Solar for background heating

[Steve Last]

Does anyone have any knowledge of whether there is a feasible way of using solar panels to keep the background temperature of an empty house raised a few degrees? We have a village house in 84 Vaucluse which gets very cold in winter when unoccupied, but there is plenty of winter sunshine. We also haved a roof section which is invisible from the ground and could take up to 40 sq metres of panels. It would be ideal to be able to use some of the solar energy to keep the basic house from getting so cold that it takes a week to get it back up to tolerable temperature. I know solar can't really be used for central heating but this would be to supplement our current woodstove and electric panels. We have considered putting in a full oil CH system but it seems a bit daft when the cost of oil is going through the roof so to speak, not to mention the environmemtal issues.  Unfortunately we have no land to even consider a geothermal system which a friend has just installed in a new house in Scotland and seems to be very effective.

Steve 

[Owens88]

This sounds attractive then I thought about it again. Now I am thinking as I type so bear with me.

You would not be doing any 'concentration' effect , merely re-locating energy which is already falling on your roof to the interior of your house. I am not sure whether that makes it easier or valueless.

In the meantime there have been some useful postings about systems which capture heat from the air (I presume wall mounted like aircon). Might that be useful ?

Good luck

John

 

 

[Deimos]

One thought – not related to the technical but rather the

commercial aspects.  From my experience

of renewable energy systems, the installation professionals have to guarantee

that the system will operate properly for 10 years.  Thus, I expect they would require a very precise written

requirement from you that the system is not required to “heat the house” –

basically something that will “let them off the hook” when you sell the house

and the next owner finds out that the solar heating does not heat the house

effectively (and thus the ensuing arguments with the installer) !!

Of course this does not affect things if you are looking to

install yourself or to get an installer to work e.g. on “time and materials”.

Also, if the system is not designed to “heat the house” then

you may not be eligible for the tax credit (if you are a French “tax payer”).

I’m sure these are not “stopping points” but may need to be

borne in mind.  When I had the people

round to look and renewable energy heating they were very cautious about

finding a system that would work and were finding loads of “issues” (e.g. high

water table, prone to mist in winter, etc.) and thus ended up after a few hours

being “totally unsure”.

Ian

[adrianpmills]

I think the installations costs would be quite high.  Would an electric radiator or two left on the frost free setting so the job?  Alternatively, an aerothermie unit would have the benefit of also providing summer air-conditioning, so better justifying the installation cost?. 

[Alex H]

To give you some idea of the cost, I have had a quote for solar panels for water heating -

2 x 2.2sq metre  = €4,650 installed

[Steve Last]

Thanks for the comments, I see there are now a couple of other threads on this subject so will think on!

Steve

[condorman]

Hi Steve,  reckon you could doo this, 40sqm of pannels would be expensive, would you reely need something that big???   you could connect them to under floor heating pipes, and have it all controled by a thermostat...     pannels heat up.. stat switches on solar powered pump..  warmed water pumped round floor all day, sun goes pump stops or stat  switches off, floor pad takes a long time to cool down.  what does theee think?

 You  can make your own quality pannels for about 150 € each, for 2.5 sq meters....  ch ch chow, best of luck with what yer doing.. mark

 

[Owens88]

I might be missing something so please be kind.

 

The sunlight falling on your roof will transfer energy to the building n'est-ce pas ? So unless you are heavily insulated up-top then a lot of what lands there will filter below  anyway?

So any mechanism, like Condorman's which I quite like, will only be re-locating the energy and by-passing your roof insulation?

 

[Brilec]

Good thermal insulation would be a prerequisite anyway, otherwise what filters in will also filter out just as quickly.

The idea is to capture what heat you can, put it where you want it to be, and keep it there.