• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.1
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• pp.64-77
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• 2020

An electric-pump cycle, which is a propellant supply system for driving pumps of a liquid rocket engine using an electric motor, has the advantages of simple system configuration and easy control of supply flow rate and pressure. This paper investigates and analyzes the overseas research trends of the electric-pump cycle. In addition, the research and development country, performing organization, application, engine thrust, pump pressure increase, motor power, and rotation speed are summarized. Among them, the design variables of the overseas research that applied the upper-stage propulsion system with the thrust range of 0.445~2.2 kN could be used in the study of a similar electric-pump cycle in Korea.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.2
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• pp.139-155
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• 2016

Present paper introduces the recent advances in space launch vehicle technologies. A brief survey is given for the space development programs in civil sector with their business model and key technologies. Advances in key technologies were reviewed in detail with more emphasis on the electric pump cycle engine for low cost high performance small launch vehicle, Electron, under development by Rocketlab Ltd., since their contributions would give good lessons for rocket scientists.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.384-389
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• 2003

전기가 공급되지 않는 농경지에 물을 공급하기 위해 태양열을 동력원으로 하고 저온에서 비등하는 물질을 작동물질로 하는 물펌프가 연구되어 왔다. 이와 관련하여 김 등(2002, 2003)은 펜탄을 작동물질로 한 태양열 물펌프 연구에서 에너지변환실험, 작동사이클의 열역학적인 해석, 장치의 설계를 수행한 바 있다. 본 연구에서는 펜탄을 작동물질로 한 태양열 물펌프를 실현하기 위하여 기존의 설계를 바탕으로 실험장치를 제작, 실험, 분석하였다. (중략)

• Journal of Energy Engineering
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• v.10 no.4
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• pp.318-326
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• 2001

To enhance thermal efficiency of thermal facility through recovery of low and medium temperature waste heat, 1 MW organic Rankine cycle system was designed and developed. The exhaust gases of 175$^{\circ}C$ at two 100 MW power plants in pohang steel works were selected as the representative of low and medium temperature waste heat in industrial process for the heat source of the organic Rankine cycle system. HCFC-123, a kind of harmless refrigerant, was chosen as the working fluid for Rankine cycle. The organic Rankine cycle system with selected exhaust gases and working fluid was designed and constructed. From the operation, it was confirmed that the organic Rankine cycle system is available for low and medium temperature waste heat recovery in industrial process. The optimum operating manuals, such as heat-up of hot water, turbine start-up, and the process of electric power generation, were derived. However, electric power generated was not 1 MW as designed but only 670 kW. It is due to deficiency of pump capacity for supply of HCFC-123. So it is necessary to increase the pump capacity or to decrease the pressure loss in pipe for more improved HCFC-123 supply.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3827-3834
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• 2012

Recently, instead of hot air type dryers that require a lot of heat, energy-efficient heat pump dryers have been used in various fields such as paper, textile, wood, food, etc. In this paper, the characteristics of heat pump cycle were theoretically evaluated with hot-gas bypass system to further improve the energy efficiency by minimizing the use of electric heaters in early warm-up stage of the dryers for frozen agricultural products. In addition, damper system that leads outside air to flow into the dryer were optimized to obtain extra heat for higher energy efficiency.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.107-121
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• 2020

The performance analysis of the small satellites launch vehicle using the electric pump cycle as the upper stage engines was performed. The first stage is the launch vehicle that uses the test launch vehicle of the Korea Space Launch Vehicle II and the second stage employs elecpump cycle engine that uses liquid methane and kerosene (RP-1) as fuel. A model for the mass estimation was presented and the analysis was conducted for the range of thrust of 20 to 40 kN and combustion pressure of 3 to 6 MPa with a nozzle expansion ratio of 60 to 100. The mixture ratio with the maximum velocity increment was calculated and the performance of the LEO and SSO payload were calculated from the stage mass estimation. In both the cases, liquid methane, and RP-1 showed maximum payload for 20 kN thrust, 3 MPa combustion pressure, and the nozzle expansion ratio of 100, with a mixture ratio of 3.49 for liquid methane and 2.75 for RP-1. In addition, the ditching points of the first stage and the fairing in the LEO mission were analyzed using ASTOS.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.49-58
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• 2009

This paper presents the vector control of single phase induction motor(SPIM) to operate water pumping system using PV system with a maximum power point tracking(MPPT). The water pumping system uses a variable speed SPIM driven a centrifugal pump by field oriented control(FOC) inverter. The MPPT using a DC-DC converter controlled the duty cycle to track maximum power from PV under different insolation conditions. The duty cycle directly relate with a flux producing current control($i_{ds}$). The FOC inverter uses a current control voltage source inverter(CC-VSI). The simulation results are shown that the characteristics and performance of drive system, which varies as each conditions of light by expresses in voltage($V_{dq}$), current($I_{dq}$), speed of motor and torque.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.5
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• pp.91-102
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• 2020

Recently, a new space era has evolved in which commercial companies' led space development has begun. In this era, commercial companies actively participate in space development as the size of the small satellite market and small launch vehicle market is expanding. Through space development, developed countries are making efforts to reduce development, production, and operation costs to secure the competitiveness of small launch vehicles. In this study, the development trend of small launch vehicles and required technologies for space development were analyzed and summarized. Thus, research and development is urgently needed so that spin-on technologies, such as electric pumps and additive manufacturing, can be utilized for space development.

• Transactions of the KSME C: Technology and Education
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• v.3 no.1
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• pp.15-21
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• 2015

In this paper a prediction method of GHP performance is proposed for increasing design accuracy. Two compressors with different capacity and 2311cc gas engine are used for prediction and the target capacity of GHP is 25HP. For predicting GHP performance at first the operation points are randomly selected and then as compared with compressor performance date and heat exchanger characteristic, more accurate operating points are decided through recursive calculation. Lastly engine performance date is used for calculating gas consumption volume. Predicting heating mode performance of GHP, evaporator is separated to the two section of absorbing heat in outdoor air and in engine. From the experimental results, it was found that the simulation model is good for the predicting GHP efficiency and the difference of predicted and measured efficiency is less than 5%.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.07a
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• pp.320-325
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• 1999

세계기후협약으로 인하여 우리나라는 화석연료 사용량을 최소한 2010년까지 2000년 수준으로 감축시켜야할 처지에 놓여 있다. 따라서 지구 온난화의 주 요인이 되고 있는 이산화탄소 배출량을 2010년 예상배출량의 21%정도를 감축해야 하며, 경제활동은 1/4이상이 축소되는 영향을 받게 된다(차재호, 1998). 따라서 현재의 화석에너지에 의존하는 난방법은 자연에너지 또는 전기에너지 등으로 대부분이 전환되어야 할 것으로 전망하고 있다 그러나 농업에 이용되고 있는 난방에너지는 화석에너지에 집중되어 있으며, 온실, 축사, 버섯재배사 등에서 겨울철 난방에 소요되는 에너지 비용은 총경영비의 10-40%를 차지하고 있다. (중략)