• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.238-238
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• 2003

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.37-43
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• 2015

Evaporative cooling is a very effective way for exhaust heat recovery that uses both latent heat and sensible heat. This study investigated the performance of a heat recovery system using evaporative cooling. The experimental apparatus comprised a plastic heat exchanger, a water spray nozzle, an air blowing fan, a water circulation pump, and measuring sensors for the temperature, humidity, and flow rate. The effectiveness of the sensible heat recovery without evaporation was measured and compared with that of the total heat recovery with evaporation. The effectiveness of the sensible and total heat recoveries decreased as the air flow rate increased, and a much higher effectiveness was obtained with the counterflow arrangement in both cases. For total heat recovery, the effectiveness increased with the water flow rate, and the parallel flow arrangement was found to be more sensitive to the water flow rate than the counterflow arrangement.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.6
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• pp.279-288
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• 2017

Heat generation rate in a telecommunication cabinet increases due to the continued usage of mobile devices. Insufficient removal of heat intensifies the cabinet temperature, resulting in the malfunction of electronic devices. In this study, we assessed both aluminum and plastic heat exchangers used for cooling of the telecommunication cabinet, and compared the results against theoretical predictions. The aluminum heat exchanger was composed of counter flow parallel channels of 4.5 mm pitch, and the plastic heat exchangers were composed of cross flow triangular channels of 2.0 mm pitch. Samples were made by installing two plastic heat exchangers in both series and parallel. Results showed that the heat transfer rate was highest for the series cross flow heat exchanger, and was least for the aluminum heat exchanger. The temperature efficiency of the series cross flow heat exchanger was 59% greater than that of the aluminum heat exchanger, and was 4.3% greater than that of the parallel cross flow heat exchanger. In contrast, the pressure drop of the parallel cross flow heat exchanger was significantly lower than other samples. The heat exchange efficiency was also the largest for the parallel cross flow heat exchanger. The theoretical analysis predicted the temperature efficiency to be within 3.3%, and the pressure drop within 6.1%.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.4
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• pp.407-416
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• 2005

The kimchi refrigerator is the electric home appliance which is used for the maturing and preserving of the kimchi in domestic and foreign market. The kimchi refrigerator is composed in 3 main parts as insulation. kimchi container, machinery room. The heat exchanger of kimchi refrigerator is made of aluminum and the other parts are made of steel and polymer. Also, kimchi refrigerator is expensive and heavy as compared with same class of refrigerator until now. In the present study, the possibility to replace heat exchanger from aluminum to thermal conductive plastic was analyzed and experimented. The thermal conductive plastic has $10{\sim}100$ times heat conductivity than that of normal plastic. It is known that heat transfer process is dependent not only conduction but convection or radiation. Thermal conductivity of the applied material in this research is over than 2 W/mK, thermal conductivity doesn't play a vital role on heat transfer. In this study, temperature is the most important parameter on the kimchi refrigerator and the temperature of kimchi refrigerator's heat exchanger was measured and compared with the temperature calibrated by CFD analysis on the inside wall of the kimchi refrigerator. It is important to keep constantly the inside temperature of the Kimchi refrigerator. Besides numerical analyses for the new thermal conductive plastic for heat exchanger were executed with the various height of evaporation tube. A series of experiments were conducted to compare the performance of the two heat exchanger made of aluminum and thermal conductive plastic at the same condition and certified the possibility of the thermal conductive plastic. According to these results, it was confirmed that the conventional aluminium heat exchanger can be replaced by thermal conductive plastic successfully.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.9
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• pp.743-749
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• 2015

The purpose of this study is to predict the performance of an indirect evaporative cooling system, and to evaluate its energy saving effect when applied to the exhaust heat recovery system of an air-handling unit. We derive the performance correlation of the indirect evaporative cooling system using a plastic heat exchanger based on experimental data obtained in various conditions. We predict the variations in the performance of the system for various return and outdoor air conditioning systems using the obtained correlation. We also analyze the energy saving of the system realized by the exhaust heat recovery using the typical meteorological data for several cities in Korea. The average utilization rate of the sensible cooling system for the exhaust heat recovery is 44.3% during summer, while that of the evaporative cooling system is 96.7%. The energy saving of the evaporative cooling system is much higher compared to the sensible cooling system, and was about 3.89 times the value obtained in Seoul.