Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity f...

This paper investigates the effects of nonazeotropic refrigerant mixtures (NARMs) as replacement of CFCs. The thermodynamic propert1es of NARM R22/R142b which is harmless to ozone layer are analyzed. The tests about water-to-water heat pump and dual-evaporator refrigerator-freezer using R22/R142b as alternative to R12 are introduced. The test results show R22/Rl42b is of energy conserving effec...

According to the results of the international testing program AREP, the most likely replacements for HCFC-22 refrigerant will be blends of HFCs. However, as concerns about their global warming potential increase, other options should also be considered. As a naturally occurring substance, propane would be an ideal refrigerant, except for its flammability. When dealing with a flammable refrigera...

Refrigerant mass migration and redistribution have been regarded as factors influencing the performance of air conditioning and refrigeration systems. This paper presents a dynamic model of an R134a automotive A/C system that is able to capture the shut-down and start-up cycling dynamics including the refrigerant mass migration transients. Building upon recent work (Li and Alleyne, 2010), the h...

Variable refrigerant flow (VRF) systems are easily subjected to performance degradation due to refrigerant leakage, mechanical failure or improper maintenance after years of operation. Ideal VRF systems should equip with fault detection and diagnosis (FDD) program to sustain its normal operation. This paper presents the fault diagnosis method for refrigerant charge faults of variable refrigeran...

Using identical mechanical hardware used in an automobile, a stationary test bench has been developed for an automotive air conditioning system (AACS). However, a number of additional sensors have been used in the system for an accurate assessment of its performance. The steady state performance of the system has been investigated for three independent variables, namely the refrigerant charge l...

Heat pump technology has been rapidly developed recently as a clean and efficient heating method. Continuous capacity modulation of heat pumps is necessary for enhancing room thermal comfort and reducing start-stop losses. A novel capacity modulation method for the scroll compressor heat pump system based on refrigerant injection and refrigerant release is proposed. The experiments indicate the...

The TEWI analysis of residential heat pumps shows that it is sensitive to refrigerant emissions and mainly dependent on the seasonal coefficient of performance of the heating unit. Otherwise for countries where electricity is mainly produced by a combination of nuclear-power and hydro-power, the direct emissions become not negligible compared to the indirect emissions. Both direct and indirect ...

In spite of the advantages of zeotropic refrigerant mixtur~" [1], the industrial >tpplications of mixtures have been very limited up to now. The major problem is seen iu the leakages occuring in refrigeration plants and so a possible change in composition. Another disadvantage is that no simple methods for determination of the concentratiou insick the t:ydc i\rc available. This paper pre$ents t...