Song G.-E.,Energy Mechanics Research Center |
Lee J.,Energy Mechanics Research Center |
Lee D.-Y.,Energy Mechanics Research Center
International Journal of Heat and Mass Transfer | Year: 2012
With the aim of improving heat exchanger compactness, this study investigates how the optimum configuration of an air-liquid plate heat exchanger changes as the heat exchanger depth decreases. In this respect, optimization of an air-liquid plate heat exchanger with a given frontal area and a given depth is achieved. The optimum fin pitch and plate pitch are obtained to maximize the heat transfer rate based on heat transfer and pressure loss correlations in finned channels. Then, the focus of this study is placed on how the optimum channel configuration changes when the heat exchanger depth decreases for compactness. The results illustrate that the heat transfer performance can remain unchanged if the geometric parameters, such as the plate thickness, the plate pitch, the fin thickness, and the fin pitch, are reduced proportionally to the square root of the flow depth reduction given that the flow remains laminar. This finding is arranged into a simple scaling rule to obtain the configuration of a more compact heat exchanger from an existing configuration. In addition, the scaling arguments are extended to practical situations where the fin thickness and the plate thickness are not properly reduced following the scaling rule due to limitations on available material thicknesses. © 2012 Elsevier Ltd. All rights reserved.
Lee J.I.,Korea University |
Hong S.M.,Korea University |
Byun J.K.,Korea University |
Choi Y.D.,Korea University |
Lee D.Y.,Energy Mechanics Research Center
Transactions of the Korean Society of Mechanical Engineers, B | Year: 2014
Desiccant cooling system is an air conditioning system that uses evaporative cooler to cool air and it can perform cooling by using heat energy only without electrically charged cooler. Thus, it can solve many problems of present cooling system including the destruction of ozone layer due to the use of CFC[chloro fluoro carbon] affiliated refrigerants and increase of peak power during summer season. In this study, cooling performance and exergy analysis was conducted in order to increase efficiency of desiccant cooling system. Especially, using exergy analysis based on the second law of thermodynamics can resolve the issue related to system efficiency in a more fundamental way by analyzing the cause of exergy destruction both in whole system and each component. The purpose of this study is to evaluate COP[coefficient of performance], cooling capacity and exergy performance of desiccant cooling system incorporating a regenerative evaporative cooler in various regeneration temperature and outdoor air conditions. © 2014 The Korean Society of Mechanical Engineers.