... flow in the vacuum tubes. Features of Xianke pressure solar energy:pressure solar collector is made of red copper and conducted ... as usual under -38celsuis 6)Bathing, washing, domestic heating 7)Pressure: 0.7Bar 8)capacity: 100L, 200L, 250L, 300L, 400L, ... of pressure solar collector: 1) When the temperature difference between solar collector and tank reaches the set value, the controller will ...