Steady state and dynamic simulation and optimization are a key step in the design of heating, ventilation, airconditioning and refrigeration (HVAC&R) systems. It is well known that the computation time in such simulations is dominated by the refrigerant thermophysical property calculations. These calculations generally involve calculating all thermophysical properties given one or two independe...

Refrigerant blends and pure refrigerants have wide applicability in thermal engineering. One of the critical parameters in the design and evaluation of thermal equipment is the heat transfer coefficient, which can be difficult to determine for refrigerants that undergo phase change within the equipment. For pure refrigerants, classical experimental relations developed by Gungor and Winterton (G...

Maintaining a high level of gasket performance with current non-asbestos materials can be difficult. The replacement of previous asbestos containing sheet gaskets with other types of fiber reinforced sheet gaskets required a thorough evaluation using a simulated service testing procedure. In this paper we will discuss the details of the fabrication of a test fixture which simulates the temperat...

In recent years, conservation of energy has become a challenging issue in air-conditioning applications. In order to overcome this issue, many researchers have recommended the use of a Parallel Flow Condenser and a low Global Warming Potential and Ozone Depletion Potential refrigerant, such as R32, in air conditioning systems. However, PFC faces the critical challenge of flow maldistribution in...

The capacity control of a vapor-compression refrigeration system is investigated for three different capacity control schemes. In a hot-gas by-pass control scheme, the refrigerant is by-passed from the compressor and injected back into the suction line to decrease the cooling capacity, whereas in cylinder-unloading scheme, one or more cylinders are unloaded to decrease the refrigerant mass flow...

Air conditioning contributes significantly to building energy consumption in hot climate regions. In addition to greater cooling requirements in hot climates, cooling equipment efficiency decreases with increasing outdoor temperature. Therefore, it is advantageous to develop improved technologies that can achieve higher efficiency at high ambient conditions. In this paper, two novel compression...

The objective of this study is to design and briefly investigate the cooling performances of an air conditioning system for a special purpose vehicle under various experimental conditions. An air conditioning system with two parallel refrigeration cycles consisting of two compressors and two condensers for satisfying the required cooling performance of the special purpose vehicle was tested und...

The Refrigerant RS02, an azeotrope of CFCllS and HCFC22, is an important refrigerant in commercial refrigeration, especially for low temperature applications using single stage compressors. current users of R502 are faced with an earlier than ~nticipated phase-out and are under great pressure to find suitable alternates for retrofit and o.E.M. (new) applications. Single components like HCFC12S,...

A fully equipped automotive air-conditioning test system consists of 5 main components: a compressor, a condenser, an orifice tube, an evaporator and an accumulator. R-134a is used as refrigerant. The coefficient of performance, evaporator cooling capacity, compressor power consumption, total mass flow rate, vapor mass flow rate, liquid mass flow rate and oil in circulation, pressures and tempe...

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...