a modification of peng-robinson equation is described wherein in the parameter b is expressed as a linear function of temperature. the modified equation is then applied to a series of light hydrocarbons and refrigerants, and predicted values for vapor pressure, saturated vapor volume, saturated liquid volume and the heat of evaporation are compared with the corresponding experimental data. cons...

Practical and empirical equations of transport properties have been developed for refrigerant compounds. These equations have been used to develop correlations for experimental heat transfer coefficient (IITC) for both evaporation and condensation in smooth tubes. Model calculations have been compared with recent experimental data, and reasonable agreement has been obtained. INTRODUCTION We hav...

Vortex tube is a simple energy separation device, also known as Ranque tube or Hilsch tube, which can separate a high-pressure stream into two different hot and cold streams. Since its simple structure and unique temperature separation characteristics, vortex tube has been widely used in various industries. In recent years, with the in-depth study of the vortex tube, it has been found that comp...

Organic fluids could be classified into wet, dry and isentropic types according to the slope of the saturated vapor envelope on a temperature-entropy diagram. Due to the limited availability of pure isentropic refrigerants, attempts are made to make isentropic mixtures by mixing wet and dry refrigerants with an appropriate composition in the present work. A simple principle for selecting potent...

The transition from CFC-12 (GWP=10,900) to HFC-134a (GWP=1,430) in the 1990’s in new vehicle air conditioners eliminated the contribution to ozone depletion potential (ODP) from new vehicles and reduced the direct Global Warming Potential (GWP) by over 80%. One proposed alternative is HFC-1234yf (GWP=4). Despite the phase-in success of HFC-134a as a zero ODP automotive refrigerant it is still a...

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...

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...

Analysis of compression mechanisms requires a prediction of the pressure during the compression and expansion processes. A common model is the polytropic process, PV = constant. This paper presents a method for determining the best polytropic exponent to use and suggests values for some common refrigerants used in the air conditioning and refrigeration industry. INTRODUCTION When a gas undergoe...

The modified square well Potential is combined with perturbed-hard-trimer-chain (PHTC) EOS to predict the solubility parameter of several fluids including alkanes, refrigerants and molten polymers. The performance of the proposed model has been evaluated by predicting the solubility parameter of 12 hydrocarbons,3 refrigerants, and 12 polymers. From the 263 data points for hydrocarbons and refri...

This paper presents the simulation study and comparison of C02 and R502 as refrigerants. At first, as a single stage vapor compression refrigeration cycle's refrigerant, C02 can be used in subcritical and transcritical situations. The performances are studied completely. The results show that C02 has the same or better performance compared to R502's in certain temperature ranges. Finally C02 an...