• 한국지반공학회논문집
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• 제30권7호
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• pp.55-61
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• 2014

최근 들어 경제적이고 친환경적인 에너지 활용을 위하여 지열에너지 필요성이 증대되고 있다. 수평형 지중 열교환기는 설치 비용이 저렴하여 비용 대비 효율면에서 우수하다. 수평형 지중 열교환기의 타입에는 여러 가지가 있으나 이 중 슬링키형과 코일형이 우수한 것으로 알려져 있다. 따라서 본 논문에서는 $5m{\times}1m{\times}1m$ 크기의 모형 토조내에 수평 슬링키형과 코일형 지중 열교환기를 각각 설치한 후 열교환율을 실험적으로 측정하였다. 모형 토조 내에는 건조 상태의 주문진 모래가 조성되었으며 수평 슬링키형과 코일형의 피치 간격에 따라 열교환율을 측정하기 위해 30시간 동안 연속으로 열응답 시험을 실시하였다. 실험 결과 코일형 지중 열교환기 이용시 수평 슬링키형 보다 약 30, 40% 정도의 높은 파이프 단위 길이당 열교환율을 보였다. 또한 수평 슬링키형과 코일형 이용시 피치 간격이 넓을 때(피치/직경 = 1)가 좁을 때(피치/직경 = 0.2)보다 약 200, 250% 정도의 높은 파이프 단위 길이당 열교환율을 나타냈다.

• Journal of Magnetics
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• 제20권2호
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• pp.155-160
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• 2015

Recently, $CO_2$ emission standards and fuel efficiency legislation has been tightened globally. Therefore automotive alternator performance becomes increasingly important to meet the requirements. Many proposed methods have suggested adding magnets or regulation control to increase alternator efficiency and output. However, this creates a significant additional cost. During the stator lamination process, the magnetic property of the stator deteriorates mainly due to stamping and slinky process for an alternator. To maximize the alternator performance, heat treatment of the stator core was performed and magnetic properties were compared to find the optimal condition. Finally, alternator output and efficiency test were performed resulting in significant output and efficiency improvement up to 6.8% and 0.6% respectively.

• 설비공학논문집
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• 제24권3호
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• pp.230-239
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• 2012

Ground-coupled heat pump (GCHP) systems utilize the immense renewable storage capacity of the ground as a heat source or sink to provide space heating, cooling, and domestic hot water. The main objective of the present study is to investigate the cooling and heating performance of a small scale GCHP system with horizontal ground heat exchanger (HGHE). In order to evaluate the performance, a water-to-air ground-source heat pump unit connected to a test room with a net floor area of 18.4 m2 and a volume of 64.4 m3 in the Korea Institute of Construction Technology ($37^{\circ}39'N$, $126^{\circ}48'E$) was designed and constructed. This GCHP system mainly consisted of slinky-type HGHE with a total length of 400 m, indoor heat pump, and measuring devices. The peak cooling and heating loads of the test room were 5.07 kW and 4.12 kW, respectively. The experimental results were obtained from March 15, 2011 to August 31, 2011 and the performance coefficients of the system were determined from the measured data. The overall seasonal performance factor (SPF) for cooling was 3.31 while the system delivered heating at a daily average performance coefficients of 2.82.

• 토지주택연구
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• 제3권2호
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• pp.169-175
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• 2012

최근, 지열 냉난방 시스템의 초기 공사비를 절감하기 위해 연구되고 있는 에너지 파일의 열교환량을 산정하기 위해 2종류(부속연결형, 슬링키형)의 현장타설말뚝형(PRD, 시공심도 4.5m, 직경 1,200mm) 에너지 파일을 시험시공하고 수치 시뮬레이션에 의해 효율을 상호 비교하였다. 상호 비교결과에 의하면 지중 교환량은 운전시작과 함께 채열에 의한 지중온도의 저하에 의해 점점 감소하였고 부속연결형의 평균 열원수의 온도차는 난방운전에서 $0.37^{\circ}C$, 냉방운전에서 $0.34^{\circ}C$로 나타났다. 또, 부속연결형의 난방운전시 열교환량 231.4W/m보다 냉방운전의 방열량은 252.2W/m로서 9% 높았고 슬링키형은 난방 기간 평균 열교환량이 168.0W/m로 부속연결형에 비해 약 27% 낮은 열교환량을 얻었다.

• 한국자동차공학회논문집
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• 제4권6호
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• pp.175-186
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• 1996

In Advanced Vehicle Control System(AVCS), Autonomous Intelligent Cruise Control(AICC) is generally understood to be a system that can be achieved in the near future without the demanding infrastructure components and technoloties. AICC is an automatic vehicle following system with no human engagement in the longitudinal vehicle direction. This paper presents a fuzzy control algorithm to develop the AICC system. The control performance was studied information of vehicles using computer simulations. The most improtant aspects of the work reported here are the adoption of the fuzzy adaptive control law, and the use of filtering concept to reduce the slinky effects that may appear in a formation of vehicles equipped with AICC systems. The simulation results demonstrate the effectiveness of the fuzzy adaptive AICC system and its beneficial effects on traffic flow.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.470-473
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• 2007

Geothermal heat exchanger(GHEX) is a major component of Geothermal heat pump system(GSHPs). In Common, We use the vertical type GHEX in Korea. But vertical type GHEX needs a high cost for installation, because of drilling the hole which has 200m depth at max. So, We suggest the use of horizontal type GHEX. When we construct buildins, We excavate the ground and we can install the horizontal type GHEX at the excavated underground. It's very cheap and convenient method compare to vertical type GHEX installation. This study is peformed to estimate the peformance of horizontal type GHEX and to analyze effects of heat exchanger types and undergroundwater. As the result, slinky type GHEX has a 66% efficiency compare to vertical type GHEX and mat type has a 201% efficiency at the undergroundwater zone.

• 한국자동차공학회논문집
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• 제8권2호
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• pp.92-101
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• 2000

The objective of this paper is to design the controller for longitudinal vehicle following which makes the vehicle follow the lead vehicle and keeps a safety distance without human driver operation. This paper presents a sliding mode control algorithm for the ACC system. The controller is based on three sliding surfaces. Each surface plays an individual control-deviation control, throttle control and brake control. In addition to sliding mode control, we propose some additional schemes to enhance controller performance. The first one is a gear shift-down controller which makes tractive force increase with a change of gear ratio. The other is a predictive correction method which reduces slinky effect.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.684-687
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• 2005

Ground source heat pump systems are used for heating, ventilating and air-conditioning systems in commercial buildings, schools, and factories because of low operating and maintenance costs. These systems use the earth as a heat source in heating mode and a heat sink in cooling mode. Ground heat exchangers are classified by a horizontal type and vertical type according to the installation method. A horizontal type means that a heat exchanger is laid in the trench bored in 1.2 to 1.8 m depth. The solar heat and the rainwater are affected by the performance of heat exchanger and causes mutual influence among heat exchangers. In this study, to evaluate the performance of straight type, slinky type, and spiral type of horizontal ground heat exchangers designed on 1 RT scale, test sections are buried on the earth and experimental apparatus is installed. Therefore the performance of these is estimated.