• 월간 기계설비
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• s.263
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• pp.74-75
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• 2012

• Journal of Energy Engineering
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• v.19 no.4
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• pp.228-233
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• 2010

About 55% of total energy is consumed in the industrial division. The industrial heat pump application will show magnificent energy saving effect as well as higher cost efficiency because of larger energy consuming volume of each facility and longer operation hour and higher stability against seasonal temperature change. Over 90% of dryer for industrial usage has hot wind heat source and hot wind dryer is the representative type covering 68.7% while its 30 ~ 50% lower heat efficiency causes lots of energy loss by exhaust air. Re-usage of exhaust air can improve energy efficiency of dryer because 68% heat energy or 78% of hot air lose in exhaust air. Therefore, high temperature heat pump dryer can be the best alternative. Comparing to the existing dryer with 30% ~ 50% energy efficiency, newly developing high temperature heat pump dryer will enhance energy efficiency up to 60% ~ 80% efficiency. In this paper, heat pump system for high temperature was designed, constructed and tested. The results have shown that system COPh is estimated as 3.3.

• The Journal of Engineering Geology
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• v.21 no.1
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• pp.35-43
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• 2011

Time series analysis was applied to groundwater level, water temperature, and electrical conductivity data obtained from monitoring wells around ground-source heat pumps at Sangji University of Wonju (standing column well type) and at Jungwon University of Goesan (closed loop type), from 21 May to 12 October 2010. We found large temporal variations in the characteristics of groundwater at Wonju, but only minor variations at Goesan. These results may improve our understanding of the effects of ground-source heat pumps on the characteristics of surrounding groundwater, according to the installation method for the pumps.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.5
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• pp.467-472
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• 2013

A raw-water source heat pump equipped with a thermal storage tank was dynamically simulated by TRNSYS, and the results were verified by using the data from a heat pump installed in the Seongnam water treatment facility. The average coefficient of performance (COP) of the raw-water source heat pump based on simulation was 4.97 and 3.17 in the cooling and heating season, respectively. When the volume of the thermal storage tank was changed from 5 to $20m^3$, the highest COP was found at a size of $10m^3$. Considering the regional locations of raw-water source heat pumps at Seoul, Incheon, Gangneung, and Gwangju, Seoul showed the lowest electric power consumption in the cooling season and the highest in the heating season. When a comparison of the performance between the present system and that of a water-air heat pump was conducted, the present system showed lower electric power consumption by 25% than that of a water-air heat pump.

• 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 $50^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.202-205
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• 2006

최근 지열원 열펌프 시스템 설치가 해마다 평균 10-30%젓도 꾸주히 증가하고 있다 주요 연구동향은 토양열전도 측정, 지열히트펌프 시스템 전주기 성능평가 하이브리드 시스템의 초기비용 저감과 이러한 지열원 열펌프 시스템 설계방법분야 개발에 대해 초점이 맞춰지고 있다. 특히 국내에서 현재 시공되어진 많은 시스템들이 부실시공의 문제에 노출되고 있으며 이러한 시점에서 현재의 저가 입찰제도 보다는 외국 사례와 같은 성능확인 제도로의 전환 및 많은 연구가 필요하다. 성능확인제도는 사전 성능 예측과 사후 성능 확인 검증으로 구성되며 본 기술현안 보고서는 최근 국내외 연구동향 및 사전 성능 예측과 사후 성능 검증 관하여 정리하여 본다.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.328-334
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• 2013

A greenhouse heating system to improve heat pump performance using inside and outside air of greenhouse as a heat source selectively and cut $CO_2$ enrichment costs by delay of greenhouse ventilation was developed. In this system, thermal storage modes divided into inside circulation mode using surplus solar energy and outside circulation mode using outside air heat. The thermal storage modes were designed to be switched mutually according to inside greenhouse temperature and six temperature values were input to control the heat pump operating, thermal storage mode switching and greenhouse heating automatically. Operating characteristics of this system were tested in a plastic greenhouse of non-ventilation condition. The results of test showed that the inside circulation mode began at about 11:00 and lasted for about 210 minutes and inside greenhouse temperature was maintained between $20{\sim}28^{\circ}C$ in spite of non-ventilation. System heating COP of the inside circulation mode in the daytime was 3.35, which was 36% and 25% higher than that of the outside circulation modes in the nighttime and daytime respectively.

• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.42-46
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• 2017

As $CO_2$ emission with imprudent using fossil fuel, annual mean temperature of earth is increased in every year. Geothermal energy is inexhaustible energy resource to solve this problem. Heat pump performance and heat exchange efficiency of ground loop are important to distribute widely. Thus, this study are performed to increase heat pump performance and heat exchange efficiency of ground loop with dual expansion valves and spacer. As a results, COP of cooling & heating is obtained improvement up to 11.4% using dual expansion valves, and heat exchange efficiency is increased up to 17.5% using spacer. It will be reduced initial installation cost due to increasing heat pump performance and heat exchange efficiency of ground loop.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2888-2897
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• 2011

The performance of a geothermal heat pump system using carbon dioxide was investigated by the steady-state cycle simulation program developed in this study. A parametric study was carried out in order to investigate the effect of various operating conditions on the performance of the basic cycle without an IHX(internal heat exchanger). The simulation program consists of several Fortran subroutines for simulating indoor and outdoor heat exchangers, compressors, and expansion valves and Visual Basic subroutines for the graphic user interface(GUI) consisted with pre-processor for input data and post-processor for the output data. Refprop V6.01 was used for estimating the thermodynamic properties and equilibrium behaviors of carbon dioxide. The simulation results were validated by comparing experimental data through a series of case studies. The cycle simulation program developed in this work would seem to be a useful tool in optimizing and establishing economical and efficient operating conditions in the $CO_2$ geothermal heat pump system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.797-802
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• 2012

In this study, the potential performance enhancement in a dual heat pump system through series operation was investigated by a comparison between the performance for parallel and series operation for a heating supply temperature of $60^{\circ}C$. To compare the performance of each configuration fairly, the heat transfer surface area of the heat exchangers was fixed. The inlet temperatures and the flow rates of the heat source and the load were also fixed. In addition, the heat transfer and pressure drop characteristics of the working fluids were considered to achieve a more realistic comparison. The results show that the heating coefficient of performance (COP) of the series configuration is approximately 5% higher than that of the parallel configuration under the simulation conditions considered in the present study.