... high-efficiency 3,Modular design and auto-operation 4,Multifunctio Solar water heater features:1.Modular design, arbitrary combination,harmonize with ... control and automatic operation.3.Multifunction: bathing, washing,domestic heating ect.4.Work longer hours. Material of model:a, ... glass 3.3e, Vaccum pipe: anti-freezing >-35°Cf, Water capacity:150L 200L 300L 500Lg, Heat preservation time:72Hr-80Hr ...