating. This would make them excellent for an ASHP installation.

Has anyone any experience or knowledge of these units, please?

yes this is how my system works.

Its basically air conditioning, so you have cooling in summer and heating in winter.

Very efficient.

See this link on the forum for full info and pictures of units: I created the first thread so hope its useful for you.

http://forums.moneysavingexpert.com/showthread.html?t=1464827

Theres also a video I produced showing the system... please ignore the state of decoration we were being decorated at the time:

http://www.youtube.com/watch?v=-0g0Y0_tL_E

bludger

Thank you Albyota for your input. I've never seen one of these things - just reading up about a possible ASHP installation. Quite a complicated business, ain't it?

albyota

as long as you know which type of system you are looking at air to air or air to water, both systems have low running costs, as richard has stated the benefit with air to air is cooling in the summer...heating in the winter. whereas air to water systems are only for heating and work best with under floor heating or slightly increased sized radiators....i.e. K2 double panel, double convectors or as you say fan coils.

richardc1983

bludger wrote: »

Thank you Albyota for your input. I've never seen one of these things - just reading up about a possible ASHP installation. Quite a complicated business, ain't it?

Bludger

See my post above... very useful info at the links.

bludger

Richardc1983,

That's quite a post you put there! I do hope that the work you've put in has been fully appreciated.

I haven't thought about air to air, probably because of the lousy embedded system that a relative of mine had back in the 80's. Huge gizmo in the kitchen and ducts under the concrete floors with vents coming out at odd places. It was a new semi built on a estate by a cheapjack builder. Horrible. The system was gas fired now I think about it.

I'll go through the thread you started which I'm sure will answer the obvious questions and come back when I need more advice.

Many thanks,

richardc1983

Feel free to PM me if you like.