• Title/Summary/Keyword: Ground Heat Source

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Preliminary Design of Supersonic Ground Test Facility (초음속 지상 추진 시험설비의 기본설계)

  • 이양지;차봉준;양수석;김형진
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.13-19
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    • 2003
  • A supersonic ground test facility to develop Ramjet and SCRamjet(Supersonic Combustion Ramjet) engine should be able to simulate high altitude and high Mach number conditions including air total pressure, oxygen level and specific heat ratio at the combustion chamber entrance. The test facility also should simulate the effect of oblique shock wave caused by the flight vehicle. The test facility developed in this study is supersonic free-jet blowdown type, which consists of high pressure air supply source(maximum pressure=32MPa), air heater(vitiation type), supersonic diffuser, ejector, and test chamber(nozzle exit dimension=200mm$\times$200mm).

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Preliminary Design of Supersonic Ground Test Facility (초음속 지상 추진 시험설비의 기본설계기법 연구)

  • 이양지;차봉준;양수석;김형진
    • Journal of the Korean Society of Propulsion Engineers
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    • v.7 no.4
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    • pp.53-62
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    • 2003
  • A supersonic ground test facility to develop Ramjet and SCRamjet(Supersonic Combustion Ramjet) engine should be able to simulate high altitude and high Mach number conditions including air total pressure, oxygen level and specific heat ratio at the combustion chamber entrance. The test facility also should simulate the effect of oblique shock wave caused by the flight vehicle. The test facility developed in this study is supersonic free-jet blow down type, which consists of high pressure air supply source(maximum pressure=32MPa), air heater(vitiation type), supersonic diffuser, ejector, and test chamber(nozzle exit dimension=200mm${\times}$200mm).

Benchmark Numerical Simulation on the Coupled Behavior of the Ground around a Point Heat Source Using the TOUGH-FLAC Approach (TOUGH-FLAC 기법을 이용한 점열원 주변지반의 복합거동에 대한 벤치마크 수치모사)

  • Dohyun Park
    • Tunnel and Underground Space
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    • v.34 no.2
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    • pp.127-142
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    • 2024
  • The robustness of a numerical method means that its computational performance is maintained under various modeling conditions. New numerical methods or codes need to be assessed for robustness through benchmark testing. The TOUGH-FLAC modeling approach has been applied to various fields such as subsurface carbon dioxide storage, geological disposal of spent nuclear fuel, and geothermal development both domestically and internationally, and the modeling validity has been examined by comparing the results with experimental measurements and other numerical codes. In the present study, a benchmark test of the TOUGH-FLAC approach was performed based on a coupled thermal-hydro-mechanical behavior problem with an analytical solution. The analytical solution is related to the temperature, pore water pressure, and mechanical behavior of a fully saturated porous medium that is subjected to a point heat source. The robustness of the TOUGH-FLAC approach was evaluated by comparing the analytical solution with the results of numerical simulation. Additionally, the effects of thermal-hydro-mechanical coupling terms, fluid phase change, and timestep on the computation of coupled behavior were investigated.

A Study on Applying the Ground Source Heat Pump System in Greenhouse and Livestock Facility (지열 시스템의 원예시설과 축사시설 적용에 관한 연구)

  • Jang, Jea-Chul;Kang, Eun-Chul;Song, Jun-Ik;Kim, Ji-Young;Lee, Euy-Joon
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.5 no.2
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    • pp.1-6
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    • 2009
  • In this paper, RETScreen program model has been investigated to predict the economic analysis for greenhouse and livestock facility. Load calculation result was 35.2[kW] of greenhouse and the calculation result of livestock facility was 35.5[kW]. Also, a case study of the RETScreen program indicated that the equity payback is 6.9 years for a greenhouse facility and the equity payback is 9.5 years for a livestock facility.

