• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.544-549
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• 2009

The purpose of this study is to investigate the field Operation Characteristics of a sea water heat source cascade heat pump system and system applicable to Building. Cascade heat pump system is composed R410A compressor, R134a compressor, EEV, cascade heat exchanger, Plate heat exchanger etc. Building area is $890m^2$ and has five floors above ground. R410A is used for a low-stage working fluid while R134a is for a high-stage. The system could runs at dual mode. One is mode of general R410A refrigeration cycle in summer and the other is cascade cycle. In order to gain a high temperature supply water in winter season, the system is designed to perform a cascade cycle. The filed test results show that the sea water heat source heat pump system exhibits a COP of about 5.5 in cooling mode along with a heating COP of about 4.0 in 1-stage heating mode. Cascade 2-stage heat pump system is enough to supply $60^{\circ}C$ water and heating COP is about 3.0

• 한국주거학회논문집
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• 제19권5호
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• pp.11-18
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• 2008

Geothermal heat pump system using sanding column well type with their ground heat exchanger can be used as a highly efficient source of heating and cooling in massive buildings. But there is no case of a small scale residential house. So in the residential house this study estimated heating coefficient of performance (COP) of geothermal heat pump system using sanding column well type which is excellent in heat recovery. As a result of analysis, The COP of heat pump is over average 6 and is excellent. And in consequence of making a comparative study according to the bleeding, the COP is higher in the case of bleeding. Therefore, bleeding affects the performance of the system. This study has shown performance result that stands on actual data. Therefore, this study provides ground data that needs when a low capacity of system designs for a residence with confidence elevation.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.588-591
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• 2009

Ground source heat pump system; GSHPs is close to most practical use for early stage investment cost and energy efficiency in new renewable energies, and currently considered utilizing to the heat and cooling system of a building. Particularly, the case to utilize 'Standing Column well heat source gathering method' in the open standards process to have the excellent capability of gathering geothermal source is increased. But the research for the optimal design technology and the assessment of a pollution level of the ground to utilize a single well for gathering geothermal is insignificant and the design is insufficient. The heating and cooling system and the equipment to utilize a large size residential development to have over 1000 households have not developed yet. Therefore, our company developed 'geothermal hybrid system' which can construct the heat and cooling system using geothermal energy for a large size residential development of over 1000 households and conducted the evaluation of economic feasibility. Moreover we developed automatic equipment for gathering geothermal source and PLC (Programmable logic controller) to have optimal efficiency and FCU (fan coil unit) considering the floors of large size apartments.

• Journal of Advanced Marine Engineering and Technology
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• 제36권4호
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• pp.437-444
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• 2012

본 논문은 지열을 이용한 코일 침적형 히트펌프 시스템의 운전변수에 대한 최적 설계를 위해서 히트펌프의 성능 특성을 실험적으로 조사하였다. 본 연구에서 고려된 작동변수로는 과냉각도, 증발온도, 응축온도 등이다. 그 실험결과를 요약하면 다음과 같다. 지열 이용 코일 침적형 히트펌프 시스템의 증발온도와 과냉각도가 증가할수록, 응축온도는 감소할수록 성능계수는 증가함을 알 수 있다. 즉, 지열 이용 코일 침적형 히트펌프 시스템의 증발온도, 응축온도, 과냉각도는 냉방과 난방의 성능계수에 영향을 미치는 것을 알 수 있다. 따라서 본 연구에서 제안하는 히트펌프 시스템이 최고의 성능을 나타내기 위한 최적의 운전조건을 결정할 필요가 있다.

• 설비공학논문집
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• 제29권3호
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• pp.119-126
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• 2017

Recently, ground source heat pump systems are being used in buildings for cooling and heating to reduce greenhouse gas and save energy. However, ground source heat pump systems mainly use the vertical closed-loop geothermal system design rather than the open-loop geothermal system design. This is due to a lack of knowledge and few research feasibility studies. In this research, a dynamic thermal analysis numerical simulation based on a standard house model was conducted for an open-loop geothermal system. Based on heating load analysis results, the life cycle costs of a standard house using an open two-well geothermal system were analyzed and compared with a vertical closed-loop geothermal system, and a diesel boiler. As a result, it was found that using an open two-well geothermal system shows economic return on investment after three years.

