CE EN12975 KEYMARK Split Pressurized Solar  Solar Collector Specification: 

In this type of vacuum collector, the absorber strip is located in an evacuated and pressure proof glass tube. The heat transfer fluid flows through the absorber directly in a U-tube or in counter-current in a tube-in-tube system. Several single tubes, serially interconnected, or tubes connected to each other via manifold, make up the solar collector. A heat pipe collector incorporates a special fluid which begins to vaporize even at low temperatures. The steam rises in the individual heat pipes and warms up the carrier fluid in the main pipe by means of a heat exchanger. The condensed liquid then flows back into the base of the heat pipe.

The pipes must be angled at a specific degree above horizontal so that the process of vaporizing and condensing functions. There are two types of collector connection to the solar circulation system. Either the heat exchanger extends directly into the manifold ("wet connection") or it is connected to the manifold by a heat-conducting material ("dry connection"). A "dry connection" allows to exchange individual tubes without emptying the entire system of its fluid. Evacuted tubes offer the advantage that they work efficiently with high absorber temperatures and with low radiation.

Key features of the Sunwe Solar Collector:

1. Internationally certified product (EN12975/SOLAR KEMARY/SRCC)
2. Copper heat pipes for rapid heat transfer and freeze resistant.
3. Reliable, efficient, tri-element evacuated vacuum tubes
4. Easy plug-in installation
5. Maintenance free
6. Suitable for mains pressure water (up to 6bars, max. 10bars)
7. Corrosion resistant material (aluminum and copper)
8. Aluminum frame 2.0mm thickness
9. Black or Silver aluminum casing in good insulated
10. Stable solar conversion throughout the day
11. The best solar collector for domestic solar water heater systems
12. Ideal for commercial solar water heater applications
13. Comprehensive 10 years limted warranty (life time will be more than 15years) 

The working principle of solar collector is very simple.

1. Solar Absorption: Solar radiation is absorbed by the evacuated vacuum tubes and converted into heat.
2. Solar Heat Transfer: Heat pipes conduct the heat from within the solar tube up to header.
3. Solar Energy Storage: Water or water mix is circulated through the header, via intermittent pump cycling. Each time the water circulates through the header the temperatures is raised by 5-10^oC / 9-18^oF. Throughout the day, the water in the storage tank is gradually heated   solar heat collectors.