%0 Journal Article
%T Calculation of Thermal Pressure Coefficient of R11, R13, R14, R22, R23, R32, R41, and R113 Refrigerants by Data
%A Vahid Moeini
%A Mahin Farzad
%J Advances in Physical Chemistry
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/327419
%X For thermodynamic performance to be optimized particular attention must be paid to the fluidĄ¯s thermal pressure coefficients and thermodynamic properties. A new analytical expression based on the statistical mechanics is derived for R11, R13, R14, R22, R23, R32, R41, and R113 refrigerants, using the intermolecular forces theory. In this paper, temperature dependency of the parameters of R11, R13, R14, R22, R23, R32, R41, and R113 refrigerants to calculate thermal pressure coefficients in the form of first order has been developed to second and third orders and their temperature derivatives of new parameters are used to calculate thermal pressure coefficients. These problems have led us to try to establish a function for the accurate calculation of the thermal pressure coefficients of R11, R13, R14, R22, R23, R32, R41, and R113 refrigerants based on statistical-mechanics theory for different refrigerants. 1. Introduction Popular interest in the use of refrigerant blends started in the late 1950s. The emphasis was placed on energy savings through the reduction of irreversibility in the heat exchanger and on capacity variation during operation through the control of the fluid composition. Worldwide legislation has been enacted through the United Nations environmental program to reduce stratospheric ozone depletion. The Montreal Protocol was approved in 1987 to control production of the suspected ozone-depleting substances, among them chlorofluorocarbons and hydrochlorofluorocarbons, commonly used as refrigerants in the industry. For example, chlorofluorocarbons-(CFCs-) 11, 12 and 113 have been successfully used to determine groundwater recharge ages in the industry. Relatively good agreement exists between individual CFC ages and ages derived from other tracers [1¨C6]. The precise meaning of the internal pressure is contained in a generalized manner in the following well-known thermodynamic equations. United forces of external and internal pressure equalize the thermal pressure which tries to expand the matter. If the thermal pressure of a refrigerant is available, then the thermodynamics properties of refrigerant can be calculated easily. Liquids and dense fluids are usually considered to be complicated on a molecular scale, and a satisfactory theory of liquids only began to emerge in the 1960. However, they show a number of experimental regularities, some of which have been known by theoretical basis [7¨C10]. The first is the internal pressure regularity, in which is linear with respect to for each isotherm, where is the molar density, is the internal
%U http://www.hindawi.com/journals/apc/2013/327419/