• 대한토목학회논문집
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• 제33권6호
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• pp.2381-2391
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• 2013

일반적으로 에너지파일의 열적 성능에 영향을 주는 중요한 인자로 지반의 열 물성, 열 교환기 형태, 운용방법, 파일 간 열 간섭 등이 고려될 수 있다. 본 연구에서는 지반의 실제 조건을 반영한 수치모델을 통해 이들 인자들이 미치는 영향을 살펴보았다. 지반의 포화 정도에 따라서 파일의 열 교환율은 최대 3배까지 차이를 보였으며, 열 저항은 최대 8.7%의 차이가 발생하였다. 또한 열 교환기 유형이 파일의 열 성능에 영향을 주며, 3U-Type이 W나 U-Type에 비해 상대적으로 높은 열 효율을 보였다. 운용방법에 있어서, 부분가동 시(8시간 가동, 16시간 휴지) 연속가동에 비해서 약 20%의 열효율을 보전할 수 있으며, 장기적인 열 축적현상을 방지하는데 유리하다. 지반의 조건에 따라 군 말뚝에 의한 열 간섭 정도가 달라지는데, 지반이 포화상태에서 건조 상태로 갈수록 군 말뚝에 의한 열 간섭효과는 감소한다. 일반적인 지반조건에서 열 교환 감소율 1%미만을 유지하는 적정 이격 거리는 U-Type에서 최대 3.2D, W-Type에서 최대 3.6D, 3U-Type에서 최대 3.7D로 산정되었다.

• 한국농촌건축학회논문집
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• 제19권4호
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• pp.49-56
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• 2017

Each country in the world currently concentrates on shifting into clean energy, which can be alternative energy, for global environment protection and solution to the problem of fossil fuel depletion. The Korean government is predicted to develop renewable energy, such as solar power, ground power, and offshore wind power, and to increase their supply ratios by ending the use of coals and nuclear power plants. This study conducted experiments on thermal storage performance of Trombe wall thermal storage materials using solar power and simulations in order to offer baseline data for the development of a hybrid air circulation system for heating that can maximize efficiency by simultaneously using solar and geothermal power. The study results are as follows: (1) In all the specimens with 3m, 5m, and 7m in the length of thermal storage pipe, $5.7^{\circ}C$, $7.8^{\circ}C$, and $10.5^{\circ}C$ rose, respectively, as the thermal storage effect of the specimens attaching insulation film and black tape to the general funnel. They were most excellent in terms of thermal storage effect. (2) As a result of thermal performance evaluation on the II type specimens, II-3 ($7.8^{\circ}C$ rise) > II-4 ($5.3^{\circ}C$ rise) > II-1 ($3.9^{\circ}C$ rise) > II-2 ($2.3^{\circ}C$ rise) was revealed, and thus II-3 (insulation film + black tape) was most effective as shown in the I type. (3) This study analyzed air current and temperature distribution inside of the greenhouse by linking actually measured values and simulation interpretation results through the interpretation of CFD (computational fluid dynamics). As a result, the parts absorbing heat and discharging heat around the thermal storage pipe could be visibly classified, and temperature distribution inside of the greenhouse around the thermal storage pipe could be figured out.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.123-128
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• 2008

Generally the window of the building is an objective of mining and having a distant view and also for a circulation it will can open and shut because becomes the structure insulation, the meat detailed drawing it does a very difficult portion, it is. To reduce the loss of the energy which leads, to an air conditioning energy and an expense increase problem the color which the interior furniture and the clothing due to the augmentation and the corpse ultraviolet rays of the unpleasant feeling which is caused by with the transient one solar energy influx which leads the window will burn, it joins in the window and it confronts and the novel solution is demanded.

• 동력기계공학회지
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• 제9권4호
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• pp.5-10
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• 2005

The effect of ultrasonic energy for diesel fuel and blend oil has been revealed in this paper. The experimental setup consisted of a high speed diesel engine with 4 cylinder, dynamometer and ultrasonic fuel feeding system. Ultrasonic energy was added to diesel fuel and blend oil, which is a blend of diesel fuel and rape-seed oil. As engine speed was changed, engine torque and power, brake specific fuel consumption and thermal efficiency were measured in detail. As the results, by adding ultrasonic energy to diesel fuel and blend oil, the engine performance was improved in range of the experiment. The effect of improvement on brake specific fuel consumption and thermal efficiency for blend oil is higher than that for diesel fuel. When ultrasonic energy was added to diesel fuel or blend oil, a rise in engine torque for diesel fuel was higher than that for blend oil, but the effect of ultrasonic energy was small. From these results, it may be desirable to add ultrasonic energy to blend oil for the use of blend oil to diesel engine.

