• Architectural research
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• v.14 no.1
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• pp.35-44
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• 2012

Build-Transfer-Lease (BTL) was introduced to the domestic construction market in 2005. Now, seven years later, the BTL model is most active for educational facilities. In 2011, 93 educational facility projects entered the maintenance stage. Considering the characteristics of today's BTL projects for educational facilities, the main issues are the initial performance and maintenance of educational facilities and the service-providing status for the 20-year operational management period, in relation to providing safety and convenience to students, the facility users. Seeking a solution, local education offices and departments in charge of BTL under the Ministry of Education, Science, and Technology have been exploring various methods of evaluating operational maintenance performance from various perspectives. For educational facility BTL projects, however, the appropriateness of initial operation performance evaluation, rather than considering the 20-year operational management period, is controversial in regards to sustainability. On this account, performance evaluation items in four areas-operational maintenance evaluation, facility performance status evaluation, maintenance subject evaluation, and sustainable change response evaluation-should be extracted. An indicator of facility performance evaluation is presented in this study through an AHP survey targeting experts, as part of establishing an operation performance evaluation system for educational facility BTL projects.

• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2652-2659
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• 2020

The methyl iodide (CH₃I) removal performance of tri-ethylene-di-amine impregnated activated carbon (TEDA-AC) used in the air cleaning unit of nuclear power plants (NPPs) should be maintained at least 99% between 24 month-performance test period. In order for evaluating the effectiveness of TEDA-AC on the removal performance of CH₃I in nuclear power plant during the operation of NPPs, the long-term test for up to 15 months was carried out under the simulated operating conditions (e.g., 25 ℃, RH 50%, ppb level poisoning gases injection) at nuclear power plants (NPPs). The TEDA-AC samples were analyzed with the Brunauer-Emmett-Teller (BET) specific surface area and TEDA content as well as CH₃I penetration test. It is clearly evident that more than 99% of CH₃I removal performance of TEDA-AC was observed in the TEDA-AC samples during 15 months of long-term operation under the simulated NPP operating conditions including the ppb level of organic and oxide form of poisoning gases. BET specific surface area and TEDA content that can affect the CH₃I removal performance of TEDA-AC were also maintained as those in new TEDA-AC during 15 months of long-term operation.

• The KSFM Journal of Fluid Machinery
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• v.7 no.3 s.24
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• pp.39-47
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• 2004

Micro gas turbines are designed with low turbine inlet temperature and pressure ratio. To overcome the efficiency defect of the simple cycle, adoption of the recuperator is an inevitable choice. In addition to the design performance, we should also pay attention to the off-design performance of gas turbines since they usually operate at part-load conditions lot a considerable amount of their lifetime. This study analyzes off-design performance characteristics of micro gas turbines and addresses the importance of the recuperation process doting the part load operation. Comparative analyses have been performed to evaluate the part load performance differences among various design and operating options : simple vs recuperative cycles, single vs two shaft configurations, various operating strategies for the single shaft configuration, and current vs advanced engines. Major finding is that maintaining high turbine exhaust temperature is crucial for efficient operation of micro gas turbines.

• The KSFM Journal of Fluid Machinery
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• v.9 no.6 s.39
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• pp.35-44
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• 2006

Operation conditions of a reheat cycle gas turbine for a combined cycle power plant was analyzed. Based on measured performance parameters of the gas turbine, a performance analysis program predicted component characteristic parameters such as compressor air flow, compressor efficiency, efficiencies of both the high and low pressure turbines, and coolant flows. The predicted air flow and its variation with the inlet guide vane setting were sufficiently accurate. The compressor running characteristic in terms of the relations between air flow, pressure ratio and efficiency was presented. The variations of the efficiencies of both the high and low pressure turbines were also presented. Almost constant flow functions of both turbines were predicted. The current methodology and obtained data can be utilized for performance diagnosis.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.2
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• pp.166-177
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• 1997

The prime mover performance of on - board Diesel Generator is well characterized by the variation of frequency and the load sharing on parallel running under electric load change. This study is aimed to configure the modeling for performance simulation regarding to DG operation which could be interested for education purpose or system analysis. The modeling had been made on the base of modules such as govenor, prime mover of diesel engine and generator with electric load system, which were then intergrated for total simula¬tion performance. One real model system has been introduced for deciding relating parameters and for the comparison of resulting performance in simulation. The responses from the modelling were confirmed in single and paralell operation, the results of which showed resonable accordance with the real system.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.345-350
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• 2000

