Commissioning a solar thermal system

[mangocrazy]

Back in June 2012 I bought a solar thermal bundle from a seller in France trading under the name of Fundiscount; I mean, how could I resist? For my €1845 I got a 300 litre stainless DHW cylinder, 30 evacuated solar thermal tubes and mounting hardware, and a control station and thermal probes. The cylinder got pressed into service first (using the electrical heating element to provide hot water) and a year or so later a builder friend and I fitted the mounting brackets and solar tubes on the covered portion of the roof terrace, which conveniently points South-Southwest.

Then I needed to connect the solar array to the DHW cylinder, which was in the adjacent attic, about 10 metres away. To my lasting shame, this has taken me approximately eight years to achieve...

So today I've been connecting my compressor to the pipework, pumping it full of air and checking for leaks. While air makes much less of a mess compared to water in pipework when it leaks, it's significantly harder to pinpoint any leaks, especially when most of the pipework has been insulated. Thankfully all the leaks I've discovered (3 in all) were traced to drain valves that hadn't been fully tightened up. So I've just pumped the system full of air again, and left the gauge reading just under 1.8 bar.

I'm really hoping it hasn't dropped when I go back to check...

[Count Steer]

Then I needed to connect the solar array to the DHW cylinder, which was in the adjacent attic, about 10 metres away. To my lasting shame, this has taken me approximately eight years to achieve...

Shame? Not at all. I'm a great believer in thinking a job through properly.

[DefTrap]

Shame? Not at all. I'm a great believer in thinking a job through properly.

I am mainly found standing staring at the job in hand, scratching my chin, deep in thought.
My missus asked me for a progress report on a decorating job I've "started" and I was happy to report that I'd got as far as drawing a line on the wall, numerous lines in fact!

[mangocrazy]

Yes, a lot of Deep Thought was involved. Other stuff got in the way as well; stuff like completely gutting and replacing the living room and kitchen. Y'know - minor stuff when viewed from the standpoint of a spouse...

And then there's the inevitable scope creep. Lots of drain points needed to be fitted retrospectively, a pressure gauge, filling points, a pressure vessel and most recently a 240v supply to the board for the control panel (that I'd completely forgotten about).

I think eight years is about par for the course...

[mangocrazy]

Well it's been an hour and a half and the gauge is still reading just under 1.8 bar, so I'm calling that a win. Once the sun has fallen below the yard-arm I'll fill it up with water and bleed it (I even remembered to fit bleed valves at the highest point!) And then wire the pump in and we should be good to go.

The real test will be tomorrow morning of course...

[Yorick]

Shame? Not at all. I'm a great believer in thinking a job through properly.

I am mainly found standing staring at the job in hand, scratching my chin, deep in thought.
My missus asked me for a progress report on a decorating job I've "started" and I was happy to report that I'd got as far as drawing a line on the wall, numerous lines in fact!

[mangocrazy]

Well slap my thighs and call me Barbara, but it appears I have a working solar thermal system. In the final event it was all quite anti-climactic. I filled the system with softened water from the filling loop, bled the flow and return legs , plugged in the pump and by the time I'd got back to the cylinder, the flow pipe was warm. Clearly the pump was working and pumping water through the collector.

The pump is a DC 12-24v job specifically made for solar applications and it's driven by a solar panel with matching output voltage situated by the side of the solar thermal array. Sun comes up, tubes start producing heat, solar panel wakes the pump up and it pumps the heated water around. At the end of the day the sun goes down, tubes stop producing heat, solar panel output drops, pump slows down and stops and water is no longer pumped. Beautifully simple and (by the look of it) effective.

I'll find out how effective and how muchf heat the tubes can produce tomorrow, but for now I'm a happy little bunny.

These are the bits on the rooftop (solar panel is small unit to the left).

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And this is the bit where the spaghetti unravels. Pressure gauge for the solar thermal is not the big blue and red one, but the one at the top.

DSCF3872.JPG (571.98 KiB) Viewed 351 times

And this is a photo of a cat.

DSCF3875.JPG (682.8 KiB) Viewed 351 times

[Count Steer]

The benefits of a not rushed job.

Nice one.

[David]

Important to apply a photo of the cat......

[KungFooBob]

Important to apply a photo of the cat......

It is a beautiful cat... and the only reason anyone ever opens any of Mango's threads

[mangocrazy]

Important to apply a photo of the cat......

It is a beautiful cat... and the only reason anyone ever opens any of Mango's threads

Harsh but probably fair...

I've told him that t'Internets appreciate him...

[mangocrazy]

It's been all day sunny here today, and the hot water cylinder sensor registered a temp of 56 deg C, which isn't half bad for early October. I'll take that, very happily,

[mangocrazy]

So I'm back in the land of baguettes, fine wine and stinky cheese, and one of my maintenance tasks today was to give the solar thermal tubes a good wash with a raggedy head mop. The amount of dirt that came off them was impressive. Yesterday I filled up the circuit with water (I leave the system empty and dry while I'm away) and it registered a high of 50 deg C before the sun went down.

Today (albeit a warmer day) it registered a mighty 63 deg C at around 17:00 - I'm well happy with that. I'm sure that not all of the increase is down to my mopping efforts, but I'm also sure it's played a part. And it's still only mid April...