• Title/Summary/Keyword: Thermal Management Performance Evaluation

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A Study on the Development of Fouling and Plugging Margin Evaluation Methods for Shell-and-Tube Heat Exchangers (다관원통형 열교환기의 파울링 및 관막음 여유 평가법)

  • Hwang, Kyeong-Mo;Jin, Tae-Eun
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.55-60
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    • 2003
  • As operating time of heat exchangers progresses, fouling generated by water-borne deposits increases and thermal performance decreases. The fouling is known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. The heat exchangers of nuclear power plants have been analyzed in terms of the heat flux and heat transfer coefficient at test conditions based on the ASME OM-S/G-Part 2 as a means of heat exchanger management. It is hard to estimate the heat performance trend and to establish the future management plan. This paper describes the fouling evaluation method which can evaluate the thermal performance for heat exchangers and estimate the future fouling variations and the plugging margin evaluation method which can reflect the current fouling level developed in this study. To develop the fouling and plugging margin evaluation methods for heat exchangers, fouling factor was introduced based on the ASME O&M codes and TEMA standards. For the purpose of verifying the two evaluation methods, the fouling and plugging margin evaluations were performed for a component cooling heat exchanger in a nuclear power plant.

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A Study on Cold-Weather Curing Quality Management Based on Using Energy Saving Electronic Heater (에너지 절감형 전기히터를 활용한 동절기 양생품질 관리방안)

  • Jo, Man-Ki;Hong, Sung-Min;Park, Jong-Hun;Kim, Jin-Sik;Lee, Dong-Hyun;Cho, Seong-Jun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.11a
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    • pp.109-110
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    • 2020
  • In This study, we tried to review an efficient curing method in consideration of safety and constructability among the problems of winter construction. In other words, as a result of the mock-up test, the measured value of carbon monoxide was 0 ppm in the case of an electric hot air fan. Since there is no carbon monoxide, problems such as suffocation are expected to be solved. In terms of temperature characteristics, electric hot air fans exhibited high thermal efficiency performance with a slight difference in upper/lower temperatures compared to the existing ones. In the future, we plan to conduct thermal efficiency evaluation through actual site performance verification. We will propose an efficient curing method through applicability evaluation.

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Overview on Thermal Management Technology for High Power Device Packaging (파워디바이스 패키징의 열제어 기술과 연구 동향)

  • Kim, Kwang-Seok;Choi, Don-Hyun;Jung, Seung-Boo
    • Journal of the Microelectronics and Packaging Society
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    • v.21 no.2
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    • pp.13-21
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    • 2014
  • Technology for high power devices has made impressive progress in increasing the current density of power semiconductor, system module, and design optimization, which realize high power systems with heterogeneous functional integration. Depending on the performance development of high power semiconductor, packaging technology of high power device is urgently required for efficiency improvement of the device. Power device packaging must provide superior thermal management due to high operating temperature of power modules. Here we, therefore, review critical challenges of typical power electronics packaging today including core assembly processes, component materials, and reliability evaluation regulations.

Analysis on the Thermal Efficiency of Branch Prediction Techniques in 3D Multicore Processors (3차원 구조 멀티코어 프로세서의 분기 예측 기법에 관한 온도 효율성 분석)

  • Ahn, Jin-Woo;Choi, Hong-Jun;Kim, Jong-Myon;Kim, Cheol-Hong
    • The KIPS Transactions:PartA
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    • v.19A no.2
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    • pp.77-84
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    • 2012
  • Speculative execution for improving instruction-level parallelism is widely used in high-performance processors. In the speculative execution technique, the most important factor is the accuracy of branch predictor. Unfortunately, complex branch predictors for improving the accuracy can cause serious thermal problems in 3D multicore processors. Thermal problems have negative impact on the processor performance. This paper analyzes two methods to solve the thermal problems in the branch predictor of 3D multi-core processors. First method is dynamic thermal management which turns off the execution of the branch predictor when the temperature of the branch predictor exceeds the threshold. Second method is thermal-aware branch predictor placement policy by considering each layer's temperature in 3D multi-core processors. According to our evaluation, the branch predictor placement policy shows that average temperature is $87.69^{\circ}C$, and average maximum temperature gradient is $11.17^{\circ}C$. And, dynamic thermal management shows that average temperature is $89.64^{\circ}C$ and average maximum temperature gradient is $17.62^{\circ}C$. Proposed branch predictor placement policy has superior thermal efficiency than the dynamic thermal management. In the perspective of performance, the proposed branch predictor placement policy degrades the performance by 3.61%, while the dynamic thermal management degrades the performance by 27.66%.

