• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.6
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• pp.474-481
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• 2001

Aluminum/Freon22 grooved hat pipes which have 26 axial grooves in a cross-section were manufactured and tested. The performance test was conducted by varying filling ratio and tilt angle. Operation limit, thermal resistance, overall heat transfer coefficient were investigated. The experimental result was compared with previous study which conducted in the case of a heat pipe with combined wick. The experimental result shows that thermal resistance of this heat pipe is twice smaller than that of the heat pipe with combined wick and operation limit is increased about 75%, comparing with that of heat pipe with combined wick.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.2
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• pp.236-243
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• 1999

Aluminum/Freon-22 heat pipes were manufactured and tested which have a special wick geometry combining axial groove and screen mesh. There were 14 axial grooves in a cross-section and these were covered by two layers of 350 mesh screens to enhance the thermal performance. The performance test was conducted by varying the thermal load and tilt angle. Furthermore, the operation limits and overall heat transfer coefficient were investigated. The experimental results will be useful in a variety of applications, especially in design and manufacturing of a high-efficiency heat exchanger and energy recovery systems.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.6
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• pp.109-119
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• 2021

Thermal environment of city is getting worse due to severe urban heat island caused by climate change and urbanization. Green roof improves the urban thermal environment and save the cooling energy in buildings. This study presented a green roof combined with a storage system that stores rain-water and supplies water through a wick and evaluated the temperature reduction effect as surface temperature and amount of evapotranspiration. For about a week, the surface temperature using a infrared thermal imager and the evapotranspiration by recording change of module weight were measured at intervals of 30 minutes from sunrise to sunset. The results show that the mean surface temperature of the green roof was 15.4 degrees lower than that of the non-green roof from 12:00 P.M. to 14:00 P.M. There was no significant difference between mean surface temperature of green roof with and without storage system immediately after rain, but more than a week after rain, there was a difference with average of 2.49 degrees and maximum of 4.72 degrees. The difference in daily amount of evapotranspiration was measured to be 1.66 times on average. As drought stress increased over time, the difference in daily amount of evapotranspiration and surface temperature between with/without storage system increased simultaneously. The results of the study show a more excellent cooling effect of green roof combined with the rainwater storage system.