Types of solar collectors

There are various types of solar collectors, but they are all designed to collect the energy of the heat of the sun’s rays, which comes along with the visible and adjacent infrared spectrum zones. They carry out the heating of the coolant and are used for heating, supplying hot water, and ventilating buildings for various purposes.

Flat type collectors

The structure of solar collectors of the flat type includes:

• The absorber is an element responsible for the absorption of sunlight and is combined with the thermally conductive structure. This is the most high-tech part of the system. To increase its effectiveness, a selective nickel coating is applied to it, and the spraying of titanium oxide is black or painted black.
• The thermal insulating coating is used to process the wrong side of the helio panel. Most often, it is made of polyisocyanurate, a rigid polymer Thermo-reactive material with closed cells.
• A transparent layer is made of polycarbonate sheets with corrugated or tempered glass with a small amount of iron.
• Polymer tubes from ethylene polymer with transversely sewn molecules (stitched polyethylene) or copper.

The basic principle of operation of a flat type collector is the operation of a greenhouse effect. Glass passes the sun’s rays inward and allows you to accumulate solar energy, and then transfer it to the coolant (water or non-freezing solution) using other parts (usually aluminum or copper). Heliopanels of this type are also treated with silicone sealant, reaching complete air permeability.

The efficiency of heating the coolant depends on the number of sunlight entering the collector. The larger the energy of energy is transmitted to the coolant, the higher the effectiveness of the unit. It can also be increased using specialized optical coatings that do not allow you to leave heat.

The effectiveness of the functioning of the helio-panel is characterized by the production of a heated fluid per 1 square.m of the surface area of the device. Flat varieties can heat the coolant to 200ºC.

Vacuum type collectors

In a collector of this type, the element absorbing sunny rays is separated from the environment, where the vacuum is created. Thanks to this, heat loss is eliminated almost completely. The use of a selective coating, in turn, greatly reduces the energy sector for radiation.

In the photo of a vacuum-type solar manifold, it is clear that the heat carriers used are tubes equipped according to the principle of the thermos. Details are inserted into each other, and a vacuum is created in the gap between them. The narrow -cylindrical shape of the devices determines the fall of rays at an angle of 90º to the axis, which increases the amount of energy received from a unit area even in the evening and morning time of the day.

Tubular systems are able to effectively collect the energy of multiple solar radiations, in fact, in this case, they work as flat models, equipped with the possibility of turning after the sun. The use of reflectors can also significantly increase the working space of the vacuum-type collector.

The almost complete absence of empty energy consumption in the functioning of the vacuum manifold makes it indispensable for use in frost, and it receives priority in front of flat heliopаnels at a temperature below 15ºC.

Vacuum collector with direct transmission of fluid heat

Structures of tubes in a vacuum manifold with direct heat transfer of the liquid are located at a specific angle. They are connected to the tank, the water from which flows directly into the tubes, where it warms up and then returns. The absence of other elements is an important advantage of the unit. Collectors of this variety can also work without a tank drive.

Vacuum collector with direct transmission of fluid heat and built-in heat exchanger

The collectors of this variety are arranged, in general, as well as devices with the direct transmission of fluid heat, but they have an effective heat exchanger connected from the inside of the tank. Such an apparatus is permissible to embed in the pressure system of the water supply.

For the use of the equipment at a low temperature (up to -10ºC), a non-freezing solution is poured into the water heating circuit. The deposits within the collector are not formed, since water flows exclusively inside the copper heat exchanger, and its measure is unchanged.

Vacuum collectors with heating pipes

For the production of expensive vacuum collectors, copper thermal tubes are used, sealed and filled with a lightly boiling solution. The mechanism of their operation is that the heated liquid when disappeared takes the energy and takes it to the coolant, condensing at the top. The condensate then flows back, and the procedure is repeated.

The transfer of heat is carried out by means of the “sleeve” of the receiver made of copper. The collector heating circuit is physically divided with pipes, so damage to one or more parts does not deprive it of its performance. Replacing the elements does not require the complete removal of the non-freezing solution from the contour of the heat exchanger.
The collector using a thermal power line is quite manufactured by frosts up to -35ºC (for glass models with heat pipes) or -50ºC (products with metal heat tubes).

Solar collectors with concentrators

The arrangement of solar collectors with concentrators is carried out through parabolic cylindrical reflectors, which are laid directly under the details that absorb the radiation of the sun. The procedure allows you to achieve the growth of operational indicators of the temperature of the coolant to 120-250ºC and more (if the tracking devices for the source of light are used in parallel).

Air collectors

The main characteristic of air solar collectors is their ability to warm the air mass. Typically, these devices belong to the type of simple flat helio panels. The heat exchanger is not needed for their work, since the air does not freeze.

The air flows through the absorber forcibly or naturally. It does not carry out heat as well as liquid-type coolants, therefore, the use of fans to improve heat transfer and enhance the formation of swirls in the atmospheric mass increases the effectiveness of the device.

Air solar collectors have a simple structure and high failure tolerance, their work is easy to control. Subject to operating rules, they can regularly function for more than 15-20 years, without needing repair and maintenance.

Types of solar collectors for warming up air can be integrated into the roofs or walls of buildings. They often serve as the main or additional system of heating and ventilation of buildings, where access to other energy sources is difficult or impossible.