• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.3
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• pp.302-307
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• 2017

An electric steam boiler equipped with a condensate recovery system, which stores the condensate generated after using steam in steam washers, steam cookers, steam irons, and steam cleaners in a condensate tank and supplies compressed air to the condensate tank so that the condensate is recovered to the boiler by the pressure of the compressed air, was studied. In the results of this study, the heat energy balance between the quantity of the heat generated by the non-metallic surface heating element and the quantity of the heat absorbed by the water was good in a range of ${\pm}5%$. In addition, the heat transfer rate increased in proportion to the electric power of the surface heating element heater, the waste heat energy was normally recovered by the recovery of the condensate of the steam boiler equipped with the high compression waste heat recovery system, and the recovery rate of the waste heat exhibited 23%.

• Solar Energy
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• v.11 no.1
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• pp.78-86
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• 1991

Heat transfer characteristics of a rotating heat pipe have been studied numerically and experimentally with using water-ethanol mixture as working fluid. And triangular fins are attached inside the rotating heat pipe. Experimental results generally agreed with numerical results. According to increasing rpm and vapour pressure of the rotating heat pipe, the heat transfer rate increased. And also according to decreasing the concentration of ethanol, the heat transfer rate increased. In the case of using the pure ethanol as working fluid, the heat transfer rate was about 80% of using distilled water. The heat transfer rate and operating temperature difference of the rotating heat pipe was much influenced by ethanol concentration, and the optimum ethanol concentration was 0.2.

• Fire Science and Engineering
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• v.22 no.5
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• pp.72-78
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• 2008

The mass loss rate and heat release rate of EPS sandwich panel cores were analysed using variable external irradiation level. The experimental materials were exposed to incident heat fluxes form 20 to 50 kW/$m^2$. For the measurement of mass loss rate and heat release rate, the size of specimen was $100mm{\times}100mm{\times}50mm$ and the samples were 3 different kinds. The combustion heat were carried out from the Oxygen bomb calorimeter and the mass loss rate and heat release rate were carried out from the Mass loss calorimeter according to ISO 5660-1. As the results of this study, the mass loss rate of Type A, B, and C were 2.7 g/$m^2s$, 2.8 g/$m^2s$, and 2.3 g/$m^2s$ and the heat release rate of Type A, B, and C were 58.23 kW/$m^2$, 47.19 kW/$m^2$, and 50.06 kW/$m^2$ respectively at the heat flux of 50 kW/$m^2$. In conclusion, when the heat release characteristics applied to a classification system of Canada, Type A and C can be classified grade C-3, and Type C can be classified grade C-2 from all data of this study.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.8
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• pp.1183-1194
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• 1998

This paper describes a theoretical model developed for analyzing the heat transfer of automotive cooling systems. From the model, heat transfer rate of automotive cooling systems can be predicted, providing useful information at the early stages of the design and development. The aim of the study is to develop a simulation program for automotive cooling system analysis and a performance analysis program for analyzing heat exchanger. Heat release rate from combustion gas to coolant through cylinder wall in engine cylinder was analyzed by using a two zone combustion model. This paper studied how cooling condition would affect engine heat release rate and measured temperature distribution of coolant in water jacket.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.4
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• pp.894-901
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• 2014

This study concerns the performance of condensation heat transfer in two-phase loop thermosyphons. In the present work, R134a has been used as the working fluid. Liquid fill charge ratio defined by the ratio of working fluid volume to total internal volume of thermosyphon, heat flux and wind speed of condensation have been used as the experimental parameters. The results show that the filling rate of working fluid and heat flux are very important factors for the operation of two-phase loop thermosyphons. The optimum liquid fill charge ratio for the best condensation heat transfer rate was 80%.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.6
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• pp.741-747
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• 2023

In this study, the heat transfer characteristics were numerically analyzed to investigate the possibility of utilizing cooling water using liquid nitrogen. From the study, as the mass flow rate of the hot fluid increased, the heat transfer rate increased by 8.9-81.7%. And lowering the inlet temperature of the hot fluid resulted in increase in the heat transfer rate by 33.8-71.5%. As for the filling level of liquid nitrogen, as higher filling level led to a decrease in the outlet temperature and an increase in the overall heat transfer coefficient.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.9
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• pp.817-824
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• 2000

The fluidized solid particles not only increase heat transfer rates but have a cleaning function eliminating contaiminated substances caused from condensate water. An experiment was performed to measure heat transfer rates and pressure drops in a fluidized heat exchanger with circulating solid particle for constant heat transfer rate. As a results, the heat transfer rate increased by 26.9~2.6%, heat transfer coefficient by 11.9~2.7%, and pressure drop by 79.1~10.9% at the gas velocity of 6.1 ~12.1 m/s and solid particle flow rate of 100~50 kg/h with the heat exchanger of H: 50 mm, $D_p=2 in,\; and\;D_{BP}$=30 mm.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.10
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• pp.886-893
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• 2000

A good understanding of the heat transfer distribution is very important to suppress the deformation of steel products. In this study, the local heat transfer coefficients are experimentally investigated to understand the heat transfer distribution of thick steel plates with even flat spray nozzle. The steel slabs are cooled down from the initial temperature of about $1000^{\circ}C$ , and the local heat transfer coefficients and surface temperatures are calculated from the measured temperature-time history. The results show that the local heat transfer coefficients of spray cooling are dominated by the local droplet flow rate, and in proportion to becoming more distant from the center of heat transfer surface, the local heat transfer coefficients decrease with the decrease of the local droplet flow rate.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1481-1486
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• 2004

This report presents experimental results on the heat transfer coefficients in the boiling region of spray cooling for actual metallurgical process. In this study, the heat flux distribution of a two dimensional dilute spray impinging on hot plate was experimentally investigated. Based on the experimental results, they classified the heat transfer area into the stagnation region and wall-flow region. In the stagnation region, the local heat transfer coefficient relates mainly to the droplet-flow-rate supplied from spray nozzle directly, so the local heat transfer coefficients is good agreement with the predicted values from correlation for spray cooling proposed by former report However, the local heat transfer coefficient in wall-flow region is larger than predicted values, and it is found that the rebounding droplets-flow-rate must be accurately evaluated to predict the local heat transfer coefficient in this region.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1358-1361
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• 2012

This paper presents a study on the analysis for activation time and threshold value of heat detection sensor using HRR(Heat Release Rate). And it is represented to quantity of heat to activate heat detection sensor. The experiment is conducted to measure activation time and HRR of fire detection sensor burning alcohol and n-heptane. In order to burn the alcohol and n-heptane using $43.5cm(L){\times}43.5cm(W){\times}5cm(D)$ and $33cm(L){\times}33cm(L){\times}5cm(D)$ steel pan and the quantity of alcohol and n-heptane are 2.5 L and 650 g, respectively. The results show that peak HRR are in case of alcohol 66.13 kW and in case of n-heptane 151.64 kW, respectively. Total heat releases of heat detection sensor are in case of alcohol approximately 20.7 MJ and in case of n-heptane approximately 18 MJ, respectively.