A high performance vacuum tube collector of the highest standard which uses the heat pipe principle. Unlike the Vitosol 200, where the solar transfer medium flows directly through the collector tubes, here a carrier medium which evaporates with heat from the sun circulates through a special absorber and transfers its heat via a heat exchanger to the solar medium.
The fact that there is no fluid flowing through the collector tubes simplifies installation and allows easy replacement of individual tubes in case of breakage. As with the Vitosol 200, the tubes can be individually rotated for best alignment with the sun.
The Vitosol 300 is available in 2.94 and 4.38m2 sizes with active absorber areas of 2 and 3m2 respectively. Note that the Vitosol 300 must be mounted on an inclined surface at an angle of at least 25 degrees.
Graph showing the Vitosol 300 absorber area needed (see 'aperture' scale) to supply x% of hot water at a standby temperature of 45 degrees Celsius assuming average incoming water temperature of 10 degrees Celsius. Average consumption is between 30 and 60 litres per day per person so, for a four person household, an absorber area of 4m2 would provide roughly 60% of hot water needs annually.