• Korea Journal of Geothermal Energy
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• v.3 no.2
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• pp.11-18
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• 2007

• Korea Journal of Geothermal Energy
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• v.4 no.3
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• pp.18-22
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• 2008

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.22 no.2
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• pp.87-100
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• 1993

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.99-104
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• 2017

This study evaluated the heating performance of a hybrid heat pump system. The system was installed in a $100-m^2$ greenhouse to utilize surplus solar energy. A hybrid heat pump system was installed at Jocheon-ri, Jeju Island, for an empirical evaluation of the performance. The system consists of a heat storage tank and plate heat exchangers for several heat exchanges between the greenhouse and heat pump or storage tank. The system uses R410a as the working fluid and is controlled automatically by a defined set temperature of the greenhouse. This system incorporates two kinds of heat sources: outdoor air and a storage tank that collects heat from the topside of the greenhouse. The results showed that the heating capacity was 19.9 kW in the outdoor air source mode and 21.4 kW with direct heating from hot water in the thermal storage tank. These results are very similar to those of a previous study.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.924-930
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• 2018

The objective of this study was to investigate heating performance characteristics of electric heat pump system in a fuel cell electric vehicle (FCEV). In order to analyze heating performance characteristics of electric heat pump system with plate-type heat exchanger using stack coolant to evaporate the refrigerant, R-134a, each component was installed and tested under various operating conditions, such as air inlet temperature of inner condenser and compressor speed. When the air inlet temperature of inner condenser was varied from $0.0^{\circ}C$ to $-20.0^{\circ}C$, heating capacity was not quite different due to similar temperature gap between inlet and outlet of inner condenser with electric-driven expansion valve (EEV). However, COP increased until certain EEV opening, especially under 45.0%, because of decreasing power consumption. According to the compressor speed variation from 2,000 to 4,000 RPM, heating capacity and COP were found to have opposite trend. In the future works, stack coolant conditions as the heat source for tested heat pump system were analyzed with respect to heating performance, such as heating capacity and COP.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.563-568
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• 2016

In this study, experiments were conducted to evaluate the performance of a heat pump system. A heat pump system with an air as heat source is adapted as reference. The developed system uses a plate heat exchanger an evaporator to absorb heat from a stack of fuel cell driven electric vehicles. Hence, the system functions as a water source heat pump system. The results indicated that the; power consumption increased with the rotational speed of the compressor. A system performance($COP_h$) of 2.03 at an electronic expansion valve(EEV) openings of 25% and a compressor speed of 1200 rpm was observed in the reference system. However, at the same compressor speed, the $COP_h$ of the water source heat pump system corresponded to 9.42 at an EEV openings of 75%. It was found that the water source heat pump system exhibited the highest performance at a water temperature of $50^{\circ}C$.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.94-94
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• 2011

본 논문은 "차세대 반도체용 진공공정의 실시간 측정/진단/제어 기술개발"과제의 제 3 세부과제 "스마트형 진공 배기 진단 제어 시스템 개발"의 주요 연구 실적을 소개한다. 본 세부과제는 (1)진공펌프 및 배기 시스템의 다중 상태변수 측정 장치 개발, (2)공정별 펌프 상태 및 공정 조건 data base 구축 및 진단 알고리즘 개발(e-Diagnostics Level 2 FDC 수준), (3)공정별 펌프 상태 변수 측정을 통한 자기 진단 기술 개발(e-Diagnostics Level 2 FDC 수준), 그리고 (4)측정/통신 PMS (Pump Monitoring System) 개발(통신속도 56k bps 이상, e-Diagnostics Level 0~1)을 최종 목표로 추진되어 왔다. 첫 번째 주요실적은 진공배기시스템의 다중 상태변수 측정 및 평가 장치를 성공적으로 개발하였다. 본 장치는 현장에서 진공펌프의 배기속도를 3% 이내로 정밀하게 측정할 수 있는 소닉 노즐을 이용한 배기속도 측정 장치 및 기술을 성공적으로 개발 완료하였다. 그리고 측정 가능한 상태변수는 20종에 달하며 이들을 이용하여 진공펌프의 성능인자 15종과 특성치 9종을 종합적으로 평가할 수 있는 능력을 갖추었다. 두 번째 주요실적은 공정별 진공배기시스템의 자기진단 및 예지보수 기수 개발이다. 연구에서 개발된 적응형 인자모델을 이용한 상태진단 기술은 이미 학회 논문으로 소개되었으며 본 기법은 기존의 시계열 상태변수를 이용한 기존의 상태진단 기법보다 메모리 소요량을 100배로 줄였으며 그리고 연산양은 10% 이하로 줄인 획기적인 기법이라 할 수 있다. 세 번째 주요실적은 상태변수 측정, 통신, 제어 및 공정적응 기능 통합형(smart) PMS(pumper monitoring system) 개발이다. 본 장치는 CAN통신 기법을 새로이 채택하였으며 한 대의 PC로 64대의 단위 진공펌프들의 운전 상태변수를 실시간으로 수집할 수 있도록 하였다. 그리고 운전 중인 개별 진공펌프들의 운전 상태진단은 적응형 인자모델을 이용한 상태진단 기술을 응적용함으로써 매우 정확한 상태진단을 매 batch마다 수행할 수 있는 기능을 제공한다.

• Journal of the Korean Solar Energy Society
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• v.27 no.4
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• pp.87-95
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• 2007

Thermodynamic analysis of water-to-water heat pump system based on the first and second law of thermodynamics is carried out in this study. This analysis shows the distribution of irreversibilities throughout the system components and informs us of a potential improvements with the temperature condition changes. Source water temperature($T_A$), utilization water temperature($T_D$) and temperature differences (${\Delta}T_{AB}$, ${\Delta}T_{CD}$) are important factors to affect system performances such as component irreversibilities, exergetic efficiency and COPH. Advantages and disadvantages with these factors are discussed. Second law optimization phenomena with $T_A$ and ${\Delta}T_{AB}$ are also indicated.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.814-820
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• 2014

Due to the development of human civilization, industrialization and urbanization, the human race demanded the food, clothing and shelter as well as a comfortable living environment. For the purpose of this, the refrigeration and air conditioning part was carried out research and development. However, high oil prices and environmental pollution having problems in the 21st century cannot be overlooked. As an alternative, thermal system was designed using the heat pump to applied sea water heat source. In this paper, outside and sea temperatures are analysed in 2010 and carried out the performance analysis simulation at All water and All Air heat pump system by HYSYS program for domestic use. As a result, total average COP of the system is 3.37 from All Water system and All Air is 3.48. It showed that high performance confirmed in both system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.409-412
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• 2009

A 75ton thrust turbopump system for liquid rocket engine was analyzed thermally and mechanically. A 2D axisymmetric model of the turbopump assembly was created. In the analysis operation cycle including chill-down, operation and post operation steps were considered. Appropriate heat transfer conditions for each step were modeled and applied. Transient temperature distribution was calculated, consequent mechanical analysis was conducted to predict stress and deformation. Effects of external heat insulators and heat dissipation at the bearings were considered in the heat transfer analysis.