• Title/Summary/Keyword: Geo-source heat pump

Search Result 15, Processing Time 0.02 seconds

Thermal Conductive Characteristics and Basic Properties of Bentonite Grouts for the Ground Heat Exchanger of Geo-source Heat Pump (지열히트펌프 지중열교환기용 벤토나이트계 그라우트재의 열전도특성 및 기본성능)

  • Bai, Kang
    • Journal of the Korean Solar Energy Society
    • /
    • v.33 no.1
    • /
    • pp.66-72
    • /
    • 2013
  • In this study, the thermal conductive characteristics and basic properties of the nine commercial products of bentonite grouts were studied. Six of the nine products for ground heat exchanger systems are imported and others for civil engineering are domestic. The thermal conductivities of all bentonite products are nearly similar among products. The free swell indexes, viscosities and filter losses of the ground heat exchanger grouts are lower than those of the civil engineering ones. These characteristics seem to increase of the fluidity to fill the bentonite slurry to bore-hall perfectly, rather than to prevent underground water penetration. Thus, the mixtures of bentonites and sands are recommended for high thermal conduction grouts.

Seasonal Variations of EWT and COP of GWHP System Using the Bank Infilterated Water from Stream-Alluvial Aquifer System (하천-충적대수층계의 강변여과수를 열원으로 이용하는 지하수 열펌프 시스템의 계절별 입구온도와 효율성 평가)

  • Hahn, Chan;Jeon, Jae-Soo;Yoon, Yoon-Sang;Han, Hyok-Sang;Hahn, Jeong-Sang
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
    • /
    • v.3 no.2
    • /
    • pp.39-51
    • /
    • 2007
  • Unconsolidated and permeable alluvial deposit composed of sand and gravel is distributed along the fluvial plain at the Iryong study area. Previous studies on the area show that a single alluvial well can produce at least 1,650m3d-1 of bank infilterated shallow groundwater(BIGW) from the deposit. This study is aimed to evaluate and simulate the influence that seasonal variation of water levels and temperatures of the river have an effect on those of BIGW under the pumping condition and also to compare seasonal variation of COPs when indirectly pumped BIGW or directly pumped surface water are used for a water to water heat pump system as an heat source and sink using 3 D flow and heat transport model of Feflow. The result shows that the magnitude influenced to water level of BIGW by fluctuation of river water level in summer and winter is about 48% and 75% of Nakdong river water level separately. Seasonal change of river water temperature is about $23.7^{\circ}C$, on other hand that of BIGW is only $3.8^{\circ}C$. The seasonal temperatures of BIGW are ranged from minimum $14.5^{\circ}C$ in cold winter(January) and maximum $18.3^{\circ}C$ in hot summer(July). It stands for that BIGW is a good source of heat energy for heating and cooling system owing to maintaining quite similar temperature($16^{\circ}C$) of background shallow groundwater. Average COPh in winter time and COPc in summer time of BIGW and surface water are estimated about 3.95, 3.5, and about 6.16 and 4.81 respectively. It clearly indicates that coefficient of performance of heat pump system using BIGW are higher than 12.9% in winter time and 28.1% in summer time in comparision with those of surface water.

  • PDF

An Evaluation of the Solar Thermal Performance of the Solar/Geo Thermal Hybrid Hot Water System for a Detached House (단독주택용 태양열/지열 융복합시스템의 태양열 급탕성능 평가)

  • Baek, Namchoon;Han, Seunghyun;Lee, Wang Je;Shin, Ucheul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.27 no.11
    • /
    • pp.581-586
    • /
    • 2015
  • In this study, an analysis was performed on the performance of the solar water heating system with geo-thermal heat pump for a detached house. This system has a flat plate solar collector ($8\;m^2$) and a 3 RT heat pump. The heat pump acts as an auxiliary heater of the solar water heating system. These systems were installed at four individual houses with the same area of $100\;m^2$. The monitoring results for one year are as follows. (1) The average daily operating time of the solar system appeared to be 313 minutes in spring (intermediate season), and 135 minutes and 76 minutes in winter and summer respectively. The reason for the short operating time in summer is the high storage temperature due to low water heating load. The high storage temperature is caused by a decrease in collecting efficiency as well as by overheating. (2) The geothermal heat pump as an auxiliary heater mainly operates on days of poor insolation during the winter season. (3) Despite controlling for total house area, hot water consumption varies greatly according to the number of people in the family, hot water usage habits, etc. (4) The yearly solar fraction was 69.8 to 91.5 percent, which exceeds the maximum value of 80% as recommended by ASHRAE. So the solar collector area of $8\;m^2$ appeared to be somewhat greater for the house with an area of $100\;m^2$. (5) The observed annual efficiency of solar systems was relatively low at 13.5 to 23.6%, which was analyzed to be due to the decrease in thermal efficiency and the overheating caused by a high solar fraction.

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
    • /
    • v.26 no.12
    • /
    • pp.605-619
    • /
    • 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 the Energy Self-Sufficiency of KIER Zero Energy Solar House II (제로에너지 솔라하우스(KIER ZESH-II)의 에너지 자립도에 대한 연구)

  • Jeong, Seonyeong;Baek, Namchoon;Yoo, Changkyoon;Yoon, Jongho
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2010.06a
    • /
    • pp.199.1-199.1
    • /
    • 2010
  • The purpose of this study is on the thermal performance evaluation of KIER Zero Energy Solar House-II, called ZeSH-II which can be sustained with the support of a very few energy. This ZeSH-II was designed and constructed in the end of 2009 to develop for the goal of 70% self-sufficiency. Several key technologies like as the super insulation, high performance window, wast heat recovery system as well as solar power and thermal system and geo-source heat pump wear used for this ZeSH-II. The monitering of ZeSH-II was conducted for six months from November 2009 to April 2010. The monthly energy consumption was calculated based on the monitering results. As a result, the ZeSH-II shows that the energy self-sufficiency during six months(from oct. to apr.) is about 80% which is higher than that of the target.

  • PDF