The phase-down of hydrofluorocarbons and substitution with low global warming potential values are consequences the awareness about environmental impacts greenhouse gases. This theoretical study evaluated energy exergy performances impact three vapor compression system configurations operating hydrocarbons R290, R600a, R1270 as alternatives to R134a. refrigeration cycle investigated in this inc...

In this study, a boil-off gas reliquefaction system that is part of liquid ethylene (LEG) carriers evaluated. The formed by two thermally interconnected two-stage refrigeration cycles. working fluid the bottoming cycle ethylene; topping propylene. research based on determining irreversibilities in cycles using entropy-cycle method thermodynamic analysis. impact process performance main componen...

F-gas phase-down schedules will remove most of the HFCs (hydrofluorocarbons) used in refrigeration systems short term. Besides refrigerant substitution, configuration modifications can be considered existing installations to increase energy efficiency. Basic cycle, direct injection, economiser, parallel compression, and cascade configurations with internal heat exchanger have been proposed effi...

The search for energy-efficient technologies for developing new refrigerator appliances has made the magnetocaloric effect a field of current scientific interest.1 The number of scientific publications on this topic is increasing exponentially in the recent years (Figure 1), which is proof of the high expectations that the scientific community is depositing on this field of research. Together w...

this paper aims at studying a trigeneration system, based on an internal combustion engine and a steam ejector refrigeration system. the designed cycle is to generate cooling and heating energies, and supply power simultaneously. the cycle is studied from thermodynamics point of view and for this purpose, the first law of thermodynamics is applied to all components of the cycle. the efficiency ...

Because of the limitations traditional refrigerants, application trans-critical CO2 technology in domestic gas conditioners and other fields is becoming increasingly popular. This paper proposes a new refrigeration system. Combining internal heat exchanger expander components, as well two-stage compression cycle, we analyzed effectiveness expander, exchanger, intercooling on system performance ...

This paper presents a new analysis of the effects of ambient temperature variations on the surge characteristics of turbo heat pumps. To this end, an analytical model capable of predicting unsteady behavior of surge in turbo heat pumps has been developed. In compression systems, surge is mostly caused by the compressor work exceeding the mechanical inertia of the system. In refrigeration system...

Recent developments in the industrial refrigeration, air conditioning and heat pump sector have included significant increases in the typical operating pressures of systems. With ammonia this offers several opportunities to capitalise on the high critical temperature and high index of compression of the refrigerant in order to deliver heat efficiently in the temperature range 70C – 90C. It also...

In this paper, the performance of various concentrat~ons, of the proposed blends, as alternatives to CFC-12_, are evaluated under different operating conditions from thermal capacity, as well as coefficient of performance point of view. Other cycle characteristics, such as pressure ratio, system pressures, temperatures and compressor power are also discussed. This has been accomplished with the...

The Cross Vane mechanism was recently invented and employed in the design and development of an expandercompressor unit, named Cross Vane expander-compressor or CVEC in short. This device replaces the compressor and expansion valve of a conventional vapour compression cycle, and improves the energy efficiency of the system. Theoretical models which include geometrical, thermodynamics, mass flow...