• 한국지열·수열에너지학회논문집
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• 제11권4호
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• pp.28-34
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• 2015

The groundwater heat pump (GWHP) systems have great potential for heating-cooling system which use annual constant groundwater temperature for heat source. Generally, the performance of GWHP system significantly depends on the geological and hydraulic properties such as hydraulic conductivity, thermal conductivity, soil condition so on. Therefore, in order to use GWHP systems efficiently, it is necessary to analyze the effect of design factors on the system performance. However, there are a few researches on the optimum design method for the open-loop geothermal system. In this research, the design factor in the open-loop geothermal system was analyzed quantitatively for the optimal design method by using numerical simulation. As a result, it was found that the temperature change of heat source depends on the design factor.

• 한국지열·수열에너지학회논문집
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• 제5권1호
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• pp.7-11
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• 2009

The purpose of this study is to investigate the performance of a water heat source cascade heat pump system R717(Ammonia) is used for a low-stage working fluid while R134a is for a high-stage. In order to gain a high temperature supply water in winter season, the system is designed to perform a cascade cycle. In this study, two experiments were carried out. One is a system starting test from the low load temperature of $10^{\circ}C$. The other is a system performance investigation over the R717 compressor capacity changes. Experimental results show that when it starts from the low load temperature, the suction temperature of the low-stage compressor is higher than that of a high-stage. The system performance increases when a water source temperature or a low-stage compressor rotational frequency goes higher.

• 한국지열·수열에너지학회논문집
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• 제16권3호
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• pp.8-16
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• 2020

This paper presents the heating performance analysis results of a ground-source heat pump (GSHP) system using hybrid ground heat exchanger (HGHE). In this paper, the HGHE refers to the ground heat exchanger (GHE) using both a surface water heat exchanger (SWHE) and a vertical GHE. In order to evaluate the system performance, we installed monitoring sensors for measuring temperatures and power consumption, and then measured operation data with 4 different load burdened ratios of the HGHE. During the entire measurement period, the average heating capacity of the heat pump was 37.3 kW. In addition, the compressor of the heat pump consumed 9.4 kW of power, while the circulating pump of the HGHE used 6.7 kW of power. Therefore, the average heating coefficient of performance (COP) for the heat pump unit was 4.0, while the system including the circulating pump was 2.7. Finally, the parallel use of SWHE and VGHE was beneficial to the system performance; however, further researches are needed to optimize the design data for various load ratios of the HGHE.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.833-837
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• 2008

GSHP(Ground Source Heat Pump) has been extensively disseminated due to the recent increasing demand over new and renewable energy. In this study, the operating performance of rain water and ground source heat pump system (RW-GSHP) was compared with GSHP during the heating test. Leaving load temperature(LLT) was $50^{\circ}C$, $53^{\circ}C$, $56^{\circ}C$, respectively and rain water tank temperature(RWT) was $13^{\circ}C$, $15^{\circ}C$, $17^{\circ}C$ in this heating test. The experiment was focused on comparison of the system operating performance depending on leaving load temperature (LLT) and rain water tank temperature (RWT). The results showed that rain water and ground source heat pump system (RW-GSHP) was higher heating performance and COPh than those of GSHP.

• 한국기계가공학회지
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• 제15권5호
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• pp.8-17
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• 2016

While greenhouses have been utilized as a sustainable alternative to traditional soil farming, they are often powered by diesel boilers that necessitate vast amounts of non-renewable energy and emit toxic fumes. Thus, geothermal heat pumps have been proposed as a more energy-efficient substitution for diesel boilers. Currently, most horticultural facilities in the United States use shallow geothermal systems, and are often equipped with horizontal underground heat exchangers as well as heat pump equipment. These shallow geothermal systems require a large drilling site and heat pump to function, which results in high maintenance costs. The heat pump itself consumes a large amount of power, which degrades system performance. Conversely, high temperatures can be attained within a single borehole in deep geothermal vertical closing systems without using a heat pump. This setup can dramatically reduce the power consumption and improve system performance. In this study, we have modeled a circulation simulator after the circulation systems in deep geothermal facilities to analyze a 2000-meter borehole in Naju-Sanpo-myeon. The simulator is operated by manipulating various putative parameters affecting system performance to analyze the system's coefficient of performance.