This paper presents the two-phase condensation heat transfer and pressure drop characteristics of R-513A as an alternative refrigerant to R-134a in a 9.52-mm OD horizontal microfin copper tube. The test facility had straight, section with active length 2.0 m was cooled by cold water circulated surrounding annular space. annular-side coefficients were obtained using Wilson plot method. average c...

The transition from CFC-12 (GWP=10,900) to HFC-134a (GWP=1,430) in the 1990’s in new vehicle air conditioners eliminated the contribution to ozone depletion potential (ODP) from new vehicles and reduced the direct Global Warming Potential (GWP) by over 80%. One proposed alternative is HFC-1234yf (GWP=4). Despite the phase-in success of HFC-134a as a zero ODP automotive refrigerant it is still a...

Supercritical (sc) CO2 is by far the most commonly used supercritical fluid. Reasons for this are that it is inexpensive, non-toxic, has low critical constants (Tc = 304.20 K, Pc = 72.8 bar) and is environmentally benign. The major problem encountered when using sc CO2 is the low solubility of polar solutes. Hydrofluorocarbon (HFC) solvents such as difluoromethane (HFC 32) and 1,1,1,2-terafluor...

This paper describes results of a multiobjective comparative assessment of several established and emerging technologies for extraction of a natural antimalarial substance, artemisinin. Extractions by hexane, supercritical carbon dioxide, hydrofluorocarbon HFC-134a, ionic liquids, and ethanol were considered. Hexane extraction is an established technology and appears to be the most cost-effecti...

The effect of the hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants on environment through attack its halogen contents-chlorine fluorine, ozone layer toxic nature such refrigerants, has paid attention researchers to work towards getting suitable alternatives using hydrocarbons (HC) or blends with HFC refrigerants. This study was centered a retrofit R-134A good coefficient ...

More than one year has passed since refrigerant for refrigerator was changed from CFC12 to HFC134a. Long term reliability of refrigerator in HFC134a refrigerant system is mainly dependent on lubrication of moving parts of compressor and clogging of capillary tube. To maintain better practical reliability in components in compressor such as refrigeration lubricant,metallic materials and motor in...