How Solar Hot Water Works

Evacuated Tubes

An evacuated tube solar hot water system consists of a hot water tank on the ground and cylindrical tubes mounted on the roof. Cold water is pumped from the tank to the tubes on the roof, where heat is captured from the sun by a vacuum-sealed outer tube. This vacuum allows the tubes to effectively retain the collected thermal energy, even in the coldest conditions. The heat is then transferred from the outer tube to an inner tube, where it rises up to the tubes’ manifold and heats the water. The heated water is then stored in the tank for later use.

 

Heat Pumps

Heat pumps use a fan to extract heat energy from the surrounding air and transfer it as liquid refrigerant across an evaporator. The liquid refrigerant is converter into a high temperature, high pressure gas by the evaporator and compressor, which then heats the water inside the tank. Once the water is heated, the refrigerant reverts back to a liquid until the process starts again.

 

Continuous Flow Gas Hot Water Heaters

When a hot water tap is turned on, water passes through the heating unit and triggers a sensor. This sensor ignites the burner for ‘on demand’ water heating, which remains on until the tap is turned off.  The water then passes through the heat exchanger where it is heated.

 

Evacuated Tubes