Newhouse Farm

[Anonwelder]

Hi All.

Last spring, with growing energy prices I did the usual thing and went online to check the most competitive suppliers, but it turned out I was already with them! Uncannily, and on the very same day, I received a circular letter through the door asking if I was interested in having a solar thermal system installed.
I thought a look on the company’s website would be good, but they were asking for £3000 installed, so I went looking for a similar DIY system and found these were £2000! It would be a long time before such a system would pay back that sort of expenditure and help me do my bit for the planet.

Further digging revealed a lot of individuals actually made their own systems but with complicated controllers, separate tanks and a myriad of extra pipe work.
I found solartwins' design did away with all that. The best form of flattery being imitation, I decided to copy it. I wanted solar collectors to gather the sun’s energy, a pump to circulate the water and to be totally zero carbon emissions, a photovoltaic panel to power the pump. I checked with the local council that installing panels would not be contravening any planning regulations etc.

The Solar Thermal panels.

I made a 2400mm x 700mm box using exterior grade timber, lagged using standard loft insulation and on top of that, a sheet of 16 swg aluminium to which I secured 10mm microbore copper pipe wound in a serpentine formation. This I painted matt black using direct to metal matt black paint and finally secured twin-wall polycarbonate to the top. On a sunny, but cold, February day I began testing.

I fitted a fishpond pump to circulate and ran three tests. Air temperature was 4 degrees and water temperature was 6.5 degrees in all cases. Start and end temperatures of the water in the bucket were measured.

Test 1) A bucket of water stood for 30 minutes and measure start and end temperatures. Start Temp= 6.5 degrees, End Temp= 5.5 degrees, so 1 degree LOSS due to air temp being colder obviously.

Test 2) A bucket of water with the pump running inside bucket, but not circulating for 30 minutes and measure start and end temperatures. Start Temp= 6.5 degrees, End Temp= 6.3 degrees, so the pump was generating a little heat, as the LOSS was just 0.2 degrees.

Test 3) A bucket of water with the pump running and circulating through the panel for 30 minutes and measure start and end temperatures. Start Temp= 6.5 degrees, End Temp= 28.5 degrees! A 22 degree GAIN! Fantastic! Warm enough to wash the car with and with air temperature being so cold, it had steam drifting out of it!

After the test I had to drain the panel down, as it would freeze overnight. I disconnected the pump and let the remaining water, which had been in the panel for 30 minutes, run out. I measured this too and found that in a cold February day, the panel gave at 68 degrees centigrade. Amazing!

Installation.

I built a second panel, made some brackets and with some help secured both panels to the roof. I installed a photovoltaic panel on the roof too, to generate 15 watts of power to run the pump. I completed the pipe work to the hot water storage tank in the airing cupboard. Using very thick pipe insulation, everything was lagged to minimise heat loss. After checking all joints, I made the final connection to the pump and the system began to fill.

The system takes the cold water from the bottom of the tank, pumps it around the panels where it heats and returns the heated water to the top of the hot water tank. On 23rd April I had the perfect day to commission, a bright sunny day with air temperature of 16 degrees. Cold water heading for the panels was 15 degrees and after its journey around both panels initially entered the tank at scary 85 degrees C! This was because the pipe work within the panels had heated the standing water inside to a very high temperature, but once this was pumped to the tank, I was getting a consistent 50 degree feed to the tank. I fitted a resistor in parallel across the pump to slow it down to a level where water entering the tank is about 60 degrees at full pelt.

Our domestic washing machine and dishwasher are ‘A’ rated, meaning they consume the least amount of energy to do a job. Surprisingly, manufacturers can trick the consumer by making equipment that just takes a cold feed so, no energy is lost from its journey from a storage tank or a boiler first. Our appliances are now fed from the hot water cylinder using the free solar heated variety, so electric saved by not using the appliances heater too. The thing I like best is all this is now free energy. It takes no external power to run the pump and the heat gained even on overcast days makes a difference. It is self regulating too, so if little sun, solar electric panel generates little energy, the pump runs slower allowing the water to pick up as much energy as possible and any heat gain is maximised. Excluding the Photovoltaic panel, I spent less than a tenth of what a commercial unit costs and it has paid for itself by November 2006! In fact, during seven weeks in summer, we never used a single whiff of gas. Well, apart from the house boiler's pilot light, but I put paid to that by isolating the supply at the meter.

Alas, while away at work one night, I could not return home and drain the system down as I usually did overnight and the frost did it's worst, splitting the copper microbore in the panels. Undeterred, and the panels having paid for themselves, I decided to further improve the system by;

A) Making one large panel instead of having to link the two
B) Make the frame, not out of timber, but aluminium profile
C) Use frost resistant black silicone tubing within the panels.
D) Use black stove paint as the other was cracking

May 2007, all modications made and the system is giving me a full tank (117 litres) at 61.8 degs on returning home on a fairly sunny day after a start temperature of 28 degs.

Our monthly energy payments were £67 in 2006 and is amended by energy company every year in spring. This year, we got the new bill in and is now £34.50 per month!

I hope some find this work interesting....

[mallettron]

I like this !!!!

You said you used a fishpond pump, can you give more details about this. How did it stand up the the 'hot'water passing through it?

Do you have any photos or diagrams or even links where you can get the microbore?

Some people on here have done their own 'radiators', do you think the copper pipe method would work in this instance

Ronnie

[Ed]

Sounds great. Are you heating the water indirectly or directly? Also, how did you attach the copper tube to your aluminium plate?

A few of us are making panels at the moment, and it's been suggested that the serpentine layout might not be as good as one with a top and bottom rail in a kind of a ladder style might be better. Yours sounds like it's working well enough, though.

How long do you reckon that polycarb sheeting will last before it turns yellow/opaque? Until it does, it seems like a good choice, because it's a lot like double glazing, especially if you seal the ends of the cut edges.

[wooden]

I Read that glass ups the efficiency by allowing the solar heat through, but reflecting the radiated heat from the metal back, have you thought of using this? Also how did you join the copper pipe to the aluminium sheet?

[RickRandom]

Excellent!

I thought the SolarTwin was a good but expensive idea, but hadn't got round to doing anything myself.

Like others, I'd be very interested in the details, especially the flexible tubing, the pump, the solar panels, and the overall layout.

[Anonwelder]

[Anonwelder]

[Anonwelder]

[Anonwelder]

[Ed]

[Anonwelder]

[cadfael]

[quote="Anonwelder"]

[Anonwelder]

[cadfael]

Hmmm..not too sure about that, I imagine most of it 'll just dry up and blow away...a long handled brush should help tho
Mike.
_________________
Minds are like parachutes, they only work when open.
I don't bodge, I improvise and innovate.
Dogs, logs and chainsaws.

[mallettron]

[quote]

If you visit the solar twin website, within this pdf document

http://www.solartwin.com/PDF/Solartwin_Installation_Method_Statement.pdf

is a photo of the same type of pump I now use.

[quote]

I think people are wondering where you got your pump from, I assume it has to be one that can cope with temperature extremes and work from a 12v panel at low amps

Ronnie