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 ...

Designing multipliers that are of high-speed, low power, and regular in layout are of substantial research interest. Speed of the multiplier can be increased by reducing the generated partial products. Many attempts have been made to reduce the number of partial products generated in a multiplication process one of them is Wallace tree multiplier. Wallace Tree CSA structures have been used to s...

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...

Turbo code is recommended as a channel coding scheme, which has been shown to be capable of performing close to the Shannon Limit. In this paper, we compare the performance of both convolutional and block turbo codes over AWGN and Rayleigh fading channels. It is observed that the performance of convolutional turbo code is slightly better in the water fall region and the coding gain ranges from ...

A turbo compressor was investigated to ensure the operational reliability of charging fuel cell systems. This study air-lubricated herringbone bearings support high-speed rotating shaft. For reliable operation rotor bearing system, stable in whole speed range (up 120 krpm), as well low lift-off speed, is an important issue. Some publications containing guidelines for optimized design terms stab...

Abstract High-speed compressor testing is costly due to mechanical complexity and hazardous the high energy involved. In past this has limited speed amount of testing. paper a new rig architecture presented that aims test scaled transonic stage rapidly. It builds upon low-speed rapid developments made at Whittle Laboratory potential accelerate technology development. The power input requirement...

Refrigerant mass flow rate is an important measurement for monitoring equipment performance and enabling fault detection and diagnostics. However, a traditional mass flow meter is expensive to purchase and install. A virtual refrigerant mass flow sensor (VRMF) uses a mathematical model to estimate flow rate using low-cost measurements and can potentially be implemented at low cost. This study e...