Forced air systems accept both air and liquid systems as supplements. Schiller Consulting, (2007, 21) on the other hand covers liquid-based solar heating. The most appropriate collectors for central heating are solar liquid collectors. The commonest of the solar liquid collectors are flat-plate collectors. Additional examples are concentrating collectors and evacuated tubes. A working fluid also referred to as a heat transfer including antifreeze and water absorbs the solar heat in the collector. The role of the controller is to operate a revolving pump to transfer the liquid through the collector as a channel at the right time. Schiller Consulting, (2007, 31) posits that the rapid flow of the liquid pushes the temperature to range from five to eleven degrees centigrade. To increase the loss of heat, the controller heats a smaller volume of liquid and enhancing the overall efficiency of the system. Other components of the system are pumps, piping, the expansion tank, valves, a storage tank, a heat exchange, and controls. Schiller Consulting, (2007, 33) finalizes that the heat transfer fluid determines the flow rate. PA Consulting Group, (2006, 19) expounds on ideas by Schiller Consulting, (2007, 44) by evaluating the storage of heat in liquid systems. Liquid systems use tanks of water to store solar heat. Alternatively, they use the masonry mass of a radiant slab. The system entails the transfer of heat from working fluid to the distribution fluid inside the tank or within the heat exchange exterior. Similarly, the State of Wisconsin, Public Service Commission of Wisconsin, (2007, 43) report holds that the Sun supplies the earth with daily energy in an enormous way. The supply exceeds primary consumption by more than eighty times if Germany as an example. The State of Wisconsin, Public Service Commission of Wisconsin report (2007, 51) holds that it is possible to exhaust the energy. It remains at the disposal of people for millions of years ahead.