Micro-scale devices based on the Stirling cycle are an attractive choice for chipand board-level electronics. A new Stirling cycle micro-refrigeration system composed of arrays of silicon MEMS cooling elements has been designed. COMSOL is used to evaluate the thermal performance of the system. Simulation of compressible flow and heat transfer with a large deformed mesh has been successfully imp...

The dependency on fossil fuels for power generation can be reduced by enhancing the energy efficiency of generating systems. refrigeration systems that typically use electricity consume a significant portion supplied to cities. STAND-ALONE system which consists combined Organic Rankine Cycle and Vapor Compression (ORC-VCR) is analyzed using first law thermodynamics. Dry natural hydrocarbons suc...

Water as a refrigerant (R718) is compared with other modern refrigerants (R717, R290 R134a, R12, R22, and R152a) regarding refrigeration capacity and COP (coefficient of performance). A computer program simulating a theoretical vapor compression refrigeration cycle was developed to calculate COPs, compression ratios, and discharge temperatures of the refrigerants from the compressor. The effect...

A cold finger attached to the second refrigeration stage of a DE-201 Displex closed-cycle helium refrigerator has been equipped with a miniature DC motor. The device allows reorientat ion of the crystal at low temperature, without remount ing or warming to ambient temperature. The axis around which the crystal is rotated is inclined by 45 ° to the cryostat axis, which gives a 90 ° change in ori...

Environmentally speaking, of assorted widely-used refrigeration systems, the trans-critical CO2 system is one of the potential competitors. In this research, a horizontal semi-hermetic rolling piston compressor is developed for trans-critical CO2 cycle. This paper also presents a series of mathematical simulation models to identify the main factors influencing compressor’s performance. Based up...

We show in this paper that the common method of specifying ∆Tmin in design of heat exchanger systems may lead to wrong decisions and should be used with care. Although specifying ∆Tmin is reasonable for heat exchanger networks synthesis with given stream data, it should not generally be used for obtaining optimal design data and especially not stream data (temperatures). An alternative simple T...

Now a days, In most of the thermal power plant, where low-pressure steam is being exhausted to the atmosphere as a waste steam. This waste heat could be use to operate many small preheating or cooling equipments or small scale plants. There are many refrigeration systems present for refrigeration and air condition purpose. Such as air refrigeration, vapour compression, vapour absorption etc. In...

Title of dissertation: EXPERIMENTAL AND THEORETICAL INVESTIGATION OF OIL RETENTION IN A CARBON DIOXIDE AIR-CONDITIONING SYSTEM Jun-Pyo Lee, Doctor of Philosophy, 2003 Dissertation directed by: Professor Reinhard Radermacher Department of Mechanical Engineering In a closed loop vapor compression cycle, a small portion of the oil circulates with the refrigerant flow through the cycle components w...

Refrigeration repair workers may be intermittently exposed to fluorocarbons and their thermal decomposition products. A case of peripheral neuropathy (distal axonopathy) in a commercial refrigeration repairman prompted an epidemiological investigation of the health of refrigeration repair workers. No additional cases of peripheral neuropathy were identified among the 27 refrigeration repair wor...