Solar hot water heater, 30m copper coil inside of tank, which could bear high ... , 58mm×18m.Accessories: Water auto-feeding tank, electrical heater. Copper coiler: For heating exchanging, Ø12mm×30m, inside of ... of vacumm tube. Higher heat absoption effciency. 2) Copper coil inside of tank could bear high hydraulic pressure, ... out from the coiler. Solar hot water heater& 30M copper coil for heat exchange