... , color of support: black16, inclination of frame: 38 to 45 degree17, capacity optional: 100L,150L,200L,240L,300L,400L,500L18 ... the heat energy can be transferred between the water tank and solar collector pressure solar water heater Advantages: 1)Double coil system can combine with ... the cold area, more effective than the other type solar water heater if in the cold winter 3)Double coil system can ...