Feasibility of use in Russia

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Real efficiency of solar collector
The overall efficiency of a solar collector is determined by the value of the collector efficiency:

Explanation:

η - collector efficiency;
η₀ - optical efficiency;
k₁ - heat loss coefficient W/(m² K);
k₂ - heat loss coefficient W/(m² K²);
∆T - temperature difference between the collector and air K;
E – total intensity of solar radiation.
The maximum efficiency value is achieved under the condition that the temperature difference ∆T is zero. In this case, the collector has no heat losses. However, such ideal conditions are not encountered in practice. The value of η₀ is the passport value of any solar collector and must be specified in the documentation for the solar collector.

The principles of development of solar collector design are japan mobile database at increasing the absorption capacity and reducing heat losses. The open collector (without transparent insulation) has the highest optical efficiency, but also has the highest heat losses.

In turn, the vacuum solar collector has the lowest heat losses, but has a low optical efficiency due to the use of two layers of transparent insulation, a cylindrical absorber shape and intermediate heat transfer.

In the climatic conditions of central Russia, solar water heating systems can be effectively used by various consumers for domestic purposes for 6-7 months a year (March/April - September).

To heat 100 liters of water, a solar installation must have 2-3 m2 of solar collectors. Such a water heating installation will provide daily heating of water to a temperature of at least 45°C in the summer with a probability of at least 70-80%.

From both an energy and economic point of view, it is advisable to use the simplest solar collectors with one transparent enclosure to create domestic solar water heaters.