A commercial solar water heater is a type of solar thermal system that uses solar energy to heat water for commercial use. This type of water heater typically uses flat plate or evacuated tube solar collectors to absorb solar energy and convert it into heat. The heat is then transferred to water or a fluid that is circulated through the solar collectors and stored in an insulated storage tank. Commercial solar water heaters are often used in hotels, hospitals, and industrial facilities, where large amounts of hot water are required.

Commercial solar water heaters are more efficient and cost-effective than traditional water heating systems, as they rely on the free energy from the sun rather than fossil fuels. They are also environmentally friendly, as they do not produce greenhouse gas emissions. They are suitable for use in regions with high solar radiation and can work in both active and passive systems. These systems also require less maintenance than traditional systems.