... high absorption rate; antifreeze, antihail 2)good heating result Storage tank:1.tank capacity (L): 100,150,200,260, 300,400, 5002.inner ... tank material: SUS304-2B, thickness (mm): 1.0, 1.5, 2.0,3.outer tank mterial: color steel4.inssulation layer ... heater: 1500w, 2000w, 3000w7.preservation hours: 72hours solar collector:1.tube size: 58*1800mm2.type: heat pipe3.tube quantity: 10 ...