Thursday, September 6, 2007

An example of a Beasley Centurion 315 (From Reid Technology) Installed May 2006

"A" writes:
I photographed this on 01/04/2006 in mid morning as I was hauling the first panel up to the roof. It was new out of its cardboard box. The shadow on it is from the lines and pegs on the clothes dryer behind the camera. Note the orange cord. It was a loop across the protruding pipe ends at the top end. The loop provided an attachment for the hauling line which passed through a pulley which itself was slung on a cord looped around an access hatch on the roof. I was concerned that by applying strain to the pipe end I could have damaged the internal structure; it was your web site information that relieved me of this doubt. You can just see the pipes inside.

This is how it looked yesterday afternoon 25/08/2007. Comparing the two pics, the same digital camera and settings were used, there is a difference in colour. The earlier one was strong deep blue, this is middling strong brown. The angle to the horizontal is nearly the same and the time is roughly four hours later. The glass looks less opaque. The sun has traveled further west. I couldn’t see the ribs in the panel in 2006 as clearly as I can now. Allowing for small differences it looks as though there has been a change in the internal conditions in the panel.

Note from Gary: the left hand panel may be more affected because the frost protection function may be reducing the amount of condensation in the right panel more than the other.

Is that down to damp affecting the flexible mask overlying the pipes? I say flexible because after contacting the supplier he said that there are four holes on the underside, so I explored with a piece of stiff wire and poked it up and felt and saw the overlay material deflected up toward the glass. I did that to prove that there was a hole and that there was nothing blocking it. Before I drilled the half inch hole in the lower edge and corner to drain contained water, I went through a week or more of doubt. Would I penetrate the pipe work? Would I damage the glass?

It took sheer determination to first drill a 1/16 hole as a leader followed by the half inch bit. Then I realised that the 20mm dia pipe inside allowed a fair bit of space around it above and below, probably 25mm top and bottom. Then I drilled a half inch hole top side just under the glass. That way I realised that I could suck saturated air out and replace it with dry air through the top hole.


Anonymous said...

It appears there is insufficient ventillation of the panel case. my own home built panels have a 1/2 inch vent hole drilled at the lowest bottom corner of each panel. They do not suffer from the excessive condensation shown by your photo's.

If condensation drips onto the blue selective coating which I believe is porous then the underlying copper fins will corrode destroying the coating.


Anonymous said...

Fantastic site and content. Saw a reference to it in Consumer magazine of June 2007. Thank you so much for compiling this information and making it available.

Anonymous said...

Solar Water Heating is most simple and down to earth technology capable of converting upto 60% solar energy (unlike photovoltaic). Corrosion of collector does not significantly affect the performance but definitely affects lifecyclecost. collectors made of blackchrome coated coppertubes and copper sheet are working flawlessly for more than 20 years without much maintenance. Performance of solar systems depend also on solar incidence,windvelocity ,ambient temperature,humidity,shadowing, layout of pipelines insulation of pipelines, dustcover, algie growth on glass,mixing of coldwater in mixing valves loss of storage due to leakage in drain systems etc

Gary Moller said...

Anonymous: Thanks for your comments.
Granted there are many factors other than corrosion. Many of these are detailed in the BRANZ reports found on this site which show about 80% of the installations studied had significant, multiple installation faults, including no building consent.

If you take time to peruse this site, you will see many examples of corrosion. After looking at these examples, one would be inclined to dispute your statement that "corrosion of collector does not significantly affect the performance...".

Anonymous said...

I agree.but not to the extent of discediting the technology. For example, under test conditions a 20 years old collector with peeled off blackcoating ,or grey powder or green coppersulphate coating (without leaks of course ) compared to a brand new collector may just be 3 to 5% less efficient. whereas even a brand new collector with any or all factors mentioned in my last post can reduce the efficiency by upto 90%. In fact considering the hazards of environmental pollution just flat black paint may be almost as efficient as chrome black coating evn at the cost of 2to 5% reduced efficieny. This is not to justify poor quality of coating which definitly lasts for twenty years without loss of more than 3to 5% efficiency.

Gary Moller said...

I am sorry but must disagree; even small amounts of corrosion/fading/bleaching can have drastic effects, especially affecting winter time performance. This is detailed with plenty of examples on other postings on this website. Incidentally, I am not setting out to knock the technology and will have a new system on our house in the next month

Anonymous said...

Thanks and good luck.Newzealand needs solar more than any other country.I think it is one of the few patches of Heaven on Earth

Gary Moller said...

Yes, and let's see every building with a sunny outlook fitted with a quality system that produces much more energy than what it took to manufacture it!

polysun said...

in solar systems solar energy is harnessed through solar panels which convert the solar heat in to the usable form of electricity and solar collectors are used to harness the sun energy to heat water for swimming pools, hot tubs and water heaters.

Edward said...

Solar panels are a very effective means of consuming light energy and producing electric energy.

solar energy
solar power
solar hot water
solar panels