Overview of types of solar collectors for heating and domestic hot water supply

Now a lot of talk is about ecology, saving resources. But, perhaps, the main reason that most people try to find any opportunity to minimize energy consumption is a rise in the cost of living, to which the permanent increase in tariffs in no small measure contributes. Our housing and communal services as if specifically encourages this. One of the savings options is on heating and hot water. How this can be done with the help of a solar collector, which is used for hot water supply and heating, and will be described in an article on our website better-house.ru.

Do not confuse it with a product that has a consonant name - a solar battery( read about them here).The principal difference is that the consumer receives electrical energy from the battery, and the heat collector from the collector. Without going into the subtleties of physical processes, we can briefly say so - solar radiation is transformed into heat, which is used to increase the temperature of the coolant.

The scheme is quite simple: the solar collector is a storage tank. The coolant circulates continuously between them. There are also installation of various additional devices, mainly electronics, which makes the operation more convenient. All the features of a particular product can be found in the accompanying documentation.

Types of solar collectors

There are several. We are interested in only those that can be used without any special difficulties in everyday life, to provide their home with thermal energy.

Models "vacuum"

Absorber( an element that absorbs and accumulates solar energy - the "black" panel) is in a vacuum. He surrounds it from all sides, thus reliably isolating from the environment. In addition, the selective coating of the absorber contributes to this, for which he received his second name. This engineering solution reduces heat loss to a minimum.

Structurally, a single element is 2 tubes( one in the other).It resembles an ordinary thermos. In the space between them there is a vacuum. The shape of the cylinder provides good absorption of the energy of the sun at any location in the sky, whether it is early morning, noon or sunset. Its rays always fall perpendicularly to the longitudinal axis of the element, which contributes to the maximum absorption of radiation.

Direct heat dissipation

All elements are connected to the storage capacity of the system. The liquid from it enters the tubes( they are located with a slope), heats up and returns back to the tank. In some designs it may not be( continuous circulation).The advantage of this solution is the absence of "intermediaries" in the process of heat exchange.

With

heat exchanger The difference is that in the storage tank there is a heat exchanger( usually copper).On its basis, it is possible to mount a second circuit - DHW, if the first one works for heating. In this case, different heat carriers can be used. For hot water, naturally, water, for the heating system, except for it, and antifreeze or other low-freezing liquid. This allows you to operate the unit in cold weather( at minus in the street).

With tubes( thermal)

Models are the most effective, but also are expensive. Structurally, the panel consists of sealed tubes( copper) filled with a low-boiling liquid. When heated, the formation of steam, which in the upper part condenses and flows down. Continuously repeating process. The vaporization temperature is known, so there is no sense in explaining how original this solution is.

All elements are connected to a common pipe( receiver), through which the coolant passes.

Pros

1. The possibility of reliable operation at temperatures below zero.
2. On efficiency exceed "flat" analogs by 45 - 50%.
3. Versatility, as they are available in several modifications.
4. Good maintainability.
5. Individual models function well at temperatures as low as -45 ° C( with metal tubes).
6. The output of one element is negligible in the operation of the collector.

Cons

1. High cost.

"Flat" models of solar collectors

They function on the basis of the greenhouse effect. Such a solar collector consists of 3 main parts - a solar absorbing element( absorber), a heat insulator and a transparent coating. Radiation of the light freely penetrates into the device and accumulates there. The heat carrier, which circulates through the system and passes through the collector, heats up due to accumulated thermal energy. In the static mode( without water extraction), the panel can heat the liquid to +200 0С.

Pros

• Simple design.
• Cheaper vacuum models.

Cons

• According to the efficiency they are much inferior.
• High dependence on illumination.
• At negative temperatures the efficiency drops sharply.
• Restriction in use. More suitable for southern regions, and in the middle latitudes and north - ineffective.

The spread of prices is so great that it makes sense to focus only on individual examples.

• The collector 1.84 m2( Czech Republic) will cost 5,150 rubles .This is taking into account the cost of all components for installation. The same model of 3,6 m2 - 8,250 rubles.
• German "Logasol" of vertical installation - 29 340 rubles( 2,026 х 1,032) .The product with dimensions of 2 070 x 1 145 costs already 43 000 rubles.

Conclusions

1. The higher cost of equipping collector structures is apparent. According to experts, the costs for all relevant activities are quite comparable to the costs of installing autonomous systems operating on traditional fuels, such as gas boilers.
2. The efficiency of the circuit is provided not least by the quality of the thermal insulation of the highway, and this must be borne in mind.
3. If you take into account the prices of the main energy sources( gas, solid or liquid fuels, the same electricity), then the savings are very significant, especially for a private house with several buildings on its plot. It must be understood that the solar collector can work all year round, most importantly, that the sun is not covered by clouds. And it accumulates radiation not only in the spectrum that is visible to us. So the expediency of mounting such a structure is obvious. Of course, much is determined by the needs of a particular house. But even if the panel( or assembly) and does not replace completely conventional systems, the savings will be significant. In addition, this is a good emergency option( a spare energy source).
4. Solar collectors can be used anywhere in the world, regardless of the climate. The main thing is to choose the optimal model and correctly design the circuit. In our country it is expedient to mount vacuum solar collectors. Flat is recommended to use only in southern regions.