There are many examples of how to make a solar collector. The most important thing is to understand its working principle, and it is very simple. The sun actively heats metals painted black and in order to make a collector, you only need to think of how to remove this temperature from a heated absorber.
Based on this knowledge, you can make a solar collector from almost anything. One author proposed an option on how to make such a device out of an unnecessary door. Of course, outwardly such homemade It will not look very good, but with it you can easily heat a greenhouse or a chicken coop. If the device should look beautiful, then for its assembly you can use plywood and boards.
Materials and tools for homemade:
- old door;
- screws and nails;
- hammer;
- screwdriver;
- mounting foam (or other sealants);
- insulation (mineral wool 5 cm thick);
- corrugated cardboard;
- absorber (aluminum sheet);
- matte black paint (heat resistant);
- wooden boards;
- ventilation tube;
- glass;
- minimal set of tools.
Manufacturing process:
Step one. Modifying the door
First you need to prepare the door, for this you need to remove all the handles along with the locks from it. Then, screws or nails are taken and with the help of them the door is tightly fixed in the box. After that, all the cracks must be carefully caulked with mineral wool and sealed with silicone, polyurethane foam or other sealants.
Step Two We warm the collector
At the next stage, the collector housing must be carefully insulated from the inside, this is necessary in order to reduce heat loss. Mineral wool with a thickness of about 5 cm is best suited for these purposes. It is not recommended to use foam for these purposes, since it deforms when heated. In addition, when exposed to high temperatures, the foam evaporates, releasing toxic gases that are harmful to health.
After laying the insulation, a sheet of corrugated cardboard lies on top of it, this is especially important in the case of using foam, it will limit direct contact with the absorber.
Step Three Absorber Installation
To make an absorber, you need a sheet of metal with good thermal conductivity, aluminum or copper is excellent for these purposes. In extreme cases, you can use steel sheet. In any case, the absorber must be painted with a black matte paint (which is painted on automobile silencers) before being installed in the housing. After the absorber is made, it can be laid on the door over corrugated cardboard.
At the same stage, to increase the efficiency inside the collector, you can make a maze of boards. With this refinement, the air will warm up more efficiently, as it will linger longer in the manifold. When creating such partitions, it is important that they closely fit the glass and the absorber.
Step Four Final completion of the collector
In order for the collector to be connected, one hole with a diameter of 100-150 mm must be made in its upper and lower parts. In them you need to insert bushings that can be cut from thin tin. Then, ventilation pipes will be inserted into these bushings. Now you just need to cover the door with glass and carefully cover all the cracks with silicone, otherwise the hot air will come out and the performance will decrease. As a glass for the collector, you can use an unnecessary glass door.
Next, you need to take the corrugated pipes and connect them to the collector, then these pipes can be brought into a heated room. It is best to use two pipes, so that the collector sucks in cold air not from the street, but from the room itself, so heating will be more efficient. Pipes should be made as short as possible and carefully insulated, otherwise heat loss will be inevitable. It is best to use not aluminum pipes, but plastic ones, since they do not heat up well and as a result the heat loss will not be so large.
As for the installation angle, in autumn and spring the sun is quite low above the ground, so the collector is placed perpendicularly. In this position, he does not need a fan, since the air will naturally circulate in the manifold. Warm air will rise and cold air will enter the collector through the lower pipe.
Tests showed that at an outdoor temperature of 6 degrees, the maximum temperature of the air leaving the collector was 75 degrees. But since the air will circulate slowly, it will not work out quickly to warm up the room even at this temperature.
You can speed up the process by installing a fan, but in this case the air will not have time to warm up, and its maximum temperature will be about 50 degrees. Accordingly, the stronger the fan will blow, the colder the air will be at the outlet.