Nowadays Heat pump water heater becomes a very hot topic in hot water industry. However it has many problems because of higher condensing temperature and large-scale operation conditions. Based on the problems, this paper presents a prototype which was assembled using a rotary compressor with refrigerant injection port. By making use of the liquid injection function of the compressor, the syste...

In this paper, we propose an FPGA design of an audio signal level compressor, based on an approximation algorithm using a polynomial. To implement a compression characteristic in a digital audio system, the gain calculation with fractional numbers is performed by using a polynomial expression to approximate the power operation, then the compressor can be designed with a number of additions, mul...

Stable operation of both axial and radial compressors is constrained by the occurence of aerodynamic flow instabilities: rotating stall and surge. Developments in the understanding of the physics behind these instabilities and ideas of how t o stabilize the compressor system, have opened the door t o a new era in the field of compressor control. This study gives an overview of the current state...

A prototype compressor for application in high temperature compression-resorption heat pumps has been designed, manufactured and tested. The paper presents details of the compressor design together with test results obtained on the pilot heat pump plant with the prototype compressor. The compressor is of the twin-screw type and its stainless steel rotors operate without timing gears. There is n...

Motivated by the high speed of real-time data acquisition, computational power, and low cost of generic PCs and embedded-PCs running Linux, this thesis addresses new methods and approaches to fault detection, model identification, and control. Fault detection. A series of faults was introduced into a 3-Ton roof-top airconditioning unit (RTU). Supply and condenser fan imbalance were detected by ...

The development and upgrade of test installations, instrumentation and the data acquisition system of an existing turbofan engine test rig are described for an experimental program which was planned and initiated to investigate the transient unsteady operation of gas turbine engines with an emphasis on compressor operation. The objective of the program was to examine aerodynamic instabilities s...

Flow losses through the valve ports contribute a significant portion to the total energy loss of a high speed compressor. As a result, in the energyconscious world of today, compressor designers are always busy finding methods and techniques to minimize these losses. It can be argued that the various fundamentally different compressor concepts would have different valve flow losses simply as a ...

This paper is intended as a review of the recent research and development of refrigeration and gas compressors in Japan. The review has been carried out by the papers as source material that are reported in the transactions, proceedings, and magazines in mechanical engineering field. Most compressor companies in Japan have long efforted to develop and apply advanced technology for innovative re...

Compressor performance for liquefied natural gas (LNG) main refrigeration units is very important due to the direct link between compressor efficiency and LNG production for a fixed amount of power. Dresser-Rand recently designed a series of new stages for the LNG market that provided improved efficiency and a wider range of operation. Industry practice is to rig test new stages prior to applic...

This study is an attempt to determine if there is any speed sensitive phenomenon in flapper valve operation. Valve motion is measured at various speeds in a reciprocating residential refrigerator/freezer compressor. Laser Doppler Velocimetry is used to measure the velocity of a point on the flapper at the center of the port for the suction valve. This velocity data is numerically integrated to ...