Solar air collector with simple DIY automation

Factory-made water solar collectors for heating water are not cheap. Although, their efficiency is high and on sunny days they save energy for you.

For the climate of central Russia in winter, little has been studied in the work, there are almost no reviews. But air solar collectors are easy to manufacture and there are more examples of homemade products. I propose to look at an example of manufacturing with work from simple automation.

The principle of operation of an air solar collector (who is not familiar): in a sealed case, sunlight heats up aluminum tubes - inside them the air is also heated. Air circulates through the room by convection or fan.

First, about the manufacture. It is necessary to purchase aluminum cans of 0.5 liters from the receivers of recyclable materials. Or save (who drinks beer and soda). Rinse off the rest of the food to get rid of the smell. Next, use metal scissors to cut the bottom and the lid on both sides. Or drill with a metal crown with a diameter of 51 mm.

Next, the cans need to be glued with a sealant. Better to use silicone, because it can withstand higher temperatures than acrylic.

For gluing, you need a stand (board). When gluing, the cans must be fixed in the gutter or simply wrapped with tape.

Next, we make a body from laminated plywood and an upper and lower retainer of tubes glued from cans. The body should have uniform compartments from below and from above for all pipes, where air will come in and out. It is better not to use OSB - a lot of formaldehyde comes out of its resins when heated. In addition, just a board or OSB from the moisture of the rains will dry out and cracks form.

We insulate the body inside with foil insulation based on basalt wool, paint it with black paint, mount the tubes and paint them black for maximum absorption of sunlight.

We mount outlets and inlets for air (available in Leroy), a cooler from a computer, glue transparent polycarbonate or plexiglass:

A short video of making a similar solar air collector:

You will need to consider fixing to the facade or roof. Better on the facade, because snow will accumulate on the roof and interfere with the operation of the collector.

Such a solar collector in clear sunny weather can produce 1-2 kW of thermal energy per day, heating the air to 70-80 gr. In winter, of course, it gives out much less heat. But in the off-season it will be a good heating device for a veranda, a terrace, a covered gazebo. In climates with warm winters, it can also be used to heat rooms on sunny days during the day.

But how do you make it work when needed? The collector is not needed in summer. The air should not circulate itself, but with a fan (heat exchange will be better). Do not manually turn it on and off. For this we do simple automation.

We buy solar panels on aliexpress, for example, this option:

To power the computer fan, which will need to be installed in the duct, you will need two such panels connected in parallel (for more current).

There is enough sun - it means that the air heats up and the batteries provide electricity, the collector works for circulation.

Next, you need to think about what can be done if we do not need heating of the room, for example, in the summer or at noon in the off-season. To do this, you need a thermal relay (temperature controller):

We buy in the same place on aliexpress an inexpensive compact device that will control switching on / off the collector fan according to the following logic: there is lighting from the sun - there is power from solar panels. If the temperature on the veranda is lower than the one set by the controller, the fan turns on to supply air. To power the thermal relay, you will need two more solar panels - in total, you will need to purchase 4 pieces. Costs with thermal relay: 1334 RUB to the electronic part.

This idea with automation was suggested by the reader in the article Solar energy products. Here is its collector:

He assembled a small solar air collector with solar-powered automation. Heats the veranda with warm air.

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Photo taken from open sources, from Yandex. Pictures

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