(Dr. Sam Shelton, advisor)
"Enhanced Finned-Tube Condenser Design and Optimization"
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-flammability, and high working pressures. Therefore, R-410A is a strong candidate to replace R-22 in the residential market. The condenser designs that have been optimized, primarily by experimental trial and error, over the last five decades will become obsolete with this new refrigerant. This study will develop models, optimization methodology, and software which will allow the designer of high efficiency R-410A air-conditioning systems to optimize the condenser design, including the use of enhanced fins. Cost and/or area constraints may be specified by the designer. This will allow the design of an optimum R-410A finned-tube condenser heat exchanger with a minimum of experimental trial and error. In addition, this study will investigate some of the unanswered issues in generic heat exchanger design optimization, including the appropriate figure-of-merit, entropy generation effects of enhanced surfaces, and second law thermoeconomic isolation. With these questions answered, a methodology will be established for heat exchanger analysis and design optimization so that alternative condenser designs for residential air conditioner systems can be compared on the same constrained basis.