In this work, the inversion scheme was used to determine the potential energy surfaces of five polar refrigerant mixtures. The systems studied here are R123-R134a, R123-R142b, R123-R152a, R142b-R134a, and R142b-R152a. The low-density transport coefficients of the refrigerant mixtures were calculated from the new invert potentials by the classical kinetic theory. The viscosity coefficient, binar...

The phaseout ofhydrochlorofluorocarbon (HCFC)-22 will require manufacturers of air-conditioning and refrigeration equipment to find suitable alternatives for this widely-used refrigerant. The R-22 Alternative Refrigerants Evaluation Program (AREP) was established by the Air-Conditioning and Refrigeration Institute (ARI) to assist manufacturers in obtaining performance data on a multitude of R-2...

A comparison of the start-up cooling capacities for an automotive R744 and an automotive R134a air conditioning system is presented. It is shown that development of the cooling capacities during start-up can be described with one correlation for both systems. The comparison of the cooling capacities and the redistribution of refrigerant mass during start-up suggest a strong relationship between...

Flow maldistribution in evaporators can lead to significant degradation of capacity and efficiency of vapor compression equipment. A significant amount of work has previously been done to mend these issues. For variable air flow maldistribution, refrigerant compensation was proposed to reduce the performance degradation. For fixed air side maldistribution, refrigerant circuitry modifications we...

Estimation of starting torque is very important for motor design and for improvement in compressor efficiency. Especially, when compressors are restarted after a period of inoperation, motors sometimes meet large starting torque. The assumed reasons are as follow . The compressors temperature is sometimes lower than any other parts of the refrigerant cycle. In this case, the refrigerant tends t...

The migration characteristics of carbon nanotubes from liquid phase to vapor phase in the refrigerant-based nanofluid pool boiling were investigated experimentally. Four types of carbon nanotubes with the outside diameters from 15 to 80 nm and the lengths from 1.5 to 10 μm were used in the experiments. The refrigerants include R113, R141b and n-pentane. The oil concentration is from 0 to 10 wt....

Numerical simulation is extensively used in heat exchanger design and performance evaluation. While evaluating potential working fluids, pure fluids and fluid mixtures with different component combinations and fractions are compared based on simulation results. Two of the challenges while conducting such studies are the uncertainties of refrigerant properties and the applicability of empirical ...

2,2-Dichloro-1,1,1-trifluoroethane (HCFC-123; CAS No. 306-83-2), a colorless light-ether-odor liquid with a boiling point of 27.6°C (at 1 Torr) and an ozone depletion potential of 0.02, is a substitute for a well-known ozone depleting substance trichlorofluoromethane (CFC-11) as a refrigerant, and 500 tons a year was shipped in Japan in 1996 according to the statistics surveyed by the Japan Flu...

At present, the method adapted to analyze the phase equilibrium properties of refrigerant mixtures is as follows: Firstly, based on some experimental data of· phase equilibrium, the interactire factor bet~een the mixed refrigerants can be derived by using a equation of stalL Second!~ the rapour and liquid phase equilibrium properties are predicted by combining the mixed rule with phase equilibr...

The interest in natural refrigerants, such as carbon dioxide, has been growing in recent years due to the high direct global warming potential of common HFC refrigerants. Despite the environment-friendly characteristics of CO2 as a refrigerant, due to high heat rejection temperatures and transcritical operation, CO2 cannot match the high energy efficiency associated with current HFC technology....