A dynamic model of a centrifugal compressor capable of system simulation in the virtual test bed (VTB) computational environment is presented. The model is based on first principles, i.e. the dynamic performance including the losses is determined from the compressor geometry and not from the experimentally determined characteristic performance curves. In this study, the compressor losses, such ...

We determine the asymptotically optimal compressor function for a multidimen-sional compander when the source is memoryless. Under certain technical assumptions on the compressor function, it is shown that the best k-dimensional compressor function consists of the best scalar compressor functions for each component of the source vector. The mean-squared error of optimal multidimensional compand...

Computer Engineering Group Technical Report Electrical and Computer Engineering Department University of Toronto November 18, 2004 Abstract This work proposes a novel checkpoint store compression method for giga-scale, coarse-grain checkpoint/restore. This mechanism can be useful for debugging, post-mortem analysis and error-recovery. The effectiveness of our compression method lies in exploiti...

Method of measurement of pressure drop in ports of hermetic compressor under discharge pressure is presented. ?,22 gas at 298 psig and 215QF condition pumped by hermetic compressor is directed into flow bench type pressure chamber where variety of orifices is installed and pressure drop is measured directly. Compressor and flow bench are installed in series on standard calorimeter which measure...

This paper presents how we improved the efficiency in rotary compressor. At first, we made effort to estimate the power losses in the compressor, to analyze the operating conditions of the bearing and to calculate the performance of the compressor. Next, the temperature in housing and pressure in cylinder were measured in real compressors in order to obtain the data on the internal conditions o...

The present paper is a numerical and experimental comparative study of hermetic and semi-hermetic reciprocating compressors working with carbon dioxide as fluid refrigerant against the conventional R134a hermetic compressors. When cooling conditions for one-stage compressor type (i.e., evaporation temperatures between 7.2oC and –10oC) have been considered, the numerical and experimental results...

Compressors are a primary cause for numerous HV AC noise and vibration problems. Typically, vibration energy is transmitted from the compressor to the chassis through piping and isolation mounts. The design of these attachments is thus of paramount importance in determining the dynamic performance of a HV AC unit. Below certain frequencies, compressor vibration can be well described as a rigid-...

This paper proposes a robust design scheme for the control of surge phenomenon appearing in a centrifugal compressor. It is known the surge instability in compressor might lead to reduce the operating efficiency and even damage the machinery while both of unstable compressor characteristics and compressor load torque are hard to exactly measure in the practical application. Based on the assumpt...

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 major problems encountered in a reciprocating compressor are because of the valve failure .The other problem of leakage past the piston because of the worn out piston rings has also been placed in the reciprocating compressor. Pressure pulsations generated inside the piping of a reciprocating compressor may be taken as one of the tool for diagnosing the nature of fault inside the compressor...