Aero gas turbine engines have been using mainly film cooling and convection cooling techniques. For operating at high gas temperature amongst different cooling options the transpiration cooling technique has emerged as the most promising technique to improve the gas turbine cycle performance by allowing higher turbine inlet temperatures. This paper investigates the advantages of transpiration c...

This paper presents a semi-empirical steady-state model of an air-cooled water chiller. The first part of the paper shows how the model is built by associating a scroll compressor and two heat exchanger sub-models. The second part of the paper presents the parameters identification process based on published manufacturer data (for the compressor and the whole chiller models). The only encounter...

The National Renewable Energy Laboratory (NREL) and U.S. Department of Energy (DOE) are interested in developing more efficient vehicle air conditioning (A/C) systems to reduce fuel consumption in advanced vehicle designs. Vehicle A/C systems utilizing electrically-driven compressors are one possible system design approach to increasing A/C system performance over various drive cycle conditions...

For a given linear compressor, the geometric configuration of the PTR (pulse tube refrigerator) affects the dynamic behavior of the linear compressor as well as the cooling performance of the PTR. The geometric configuration of each component precisely determines the flow impedance which contains the flow resistance, the inertance effect, and the compliance effect. In this paper, several simula...

This study, which developed a laboratory prototype of a hermetic C02 compressor, was motivated by three primary factors. First, the C02 cycle is important because of global concern about ozone depletion and global wanning. Second, the leak tightness, efficiency, size and weight of hermetic motor-driven compressors make them preferable to open-type compressors for conventional residentiallcommer...

A thermodynamic process of power generation has been developed for a gas turbine, a steam turbine, and a compressor, supported by adiabatic expansion or compression processes. Recently, the possible inlet temperature of gas turbines has been increased to 1500°C or more, and the inlet temperature of steam turbines also has been increased to 650°C. At these high-temperature conditions, turbine no...

Since conventional crank-driven compressor had many difficulties to increase efficiency due to mechanical loss, new kind of compressor has been paid much of attention by the compressor manufacturers. The free piston compressor mechanism has been one of those kinds. The compressor manufacturers developed an energy efficient free piston linear resonance compressor for a household refrigerator. In...

This article presents the results of the experimental runs of a prototype of R744 (CO2) refrigeration system operating in a both air conditioning and heat pump mode when heat rejection is done in supercritical region. The prototype system is sized for a compact car. Data presented are in the limited range of operation. Further optimization and extension of operating range is underway. Test faci...

Refrigeration or cooling technology is increasing, especially regarding the coolant, almost all new vehicles now use air conditioning to condition in vehicle cabin, but there are still many aspects that currently have not been paid much attention, compressors, compressors for rely on engine as a direct driver which makes fuel consumption more wasteful and reduces performance of vehicle. The pur...