Profile: Integrated Solar LLC provides solar water heater systems. Our brands include CopperSun™ and Radco™. Our heat-transfer fluid system, usually distilled water, will circulate through the system when the collector's solar sensor determines that there is an usable amount of heat from the sun's rays. The fluid is pumped from the Drainback heat transfer tank to the collector on the roof where it is heated. It is then pumped back to the tank, from where it transfers its heat to the domestic hot water tank.