Thermodynamic power and cryogenic refrigeration system using low temperature heat source

Abstract

A thermodynamic power and cryogenic refrigeration system using a first and second (binary) working fluid has a low-temperature closed bottoming cycle and an open or closed topping cycle. In the bottoming cycle a mixture of a first gas such as helium or hydrogen and a low temperature liquid such as liquefied nitrogen is compressed in a polytropic process and then the liquid content is separated. The separated first gas is heated using rejected heat from a second gas expanded in the topping cycle or ambient air and then the heated first gas is adiabatically expanded and supercooled while performing useful work and thereafter is fed to the compressor and mixed with the separated liquid to serve as a coolant and facilitate rejection of polytropic heat and to supplement the cool gas/liquid mixture providing polytropic compression of the first gas and thus completes the bottoming cycle. The bottoming cycle functions to cool the second gas and liquefy it in the topping cycle. The topping cycle is an open or closed modified Rankine cycle. The topping cycle uses heat of seawater and/or ambient air or other low-temperature heat source to simultaneously produce a refrigerant and power. The apparatus of the closed bottoming cycle may also function without the apparatus of the topping cycle using a low temperature heat source to produce a refrigerant and power.