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The paper presents an exergy analysis of a heat pump with a steam injection. Different refrigerants as R290, R152A and R1234yf are considered. Constructive schemes such as two-stage heat pumps or cascade couplings are known and used to reduce the temperature at the compressor discharge level, but the presence of two or more compressors increases the cost of the initial investment of the equipment. This paper presents the design of a steam injection heat pump that has the advantage of a simple construction and can ...

Cryogenic energy storage (CES) is a large-scale energy storage technology that stores electricity in the form of liquefied gas at cryogenic temperatures. The CES system has three sub-processes, namely, charging or liquefaction, storage, discharging or power cycle. Because the main energy costs in this system are related to the liquefaction module, we will focus on the analysis of liquefaction processes. The present work aims at performing a comparative study between cycles commonly used for the liquefaction of air...

The paper presents an analysis of the behaviour of an air-water vapour compression heat pump at the variation of some of the decisional parameters as the state of the fluid at the compressor intake. Different refrigerants as CO2, NH3 and R600a, and different schematics are considered. The large use of rotary compressors in the industrial and domestic heat pump area has determined the investigation of the influence of the wet compression. The analysis is based on the exergy concept that enables to point out the loc...