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...

A multi-connected air-conditioning system having one outdoor unit and four indoor units, with 5 HP constant speed scroll compressor paralleled with 4 HP frequency inverter scroll compressor, was developed. Many experiments were taken under different working conditions and different system parameters. The performances and the operating characteristics were obtained. The oil-back ability was vali...

Free cooling techniques can be used to substantially reduce energy costs. During cold weather, the outside ambient temperature can help in saving energy in refrigeration systems. The low temperature of the cooling ambient air supply enables free cooling technique to store fresh fruits and vegetables. This energy-efficiency measure can save enough compressor electric power to pay for modulating ...

A comparison of the start-up cooling capacities for an automotive R744 and an automotive R134a air conditioning system is presented. It is shown that development of the cooling capacities during start-up can be described with one correlation for both systems. The comparison of the cooling capacities and the redistribution of refrigerant mass during start-up suggest a strong relationship between...

A dynamic simulation model of a rolling piston type rotary compressor is developed to predict the dynamic characteristics of a variable speed compressor. The model is based on the principles of conservation, real gas equations, kinematics of the crankshaft and roller, mass flow loss due to leakage, and heat transfer. For the computer simulation of the compressor, the experimental data were firs...

The development and application of a software package for the design of twin screw compressors is presented in this paper. The package can be used to calculate the rotor profile, geometrical characteristics, thermodynamic performance, forces on rotor, rotor deflection and cutter shape. A user-friendly interface and some powerful post-processing programs are also included in the package. The app...

A novel aproach to active surge control is presented for a centrifugal compressor driven by an electrical motor. The main idea of the paper is to use the drive itself for surge control. This eliminates the need for additional actuators, and has the potential of energy efficient operation. It is shown that previous unstable operating points to the left of the surge line can be made globally expo...

Two’s complement multipliers are performance and power-critical components for wireless baseband signal processing applications. Parallel clusters of multiplier, multiply-add, multiply-accumulate cores are required to perform complex filter operations in Fast Fourier Transform (FFT) accelerators while consuming ultra low energy/operation [1]. A 12x9b single-cycle two’s complement twiddle multip...