Figure 1 illustrates an example of the proposed solar-driven rainwater cooling system. The system consists of a PV module with an area of 1.46 m2, maximum efficiency of 15.4% and maximum power output of 250 W, a gas expansion chamber, a rainwater storage tank and a secondary water tank. A cylindrical gas expansion chamber is installed at the eaves whereas the secondary water tank, which is connected to the gas expan-
sion chamber, is hung at the side of the house. Gutters are installed on both south – and north-facing roofs in order to maximize the rainwater harvesting. On receiving the solar radiation, the gas in the chamber expands with the temperature increase. The rainwater in the tank is pushed upwards by the expanding gas so that it flows over the PV panel through a distribution tube on the top as shown in Figure 2. The rainwater is not considered being reused to reduce the cost and simplify the system structure in this case.