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  • Title/Summary/Keyword: Ground heat source

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Economic Analysis of a Residential Ground-Source Heat Pump System (단독주택용 지열원 열펌프 시스템 경제성 분석)

  • Sohn, Byong-Hu;Kang, Shin-Hyung;Lim, Hyo-Jae
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.515-518
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    • 2007
  • Because of their low operating and maintaining costs, ground-source heat pump(GSHP) systems are an increasingly popular choice for providing heating, cooling and water heating to public and commercial buildings. Despite these ad- vantages and the growing awareness, GSHP systems to residential sectors have not been adopted in Korea until recently. A feasibility study of a residential GSHP system was therefore conducted using the traditional life cycle cost(LCC) analysis within the current electricity price framework and potential scenarios of that framework. As a result, when the current residential electricity costs for running the GSHP system are applied, the GSHP system has weak competitiveness to conven- tional HVAC systems considered. However, when the operating costs are calculated in the modified price frameworks of electricity, the residential GSHP system has the lower LCC than the existing cooling and heating equipments. The calculation results also show that the residential GSHP system has lower annual prime energy consumption and total pollutant emissions than the alternative HVAC systems considered in this work.

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Performance Prediction on the Application of a Ground-Source Heat Pump(GSHP) System in an Office Building (업무용 건물의 지열 히트펌프 시스템에 대한 성능 예측)

  • Sohn, Byonghu;Kwon, Han Sol
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.9
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    • pp.409-415
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    • 2014
  • Ground-source heat pump (GSHP) systems have become an efficient alternative to conventional cooling and heating methods due to their higher energy efficiency. These systems use the ground as a heat source and the heat sink for cooling mode operation. The purpose of this simulation study is to evaluate the performance of a hypothetical GSHP system in an office building and to assess the energy saving effect against the existing HVAC systems (boiler and turbo chiller). We collected monthly energy consumption data from an actual office building (32,488m2) in Seoul, and created a model to calculate the hourly building loads with EnergyPlus. In addition, we used GLD (Ground Loop Design) V8.0, a GSHP system design and simulation software tool, to evaluate hourly and monthly performance of the GSHP system. The energy consumption for the GSHP system based on the hourly simulation results were estimated to be 582.6 MWh/year for cooling and 593.2 MWh/year for heating, while those for the existing HVAC systems were found to be 674.5 MWh/year and 2,496.4 MWh/year, respectively. The seasonal performance factor (SPF) of the GSHP system was also calculated to be in the range of 3.37~4.28.

Study on Capacity Alteration of Geothermal Heat Exchanger by Changing Design Condition (설계조건 변화에 따른 지중열교환기 길이 변화 연구)

  • Park, Jong Il;Park, Kyung Soon
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.9 no.4
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    • pp.9-14
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    • 2013
  • A ground loop heat exchanger for the ground source heat pump system is the important equipment determining the thermal performance and initial cost of the system. The length and performance of the underground heat exchanger is dependent on ground thermal conductivity, operation hours, ground loop diameter, grout, ground loop arrangement, pipe placement and design temperature. In this study we find out heat exchanger length with various design factor.

Effect of the Design Parameters of Geothermal Heat Exchanger Design Length (설계변수가 수직밀폐형 지중열교환기 설계길이에 미치는 영향)

  • Min, Kyong-Chon;Choi, Jae-Ho
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.7 no.2
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    • pp.10-15
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    • 2011
  • A ground loop heat exchanger for the ground source heat pump system is the core equipment determining the thermal performance and initial cost of the system The length and performance of the heat exchanger is dependent on the ground thermal conductivity, the operation hours, the ground loop diameter, the grout, the ground loop arrangement, the pipe placement and the design temperature. The result of this simulation shows that higher thermal conductivity of grouting materials leads to the decrease length of geothermal heat exchanger from 100.0 to 84.4%.

An Experimental Study on the Performance of Semi-Closed Loop Ground Heat Exchanger (반밀폐형 지중열교환기 성능에 관한 실험적 연구)

  • Kim, Ook-Joong;Yeom, Han-Kil;Lee, Chun-Woo
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.542-545
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    • 2007
  • A semi-closed loop ground heat exchanger is proposed and its performance is compared through the measuring the effective thermal conductivity of the ground. In-situ tests based on the line source model are carried out to evaluate the thermal characteristics of each ground heat exchanger which has different penetration water flow rate. The test results show the increasing effective thermal conductivity of ground as the penetration water flow rate(PWFR) is increased. Therefore, the higher thermal performance of the proposed semi-closed ground heat exchanger can be expected.

