Solar panels for heating water?

Question

Anyone know of a good or bad solar panel for heating water?

Answer 1

Depends on where you live. Here the cheapest also happens to be the best. Made in China, stainless steel pressure tank, coated welded copper receivers, treated glass panels. About US$1000 for a 2 panel 300L kit complete with pressure/temp relief valve and electric backup heating. Australian models invariably come with a glass lined steel tank which rusts out after 10-15 years. The panels are no more efficient but the whole set costs around 30-50% more. (depending on brand). For some unknown reason, in Australia  installation of solar domestic hot water systems cost around US$6000 -10,000. I Do not understand why that is so at all! Here I can buy the Australian product (If I wanted to) and install it for well under US$2000! And that is after paying extra for the freight to get it here, the import taxes, the duty and the rip off mark ups at the local suppliers!

Bottom line, it depends more on where you live than on the actual cost of the units.

Things to look out for

Try to buy a mains pressure tested tank. (Must have both pressure and heat safety relief valves)

Try to get a stainless steel tank, less hassles less maintenance and will last longer.

Make sure you have enough panels to gather the heat you need even in winter. (Depends on your hours of sunshine and latitude).

Make sure the panels have good backing insulation and have treated glass fronts (reflects less light, and retains more heat). Make sure the absorbers are properly coated, (the right coating can more than double efficiency)

Ensure that the crew installing the set up know what they are doing, This means placing it in the most suitable location and angle to maximize sunlight collected. Make sure all the hot water pipes are properly insulated.

In really poor climatic conditions you may have to resort to the vacuum tube models, these are more expensive and need more experience to install properly.

Here any fool is allowed to install them and its not an issue unless they are really stupid, but then I live in the tropics.

Answer 2

You can go on courses to make your own, The CAT Centre for Alternative Technology has loads of information.

Ive seen one made out of old radiators painted black, but its probably too basic for heating all your household water, depends where you want to use it and the type of home you have.

CAT is in Machynlleth, wales, uk.

Answer 3

Just a point of clarification to above posting (Walaka's)...I've  installed a new split solar HWS 12 months ago , just up the road from Sydney - strong market brand , 2 panels, 400l tank, cost just under $3000(AUS) fully installed. There were a number of other products/suppliers on the market at comparable prices.

With growing market acceptance (and regulations) solar HWS is a great option and we've only had very few days (<20) where we've had to user the booster.

Good luck...

Answer 4

I quite like these ones http://www.scan.co.uk/Products/ProductIn...

Answer 5

If you are in the UK it is not really worth using solar panels for water heating as the payback period is over 20 years.We simply do not have enough reliable strong sunlight.  It may be worthwhile using a home made 'hippy' type system to heat your greenhouse or swimming pool if you have one.