• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1523-1528
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• 2000

Four Suffolk ewes were used in Latin Square switch over design to study the effects of varying levels and sources of protein on heat production and thermoregulatory responses at daytime high ($33^{\circ}C$ temperature. They were fed Italian ryegrass hay supplemented with fishmeal and/or urea, providing three different levels of crude protein (CP) (low/unsupplemented: 7.9, medium: 11.6, and high: 15.8%) at $1.5{\times}maintenance$. Feeds were distributed at 0900 (30%) and 1700 (70%). Urea diet caused higher heat production and increased vaginal temperature compared to fishmeal and fishmeal-urea mix diets. Time spent standing, skin temperature and respiration rate of sheep fed urea were similar with those of sheep fed fishmeal. Sheep fed diet with low CP level had higher heat production, increased vaginal and skin temperature than sheep fed diet with medium CP content. Sheep on high CP diet produced significantly more heat than sheep fed medium CP diets. Their vaginal temperatures were similar with those of sheep fed medium CP diet but lower than those of sheep fed low CP diet. Respiration rates of sheep and time spent by them for standing on all diets did not differ significantly. These results suggest that urea is inferior protein supplement for thermoregulation of animal at hot environment, as it induced higher heat production than fishmeal and fishmeal-urea mix. Thermoregulatory response on fishmeal-urea mix diet was similar to fishmeal diet. Increasing CP of the diet from low to medium gives advantage for thermoregulation of animal. Increasing CP further to high level was not beneficial as it resulted in the responses of sheep similar to those on low protein diet.

• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.36-42
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• 2000

An experimental study was carried out to investigate the effects of inclined angles of channel on thermal stability of electronic components. In this study, it is focused on the natural convection heat transfer from an inclined parallel channel with discrete protruding heat sources. The material used for the inclined parallel channel was epoxy-resin, while air as the cooling fluid. Heat transfer phenomena for inclined angles of $\psi$=$15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$ and for the range of $9.52{\times}10^5/ were analyzed. The thermal fields in the channel were visualized by Mach-Zehnder interferometer. Also, local temperatures were measured by thermocouples along the channel wall and heat sources surface. As a result, for the range of $4.29{\times} 10^5/, a useful correlation of mean Nusselt number was proposed as a function of modified channel Rayleigh number.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.3
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• pp.237-245
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• 2020

In this paper, I introduce Phase-Change Cooling for thermal management of high power devices that can be applied to High Power Laser and Electric Propulsion Systems which are composed of multiple distributed superheat sources. Phase-Change Cooling can be good used to efficient cooling of their heat sources. Phase-Change Cooling has extremely high efficiency of two-phase heat transport by utilizing heat of vaporization, relatively low flow rates and reduced pumps power. And I suggest TPI(Thermal Performance Index) which is a quantitative performance index of Phase-Change Cooling for thermal management. I quantify the performance of Phase-Change Cooling by introducing TPI. I present the test results of TPI's changing refrigerant, heat sink and flow rate of the Phase-Change Cooling system through the experiments and analyze these results.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.131-132
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• 2022

Looking at recent construction cases at winter construction sites, there is a risk that heat sources such as kerosene fans and fossil fuels (brown coal, molded carbon) used in concrete will cure rapidly, so in situations where further curing is impossible after formwork removal, the outer wall and the entire slab are exposed to rapid external deterioration, resulting in delays in concrete strength expression and until collapse accidents. In this study, we applied kerosene fans and tropical circulating electric heat fans mainly used as curing heat sources at construction sites, comparative analysis. also verified the performance of structures during concrete curing due to thermal convention / circulation performance, concrete demand strength expression, and implementation of electric heat fans by heavy disaster methods.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.1
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• pp.1-10
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• 2001

The present study investigated the effects of experimental parameters on the thermal characteristics of an in-line 6x1 array of discrete heat sources for a test multichip module using water, PF-5060 and paraffin slurry. The parameters were heat flux of 10-40W/$cm^2$. Reynolds number of 3,000~20,000 and mass fraction up to 10% for paraffin slurry The size of paraffin slurry was within 10~40$\mu$m before and after experiments. The local heat transfer coefficients for the paraffin slurry were larger than those for water. Thermally fully developed conditions were observed after the third or fourth row (five or seven times of the chip length) and the paraffin slurry showed effective cooling performance at the high heat flux The paraffin slurry with the mass fraction of 5% showed the most efficient cooling performance when the heat transfer and the pressure drop in the test section are considered simultaneously. The experimental data at the fourth and sixth rows are best agreed with the values predicted by the Malina and Sparrow`s correlation among other correlations, and the empirical correlations for water and 5% paraffin slurry were obtained at the first and sixth rows when the channel Reynolds number is over 3,000.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.469-475
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• 2016

