Solar Energy Collector
Rayotec has been installing solar energy systems since 1987. Because of their experience in this field having fitted over 6000 solar systems, we offer the Rayotec CPC 6 INOX with its reliability, high build quality and performance.
The solar energy collector CPC 6 INOX consists of 3 main parts, and comes fully pre-assembled.
- Evacuated tubes
- CPC mirrors
- Manifold with heat transfer unit
The Evacuated Tube
Each solar vacuum tube is composed of two Borosilicate 3.3 glass tubes, one slightly smaller than the other, fused together at the top to make a single tube. The air in the void between the two tubes is then pumped out, creating a vacuum thermal insulation layer.
To convert the daylight into useful solar heat, the internal glass tube is coated with an environmentally friendly, highly "selective" light absorber (Aluminium Nitrite). The absorber converts both direct and diffused light from a large spectrum of wavelengths into heat. The heat produced by the absorber is protected from the atmosphere by the vacuum layer, thereby eliminating thermal-loss. This significantly increases the performance of the solar collector.
The CPC Mirror
In order to increase the output of the evacuated tubes, a highly reflecting, weather-proof CPC mirror (Compound Parabolic Concentrator) is placed behind the evacuated tubes. The special mirror geometry ensures that direct and diffuse light, travelling from all orientations, falls onto the absorber. This substantially improves the energy yield of a solar collector in unfavourable conditions, such as Easterly early morning and Westerly late afternoon light. It is also beneficial when it is not possible to install the panels in the ideal south-facing orientation.
Manifold and "U" Tube
Within each glass tube there is a stainless steel "U" tube collection pipe, with a circular metal heat absorber plate. All the "U" tubes are connected to a well insulated manifold, which is designed to allow a direct flow of the heat transfer fluid through the system. The heat transfer fluid collects the heat from the absorber inside the glass tube and transports it to the cylinder. The manifold has a special design which ensures all the tubes exhibit the same hydraulic resistance. The heat transfer fluid collects the heat from the absorber in the glass tube and carries it down to a twin coil cylinder where it heats the bottom part of the cylinder, being the coolest part. The second, upper coil within the cylinder, is connected to the boiler.
A typical installation
How is it controlled?
The whole system is controlled by a differential temperature control unit. The controller has three temperature sensors: Collector, Cylinder and Return. When the temperature of the collector is 8°C hotter than the bottom of the hot water cylinder, the control unit will turn on the pump starting the solar thermal transfer process. The controller ensures the pump is only running when positive solar gain is available.
The control unit also has various safety features, as well as useful solar gain information.