The heat produced by the fission in the fuel of HANARO, 30 MW research reactor, is transferred from the primary cooling water to the secondary cooling water through heat exchangers, and the heat absorbed by the secondary cooling water is released into the atmosphere by the 33 MW cooling tower which is a mechanical induced draft and counter flow type. If the outlet temperature of cooling tower exceeds 33 of due to the loss of the cooling tower performance under reactor operation above $50\%$ of the full power, the reactor power should be reduced to half of the full power for safe operation. Therefore, the cooling capability of cooling tower should be maintained for the reactor to be normally operated. To predict the capability of cooling tower for full power reactor operation of 30 MW, the performance test of cooling tower was done at the reactor present power of 24 MW and the capability was respectively evaluated by characteristics and performance curves methods in accordance with the Code of Cooling Tower Institute of U.S.A. to confirm the reliability of evaluation. As a result, it was confirmed, through the results of each evaluation, that the cooling capability of cooling tower meets the design required heat load. Also, the equations of the performance and the characteristics curves of the cooling tower, based on the collected data during this performance test, was obtained for developing the calculation program to predict the cooling capability during reactor operation.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.66-72
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• 2008

In this study, the ground source heat pump was installed at a research center in Jeju Island to verify the performance of the system and to give an information for a economic feasibility. The performance test was conducted until the heat storage tank temperature reached at $5^{\circ}C$ from $50^{\circ}C$ in the cooling operation, and until the storage temperature goes up to $50^{\circ}C$ from $10^{\circ}C$ in the heating mode. As results, the system performance shows that $2.2{\sim}3.5$ for the cooling operation and $2.5{\sim}3.5$ for heating operation. It is found that the underground is good heat source for the heat pump with $3{\sim}10^{\circ}C$ variation range. The ground source heat pump could be connected one of air conditioning system without any problem in system performance. Based on the economic analysis, the initial cost for the ground source heat pump will be compensated after 4 years operation. If the system runs 20 years, approximately 300 million Won will be saved when the air conditioning system adapt the ground source heat pump based on Life Cycle Cost analysis.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.669-674
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• 2006

The optimal control of heat pump performance for heating mode operation was investigated. Fuzzy logic was applied to control the heating performance of heat pump system and superheat at compressor discharge was taken as a control variable. Regression model was adapted to determine the optimal points where COP is maximized. Optimization of fuzzy rule table was investigated to improve operation performance of heat pump system. Experiments were carried out using original fuzzy table and the modified fuzzy rule table for heating mode operation of heat pump system. The results show that control performance of heat pump system with the modified fuzzy rule table was better than that with the original rule table.

• Journal of IKEEE
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• v.18 no.3
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• pp.392-397
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• 2014

In this paper, we propose a memory operation system architecture for memory latency penalty reduction in SIMT architecture based stream processor. The proposed architecture applied non-blocking cache architecture to reduce cache miss penalty generated by blocking cache architecture. We verified that the proposed memory operation architecture improve the performance of the stream processor by comparing processing performances of various algorithms. We measured the performance improvement rate that was improved in accordance with the ratio of memory instruction in each algorithm. As a result, we confirmed that the performance of stream processor improves up to minimum 8.2% and maximum 46.5%.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.110.1-110.1
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• 2011

This study analyzed the performance of long term operation photovoltaic system The 50 kWp grid connected photovoltaic system which was installed at KEPRI site in 1999 has been operated more than 12 years. In order to acquire long term operation characteristics of medium size photovoltaic system, the operation test data related on power generation electricity and capacity factor of 50 kWp system, which have been collected since 1999, were analysed. From the analysing results, 57.7 MWh in annual power generation electricity of 50 kWp photovoltaic system in 1999 has been decreased 49.1 MWh in 2005 and reached 38.0 MWh in 2010. In addition to, the capacity factor of 50 kWp photovoltaic system also showed 13.2 % in 1999, 11.2% in 2005 and finally reached 8.8% in 2011. The operation test data showed a trend of decreasing of generation electricity and capacity factor during the 12 years operation time and we guessed that was caused by solar cell performance degradation and decreasing of PCS system efficiency.