This type of water-heater (with a high number of collectors and double-walled storage tanks) uses a pump to perform better circulation of water. These water-heaters are commonly used for factories and industrial areas; however, they can also be utilized at home. In this type of water heater, the storage tank can be placed anywhere in the building. the pump in such heaters is installed on the entry of the cold-water inlet and the collectors, the cold water will return to the storage tanks after being heated by absorbing collector plates. Because of an additional pump in the circulation circuit, the process of circulation improves significantly in these types of water heaters. The storage tank is installed far from the collectors and near the place where the water is being consumed. This system is also equipped with a temperature controller turning the water on and off automatically. In the solar storage tank, there is a hidden tank for the process of evacuation. When the circulation of pump is stopped by the controller, the water available in the collectors will return to the evacuation storage tank due to height discrepancies and the collectors will emptied, therefore, there will be no need for antifreeze in winter.