Never fear a power outage will leave you without hot water with a thermal water heating system from Alternate Energy Technology. This system is built with a 120 gallon storage tank and is connected to a 80 square foot solar collector for plenty of hot water. The water is heated while flowing through the drainback tank at the same time the heating water passes through the drainback tank. The water never mixes in this closed loop design. The system can be used in colder climates.