• 한국자동차공학회논문집
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• 제22권3호
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• pp.60-67
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• 2014

The battery cells in lithium-ion battery pack assembled with high-capacity and high-power pouch cells, are commonly cooled with thin aluminum cooling plates in contact with the cells. For HEV/EV lithium-ion battery systems assembled with high-capacity, high-power pouch cells, the cells are commonly cooled with thin aluminum cooling plates in contact with the cells. Thin aluminum cooling plates are cooled by cold plate with coolant flow paths. In this study, the effect of the battery cooling system design including aluminum cooling plate thickness and various position of cold plate on the cooling performance are investigated by using finite element methods (FEM). Optimal cooling plate and cold plate design are proposed for improving the uniformity in temperature distributions as well as lowering average temperature for the cells with large capacities based on the simulation results.

• Design & Manufacturing
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• 제12권1호
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• pp.18-25
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• 2018

Both injection and injection molding dies have evolved into advanced technology. Product quality is also evolving day after day. Therefore, the conditions of the injection mold and the injection conditions are becoming important. In order to improve the quality of the product, the Hardware part of the mold has developed as an advanced technology, and the Software part has also developed with advanced technology. This study deals with the cooling part, which is part of the hardware. In addition to fluid cooling, which is commonly used in the industry, by using gas cooling identify the phenomena that appear on the surface of the product and the critical point strain of the product to find the optimal cooling. Electronic parts and automobile parts whose surface condition is important, the cooling process is important to such a degree that they are divided with good products and defective products according to the cooling process at the time of injection. By controlling this important cooling and reducing the injection time with additional cooling, the product quality can be increased to the highest production efficiency. In addition, high efficiency can be achieved without additional investment costs. This study was conducted to apply these various advantages in the field.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.217-222
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• 2011

This study examined the cooling performance of a solar heating and cooling system for an office building using the dynamic simulation program (TRNSYS). This solar heating and cooling system incorporates evacuated tube solar collectors of $204m^2$, storage tank of $8m^3$, 116.2kW auxiliary heater, single-effect $LiBr/H_2O$ absorption chiller of 20RT nominal cooling capacity. It was found that for the representing day showed peak cooling load the annual average collection efficiency of the collector was 32.9% and coefficient of performance of single-effect $LiBr/H_2O$ absorption chiller was 0.68. And the results shows for the cooling season the solar fraction of the solar heating and cooling system was 32.2% and maximal and minimal solar fraction was 63.4% for May 17.9% for July respectively.

• Corrosion Science and Technology
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• 제9권5호
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• pp.216-222
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• 2010

Most of the thirteen substations in operation in the metropolitan area were installed around the year 2000, and since water cooling methods are used to directly withdraw heat from transformer oils, a stable supply of electric power is required through optimal maintenance of facilities. The water cooling tower installed outdoors, which uses the water supply as sprinkler water, experiences the most problems. Since more than 90% of the cooling water is reused, the dissolved composition in the water becomes concentrated due to long operating hours, and impurities dissolve in the water due to air flowing in from the outside, forming hard scales on the outer surface of the cooling tube, and in extreme cases, reacting with the tube material composition, leading to corrosion. As a result, not only is cooling efficiency lowered, but in extreme cases the cooling tube must be replaced. In this study, the characteristics and composition of the scales formed on the cooling tube were analyzed and corrosion characteristics of material types were identified in order to find an efficient maintenance method for cooling tubes. In addition, the degree of dissolution of various chemicals were investigated during the removal of scales that have been formed.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.578-584
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• 2019

The occurrence of white plume in the cooling tower is phenomenon that the steam in the air through the cooling tower fan is condensed again by the cold ambient air to become saturated moist air. Accordingly, this can cause many problems like spoiling landscape around the cooling tower, odor of ambient air, falling accident by frozenness in the winter, and traffic accident, etc. This study was to install the heat exchanger in the inside of the cooling tower in order to prevent the white plume phenomenon in the cooling tower without affecting the performance of cooling tower. In addition, this study was to discharge the part of cooling water into the atmosphere through the recirculation of heat exchanger after creating dry air by heating the saturated moist air to the dew point temperature. At that time, this study was to conduct the experimental study in order to secure the optimal design data to prevent the white plume in the cooling tower because it checked the dry·moist temperature and relative humidity in the inside·outside of cooling tower on the moist air, and evaluated the performance of the heat exchanger.

