For solar water heating in your home, there are basically two types of solar collectors: conventional flat-plate collectors and evacuated tube collectors. Evacuated tubes have a number of advantages: the work on overcast days, in colder weather, and the tubes can be installed and replaced individually without special tools.
Apricus makes a unique solar hot water heater which is 30-40% more efficient than flat plate solar systems. The secret to the performance is the use of cylindrical evacuated glass tubes to absorb the heat from the sun. Because the tubes are cylindrical, there is always a surface area that is perpendicular to the sun. […]