Recognition of Occupants' Cold Discomfort-Related Actions for Energy-Efficient Buildings

  • Song, Kwonsik;Kang, Kyubyung;Min, Byung-Cheol
    • International conference on construction engineering and project management
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    • 2022.06a
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    • pp.426-432
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    • 2022
  • HVAC systems play a critical role in reducing energy consumption in buildings. Integrating occupants' thermal comfort evaluation into HVAC control strategies is believed to reduce building energy consumption while minimizing their thermal discomfort. Advanced technologies, such as visual sensors and deep learning, enable the recognition of occupants' discomfort-related actions, thus making it possible to estimate their thermal discomfort. Unfortunately, it remains unclear how accurate a deep learning-based classifier is to recognize occupants' discomfort-related actions in a working environment. Therefore, this research evaluates the classification performance of occupants' discomfort-related actions while sitting at a computer desk. To achieve this objective, this study collected RGB video data on nine college students' cold discomfort-related actions and then trained a deep learning-based classifier using the collected data. The classification results are threefold. First, the trained classifier has an average accuracy of 93.9% for classifying six cold discomfort-related actions. Second, each discomfort-related action is recognized with more than 85% accuracy. Third, classification errors are mostly observed among similar discomfort-related actions. These results indicate that using human action data will enable facility managers to estimate occupants' thermal discomfort and, in turn, adjust the operational settings of HVAC systems to improve the energy efficiency of buildings in conjunction with their thermal comfort levels.

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A Study on the Economic Evaluation of Thermal Spray Methods for the Corrosion Protection of Steel (금속용사 방식공법의 경제성 평가에 관한 연구)

  • Jung Sung-Ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.05a
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    • pp.13-16
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    • 2005
  • Generally, as corrosive protection processing of a steel structure, zinc galvanizing and heavy duty coating paint are applied. However, zinc galvanizing has the difficulty of restriction of a size, or on-site construction. Moreover, heavy duty coating paint has a problem with many administrative and maintenance expenses with short problem of adhesion, corrosion generating of a damage portion, and maintenance management cycle. In this study, a salt water spray test, CASS test, and the electrochemistry examination were carried out for the thermal metal spray method of construction for corrosive protection performance evaluation. Moreover, the corrosive protection life of a thermal metal spray method of construction was quantitatively calculated on the basis of this experiment. in consideration of LCC, the economical efficiency of a general corrosive protection method of construction and a thermal metal corrosive protection method of construction was compared. Consequently, although initial construction expense was estimated 16 to $30\%$ high, as for a thermal metal spray method of construction, it turns out that the administrative and maintenance expenses for 100 years became cheap 9.3 to 13 or more times.

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A Study on Development of a Plugging Margin Evaluation Method Taking Into Account the Fouling of Shell-and-Tube Heat Exchangers

  • Hwang, Kyeong-Mo;Jin, Tae-Eun;Kim, Kyung-Hoon
    • Journal of Mechanical Science and Technology
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    • v.20 no.11
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    • pp.1934-1941
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    • 2006
  • As the operating time of heat exchangers progresses, fouling caused by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of Korean nuclear power plants have been analyzed in terms of heat transfer rate and overall heat transfer coefficient as a means of heat exchanger management. Except for fouling resulting from the operation of heat exchangers, all the tubes of heat exchangers have been replaced when the number of plugged tubes exceeded the plugging criteria based on design performance sheet. This paper describes a plugging margin evaluation method taking into account the fouling of shell-and-tube heat exchangers. The method can evaluate thermal performance, estimate future fouling variation, and consider current fouling level in the calculation of plugging margin. To identify the effectiveness of the developed method, fouling and plugging margin evaluations were performed at a component cooling heat exchanger in a Korean nuclear power plant.