• 한국농공학회지
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• 제36권3호
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• pp.113-121
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• 1994

Since it is difficult to expect the normal production of plants in greenhouses during hot summer season in Korea, certain provisions on the control of extreme environmental factors in summer should be considered for the year-round cultivation in greenhouses. This study was carried out to find a method to suppress the temperature rising of nutrient solution by cooling, which is able to contribute to the improvement of the plant growth environment in hydroponic greenhouse during hot summer season. A mechanical cooling system using the counter flow type with double pipe was developed for cooling the nutrient solution efficiently. Also the heat transfer characteristics of the system was analysed experimentally and theoretically, and compared with the existing cooling systems of nutrient solution. The cooling capacities of three different Systems, which used polyethylene tube in solution tank, stainless tube in solution tank, and the counter flow type with double pipe, were evaluated. The performance of each cooling system was about 41 %, 70% and 81 % of design cooling load in hydroponic greenhouse of 1 ,000m$^2$ on the conditions that the flow rate of ground water was 2m$^3$/hr and the temperature difference between two liquids was 10 ˚C According to the results analysed as above, the cooling system was found to have a satisfactory cooling capability for regions where ground water supply is available. Fer the other regions where ground water supply is restricted, more efficient cooling System should be developed.

• 설비공학논문집
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• 제15권11호
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• pp.943-956
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• 2003

A numerical program has been developed for the simulation of automotive engine cooling system. The program determines the mass flow rate of engine coolant circulating the engine cooling system and radiator cooling air when the engine speed is adopted by appropriate empirical correlation. The program used the method of thermal balance at individual element through the model for radiator component in radiator analysis. This study has developed the program that predicts the coolant mass flow rate, inlet and outlet temperatures of each component in the engine cooling system (engine, transmission, radiator and oil cooler) in its state of thermal equilibrium. This study also combined the individual programs and united into the total performance analysis program of the engine cooling system operating at a constant vehicle speed. An air conditioner system is also included in this engine cooling system so that the condenser of the air conditioner faces the radiator. The effect of air conditioner to the cooling performance, e.g., radiator inlet temperature, of the radiator and engine system was examined. This study could make standards of design of radiator capacity using heat rejection with respect to the mass flow rate of cooling air. This study is intended to predict the performance of each component at design step or to simulate the system when specification of the component is modified, and to analyze the performance of the total vehicle engine cooling system.

• 한국지열·수열에너지학회논문집
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• 제20권2호
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• pp.1-10
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• 2024

The introduction of the sector coupling concept has expanded the scope of ESS utilization, resulting in the importance of thermal management of ESS. To ensure the safe use of the lithium-ion batteries that are used in ESS, it is important to use the batteries at the optimal temperature. To examine the utilization of liquid cooling in ESS, numerical study was conducted on the thermal characteristics of 21700 battery modules (16S2P array) during liquid cooling using Novec-649 as insulating fluid. The NTGK model, an MSMD model in ANSYS fluent, was used to investigate thermal characteristics on the battery modules with liquid immersion cooling. The results show that the final temperature of the battery module discharged at 5 C-rate is 68.9℃ using natural convection and 48.3℃ using liquid cooling. However, the temperature difference among cells in the battery module was up to 0.5℃ when using natural convection cooling and 5.8℃ when using liquid cooling, respectively, indicating that the temperature difference among cells was significantly increased when liquid cooling was used. As the mass flow rate increased from 0.01 kg/s to 0.05 kg/s, the average temperature of the battery module decreased from 48.3℃ to 38.4℃, confirming that increasing the mass flow rate of the insulating fluid improves the performance of liquid immersion cooling. Although partial liquid immersion cooling has a high cooling performance compared to natural convection cooling, the temperature difference between modules was up to 8.9℃, indicating that the thermal stress of the battery cells increased.

