Getting my boiler replaced which raised the likelihood of having to replace my existing vented tank in the airing cupboard as it is about 25 years old. Always wanted to get a solar thermal system installed which would need a new tank anyway, so it makes sense to get it done all at once. Problem is, I can't decide what to go for. Roof space (height) is limited which means I can't fit a huge new tank up there. Unvented appeals to my engineering nature along with being able to do away with the shower pump. Thermal store sounds interesting as the solar will be contributing to the heating as well as hot water. It's also intrinsically safe like the traditional vented tank that I already have.
Any experiences?
Check out www.navitron.org.uk for cheap solar heating systems, they have an active forum too.
I have converted my heating over a number of years. Firstly to an unvented combi system to do away with the hot water and expansion tanks. Then when the combi died I decided to fit a Range Tribune twin coil tank with the new boiler. Still haven't gotten around to fitting the solar panels to it yet however! More time in the day required. Looking at days like today really makes me think I should get it in gear to take advantage of the sun's lovely, freely available heating.
There's a few threads to have a look at in here if you go bak over the last 6 months or so.
One thing Id say based on my own experience, is that if you have the space, then having a separate solar tank that feeds into a second thermal store will improve the low-temp efficiency of any solar system IMO. I didnt, and while my solar is extremely productive, I reckon it would be moreso if I had another tank through which it went first. Whether the expense of a second tank would make sense or not though, Im not sure.
This graph shows my biomass energy consumption (thick blue line) and since installing solar at the beginning of July, the thin blue line represents an approximation of the solar energy that my panels have collected. This is based on a local weather station insolation recordings and the surface area of my collectors. Its not adjusted for transmission losses or other losses in efficiency, but then I dont have the quipment to do that.
What is interesting is that my biomass energy consumption of about 25kWh a day for hot water (two kids baths and on average 1.5 showers a day, as well as dishwasher, but not washing machine) has easily been replaced by the solar panels which appear to be collecting on average something like 30kWh a day and some days much more.
I dont have the insolation data yet for september, but have turned the boiler on. The last bit of thick blue line isnt accurate as we have been consuming something like 15-20kWh of biomass fuel instead + whatever solar we can. But once the biomass raises the tank temp too much the solar collection cant work very well (temp too high) as alluded to above.
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It will all depend on the cost. I installed a 20 tube array on the roof last Autumn and ran it through a 160 litre cylinder in the attic that I got unused from Ebay for £100. This is plumbed (open vented) in tandem with the existing airing-cupboard cylinder so we are simply pre-heating the water coming into the house. You can see a slideshow of my project here:
[url= http://s36.photobucket.com/albums/e49/C957/Solar%20project%202011/?albumview=slideshow ]Cheap solar panel project[/url]
I have modified it since then with an additional "heat dump" loop down to the house cylinder, controlled by a 12v motorised valve that will open when the attic cylinder reaches 60c. The house cylinder has two coils, one for the boiler and one for the solar.
Total cost of all this was around £700.
Interesting post.
Been looking into this for a while and spoken to lots of people.
One thing I have got from each and every one is. If your house is already well insulated and heat loss is minimal going green is a money saver in the long run.
If you have poor insulation spend your money on that first.
Obviously if you need a new system or hardware anyway it makes more sense, but with technoligy moving so fast it may be worth just replacing like-for-like and spending the saved money on better insulation.
In the industry they call it 'Pay Back' better insulation wins every time.
Still on 100% solar hot water down here, there's rain frecasr for Tuesday though.
Go on , double insulate all those pipes from the solar panels to the store, Stoner.
😛
The solar is still doing most of the work for us, and TBH if I had kept the boiler off, I reckon there would have only been five days this month that we didnt have hot enough water. I need to put an additional controller on the boiler I think.