A Study on the Development of Plugging Margin Evaluation Method Reflected the Fouling of a Shell-and-Tube Heat Exchanger (다관원통형 열교환기의 파울링 현상을 고려한 관막음 여유 평가법 개발 연구)

  • Hwang, Kyeong-Mo;Jin,Tae-Eun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.11
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    • pp.1384-1389
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    • 2004
  • As operating time of heat exchangers progresses, fouling generated by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of domestic nuclear power plants have been analyzed in terms of the heat flux and heat transfer coefficient at test conditions as a means of heat exchanger management. Except for the fouling level generated in operation of heat exchangers, also, all of the tubes of heat exchangers have been replaced when the number of plugged tubes exceeds the plugging criteria based on design performance sheet. This paper describes the plugging margin evaluation mettled reflected the fouling of shell-and-tube heat exchangers, which can evaluate the thermal performance for heat exchangers, estimate the future fouling variations, and reflect the current fouling level. To identify the effectiveness of the developed method, the fouling and plugging margin evaluations were performed for a component cooling heat exchanger in a nuclear power plant.

Artificial Neural Network-based Thermal Environment Prediction Model for Energy Saving of Data Center Cooling Systems (데이터센터 냉각 시스템의 에너지 절약을 위한 인공신경망 기반 열환경 예측 모델)

  • Chae-Young Lim;Chae-Eun Yeo;Seong-Yool Ahn;Sang-Hyun Lee
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.6
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    • pp.883-888
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    • 2023
  • Since data centers are places that provide IT services 24 hours a day, 365 days a year, data center power consumption is expected to increase to approximately 10% by 2030, and the introduction of high-density IT equipment will gradually increase. In order to ensure the stable operation of IT equipment, various types of research are required to conserve energy in cooling and improve energy management. This study proposes the following process for energy saving in data centers. We conducted CFD modeling of the data center, proposed an artificial intelligence-based thermal environment prediction model, compared actual measured data, the predicted model, and the CFD results, and finally evaluated the data center's thermal management performance. It can be seen that the predicted values of RCI, RTI, and PUE are also similar according to the normalization used in the normalization method. Therefore, it is judged that the algorithm proposed in this study can be applied and provided as a thermal environment prediction model applied to data centers.

Performance Evaluation of a $CO_2$ Heat Pump System for Fuel Cell Vehicles (연료전지 자동차용 이산화탄소 열펌프 시스템의 성능평가)

  • Kim, Sung-Chul;Park, Jong-Chul;Kim, Min-Soo;Won, Jong-Phil
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.1
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    • pp.37-44
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    • 2008
  • The global warming potential (GWP) of $CO_2$ refrigerant is 1/1300 times lower than that of R134a. Furthermore, the size and weight of the automotive heat pump system can decrease because $CO_2$ operates at high pressure with significantly higher discharge temperature and larger temperature change. The presented $CO_2$ heat pump system was designed for both cooling and heating in fuel cell vehicles. In this study, the performance characteristics of the heat pump system were analyzed for heating, and results for performance were provided for operating conditions when using recovered heat from the stack coolant. The performance of the heat pump system with heater core was compared with that of the conventional heating system with heater core and that of the heat pump system without heater core, and thus the heat pump system with heater core showed the best performance among the selected heating systems. On the other hand, the heating performance of two different types of coolant/air heat pump systems with heater core was compared each other at various coolant inlet temperatures. Furthermore, to use exhausted thermal energy through the radiator, experiments were carried out by changing the arrangement of a radiator and an outdoor evaporator, and quantified the heating effectiveness.