Typical automotive air conditioning refrigeration systems employ thermostatic expansion valve or orifice tube controls in a single stage refrigerant circuit. A new automotive air conditioning compressor has been developed that has a two stage compression process, which makes designing and producing a two stage refrigerant circuit more practical. Since this compressor can function in a single st...

the present work is the successful extension of an improved equation of state (eos) to refrigerant fluids. the objective is the prediction of isothermal and saturated liquid densities of refrigerants. two temperature-independent parameters appearing in the modified eos are closely related to critical point properties of refrigerant fluids. our results showed that, the proposed eos can predict w...

an analytical equation of state has been previously modified by papari et al. for representing the volumetric properties of molecular fluids. however the performance of that eos has not been yet well investigated for refrigerant fluids. this study extended that equation to 19 liquid refrigerants to predict their densities at isothermal and saturated states. two temperature-independent parameter...

Present study is undertaken to optimize the lubrication reliability and frictional loss of the dynamically-loaded jownal bearing with R600a refrigerant application. A mathematical model is developed for analyzing the dynamics of the journal bearing system with the mobility method. It takes into account the effects of the refrigerant species, aspect ratio, clearance ratio and surface roughness. ...

This paper investigates the feasibility of hydrocarbon refrigerant mixtures as a replacement for HCFC-22 in residential air-conditioning and heat pump systems. The COP and the seasonal performance factor (SPF) were calculated using a UA-model for single component refrigerants and refrigerant mixtures. Simulations were run for pure propane and the mixtures of propane/i-pentane, propane/n-butane,...

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...