• Title/Summary/Keyword: 지중축열

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A study of geothermal heat dump for solar collectors overheat protection (태양열 집열관 과열방지를 위한 지중열교환기 연구)

  • Hwang, Hyun-Chang;Chi, Ri-Guang;Lee, Kye-Bock;Rhi, Seok-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.616-622
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    • 2016
  • The heating load using solar hot water is lower in summer than in the other seasons. This decreased heating load leads to the overheating solar collectors and related components. To prevent overheating of the solar collectors, air cooling and shading shields were used. On the other hand, it requires additional mechanical components, and reduces the system reliability. The geothermal heat dump system to release the high temperature heat (over $150^{\circ}C$) transferred from the heat pipe solar collectors was investigated in the present study. Research on the heat dump to cool the solar collector is rare. Therefore, the present study was carried out to collect possible data of a geothermal heat dump to cool the solar collector. A helical type geothermal heat exchanger was buried at a 1.2m depth. Experimentally and numerically, the geothermal heat dump was investigated in terms of the effects of parameters, such as the quantity of solar radiation, aperture area of the collector and the mass flow rate. A pipe length of 50m on the geothermal heat exchanger was suitable with a 0.33 kg/s flow rate. The water reservoir was a possible co-operation solution linked to the geothermal heat exchanger.

The Actual State of Heat Conservation, Heating and Cooling in Greenhouses (온실의 보온 및 냉난방실태 분석)

  • 김문기;이석건;서원명;남상운;김란숙
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1998.05a
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    • pp.39-44
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    • 1998
  • 현재 국내에 보급되어 있는 현대화 온실 203개를 대상으로 냉난방과 관련된 설비현황을 조사하여 분석한 결과를 요약하면 다음과 같다. \circled1 온실의 건설방위는 남북동(58.1%)과 동서동(26.8%)이 대부분이었고, 철골온실은 Wide-span형이 81.8%, 플라스틱온실은 1-2W형 온실이 97.5%였다. 휴작하는 온실은 약 41%정도였고, 재배작물은 채소류가 약 80%, 화훼류가 약 20%정도였으며, 재배방식은 철골온실의 경우 양액재배가 57.2%, 플라스틱온실에서는 토양재배가 88.5%였다. \circled2 온실의 외부 피복재는 철골온실은 유리가 92.2%, 플라스틱온실에서는 PE가 43.3%, EVA가 51.9%로 대부분이었다. 철골온실은 1중피복이 98.7%로 거의 전부이었고, 플라스틱온실에서는 2중피복이 78.7%로 나타나, 철골온실에서 보온커튼을 통한 보온성 향상과 밀폐성이 더욱 중요함을 알 수 있다. \circled3 보온용 피복재는 부직포가 64.9%로 가장 많았고 대부분 2층커튼(85.9%)이었으며, 개폐방식은 대부분 예인식(92.7%)의 자동개폐방식(75.2%)이었다. 한편 바닥을 피복한 온실은 약 30% 정도로 나타나, 바닥피복으로 인한 축열이나 반사효과를 감안할 때 효율적인 바닥처리가 요망된다. \circled4 온실의 난방방식은 철골온실에서는 온수안방(47.3%)이 온풍난방(33.8%)보다 다소 많았으며, 플라스틱온실에서는 대부분 온풍난방(90.8%)이었다. 온실의 난방위치는 대부분 지상난방(89.8%)이었고 지중난방은 극소수로 나타나, 앞으로 지중난방을 통한 난방비 절감과 품질향상에 관한 실용화 연구가 요망된다. 난방용 연료는 대부분 경유(83.9%)로 나타나, 난방비를 절감할 수 있는 저가의 연료를 사용할 수 있는 난방시스템의 개발이 요청된다. \circled5 온실의 냉방방법은 차광(51.8%)과 지붕살수(33.9%)가 대부분이었으며 미스트와 포그시스템을 설치한 온실은 소수에 불과하였고, 극소수의 온실에서는 지붕위나 온실내에 지붕면과 평행하게 설치한 경우도 있었다.