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Validation of Some Protection Guidelines for Neighboring Pipelines against Fault Currents from Power Transmission Tower

  • Lee, Seong-Min;Song, Hong-Seok;Kim, Young Geun
    • Corrosion Science and Technology
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    • v.6 no.2
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    • pp.77-81
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    • 2007
  • Fault current can be discharged from power transmission tower due to lightning or inadvertent contact of crane, etc. Pipelines in proximity to either the source of the ground fault or the substation grounding grid may provide convenient conductive path for the fault current to travel. Inappropriate measures to the neighboring pipelines against the fault current may cause severe damages to the pipes such as coating breakdown, arc burn, puncture, loss in wall thickness, or brittle heat-affected zone. Like inductive and conductive AC coupling, steadily induced fault current right after the coating breakdown can lead to corrosion of the pipeline. In this work, some protection guidelines against fault currents used in the field have been validated through the simulation and analytical method.

A Study on the Application of the Radiant Floor Cooling System in Residential Building (주거 건물의 복사냉방시스템 적용에 관한 연구)

  • 임재한;여명석;김광우
    • Journal of the Korean housing association
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    • v.15 no.3
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    • pp.73-82
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    • 2004
  • The objective of this study is to demonstrate the potential of radiant cooling systems using Ondol as an alternative cooling system in residential buildings. For this purpose, computer simulation and model experiments have been performed for the system performance analysis regarding comfort, floor surface condensation, and supply water temperature. The results of this study is the following: In radiant floor cooling system, room air temperatures were maintained within the set temperature range of $\pm$1$^{\circ}C$ without any discomfort condition. And taking into account only the condensation occurrence, it was possible to achieve radiant floor cooling for a period of about 77% of the total cooling period in weather condition of Seoul. The minimum supply water temperature is about 15$^{\circ}C$, so renewable energy system such as ground heat exchange system can be used as an alternative in cooling source. Also, floor surface condensation can be prevented by integrating with the dehumidification system.

Status of GSHP System Development (지열원 열펌프 시스템 기술 연구 현황 및 현안)

  • Lee, Euy-Joon
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.1238-1243
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    • 2006
  • 최근 열펌프 시스템 설치가 해마다 평균 10-30% 정도 꾸준히 증가하고 있다. IEA HP Annex 28, 29('열펌프 성능평가 기술', '열펌프 시장 현황 현안')등 국제공동연구를 통한 꾸준한 지열원 열펌프 시스템 응용분야의 발전은 기존의 지열원 시스템에 비해 비용과 더불어 보다 많은 에너지 절감효과를 가져왔다. 지열기술의 성공적 사용여부는 기술의 견실함, 설계기술의 개발, 기반시설설치, 히트펌프와 부품제조업자의 반응에 기인한다. 최근 주요 연구동향은 토양열전도 측정, 지열히트펌프 시스템 전주기 성능평가, 하이브리드 시스템의 초기비용 절감과 이러한 열펌프 시스템 설계방법분야 개발에 대해 초점이 맞춰지고 있다. 본 기술현안 보고서는 최근 국내외 연구동향을 정리하여 본다.

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 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.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. 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 fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (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 for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

A Study on Significant Parameters for Efficient Design of Open-loop Groundwater Heat Pump (GWHP) Systems (개방형 지열시스템의 효율적 설계를 위한 영향인자에 대한 연구)

  • Park, Byeong-Hak;Joun, Won-Tak;Lee, Bo-Hyun;Lee, Kang-Kun
    • Journal of Soil and Groundwater Environment
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    • v.20 no.4
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    • pp.41-50
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    • 2015
  • Open-loop groundwater heat pump (GWHP) system generally has benefits such as a higher coefficient of performance (COP), lower initial cost, and flexible system size. The hydrogeological conditions in Korea have the potential to facilitate the use of the GWHP system because a large number of monitoring wells show stable groundwater temperatures, shallow water levels, and high well yields. However, few studies have been performed in Korea regarding the GWHP system and the most studies among them dealt with Standing Column Well (SCW). Because the properties of the aquifer have an influence on designing open-loop systems, it is necessary to perform studies on various hydrogeological settings. In this study, the hydrogeological and thermal properties were estimated through various tests in the riverside alluvial layer where a GWHP system was installed. Under different groundwater flow velocities and pumping and injection rates, a sensitivity analysis was performed to evaluate the effect of such properties on the design of open-loop systems. The results showed that hydraulic conductivity and thermal dispersivity of the aquifer are the most sensitive parameters in terms of performance and environmental aspects, and sensitivities of the properties depend on conditions.