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...

Due to the entry into force in 2014 of European F-Gas Regulation n° 517/2014 and subsequent Kigali amendment, phase-out medium high-GWP refrigerants has speeded up all refrigeration fields. The effect on plug-in or stand-alone systems meant that other environmentally friendly must replace R134a with low ultra-low GWP maintaining same operating conditions reducing energy consumption. Extended ex...

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...