Solar is unlimited natural sources in the world, one of solar utilization is for solar water heater. Utilization of solar energy can be divided into two general categories: solar active system and solar passive system. The difference between these two systems is the presence or absence of solar collector on the system.
Solar collector is the key to an active system, while passive system relies on the sun that comes naturally without the use of solar collector. Furthermore solar water heater can be categorized in active system if use solar collector tool.
Solar collector is a tool that utilizes thermal energy from solar radiation which is then transmitted to the working fluid. According to the ways of collecting solar energy, solar collectors are divided into concentrating solar collector and non-concentrating solar collector.
Concentrating solar collector generally has reflector to concentrate solar radiation toward the absorber plate. Non-concentrating solar collector takes advantage of solar radiation exposure directly to heat the absorber plate through greenhouse effect. Solar water heater system for housing generally uses non-concentrating solar collector, namely flat plate solar collector.
|Figure 1: Flat Plate Solar Collector for Water Heater|