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A ground source heat pump system is one of the high-efficient technologies for space heating and cooling since it uses stable underground temperature. However, in actual application, many situations cannot be achieved due to the unsuitable design of operation. In particular, the design characteristics of buildings with different building load patterns are not reflected by the conventional design method. Moreover, the design capacity of the heat pump can be reduced by designing less capacity than the peak load through the introduction of the heat storage tank, but there is no related quantitative design method. Therefore, in this study, the effect of the ground source heat pump system design factors such as shape, length of the ground heat exchanger, and the capacity of the heat storage tank on the system performance was analyzed. To quantify the effect of such factors on system performance, an experimental plant was constructed and case studies were conducted for each design factor.

An electromagnetic launcher or accelerator is a useful device for obtaining a wide range of payload velocities. Electromagnetic launchers have smaller space requirements compared to compressed air gas launchers and can use easily obtainable grid electricity to provide thrust in place of a conventional propellant. Despite these advantages, it is difficult to measure launcher muzzle velocity, as the flames and light produced by the muzzle during launch make velocity measurement using a light sensor or high-speed camera impossible. To overcome this problem, B-dot probes can be used to track the projectile position within the launcher by sensing changes in the magnetic field, which generate an induced voltage in the probe following Faraday’s law. This paper proposes a B-dot probe based method for measuring an electromagnetic launcher’s muzzle velocity. After determining the sensing effect as the probe positions and orientations through numerical simulation, the B-dot probe was used to measure the muzzle velocity, which was compared to a muzzle velocity obtained using a high-speed camera to validate the proposed method.

Groundwater heat pump (GWHP) system can achieve higher performance of the system by utilizing heat source of the annual constant groundwater temperature. The performance of GWHP system depends on the ground thermal environment such as groundwater temperature, groundwater flow rate and hydraulic conductivity. In this study, the geothermal environment was analyzed by using numerical simulation for develop the two-well geothermal system. As the result, this paper shows the change of the groundwater level and underground temperature around wells according to the conditions of flow rate and hydraulic conductivity.Key words: Underground thermal environment(지중 열환경), Groundwater heat pump system (지하수 이용 히트펌프 시스템), Numerical simulation(수치해석 시뮬레이션)