BA-92-05-2 -- Boiling Heat Transfer Enhancement in Tube-Bundle Evaporators Utilizing Electric Field Effects PDF

To study utilisation of the electrohydrodynamic (EHD) boiling augmentation in a tube bundle, three types of apparatus have been made. One is a bundle element with five tubes, another is a short bundle with 50 tubes, and the third is a bench-scale model with a capacity of 2.09 X 10 to the power 5 kJ/h. The experimental results clarified that the EHD augmentation of boiling heat transfer in the bundle is as effective as that in a single tube. However, a phenomenon called absorption current for HCFC-123 has been observed, which occurs at the beginning of the application of high voltage to the fluid. This phenomenon is described, and the development of a new high-voltage power supply to avoid this phenomenon is explained. Finally, a cost analysis demonstrates that commercial plants with EHD evaporators utilising waste energy as a heat source have a higher coefficient of performance (COP) and lower production costs than conventional ones.

KEYWORDS: heat flow, evaporators, tubes, boiling, experiment, R123, refrigerants, high voltage, cost benefit analysis, heat recovery, commercial, coefficient of performance, heat pumps