In this paper, a new type of compound refrigeration cycle combined Mixed-refrigerant Auto-Cascade J-T cycle with vortex tube is introduced, and expected to attain below liguid nitrogen temperature(77.

Some methods were introduced to solve the problem that was encountered when applying ASHP in colds regions, these includes as employing two-stage compression and cascade cycle to decrease pressure ratio, employing variable frequency compressor to increase refrigerant cycle volume, employing Turbo technology, high efficiency compressor and he.

The cascade heat pump unit functions in both single-stage cycle and cascade cycle by optimizing control conditions and maximizing energy-saving.

Simulation and experiment on two-stage temperature refrigerator using auto-cascade refrigeration cycle;

A two-stage temperature refrigerator using auto-cascade refrigeration cycle and non-azeotropic mixture refrigerant was proposed.

The R290 water-cooling condenser is designed taking into account the performance characteristic of R290 used in R290/CO2 cascaded refrigeration cycle and the characteristics of condensation heat transfer of R290 two-phase flow.

The R290/CO2 condenser-evaporator is designed taking into account the heat exchange characteristic of CO2 condensation and R290 evaporation in R290/CO2 cascaded refrigeration cycle.

Experiment of vapor compression cascaded refrigeration cycle with R290 and CO_2 as the refrigerants was carried out by setting up R290/CO_2 cascaded refrigeration system.

Analysis of thermodynamic performance in CO_2 cascade refrigeration cycle;

The COP variation trends and its maximum COP of the cascade refrigeration cycle adopted hydrocarbon mixtures under different evaporation temperature from-80℃ to-60℃ are obtained through theoretical thermodynamic calculation.

Focuses on the effect of heat exchangers on the performance of CO_2/R290、CO_2/NH_3 cascade refrigeration cycle.