• 태양에너지
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• 제19권4호
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• pp.11-20
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• 1999

The study on ice thermal storage system is to improve total system performance and increase the economical efficiency in actual air-conditioning facilities. To obtain the high charging and discharging efficiencies in ice thermal storage system, the improvement of thermal stratification is essential, therefore the process flow must be piston flow in the cylindrical type. In the influence of the inlet port type, the inflowing water in the distributor type diffuses through the whole storage tank more than in the slot type. In case of the flow process in the ice storage tank, the upward flow type in the charging process and the downward flow type in the discharging process make the stratification well, thereby the loss of energy wored be smaller. The influence of the inlet temperature difference and the change of the inlet flow rate is intensive when the temperature difference is larger, the flow rate is smaller in case of charging and the results are opposite in case of discharging with the reason that the good coduction condition. The total effeciency of the ice thermal storge system is 73% on condition that the porosity in the thermal storage tank is 0.55. This result shows that cylinderical ice storage tank has better storage capacity than rectangular type in case of the same porosity.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.280-285
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• 2001

This paper presents a modelling of thermal discharge performance for a static ice-on-coil ice-storage tank. Through the present study, discharging characteristics were examined with the existing results of theoretical and numerical heat transfer analyses. Also, an experiment was conducted to obtain a real set of discharge performance. The thermal effectiveness, the ratio of the actual heat transfer rate to the maximum possible heat transfer rate, decreased when the stored energy decreased during discharging period. And the effectiveness increased as the coolant flow rate through the storage increased, of which increasing rate decreased abruptly near the maximum and the minimum stored energy. An empirical correlation was obtained from the experimental and the numerical analysis data.

• 한국태양에너지학회 논문집
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• 제36권4호
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• pp.1-9
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• 2016

The purpose of this study was to compare heat shading performance of various blind types in summer. 4 types of blinds were employed and the results are summarized as follows: 1) There were significant differences in indoor thermal environment and heat shading performance between different heat shading devices, and functional blinds demonstrated relatively superior heat shading performance. 2) Indoor long wave radiation influx measures were lowest for the coating roll blind (Blind B), followed by the coating venetian blind (Blind C), the venetian blind (Blind A), the roll blind, and not having any blinds at all. 3) Such examination results carry implications to reduce cooling load and enhance the indoor environment.

• Nuclear Engineering and Technology
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• 제48권5호
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• pp.1083-1095
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• 2016

The design of Prototype Gen-IV Sodium-Cooled Fast Reactor (PGSFR) has been developed and the validation and verification (V&V) activities to demonstrate the system performance and safety are in progress. In this paper, the current status of test activities is described briefly and significant results are discussed. The large-scale sodium thermal-hydraulic test program, Sodium Test Loop for Safety Simulation and Assessment-1 (STELLA-1), produced satisfactory results, which were used for the computer codes V&V, and the performance test results of the model pump in sodiumshowed good agreement with those in water. The second phase of the STELLA program with the integral effect tests facility, STELLA-2, is in the detailed design stage of the design process. The sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger performance test, the intermediate heat exchanger test facility, and the test facility for the reactor flow distribution are underway. Flow characteristics test in subchannels of a wire-wrapped rod bundle has been carried out for safety analysis in the core and the dynamic characteristic test of upper internal structure has been performed for the seismic analysis model for the PGSFR. The performance tests for control rod assemblies (CRAs) have been conducted for control rod drive mechanism driving parts and drop tests of the CRA under scram condition were performed. Finally, three types of inspection sensors under development for the safe operation of the PGSFR were explained with significant results.

• 한국정밀공학회지
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• 제21권3호
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• pp.117-123
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• 2004

A brake disc with helical grooved vent in radial direction is proposed for the improvement of thermal dissipation. The heat transfer phenomenon is analyzed far both the proposed disc and the conventional one using finite element method. The thermal dissipation is considerably influenced by the geometrical differences of the brake discs. The results of the analysis show that the proposed brake disc with helical grooved vent has the improved performance to dissipate the thermal energy more effectively.

• 한국지열·수열에너지학회논문집
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• 제10권1호
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• pp.1-6
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• 2014

In order to evaluate the performance of ground heat source in thermal labyrinth on pre-heating in winter season and pre-cooling in summer season, the followings are made as a conclusion through case study of H project by using the weather data from Korea meteorological administration and CFD model. By making outdoor air inlet via ground heat source in thermal labyrinth for conduction, convection and etc., the temperature rise is $13.4^{\circ}C$as the effect of pre-heating in winter season. On the other hand, as the effect of pre-cooling in summer season, the temperature decrease is $7.2^{\circ}C$. The energy saving rate by the application of ground heat source in thermal labyrinth is 9.1%.