Optimal Operating Temperature for Solar Thermal Power System

Solar thermal power is currently one of the important trends and research hotspots of solar energy. In present paper, basic physical model is proposed to investigate the solar thermal power, and the operating temperature is optimized to maximize the electricity generating efficiency. As the incident energy flux rises, the wall temperature almost linearity increases, while the heat absorption efficiency will first increase and then decrease. The increasing of flow velocity will benefit the heat receiver performance by decreasing the wall temperature and increasing heat absorption efficiency. Since the heat loss of infrared radiation increases with the temperature, the heat convection flux and local absorption efficiency of the heat receiver will evidently decrease along the flow direction. As the operating temperature increases, the Carnot efficiency of the steam turbine cycle obviously increases, while the average absorption efficiency of heat receiver decreases, so the electricity generating efficiency will reach maximum at optimal operating temperature.