A refrigeration system which was originally designed using R502 as refrigerant was rebuilt to adapt the special requirements of R404A. The experiments, both for R502 and R404A, on this system were done and some parameters such as evaporating temperature, condensing temperature, discharge temperature, compressor input power and so on were measured under different working conditions. Then the ope...

This study attempts to establish a general method to analyze the performances of evaporator coils with complex tube circuitry using a distributed simulation model, which has three elements: branch, tube and control volume. The governing equations for a control volume are presented in the paper together with the computer simulation procedure for branches, tubes and control volumes of a coil. Usi...

Suction accumulator in rotary compressor is an important component from standpoints of compressor cost, performance, sound and ability of controlling excess liquid refrigerant. Because of its importance, it deserves its due attention to enhancement of its functions. This paper first defines functions of an accumulator, lists major design parameters and their common ranges. Then, a couple of maj...

AN EVALUATION OF TWO REFRIGERANT MIXTURES IN A BREADBOARD AIR CONDITIONER William Mulroy Michael Kauffeld Mark McLinden David Didion National Bureau of Standards Gaithersburg, Maryland 20899 An experimental, water-to-water, breadboard heat pump, tha t is one which could easily be reconfigured, was constructed fo r comparison of pure R22 to the refrigerant mixtures R22/R11 4 ahd R13/Rl2. Three e...

A considerable amount of large scale heat pumps working mainly with Rl2 but also partially with Rll4 has been installed in Germany in the past. -As considerable investments have been made, a conversion from Rl2 to Rl34a seems to be an important task. Due to this reason a research project has been started at the University of Hannover to evaluate the possibility of such a conversion. To achieve ...

In Japan, the refrigerant used in room air-conditioners has been changed from HCFC-22 (R-22) to R-410A, a blend of HFC-32 and HFC-125 (50/50 vt%), in order to protect the ozone layer. Generally, the miscibility between the refrigerant and refrigeration oil must be assured, because the oil needs to return to the compressor from the refrigeration cycle and lubricate the sliding parts. Alternative...

When a refrigeration plant operates with a large difference between condensing and evaporating pressures, multistage operation is required to obtain an acceptable performance. In two-stage systems, vessels that combine flash-gas removal and intercooling are commonly used. The disadvantage of these vessels is the large amount of refrigerant required for proper operation. An alternative for these...