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inverter central heating


maxsan
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I have just come across a type of central heating which seems to be powered by electricity and uses an external compressor to push air through to units in your living accomodation where the air passes through a heat exchanger of sorts to provide heat.  As the deal for installation seems to be pretty good I was wondering if anyone else had experience of this type of heating.   I have a sous sol and do not wish to have gethermic heating and am about to swaop for another oil-fired system. 
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Not quite sure what this is.

Obviously, the Heat Exchanger has to draw its primary heat from somewhere. Presumably in this case an oil fired source?

Hot Air CH was of course, widely used in the 60s/70s by new house builders, because it was a very cheap way to provide "Central Heating": but not really very effective.

Forced air heating, to be much good, does really need quite a bit of ducting: great consideration has to be given to the Thermo-Cycle effect: i.e. warm air rises (it's lighter) and then falls to the ground.

If you give this a bit of thought, for a minute and then think when you have used a step ladder to work above your head, you find the air at the ceiling is unbearable!

I have used forced draft warm air in a couple of commercial premises and have gone into the loft, mid-morning and almost suffocated![:(]

Thus hot air systems do tend to have quite uneven "Hot Spots" and conversely "Cold Spots", unless you have floor ducting and ceiling ducting which tends to be far more expensive than using water radiators as the heat carrying medium.

Additionally, forced air systems tend to shove dust around and are no good for people with any respiratory illness. Better (when correctly designed/fitted) on a new build rather than a retro-fit.

On a new build, some form of heatpumped geothermal is excellent: with underfloor heating. Chum of mine has used this on a barn conversion in Wales and is so far delighted: I await the figures for electricity consumption for the Winter with keen interest!

 

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Actually it eworks by extracting calories from the outside air and then sends them via a compressor, evaporator and condenser to units in your living space or to your existing system. the amount of electricity it uses is apparanetly quite low .  It comes under renewable energy and there is a credit d'impot for the equipment. A lot of new houses are having it installed.  it also has the benefit of providing cool air in the summer. EDF are offering low cost finance for this system. I am still learning more about it every day.
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Aha! So it is in fact a heatpump, then. I would be very interested to learn what the payback cycle is.

Presume in new builds, the insulation factors would be far higher than retro-fitted and walls can be a problem with older traditional French properties: certainly is with mine!

Interesting............................[geek]

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The high pressure salespeople say it would cost around 300 euros a year for a sous sol 180 sq. metres which is what ours is. EDF say it could be anything up to 600 euros a year depending on the level of insulation. As there are grants fopr everything at the moment to do with insulation, including electric roller blinds, It makes it all worth while for us. We pay around 900 euros at present for heating and hot water in the winter via an oil-fired boiler. With oil prices constantly rocketing and our boiler getting old the cost of replacement is noit an issue. The plus is that you get cool air in summer.
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I believe that these grants are only for those registered and paying tax in France?

Insulation is difficult (and very expensive!) on places like ours. Either exterior cladding, or interior, which takes away considerable room space, too. No Cavity walls, you see!

I do find this interesting: I researched slinkies and boreholes for geothermal, but this is apparently only really effective when you use underfloor and I do not wish to ruin the old tiles. Plus far more expense to replace all over the house!

Taking all into account, the front end capital costs made a very long payback cycle and by the time it actually paid back, it would need replacing! Great for the environment but not the pocket!

So, I am most interested to know more about this system, in terms of total projected costs, for example.

 

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I would also be interested. My place is in mountain foothills so I would like any pointers to where I might learn:

*whether the system fails to work if the outside temp falls below n degree c

*whether the outside air capturer/heat condensor has to be on sunny aspect wall.

*what the little devils look like (inside and out) .

 

Regards

 

John

 

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I saw a thread on just this somewhere, but can't find it now.

Basically, you are talking about air conditioning, which works both ways, either to take heat out of the house, or take heat out of the exterior. I think the running costs were in the region of - use 1kw of power and get something like 3kw of heat. There was a lower temp. limit, but this is compared to the temp of the refrigerant, which is already quite low. I also seem to remember that the outlay in terms of the equipment was not very high.

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http://www.ciat.com/index_gb.html

This is one site that has something about the system as does the EDF site. Basically EDF say that the installation costs around 60 to 90 euros a sq. metre of heated space to put in. That includes the equipment. The Cop (??) is about 3 to 1 i.e. for every 1 kw that you put in you get 3kw out although some claim 4 to 1 or higher.  Basically you have to search via google or whoever for geothermic air to air heating..  It is somewhat difficult to get informationm save that a lot of newbuilds are putting it in. Oh yes it only works to -15 degrees.

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Personally, I do believe that often people are blinded by technical data, in these matters.

Engineering is all governed by physics: physics is governed by Quantum Mechanics: no heat capture or conversion system is ever 100% efficient. Oh that it were![:(]

The basic rule (entropy) is that, effectively, there is nothing for nothing. If this were not true, then by now, perpetual motion machines would have been invented![;-)]

With all alternative "Green" or "Soft Technology", at the end of the day, my perspective is that it must be considered in fairly simple terms. What is the Payback Cycle?

In other words, at what point is the capital cost overcome by the energy cost saving?

Thus far, I have found no alternative system which demonstrates really effective cost savings.

It is wholly different, for example, with major installations for office blocks (e.g.). In Sydney, there are office blocks heated and cooled using heat pumps where the water in the harbour provides either heat input or cooling input. The cost of conventional heating/cooling is quite rapidly overcome, or defrayed, despite the capital costs.

I am following my chum's adventures with his borehole heatpump installation on a barn conversion in Wales. He uses floor heating (the most effective) but then this was a new build, basically, rather than a retro-fit. Thus I look forward to his eventual report on actual energy consumption.

 

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