Friday, April 17, 2009

Solar water heating

We have lived here for four and a half years now. Since we arrived I have wanted to do my bit for the environment and install a solar water heating system.
In France the hot water cylinder is normally electrically heated and at mains pressure. These heaters are a huge drain on electricity and may use 3000 watts when heating. Our 200 liter one had no thermostat to alter the water temperature and was, I suspect quite an old one.
Last week the plumber arrived to start the installation of the new system. I had offered to labour for him when he came for the quote. The first job was to remove a couple of roof tiles and fit the evacuated tube solar panel to the roof. This took about half a day. The protection film was left on the panel to stop the tubes heating with no water in them. The next step was to fit the 300 liter solar cylinder in the cellar. This was a very well made part of the system and was also capable of being connected to a central heating system, if we had central heating. What seemed like masses of plumbing pipes were then fitted to the cylinder and the electric backup element was also fitted.
The solar controller was the bit that I fitted. It was connected to temperature sensors in the panels, the pump and the water cylinder, the pump supply was then also connected to the controller.
After 3 days work the system is working and we have not yet had a sunny day without clouds, but the hot water is hot and plentiful. The electric heating element has been switched off since the system was finished. The added bonus is that the hot water pressure seems to be much higher than it was before, I can only assume that the old heater was blocked with lime-scale.
It is now such fun to look at the controller and see that the temperature in the panels is at 80C during the day and know that the water is being heated without adding to the overall CO2 levels that are polluting our world.
If anyone in the Dordogne area wants a quote for a system then send me an email and I will pass it on to a good local installer.


At 12:00 pm, Blogger aussibattler said...

Welcome back! thought you had gone AWOL after 3 months with nothing to report!!!!
What havn't you been doing all this time? Rgs.

At 8:40 pm, Blogger Kevin said...

When we built our pool two years ago, I put in solar and propane heating. We don't use the propane at all until October, and the water runs at about 75-80 F from May through September.

The solar works by pumping the water through a grid of thin black rubber tubes on our roof.

The pool is 17,000 gallons (US) and the additional electricity charge from the uplift pump is negligible. :)

Mind you, living in Arizona probably helps just a tad with the availability of sunshine...

Kevin K

At 9:12 pm, Blogger madman said...

Has been in about 3 weeks now. I switched the 3 Kw electric heater off on day one and have had 300 liters of hot water at 80C since.
There is a valve which mixes cold into the hot water for the taps and keeps it at 60C - so in effect we have about 450 liters at 60C.
We have found that even on overcast days without sun the collectors get up to 85C so I think that we will still be using solar on sunny winter days.
Nina, I am too busy flying to spend much time on the blog at the moment, and won't be going to Thailand so will probably not manage the visit to Australia either.
Kevin, Hows the flying going? If you ever visit these parts then let me know.

At 7:55 am, Blogger david lloyd-jones said...

Dave here, tech from - will halp you optimise solar/ wood/ lpg - any and all het input/outputs. Design/support/supply for DIY


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