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Air-source Heat Pumps

 
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Lozzie



Joined: 25 May 2005
Posts: 2595

PostPosted: Wed Apr 19, 06 4:47 pm    Post subject: Air-source Heat Pumps Reply with quote
    

Has anyone any experience of these, please? Good or bad?

https://www.powertech-solar.com/air-to-water-heat-pump.htm

dougal



Joined: 15 Jan 2005
Posts: 7184
Location: South Kent
PostPosted: Wed Apr 19, 06 5:33 pm    Post subject: Reply with quote
    

There isn't very much heat in *air* compared to the same amount of say, water or soil...
What that means is that you have to shift a *lot* of air through the machines collector to get any significant amount of heat out of it... which means fans and noise.
Probably perfectly acceptable in a commercial/industrial installation. Not such a nice idea for residential.

And then there's the question of efficiency. A ground (or water) source for the heat is never going to be below +4C or thereabout.
One wants to use the heat pump to deliver an output temp of perhaps 34C for underfloor heating - and uplift of never more than 30C.
However, its when the outside *air* temperature falls to something like -6C that you most want the heating... and its going to struggle, because it now has to do a 40C uplift, 33% more. The greater the temperature uplift, the lower the efficiency (the "coefficient of performance" will be rather less than 4). Just when you want it most, it doesn't do so well...

Air source heat pumps are rather less attractive than ground or water source units. If you have enough convenient water, you can get away with a fairly small collector (and avoid digging up the garden for burying lots of pipe!)

Geothermal BTW should, strictly speaking, be used only to describe collecting heat from the hot rocks that are usually well underground (but much closer to the surface in places like Iceland!) {Added as much as anything to help find this post by 'Search'... }

Lozzie



Joined: 25 May 2005
Posts: 2595

PostPosted: Thu Apr 20, 06 6:47 am    Post subject: Reply with quote
    

Thank you, Dougal.

H.I.S



Joined: 22 Apr 2006
Posts: 40

PostPosted: Sat Apr 22, 06 1:41 pm    Post subject: Reply with quote
    

i would beg to differ dougle.

the company install all renewable technolergies, including air to water heat pumps.

For instance, we installed a system in a new build property over 1 year ago, it consits of underfloor heating, a 6 shott panell solar thermall system and a air to water heatpump in the plant room at high level. The property also has a 15kw wind turbine.

The thing with a air to water heat pump is that is is like a trickel charge, every thime water passes the heat exchanger it is raised by 1 or 2 degrees.

Strangely enough dougle a air to water heat pump is classed as more efficient than a ground source heat pump.

the property i reffered to gets all its heat and hot water form both the solar and the heat pump due to the fact the underfloor heating is plumed into a torrent cylinder, the cylinder also has the solar and the heat pump plumed into it.

THIS HOUSE HAS NO BOILER within it, no elecktric heating or any type of secondry heating. The property is kept at a constant 21 degrees.

My i also say, when was the last time it was -6 inside your home ?

The air to water heat pump reycles heat it has produced and reuses it.

also look at it this way, Your fridge is very un efficient, put a air to water heat pump in a room you dont use, it will pull the heat out of that room there for turning it into a cold room. A cold room = a lada.

H.I.S



Joined: 22 Apr 2006
Posts: 40

PostPosted: Sat Apr 22, 06 1:41 pm    Post subject: Reply with quote
    

i would beg to differ dougle.

the company install all renewable technolergies, including air to water heat pumps.

For instance, we installed a system in a new build property over 1 year ago, it consits of underfloor heating, a 6 shott panell solar thermall system and a air to water heatpump in the plant room at high level. The property also has a 15kw wind turbine.

The thing with a air to water heat pump is that is is like a trickel charge, every thime water passes the heat exchanger it is raised by 1 or 2 degrees.

Strangely enough dougle a air to water heat pump is classed as more efficient than a ground source heat pump.

the property i reffered to gets all its heat and hot water form both the solar and the heat pump due to the fact the underfloor heating is plumed into a torrent cylinder, the cylinder also has the solar and the heat pump plumed into it.

THIS HOUSE HAS NO BOILER within it, no elecktric heating or any type of secondry heating. The property is kept at a constant 21 degrees.

My i also say, when was the last time it was -6 inside your home ?

The air to water heat pump reycles heat it has produced and reuses it.

also look at it this way, Your fridge is very un efficient, put a air to water heat pump in a room you dont use, it will pull the heat out of that room there for turning it into a cold room. A cold room = a lada.

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