Fluorinated hydrocarbon refrigerants have especially in Europe been drawn into the focus of the public debate concerning the background of reducing greenhouse active substances. This debate concentrates mainly on the GWP (Global Warming Potentials) properties of the substances. To step forward from a material based discussion to a useful dialogue about substances in their respective application...

Performance of a reciprocating refrigerator compressor with mixed-refrigerants (MR) was investigated experimentally. The current, standard methods of testing compressors and presenting performance data were found unsuitable for MR, and a new experimental apparatus was designed for a ·direct flowrate measurement with MR. Representative test data for Refrigerant R-12 and for a mixture of R-22/R-1...

Recent interest in natural refrigerants has created a new impetus for studies of CO2 as a working fluid in vapour compression systems for refrigeration and air conditioning. Two major drawbacks to its use are the very high pressure differences required across the compressor and the large efficiency losses associated with the throttling process. To overcome the throttle losses, a number of propo...

Compression of pure refrigerants in the two-phase flow region has a number of advantages for the performance of vapor compression systems. Compressors may be lubricated by liquid refrigerant so that the process side of the cycle is not contaminated by lubricant. The compression process can be realized in the two-phase region preventing superheating with its associated irreversibility losses. Th...

The present paper summarizes the activities at LTT-Erlangen on the field of thermophysical properties research for pure refrigerants and refrigerant mixtures. For the characterization of their thermophysical properties dynamic light scattering (DLS) has been intensively applied as a key tool during the past two decades. Beside a representation of the essential features of DLS for the determinat...

Two phase flow in a horizontal tube has widespread applications, particularly in the condensers of refrigeration and air conditioning systems. Pressure drop prediction is especially important for condensers because the local condensing temperature is a function of local pressure, affecting the mean temperature difference in the heat exchanger. In the present analysis, two phase flow is treated ...

New lubricants have been developed to meet the performance demands of modem refrigerants and system components. A brief review of current refrigeration oil developments is presented. It is well known that the new lubricants used with polar refrigerants tend to absorb water. The ester hydrolysis process and the effect on the essential lubricant properties are described. The effect of increased w...

The imminent phaseout of R-11, R-12, and R·llS because of their high ozone depletion potentials has prompted many independent investigations of alternative or subst:i t:uee refrigeranes, ei eher as pure compounds or as mixtures of t:wo or more environmentally acceptable fluids. There are several motivations for investigating mixtures. There are very few pure compounds which can be used for refr...

It is good to be able to pass on the best wishes of the International Institute of Refrigeration (IIR) and to remind you that the IIR will be holding its Gustav Lorentzen Memorial Conference in Glasgow next year. I hope that the IIR conference will be as well supported and as valuable as this CIBSE/ASHRAE conference. You are warmly invited to attend the Gustav Lorentzen conference in Glasgow, w...

Refrigerants are commonly used as heat transfer fluid in refrigeration, pumps, and air conditioning systems. Nanorefrigerants a special kind of nanofluid synthesized by dispersing nanoparticles into refrigerants or lubricant oil to improve its thermophysical characteristics. The optimization the properties nanorefrigerant strongly depends on successful synthesis procedures for producing stable ...