Heat Pipe Solar Collector

Working principle:
Heat Pipe solar collector consists of a vacuum tube and a copper heat pipe inside. The vacuum is placed in an inclined mode. The selective coating on the inner tube converts the solar energy into heat and transfer the heat to the heat pipe via the aluminum fin. When heated, the medium liquid in the heat pipe changes into vapor, which rises to the condenser. When passing through the heat exchanger, the heat is absorbed and the temperature is lowered, then the vapor becomes liquid and returns to the base of the heat pipe. This transference of heat is a continuous circulation as long as the collector is heated by the sun. Even though the heat pipe is a vacuum and the boiling point of the medium liquid has been reduced to only 25-30^oC, the freezing point is still the same as water at sea level, which is 0^oC. As the heat pipe is located within the evacuated tube, brief overnight temperatures as low as -30^oCwill not cause the heat pipe to freeze.