Heat recovery system including a dual pressure turbine

Abstract

Heat recovery systems are useful, for example, in vehicles that generate large amounts of heat energy during operation. The heat energy is used to drive a turbine that produces useful work. In order to fully utilize the great majority of the heat energy produced, the engine exhaust is used to convert a fluid to a gas and superheat the gas to a preselected temperature at a preselected pressure. If the fluid entering the heat exchanger in the exhaust system is to cool, soot collects on the heat exchanger thus greatly reducing system efficiency. Also various oxides precipitate out of the exhaust and chemical attack the elements in the exhaust system. The present heat recovery system utilizes the heat energy from the oil cooling system to preheat all of the fluid before it reaches the exhaust system. Furthermore, the heat energy from the jacket water of the engine is used to convert a portion of the preheated fluid to a gas. The system converts the remaining portion of fluid to a gas and superheats the gas to a higher preselected temperature. A first stage of a dual pressure turbine receives the superheated gas and directs the gas at a supersonic velocity against the blades of the rotor. The gas exiting the first stage and the superheated gas at a lower preselected temperature is controllably and substantially separately directed to a second stage at substantially the same velocity.