Thermal modeling and designing of microchannel condenser for refrigeration applications operating with isobutane (R600a)
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2021
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Abstract
The present study has focused on thermally performance modeling and designing of microchannel condenser (MC-C). It is aimed at contributing to new MC-C designs for refrigeration applications working with isobutane (refrigerant R600a). To this purpose, a novel thermal simulation model has been developed as a design tool to predict the heat capacity, outlet temperature and pressure of the MC-C. The existing correlations in the literature about heat transfer and pressure drop of refrigerant flow inside the microchannel have been evaluated to improve the accuracy of the thermal simulation model. A new heat transfer coefficient correlation has been employed in the model with the purpose of further improvement of the accuracy. An experimental study has been performed to validate thermal simulation model results. It is found that the model predicted isobutane temperature at the outlet of the MC-C and heat transfer capacity with deviations in the range of ±2% and ±1%, respectively. The model has an average of 6.8% MAE for the prediction of the isobutane pressure at the outlet of the MC-C The theoretical air-cooled MC-C designs have been performed to investigate the effect of hydraulic diameter microchannels and pass arrangement on heat transfer performance. The theoretical air-cooled MC-C designs have been modeled and discussed with the experimentally validated thermal simulation model for refrigeration applications. According to the model results, although the heat transfer coefficient inside microchannels increases as the hydraulic diameter decreases, heat transfer capacity decreases. When the pass arrangement is modeled, it is concluded that the designs with high tube numbers in the passes at which vapor quality is still high exhibit higher heat transfer capacity in the MC-C. © 2021
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Keywords
Cooling systems , Heat transfer coefficients , IIR filters , Microchannels , Refrigerants , Refrigeration , Specific heat , Condenser design , Heat-transfer coefficients , Isobutanes , Microchannel condenser , Microchannel heat exchanger , Modeling results , Performance Modeling , Simulation model , Thermal simulations , Transfer capacities , Heat exchangers