Abstract: In this paper, a solar energy and natural gas combined heating system is designed. The structure and circuit design of the control device are discussed in detail. The system is equipped with temperature sensors, circulating water pumps and valves. The temperature values of each point of the pipeline are measured by single chip computer control system, according to distinguish different working modes, the system can circulate cold and hot water and enhance heat transfer based on the pre-designed program, thus realizing the combination of the solar energy and natural gas heating systems. Through simulating different working conditions and testing, the results show that the expected effect has been achieved. The system can automatically switch the heat source through program control, and the water temperature provided by the heating device meets the specified requirements, The goal of energy saving and emission reduction has been achieved.

Key words: joint heating system, control device, circuit system, energy conservation