A collector in a Solar Water Heater (SWH) is a device for capturing solar radiation which have a significant contribution to the performance of the SWH. In this research, a modifications were applied to dual absorber plate and flow channels to increase heat absorption have been investigated. The purpose of this model collectors is to enlarge the surface area that can directly absorb solar radiation, and extend water passage to absorp heat from the absorber plate. Flow rate were varied of 1500 mL/min, 1200 mL/min, 900 mL/min, and 700 mL/min to determine the useful energy and convection coefficient plate absorber to the water, as well as energy losses produced by the collectors. The results showed that an increase in solar radiation intensity affect the useful energy and energy losses. The highest energy losses at the collector obtained was 92.23 Watt, useful energy high was 652.13 Watt, and plate-air convection coefficient high was 4728.54 W/m~2.°C on a Reynolds number of 241.15 (volume flow rate of 700 mL/min) with a total solar radiation of 672.78 W/m~2. This indicates that the smaller volume flow rate of water (700 mL/min), the greater useful energy. This is because as the volume flow rate is small, water have a longer time to absorb the heat supplied from the absorber plate.
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