• 생물환경조절학회지
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• 제24권3호
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• pp.147-152
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• 2015

온실의 냉방부하 산정방법 개발을 위하여 열수지 방법에 기초한 냉방부하 산정식을 구성하고, 포그냉방 온실에서 냉방부하를 실측하여 검증하였다. 포그냉방 온실의 냉각열량은 포그분사에 의한 증발수량에 물의 증발잠열을 곱하여 구할 수 있다. 여기서, 증발수량은 포그 분사량에 증발효율을 곱하면 구할 수 있으며, 즉 분무수량을 계측하고 포그시스템의 증발효율을 알면 온실의 냉방부하를 실측할 수 있다. 따라서 온실의 냉방부하 실측을 위하여 실험온실에서 포그시스템의 증발효율을 실험하고, 실험온실의 열환경 계측과 더불어 포그 분사량을 계측하여 냉방부하 산정방법을 검토하였다. 먼저 냉방부하 산정식의 환기전열량을 검토하기 위하여 냉방을 실시하지 않은 상태에서 환기량 실측 실험을 통해 비교한 결과 열수지식을 이용한 환기전열량 예측은 비교적 양호한 결과를 보이는 것으로 나타났다. 이류체 포그시스템의 증발효율은 0.3~0.94의 범위를 보였으며 평균 0.67로 나타났고, 환기율이 증가함에 따라 커지는 것으로 나타났다. 포그냉방을 실시하면서 온실의 환경을 계측하여 열수지식으로 냉방부하를 계산하고, 분무량 실측치로부터 증발 냉각열량을 구하여 비교한 결과 냉방부하 계산치와 실측치는 대체로 유사한 경향을 보이는 것으로 나타났다. 냉방부하가 낮은 경우에는 실측치에 비하여 약간 크게 예측되었고, 냉방부하가 높은 경우에는 실측치보다 작게 예측되었다. 온실의 냉방시스템 설계 시에는 최대냉방부하를 이용하여 냉방설비의 용량을 결정하게 된다. 따라서 냉방부하가 큰 쪽에서 실측치보다 작게 예측되는 부분은 검토가 필요하지만 설비용량 산정시의 안전계수를 고려하면 본 연구에서 제시한 냉방부하 산정방법은 온실의 환경설계에 적용할 수 있는 것으로 판단된다.

• 한국항해학회지
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• 제15권4호
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• pp.41-58
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• 1991

The cooling degree days and the number of cooling days are used as important research materials not only in the field of design for building and cooling facilities but also in the government's establishment of energy policy. The purposes of this dissertation are to clarify the distribution of the cooling degree days and the number of cooling days by using the daily mean air temperature of 95 weather stations in Korea, and to show the distribution charts of the same cooling degree days and the same number of cooling days in order to help the practical uses of the materials. In cases of the base temperatures $24^{circ}C$, $25^{circ}C$, $26^{circ}C$, and $27^{circ}C$, the cooling degree days and the number of cooling days are shown in Table 5. The distribution charts of the same cooling degree days and the same number of cooling days are shown in Fig. 6 to Fig. 8 and Fig.9 to Fig. 11 respectively. As a result of this dissertation, Jeju Island and southern inland regions(especially Jeonju, Daegu, Gwangju) have a larger value than central regions and northern regions because of the influences of the terrain effect, and western coast regions have usually a larger value than eastern coast regions at the same latitude. The largest value appears in August of the year and the second in July, and the smallest in September. And southern inland area surrounded by Imshil, Goechang, and Boeun has a much smaller value than the other areas of its vicinity.