Numerical simulation is extensively used in heat exchanger design and performance evaluation. While evaluating potential working fluids, pure fluids and fluid mixtures with different component combinations and fractions are compared based on simulation results. Two of the challenges while conducting such studies are the uncertainties of refrigerant properties and the applicability of empirical ...

2,2-Dichloro-1,1,1-trifluoroethane (HCFC-123; CAS No. 306-83-2), a colorless light-ether-odor liquid with a boiling point of 27.6°C (at 1 Torr) and an ozone depletion potential of 0.02, is a substitute for a well-known ozone depleting substance trichlorofluoromethane (CFC-11) as a refrigerant, and 500 tons a year was shipped in Japan in 1996 according to the statistics surveyed by the Japan Flu...

The interest in natural refrigerants, such as carbon dioxide, has been growing in recent years due to the high direct global warming potential of common HFC refrigerants. Despite the environment-friendly characteristics of CO2 as a refrigerant, due to high heat rejection temperatures and transcritical operation, CO2 cannot match the high energy efficiency associated with current HFC technology....

A. 1 ohansson and P. Lundqvist Dept. of Energy Technology Div. of Applied Thennodynamics and Refrigeration The Royal Institute of Technology, KTH Stockholm, Sweden Test results from field retrofit situations, where R22 has been changed to Isceon 59 1 and R407C in two identical chillers, shows that both substitutes require more subcooling than R22 to give the system a satisfying performance. It ...

Name: S u s a n W. S t e w a r t Brief Description: The HCFC refrigerant, R-22, is the most widely used residential air-conditioner refrigerant in the U.S. However, it is scheduled to be banned in new equipment beginning in 2010 due to its high ozone depletion potential (ODP). A new refrigerant, R-410A has zero ODP and favorable performance characteristics such as good cycle efficiency, non-fla...

A pulse width modulation (PWM) bypass capacity control technique for air conditioners has been developed to achieve high scroll compressor efficiency over a wide capacity range, and we investigated the technique’s fundamental characteristics in this study. With this capacity control technique, the refrigerant flow rate is controlled by periodically switching a full load mode, in which the refri...

UNLABELLED Topical anesthesia is widely advocated in pediatric dentistry practice to reduce pain and anxiety produced by administration of local anesthesia. Cryoanesthesia to lessen the injection pain has also been reported to be promising. However, sparse literature reports exist regarding clinical efficacy of these agents. AIM The purpose of this study was to compare the efficacy of the ref...

A hybrid algorithm of an enhanced version of Mann-Kendall trending and data analysis is proposed to solve the limitations of current technology in detecting and diagnosing cooling system refrigerant faults in general and refrigerant leakage specifically. A data abstraction mechanism is applied over feed of temperatures and power measurement to calculate and store only the significant informatio...