Thermal batteries are primary reserve power sources, which are activated upon the melting of eutectic electrolytes by the ignition of heat sources. Therefore, sufficient thermal insulation is absolutely needed for the stable operation of thermal batteries. Currently, excessive amount of heat sources is being used to compensate the heat loss in the cell stack along with the insertion of metal plates and thermal insulators to reserve heat at the both ends of cell stack. However, there is a possibility that the excessive heat flows into the cell stack, causing a thermal runaway at the early stage of discharge. At the same time, the internal temperature of thermal batteries cannot be maintained above the battery operating temperature at the later stage of discharge because of the insufficient insulation. Therefore, the effects of Phase Changing Material(PCM) plates were demonstrated in this study, which can replace the metal and insulating plates, to improve the thermal insulation performance and safety of thermal batteries.

• Environmental and Resource Economics Review
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• v.32 no.3
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• pp.191-215
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• 2023

This study focuses on evaluating and comparing residents' acceptance of unutilized heat such as hydrothermal energy and waste heat from waste incineration and data centers in the case that they are used as district heat sources. This is because securing residents' acceptance is significantly important in order for unutilized heat to be considered as a heat source of district heating and cooling to achieve neutrality in the heating and cooling sector. A survey of heating consumers' perception on unutilized heat energy is conducted and a conjoint model is used to analyze the willingness to pay of heating consumers on incineration heat, water heat, and data center waste heat and to compare them with existing gas heat sources. As a result of the analysis, it is confirmed that district heating using hydrothermal energy and data center waste heat is preferred to district heating from heat from a natural gas plant or waste incineration.

• The KSFM Journal of Fluid Machinery
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• v.19 no.6
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• pp.19-25
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• 2016

Anti-icing is important in gas turbines because ice formation on compressor inlet components, especially inlet guide vane, can cause performance degradation and mechanical damages. In general, the compressor bleeding anti-icing system that supplies hot air extracted from the compressor discharge to the engine intake has been used. However, this scheme causes considerable performance drop of gas turbines. A new method is proposed in this study for the anti-icing in combined cycle power plants(CCPP). It is a heat exchange heating method, which utilizes heat sources from the heat recovery steam generator(HRSG). We selected several options for the heat sources such as steam, hot water and exhaust gas. Performance reductions of the CCPP by the various options as well as the usual compressor bleeding method were comparatively analyzed. The results show that the heat exchange heating system would cause a lower performance decrease than the compressor bleeding anti-icing system. Especially, the option of using low pressure hot water is expected to provide the lowest performance reduction.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.3
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• pp.279-286
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• 2006

The present study concerns the annual performance evaluation of a hybrid-renewable energy system with geothermal and solar heat sources for hot water, heating and cooling of the residential buildings. The hybrid energy system consists of ground source heat pump of 2 RT for cooling, solar collectors of $4.8m^2$, storage tank of 250 liters and gas fired backup boiler of 11.6 kW. The averaged coefficients of performance of geothermal heat pump system during cooling and heating seasons are measured as 4.1 and 3.5, respectively. Also solar fraction for hot water is measured as 35 percent. Overall, the results shows that the hybrid-renewable energy system satisfactorily operated under all climatic conditions.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.841-855
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• 2018

The purpose of this study is to estimate the available potential heat source for heat pump in the district heating supply area in the city. Unused energy potentials were estimated and integrated based on open source based data. In particular, geographical spatial analysis of recoverable heat energy density and heat demand in the heat source area of large retailers and public sauna facilities in the DH network located in the southern part of the metropolitan area (Pyeongtaek-si) was conducted. As a result of the study, the DH network area had a total potential energy of 1,741.7 toe/year for the two heat sources of large retailers and public saunas. It is estimated that 1,006.9 toe/year, which is 57.8% of the total, can be linked to the district heating. The large retailers showed a positive correlation with the floor area and energy use of 0.4937. The recoverable energy intensity was estimated to be $0.0017toe/m^2$ per unit area and $0.0069tCO_2/m^2$ for greenhouse gas emissions. In addition, public saunas were analyzed by comparing the empirical case with the theoretical calculation, and it was estimated that energy conservation estimate of 80% was $0.0315toe/m^2$ per bath area and $0.1183tCO_2/m^2$ for greenhouse gas emissions. The total potential energy amount of this area was positively correlated with the heat demand of apartment house by administrative district, and it was confirmed that it had a relatively high potential energy especially in traffic and commercial center.