fridges are used in various industries, and heat exchanger is one of the main components of these systems; therefore, efficiency analysis of these systems is very important. in many fridges, frost over the heat exchanger tubes or pipes affects the system operation and reduces heat transfer between the refrigerant and ambient, so defrosting systems are usually used to enhance heat transfer. desi...

Results of a high-speed 10-stage axial-flow compressor test involving overall compressor and individual stage performance while stalling and operating in quasi-steady rotating stall are described. Test procedures and data acquisition methods used to obtain the dynamic stalling and quasi-steady in-stall data are explained. Unstalled and in-stall time-averaged data obtained from the compressor op...

It will bring about many problems for a Rl2 refrigerator compressor to use Rl34a as refrigerant directly, such as power increasing, capacity dropping, and noise rising up etc. In order to solve these problems, the mathematical model, optimization model and special test system were built up, many improvements were made by means of the calculating and the testing results. Finally, the performance...

surge is one of the two destructive factors in compressors. surge is the stream instability phenomenon in compressor that imposes severe damages to the compressors. nowadays, suppressingsurge phenomenon is one of the most important issues in oil and gas industries, especially when flow reduction or gas reflux is considered. according to moore-greitzer compressor model, this paper designs an act...

The AeroEclipse® BAN (Trudell Medical International (TMI), London, Canada) was initially developed for use in the hospital environment, optimized for medication delivery using air or oxygen supplied at 50 psig pressure (2, 3). This article describes initial laboratory data with a version (AeroEclipse-XL®) optimized for operation by either table-top (OmbraTM table-top compressor, TMI, 230V AC ve...

In a compressor the existence of the clearance volume is inevitable, even rolling piston compressor is a kind of compact structure compressor, overflow is a method to decrease the effect of clearance volume. In this paper, the overflow design on a rolling piston rotary compressor is discussed, which uses the high-pressure gas in the clearance volume, and discuss its effect on the performance of...

The presence of liquid refrigerant in the compressor cylinder during operation, or liquid slugging, is one of the most common causes of failure in reciprocating compressors. We propose to detect this fault by analyzing the electrical current flowing into the compressor and identifying the change in the load on the motor caused by the presence of liquid in the compressor cylinder. Two different ...

The last decade has seen an increasing awareness that the manner by which a compressor meets the part load conditions of residential air conditioning is a strong dete:cninant of the a.easonal SEER of the air conditioner. The compressor can reSPond to part load needs by cycling if of the single SPeed variety, by cycling between capacity levels if of the multiSPeed variety, by use of internal cap...

There are different technologies to adapt the compressor’s cooling capacity to the changing requirements of the A/C and refrigerant systems when operating with screw compressors. • Distribution of the requirements to several compressors (parallel operation) • Evaporation pressure control with hot gas bypass • Internal bypass in the compressor • Reduction of the compressor displacement by a cont...

HVAC compressor units are major energy consumers in both residential and commercial buildings today. Faulty and energy wasting operation of these units often goes unnoticed due to the corrective action of feedback control. Power system monitoring is an exciting approach for creating inexpensive, highly capable methods to monitor compressor unit performance. In this paper we develop a method to ...