Closed-cycle cryogenic engine and operating method for propelling vehicles and generating electricity

摘要

A closed-cycle cryogenic engine is provided for propelling vehicles or generating electricity at high power densities without consuming any working fluid. The engine comprises a working fluid having a high specific heat that remains in a gaseous phase. The high temperature heat reservoir is the natural environment and the low temperature heat reservoir is created artificially by evaporating water. By isothermally compressing the working fluid at low temperature by absorbing the heat of compression by evaporating water, it is possible to extract a large amount of natural heat energy from the environment and convert a large fraction of it into net output work. Since the latent heat of evaporating water is very high, very little water is consumed which represents the engine's only fuel.

主权项

1. A method for operating a cryogenic engine having a high temperature heat reservoir represented by a natural heat energy in a surrounding environment at an ambient temperature and a low temperature heat reservoir in a closed cycle comprising the steps of:
creating an artificial low temperature heat sink of at least two degrees Kelvin below the temperature of the surrounding environment by evaporating a supply of water; isothermally compressing a gaseous working fluid at said low temperature from an initial low pressure to a high pressure by absorbing the heat of compression by evaporating water, heating said compressed low temperature gaseous working fluid by absorbing said natural heat energy in the surrounding environment at a higher temperature; expanding said heated compressed working fluid thereby converting a portion of said absorbed natural heat energy into mechanical work; repeating said heating and expansion steps with a plurality of at least three heating and expansion steps in series, wherein the working fluid discharged from one expander in the series is fed into a heat exchanger, heated, and fed into a next expander in the series thereby extracting and converting most of the absorbed natural heat energy from the environment and converting most of the absorbed natural heat energy into mechanical work; and repeating said heating and expansion steps in a closed cycle wherein said working fluid remains in the gaseous state.