compact unpressurized solar water heater

Compact unpressurized solar water heater (SP-R) relies on the natural circulation of water between the collector and the tank or heat exchanger. As water in the vacuum tubes is heated it rises naturally into the tank, while cooler water in the tank flows down to the bottom of the vacuum tubes, causing circulation throughout the system. The available size of tank ranges from 85L to 300L. 1) Inner tank and outer tank are both 0.5mm SUS304 food grade stainless steel, welded byargon arc. Heat insulation of water tank adopts polyurethane foam, thickness is 55mm. 2) The tubes and supports are adjustable, power bearing is average and assure the tubes to use long time. 3) Whole vacuum tube adopts super borax and silica glass. Absorb rate≥93%, thermal radiation rate≤6%. Resist 25mm hail, using life lasts 15 years. 4)Silicon ring to connect and seal them. 5) Temperature when exposed to sun without water: 250 degrees, 2.5 hours to boiling point if using single tube. 6) If you use electrical appliances to aid heating and to switch off the power supply before bathing. 7) Please test the water temperature before using, in order to avoid scalding. ModelOuter tankInner tankVacuum tubeVolume(L)Dia.(mm)Length(mm)Qty(pcs)SP-420-47/1500-15-R0.4mm SUS304 2B food grade stainless steel or color steel0.5mm SUS304 2B food grade stainless steel4715001584SP-420-47/1500-18-R47150018100SP-420-47/1500-20-R47150020111SP-420-47/1500-24-R47150024133SP-420-47/1500-30-R47150030166SP-470-47/1500-15-R47150015113SP-470-47/1500-18-R47150018139SP-470-47/1500-20-R47150020150SP-470-47/1500-24-R47150024179SP-470-47/1500-30-R47150030226SP-470-58/1800-15-R58180015122SP-470-58/1800-18-R58180018150SP-470-58/1800-20-R58180020165SP-470-58/1800-24-R58180024200SP-470-58/1800-30-R58180030250