Since conventional crank-driven compressor had many difficulties to increase efficiency due to mechanical loss, new kind of compressor has been paid much of attention by the compressor manufacturers. The free piston compressor mechanism has been one of those kinds. The compressor manufacturers developed an energy efficient free piston linear resonance compressor for a household refrigerator. In...

Mathematical models have been popularly applied to study the compression processes of superheated refrigerant vapor in compressors. As to the case when refrigerant enters a compressor cylinder in the state of liquid and vapor mixture, however, the availability of fundamental studies is very limited. -A mathematical model is presented to simulate the compression processes of two-phase saturated ...

We present a novel 4-2 compressor for designing multi-operand addition circuits. The design is based on a current mode circuit from which the equivalent voltage mode circuit is derived. This circuit can be used to build very fast multi-operand addition structures. We provide a gate level cost and speed comparison between our design and existing 4-2 compressors. Also, we make an analytical compa...

Possibility of a system leakage in an air-conditioning system always exists. Once a leakage occurs refrigerant and oil escape from the system and compressor. This paper determines the characteristics of the losses. Two important factors affecting the loss characteristics are location of leakage in the system and speed ofleakage or leakage rate. This paper then reasons the tested actual loss cha...

A novel aproach to active surge control is presented. A centrifugal compressor driven by an electrical motor is studied, and the drive itself is used for surge control, thus elliminating the need for additional actuators. It is shown that by using the rotational speed of the motor as control, previous unstable operating points to the left of the surge line can be made globally exponentially sta...

Based on the low of the eighth power of speed of M.J. Lighthill this article has derived the calculating formula for the air dynamic noise power in the compressor, and analysed the factors to affect the noise, also indicated that the dynamic noise in the compressor mainly comes from the valve jet noise; the principle to reduce the dynamic noise is to get a small Reynolds number Re; the emphasis...

In the recent years, the main obstacles for raising the operating efficiency are instabilities of the compressor system. The related dynamics and control schemes then cause lots of interests among engineers and researchers. Two main phenomena, which cause the instabilities, are the “surge” and the “stall” behaviors of the compressed gas. The so-called “surge” is characterized as a one-dimension...

A dynamic model based on the thermoand ‡uidmechanic processes taking place in a centrifugal compressor is validated. The background for this is the need for a energy based model including the rotational speed as a state in order to perform energy based active surge control. The response of the model is compared with experimental results from the Energy Technology Laboratory at Eindhoven Univers...

This paper describes the concept and the design features of a new, oilfree, reciprocating high pressure compressor for technical gases. The compressor is unique in concept and design, and introduces various new design elements. A magnetic coupling makes the compressor hermetic and allows inlet pressures of up to 16 bar. A new kind of clearance seal in the high-pressure stages allows reliable oi...