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A Study on Field test of the Horizontal Ground Source Heat Pump for Greenhouse (시설원예용 수평형 지열히트펌프 시스템 실증연구)

  • Park, Yong-Jung;Kang, Shin-Hyung
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.505-510
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    • 2007
  • Greenhouses should be heated during nights and co Id days in order to fit growth conditions in greenhouses. Ground source heat pump(GSHP) or geothermal heat pump system(GHPs) is recognized to be outstanding heating and cooling system. Horizontal GSHP system is typically less expensive than vertical GSHP system but requires wide ground area to bury ground heat exchanger (GHE). In this study, a horizontal GSHP system with thermal storage tank was installed in greenhouse and investigated as performance characteristics. In the daytime, heating load of greenhouse is very small or needless because solar radiation increases inner air temperature. The results of study showed that the heating coefficient of performance of the heat pump($COP_h$) was 2.9 and the overall heating coefficient of performance of the system($COP_{sys}$) was 2.4. Heating energy cost was saved 76% using the horizontal GSHP system with thermal storage tank.

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Performance Analysis of the Horizontal Ground Source Heat Pump for Greenhouse (시설원예용 수평형 지열 히트펌프 시스템의 성능분석)

  • Park, Yong-Jung;Kang, Shin-Hyung
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.447-452
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    • 2007
  • Greenhouses should be heated during nights and cold days in order to fit growth conditions in greenhouses. Ground source heat pump(GSHP) or geothermal heat pump system(GHPs) is recognized to be outstanding heating and cooling system. Horizontal GSHP system is typically less expensive than vertical GSHP system but requires wide ground area to bury ground heat exchanger(GHE). In this study, a horizontal GSHP system with thermal storage tank was installed in greenhouse and investigated as performance characteristics. In the daytime, heating load of greenhouse is very small or needless because solar radiation increases inner air temperature. The results of study showed that the heating coefficient of performance of the heat pump ($COP_h$) was 2.9 and the overall heating coefficient of performance of the system($COP_{sys}$) was 2.4. Heating energy cost was saved 76% using the horizontal GSHP system with thermal storage tank.

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Study of occurrence of cool air in summer and warm air in winter of Chonbuk Jinan Poonghyeol (전북 진안 풍혈의 여름철 냉풍 및 겨울철 온풍 발생 연구)

  • Kim, Young-Il;Shin, Young-Gy;Seo, Jeong-Ah;Choi, Yong-Don;Song, Tae-Ho;Kang, Chae-Dong;Kim, Seong-Sil;Rho, Jeong-Sun;Jeong, Si-Young;Kim, Yong-Chan
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.879-884
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    • 2006
  • Jinan Poonghyeol in Chonbuk province Is famous for emitting cool air in summer and warm air in winter. Cause for these phenomena is studied by measuring temperature, humidity and air velocity of several locations around Jinan Poonghyeol Temperature variations under the ground are also measured. Analyzing data compiled from July 21, 2005 through May 26, 2006, it is presumed that storage effect of rocks and soil in this area and buoyance effect are the main causes for this mysterious natural air-conditioning phenomena.

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Development of Optimum Design Method for Geothermal Performance based on Energy Simulation (지열 성능해석 시뮬레이션에 기반한 최적 설계 수법 개발)

  • Moon, Hyeongjin;Kim, Hongkyo;Nam, Yujin
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.3
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    • pp.43-48
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    • 2019
  • Since the revision of the Rationalization of Energy Use Law, the spread of new and renewable energy in buildings has been promoted. In addition, the production of electric power and thermal energy is an important issue in the change of energy paradigm centered on the use of distributed energy. Among them, geothermal energy is attracting attention as a high-performance energy-saving technology capable of coping with heating / cooling and hot water load by utilizing the constant temperature zone of the earth. However, there is a disadvantage that the initial investment cost is high as a method of calculating the capacity of a geothermal facility by calculating the maximum load. The disadvantages of these disadvantages are that the geothermal energy supply is getting stagnant and the design of the geothermal system needs to be supplemented. In this study, optimization design of geothermal system was carried out using optimization tool. As a result of the optimization, the ground heat exchanger decreased by 30.8%, the capacity of the heat pump decreased by 7.7%, and the capacity of the heat storage tank decreased by about 40%. The simulation was performed by applying the optimized value to the program and confirmed that it corresponds to the load of the building. We also confirmed that all of the constraints used in the optimization design were satisfied. The initial investment cost of the optimized geothermal system is about 18.6% lower than the initial investment cost.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.