A new method is proposed to control the evaporator's superheat with an electronic-expansion-valve (EEV). The conventional PID control with invariable parameters can not receive sound performance because of the variation of evaporators' characteristic parameter under disturbances. To solve this problem, fuzzy algorithm is utilized to adjust parameters ofPID control on line, two practical methods...

Due to the undesirable environmental consequences ofR12, there is a great challenge to find a suitable substitute for Rl2. A new refrigerant blend Rl34a!R218/R600a (88'Yoi9'Yol 3%) called JSCEON 49 has been developed as a long term, zero ozone depletion-potential replacement for Rl2. A computer program was written to calculate the cycle characteristics, such as cooling capacity, coefficient of ...

The pressure drop of refrigerant R-134a flow boiling inside a horizontal tube has been investigated experimentally. The test set-up which was used in this investigation is a well instrumented vapor compression refrigeration system. These instruments are thermocouples, flow meter, pressure gauges and the pressure drop measuring apparatus. This system consisted of three electrically heated evapor...

Continuous capacity modulation, for example by varying compressor speed, is only one alternative to conventional cycling of vapor compression systems. Cycling the compressor at higher frequencies (~0.01–0.1 Hz) than conventional systems (~0.001 Hz) offers a potentially simpler and less costly alternative. Experiments were conducted to quantify effects of steady vs. pulsed flow on the performanc...

The ability of zeotropic mixtures with a temperature glide to operate in liquid recirculation systems is investigated in this paper, and the preliminary results of an experimental comparison between the performance of R134a and of zeotropic mixture R32/Rl34a, (25/75 by mass) are presented. The perfonnance of Rl34a operating in dry expansion mode are also presented as baseline data. INTRODUCTION...

Small amounts of useful power may be generated in polar or subpolar regions during the winter period by placing a heat engine between a large body of water (near PC), acting as a heat source, and the atmosphere (near -25OC), acting as a heat sink. The scheme consists of a fuelless modular system operating on the Carnot cycle. Power is extracted by a reciprocating vapour engine drawing saturated...