Adaptive thermal controller for heat engines

Abstract

A solar to mechanical or electric power conversion system which has a controller that varies the speed of a cooling fan and cooling fluid pump fan in accordance with the available solar energy intensity, ambient temperature surrounding the system and other operating conditions. The system includes a suitable heat source such as an isotope heat source, fuel combustor, or a solar concentrator that delivers solar energy to a focal point by reflection from mirrors or by Fresnel lens. A suitable solar concentrator may also be based upon on densifying the solar photon count by a Winston concentrator. For solar heated devices based on concentrated solar energy, a receiver is located at the focal point. This receiver is heated by concentrated solar energy. Heat is transferred to a working fluid which powers a heat engine. The heat engine converts the thermal energy into mechanical energy. The mechanical energy is transmitted to a load coupled to the engine. The temperature of the working fluid is lowered by transfer to the surroundings by operation of means selected from the group including a cooling fluid valve means, variable rate fan, a variable rate pump, a cooling fluid to air heat exchanger, a cooling fluid to ground heat exchanger, and a change of phase heat exchanger. The speed of the fan and pump are controlled by a controller which also senses the ambient temperatures that are available and the temperature of the cooling fluid. The controller computes an optimum cooling fluid temperature as a function of energy expenditure and controls fan, valve, and pump operations to achieve the desired energy conversion optimization.