19 April, 2017

Maintenance of the DIY solar thermal collector

Getter and repaired
Hello dear readers, I do not know in your area, but here in northern Spain we have had a February 2017 very very windy, with gusts over 100 km / h  (some kind of cyclogenesis ), so strong that it removed literally one of the panels of cellular polycarbonate, and after the noise we heard, we have found, pushed by the wind literally against a tree!


So light it is (1 cm wide and 1 mm wall), who knows where we have found it if the tree was not in the middle of his path. Even it had a brown mark, a sign that before it arrived there, it hit the tiles of the house, partially breaking it.


But this would not have happened if the panels had been properly anchored, and better protected from the wind. On the one hand, the wood of extreme suffering the ravages of rain, rotting it, it should put more sheltered. And secondly, the screws that secured panels only the timber were fastened, when should having crossed and fastened to the rigid metal under it much safer.

So we had to repair the collector, because it works very well saving on the energy bill.
Now with the Arduino screen , it calculates approximately the KW of energy saved, and within three months of operation, already has 15,000 kW (of which 60% would be from biomass). So in a year I estimate that at least saved 24,000 kW of gas, at the actual price, we have saved nearly 1,000 € per year using the energy from the sun, and in 7 years since the system is working... has already paid itself various times. I am never tired of insisting that we must use more energy from the sun to heat the water at least, we are wasting energy not doing so, which is fossil (gas) and produces CO2.
Let's do it
The first to do was unscrewed the remaining bolts with a socket wrench and screwdriver battery, release the tubes and remove them where they do not clog:


You can see the condition of the wood, it was worth watching:



We take the reform to improve the insulation of the bottom. I placed extruded polystyrene strips, glued together with some silicon in the contact areas with the metal floor:


I helped to cut a ruler and a knife or cutter, with cuts sloped according to the shape of the floor:


To let dry the silicon, I placed weights, firebricks, 1 kg. each, to ensure they stay in place. The length would be approximately the same as would clog the base of the sensor, shorter than before so it avoids rain:


Then I placed thin wooden plates, in this case box lids, with a thickness of 4 mm. in the center and 2 cm. in the frame. The process is very  similar to the already made above in the previous version  of the collector; silicone covering the joints to prevent air leaks:


Let screwing with screws thread-plate  10 mm. head and 9 cm long timber to the peaks of the metal roof first making a through hole with a drill HSS-Co thinner than the bolts to avoid cracking the timber and expedite the work.


Before painting of black, I applied a protective paint for wood (pine this is sleazy) to protect longer, in areas where it will be exposed to climate:


Once all screwed, I painted with matt black paint the entire base:


Subsequently placed under where the transparent cover, slats of the same height would anchor tubes of moisture resistant wood (used to baseboards) and screwed with large screws to the wood, and then painted as the rest:


At this point I had another improvement. To better protect from the wind and rain, the lower end is left without raising up, so that the polycarbonate curved left, closing better,  and also anchor the edge directly to the metal:


We put back the circuit stainless tube. with aluminum plates, and we connect again:



I will paint again, but not before some wood screws hold the base so that it does not move:




This time the connections and temperatura sensor are on the outside, so it will be easier to maintain:


With the paint dry, the next day we put back the polycarbonate sheets in place, they still retain 90% of its transparency. To avoid losses, before I put them, a aplied a bead of silicone all around (in the picture had not yet applied):


A powerful screwdriver and the same procedure, but this time looking for the ridge of metal floor, to make it very safe and much more durable. It is advisable to leave 30 cms between screw and screw for possible expansion of the summer heat.
It is essential to place the screws with rubber washer to catch more surface and stay safer, as the polycarbonate hardens and weakens the sun.
We put the panels 10 cm one over other, wherein neutral translucent silicone applied, leaving spaces of 20 cms screwless margin for expansion zone.


And this is the aspect that taked:


Finally screwing, each 40 cm, also the corner to the plate:


A greater drop that will help drain the end shown , in turn preventing that wind gusts have a greater hole through which pressure meter:


And this is all, the thermal collector is repaired, hopefully for 20 years (we'll just change it when whiten too). 
In the next post we will see how best I have isolated 20 m of tubing that cames to the water accumulator. Thanks for reading me!
Update 04/06/17:  You can see how the first heats, the top folds up, as it did before; It is important to allow between tie and tie as indicated, with the screw holes with 3 mm. slack to avoid cracking / breaking:

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