The heat transferred to the tip of the heat pipe is in turn transferred to a copper manifold in which water circulates to heat the domestic hot water tank. If a tube is placed in direct sunlight on a summer day, the tip temperature can reach 250°C - so the system easily heats domestic hot water cylinders to 60°C even in cooler weather! The manifold is heavily insulated with a 2" thickness of pre-formed rockwool to keep the heat in. Unlike flat plates, these headers are so well insulated that they should not require antifreeze in normal operation - the temperature of the header is unlikely to fall below 10°C even in very cold weather. The more advanced solar controllers include a low-temperature facility- should the temperature of the collector fall below a defined level, the pump will operate to allow the the water at the bottom of the tank to heat the collector slightly. In normal conditions, this would never be necessary - but it acts as a good safety margin.
The heat transferred to the tip of the heat pipe is in turn transferred to a copper manifold in which water circulates to heat the domestic hot water tank. If a tube is placed in direct sunlight on a summer day, the tip temperature can reach 250°C - so the system easily heats domestic hot water cylinders to 60°C even in cooler weather! The manifold is heavily insulated with a 2" thickness of pre-formed rockwool to keep the heat in. Unlike flat plates, these headers are so well insulated that they should not require antifreeze in normal operation - the temperature of the header is unlikely to fall below 10°C even in very cold weather. The more advanced solar controllers include a low-temperature facility- should the temperature of the collector fall below a defined level, the pump will operate to allow the the water at the bottom of the tank to heat the collector slightly. In normal conditions, this would never be necessary - but it acts as a good safety margin.