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An Experimental Study on the Effect of Ground Heat Exchanger to the Overall Thermal Conductivity (지중열교환기 설치 조건이 지중 유효 열전도도에 미치는 영향에 관한 실험적 연구)

  • Kong, Hyoung-Jin;Lim, Hyo-Jae;Choi, Jae-Ho;Sohn, Byong-Hu
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.45-51
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    • 2009
  • A ground-loop heat exchanger in a ground source heat pump system is an important unit that determines the thermal performance of a system and its initial cost. The size and performance of this heat exchanger is highly dependent on ground thermal properties. A proper design requires certain site-specific parameters, most importantly the ground effective thermal conductivity, the borehole thermal resistance and the undisturbed ground temperature. This study was performed to investigate the effect of some parameters such as borehole lengths, various grouting materials and U-tube configurations on ground effective thermal conductivity. In this study, thermal response tests were conducted using a testing device with 9-different ground-loop heat exchangers. From the experimental results, the length of ground-loop heat exchanger affects to the effective thermal conductivity. Among the various grouting materials, the bentonite-based grout with silica sand shows the largest thermal conductivity value.

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A Study on the Determining Initial Ignoring Time for the Analysis of Ground Thermal Conductivity of SCW Type Ground Heat Exchanger (SCW형 지중 열교환기의 지중 열전도도 해석에서 초기제외시간 결정에 관한 연구)

  • Chang, Keun-Sun;Kim, Min-Jun;Kim, Young-Jae
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.10
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    • pp.453-459
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    • 2014
  • This paper presents an analysis on the initial ignoring time of SCW type GHX using Mean Square Error method. Line source method is a useful method for estimating the ground thermal conductivity for the vertical type and SCW type GHX in Korea. The line source method for ground thermal conductivity of geothermal in-site test is the basis of linear approximation between the temperature of a borehole and logarithmic time in a GHX. To apply the line source method to the estimation of SCW type GHX, it is necessary to ignore the initial time of data at the stage of a linear approximation. This paper proposed a new initial ignoring time of SCW type GHX among various initial ignoring time at the time for reaching MSE of 0.02C2.

Evaluation on Cooling Performance of Ground Source Heat Pump System Equipped with Steel-pipe Civil Structures (강관 토목구조물이 설치된 지열 히트펌프 시스템의 냉방 성능 평가)

  • Seokjae Lee;Jeonghun Yang;Hangseok Choi
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.19 no.3
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    • pp.14-22
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    • 2023
  • Steel-pipe civil structures, including steel-pipe energy piles and cast-in-place piles (CIPs), utilize steel pipes as their primary reinforcements. These steel pipes facilitate the circulation of a working fluid through their annular crosssection, enabling heat exchange with the surrounding ground formation. In this study, the cooling performance of a ground source heat pump (GSHP) system that incorporated steel-pipe civil structures was investigated to assess their applicability. First of all, the thermal performance test was conducted with steel-pipe CIPs to evaluate the average heat exchange amount. Subsequently, a GSHP system was designed and implemented within an office container, considering the various types of steel-pipe civil structures. During the performance evaluation tests, parameters such as the coefficient of performance (COP) and entering water temperature (EWT) were closely monitored. The outcomes indicated an average COP of 3.74 for the GSHP system and the EWT remained relatively stable throughout the tests. Consequently, the GSPH system demonstrated its capability to consistently provide a sufficient heat source, even during periods of high cooling thermal demand, by utilzing the steel-pipe civil structures.

Verification experiment of a ground source multi-heat pump at heating season (지열원 멀티 히트펌프의 동절기 난방성능에 관한 실증 연구)

  • Choi, Jong-Min;Lim, Hyo-Jae;Kang, Shin-Hyung;Choi, Jae-Ho;Moon, Je-Myung;Kwon, Young-Seok;Kwon, Hyung-Jin;Kim, Rock-Hee
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.52-57
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    • 2009
  • This paper describes the multi-heat pumps applied in an ground source heat pump system for an actual building. The performance of a ground source multi-heat pump installed in the field was investigated at heating season. The average COP of the systems with single U-tube and double tube type GLHXs were 4.8 and 5.0, respectively. It is needed to investigate the long term performance of double tube type GLHX, because the reduction of inlet temperature of OD HX for this GLHX was larger than it for U-tube GLHX.

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Application study of heat storage type GSHP system in Apartment building with central cooling and heating facilities using life cycle cost analysis (LCC 분석을 이용한 중앙공급식 공동주택의 수축열식 지열원 히트펌프시스템의 적용연구)

  • Lee, Sang-Hoon;Park, Jong-Woo;Cho, Sung-Hwan
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1497-1502
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    • 2009
  • The present study has been conducted economic analysis of heat storage type ground source heat pump system(HSGSHP) and normal ground source heat pump (GSHP) and central boiler system with individual air conditioning facility which are installed at the same building in the shared an apartment house. Cost items, such as initial construction cost, annual energy cost and maintenance cost of each system are considered to analyze life cycle cost (LCC) and simple payback period (SPP) with initial cost different are compared. The initial cost is a rule to the Government basic unit cost of production. LCC applied present value method is used to assess economical profit of both of them. Variables used to LCC analysis are prices escalation rate and interest rate mean values of during latest 10 years. The LCC result shows that HSGSHP (1,351,000,000won) is more profitable than central boiler system with individual air conditioning facility by 86.7% initial cost. And SPP appeared 8.0 year overcome the different initial cost by different annual energy cost.

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