This chapter provides the engineer and the researcher with correlations and models for the prediction of the critical aspects of the boiling heat transfer of mixtures. This chapter offers a reliable, hands-on resource for solving common problems across pool boiling and flow boiling applications such as miscible mixtures, refrigerant/lubricant mixtures, additives, and refrigerant/nanolubricants....

Roger Morgan, Lecturer, Brian L. Sutcliffe, Laboratory Technician, Oil is required in refrigeration and heat pump systems for lubrication of the compressor, expansion valve and other moving p~rt7. Ho~ever, the oil is often highly m~sClble wlth the refrigerant, in proportlons which depend on pressure and temperature, as well as oil and refrigerant type. As some of the oil circulates around the s...

An interpolation-based method for computing refrigerant properties which can be used in simulations of vaporcompression air-conditioning equipment is presented. This method uses bicubic functions to interpolate between samples of the Helmholtz energy surface as a function of temperature and density. Three beneficial characteristics of this method are discussed: speed, accuracy, and consistency,...

In this study, condensation heat transfer experiments were conducted with two types of plate and shell heat exchangers (P&SHE) using R-134A. An experimental refrigerant loop has been established to measure the condensation heat transfer coefficient of R-134A in a vertical P&SHE. Two vertical counter flow channels were formed in the P&SHE by stacking three plates of geometry with a corrugated tr...

This paper gives a study of how to carry out a combined refrigerant volume control using an electronic expansion valve (EEV) and the specific measures to apply selftuning fuzzy algorithm to refrigeration control system. The simulation analysis on the superheat fuzzy controller was completed by Simulink. Different scale factors and weight factors were employed during the process, and their effec...

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...

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 ...