Solar collectors

Solar collectors use the energy of incident sunlight and efficiently use it to heat water in a tank heater or storage tank. They thus reduce the need for heat supply from the main source, reduce the burden on the environment and household costs. Solar collectors can be used in combination with low-temperature heating and to support heating.

The solar collector meets the technical conditions if the certificate of performance specified in the test protocol of the Solar Keymark certificate is issued by an accredited testing company under test conditions (irradiance 1000 W/m², temperature difference 30 °C).

Collector systems are able to convert 35-45 percent of the solar energy they receive during the year into useful heat. The efficiency of the system is determined by the type of collector, the temperature difference between the collector and the environment and the intensity of radiation at the installation site, as well as the system piping, thermal insulation and the type of storage tank.

The central element of the collector is the absorber, in which the transformation itself takes place. The heat is transferred through the heat conduction in the absorber to the heat-carrying medium, which flows through the tubes of the absorber and is then transported to the reservoir (boiler). In order to fulfill this task optimally, the absorber consists of a well-conducting metal sheet (copper or aluminum) and a selective conversion layer, which must show the highest possible absorption capacity (absorption) of solar radiation and should have a minimum emissivity (radiation of heat).

Flat collectors
Flat collectors are used to heat water and, increasingly, to support heating. A flat collector consists of a collector shell (mostly in the form of an aluminum tub), an absorber, thermal insulation from mineral wool and a transparent cover.

The absorber is usually made of copper or aluminum sheet with a solar varnish or a selective surface layer, thanks to which it almost completely converts sunlight into heat. The glass used should be low in iron and resistant to hail. Solar radiation passes through the cover glass and hits the absorber, where the heat-carrying liquid is heated.

Commonly available flat collectors show an average annual efficiency of around 50%. For solar collector installations, a 45° slope is used as standard, when the use of solar radiation intensity is optimal.

Flat collectors are suitable for heating the water in the pool only if, in addition to the pool, we also supply another appliance (e.g. hot water preparation or heating support)