A thermodynamic limitation of single-component working fluids in organic Rankine cycles (ORCs) is the large exergy destruction (and, consequently, useful power loss) associated with evaporation and condensation. Due to their non-isothermal phasechange behaviour, non-azeotropic working-fluid mixtures have shown reduced exergy losses, leading to improved cycle efficiencies and power outputs. Thes...

The refrigerant used in heat pumps significantly influences the overall system performance. However, selecting a proper is no trivial matter due to pumps’ sensitivity selected flowsheet, components, and operating conditions. Herein, holistic approach that covers all these interdependencies simultaneously considering fluid‐dependent compressor efficiencies, point. Six low global warming potentia...

CFD was applied to evaluate the performance of both existing and improved designs for refrigerant distributors. In general, it is better to utilize a spherical base as compared with other shapes and to locate the orifice close to distributor base. These changes tend to improve the robustness of the distributor in terms of providing even flow and phase distribution in different outlet branches w...

refrigerants that are used in refrigeration systems, cause environmental difficulties such as depletion of ozone layer and greenhouse effect. thus, we must find substitutes for such refrigerants, in this paper, the effect of refrigerant on the thermodynamics performance of refrigeration cycles are studied. to do this, a refrigerator that has designed for r12, is simulated. results show that pur...

Properties, such as specific heat, viscosity, and thermal conductivity, are important thermophysical properties in any heat transfer study. Today, these properties are known for numerous fluids, however, there are still many fluids which have not been measured, especially those under the classification of refrigerant mixtures. This paper proposes a new approach for simultaneously measuring thes...

There is no single perfect refrigerant for diverse air conditioning, refrigeration, and industrial applications. The predominant halocarbons (CFCs, HCFCs, and HFCs) combine excellent efficiency and safety with acceptable costs. However, they contribute to ozone depletion potential (ODP) and/or global warming potential (GWP). The Montreal Protocol has eliminated ODP by requiring replacement of C...

Mathematical models have been popularly applied to study the compression processes of superheated refrigerant vapor in compressors. As to the case when refrigerant enters a compressor cylinder in the state of liquid and vapor mixture, however, the availability of fundamental studies is very limited. -A mathematical model is presented to simulate the compression processes of two-phase saturated ...

This study proposes a procedure for a risk analysis for leakages of flammable refrigerants into a poorly ventilated three-dimensional space. It also presents several test cases of risk analyses on flammability and ignitions to a leaked refrigerant. Concentration of a leaked flammable refrigerant at a leakage window, Cin, is determined by mass balance, providing information on the capacity of an...