What is Solar Water Heating?
Solar water heating systems use solar collectors and a liquid handling unit to transfer heat to the load, generally via a storage tank. The liquid handling unit includes the pump(s) (used to move the working fluid from the collectors to the storage tank) plus control and safety equipment.
SWH performs three basic operations:
Collection: Solar radiation is “captured” by a solar collector.
Transfer: Circulating fluids transfer this energy to a storage tank; circulation can be natural (thermo siphon systems) or forced, using a circulator (low-head pump).
Storage: Hot water is stored until it is needed at a later time in a mechanical room, or on the roof in the case of a thermo-siphon system. Selective coatings are often applied to the absorber plates to improve the overall collection efficiency. A thermal fluid absorbs the energy collected.
The most common solar collector types are:
Evacuated tube solar collectors: These collectors have absorbers with a selective coating enclosed in sealed glass vacuum tubes. They are good at capturing the energy from the sun and their thermal losses to the environment are extremely low. Systems presently on the market use a sealed heat-pipe on each tube to extract heat from the absorber (a liquid is vaporised while in contact with the heated absorber, heat is recovered at the top of the tube while the vapour condenses, and condensate returns by gravity to the absorber).
Glazed liquid flat-plate collectors: This is a flat-plate absorber (which often has a selective coating) is fixed in a frame between a single or double layer of glass and an insulation panel at the back. Much of the sunlight (solar energy) is prevented from escaping by a glazing (utilizing the “greenhouse effect”).
Contact us to schedule an on-site assessment and find out if Solar Water Heating is an ideal solution for you.
