Key
1469
Conference Year
2014
Keywords
Rolling piston compressor, overflow, volumetric efficiency
Abstract
The rotary compressor with rolling piston is a widely used compressor with less clearance volume, while it is minimized from normal scale to meso or micro scale, the input and exit ports dimension is limited by port requirement and lead to a certain clearance volume, therefore, keeping or improving its volume efficiency is an important issue. Although rolling piston compressor is a kind of compact structure compressor, the existence of the clearance volume is inevitable in a compressor, the more the clearance volume, the lower the volumetric efficiency of compressor. The overflow is a method to improve the volumetric efficiency of a compressor which had been discussed in wankel compressor, in the overflowing process the clearance space with high pressure is connected directly with the space with lower pressure, mostly that is in the moment, one of the chambers in the rotary compressor is at the end of the exhaust process, and another chamber is at the sucking stage or the initial compression process. The gas pressure in the clearance volume is visibly higher than that in the compression chamber. The high-pressure gas in the clearance volume flows into the compression cylinder via a certain way; this flow considerably increases the pressure in the compression cylinder and decreases the pressure in the clearance volume. Thus, the intake and exhaust times means to be extended, and the volumetric efficiency and the cooling capacity of the compressor can be substantially enhanced. In this paper, we introduce the effect of input and exit dimensions on the volume efficiency of rolling piston compressor, and the overflow design on a rolling piston compressor that fully uses the high-pressure gas in the clearance volume, and discuss its effect on the performance of a compressor by theoretical analyses. Usually, the coefficient of performance of a vapor refrigeration cycle with the compressor overflow has a certain decrease compared with the conventional compressor, but the volumetric efficiency of the compressor with overflow and the cooling capacity of the thermodynamic cycle recesses are visibly higher than those of the conventional compressor in terms of the same operation and dimension parameters. The overflow has beneficial effect on miniaturizing the compressor
Volumetric Efficiency Improvement by Overflow in Rolling Piston Compressor