Abstract: The hardware and the software of the current solar water heater are upgraded.A control system of solar water heater based on AT89S52 microcontroller is designed,which solves the problem that the residual hot water will cool down due to poor insulation of the pipe.The design increases the daily utilization rate and the popularity rate of the solar water heater,and is of great significance to energy conservation and emission reduction.

Key words: solar water heaters;pipe emptying;intelligent watering;energy conservation and , emission reduction