• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2000년도 제15회 학술강연회논문초록집
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• pp.18-18
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• 2000

산업용 가스터빈에서 대기로 방출되는 배기열을 효과적으로 이용하기 위한 역 브레이튼 사이클 가스터빈(Reverse Brayton Cycle Gas Turbine) 엔진의 출력과 비연료 소비율 및 열효율을 기본 브레이튼 사이클 엔진, 재열사이클에 역 브레이튼 사이클을 추가한 엔진, 역 브레이튼 사이클에 중간냉각기를 추가한 엔진의 출력, 비연료 소비율 및 열효율을 비교하였다.(중략)

• KEPCO Journal on Electric Power and Energy
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• 제2권2호
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• pp.299-305
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• 2016

초전도 전력 케이블의 상용화 노력에 따라 점차 장선화 되면서, 단위 냉각 시스템당 냉각용량이 큰 대용량 냉동기의 필요성이 증가하고 있다. 국내에서는 극저온 냉동기에 대한 기술 부족으로 인해 현재 극저온 냉동기는 해외 선진사로부터 고가의 비용으로 수입되고 있다. 초전도 전력 케이블의 상용화를 위해서는 대용량 브레이튼 냉동기의 국내 개발이 시급하다. 대용량 브레이튼 냉동기의 구성은 복열식 열교환기, 압축기, 극저온 터보 팽창기로 구성되어 있으며, 냉동기 효율과 가장 직접적인 연관이 있는 것은 극저온 터보 팽창기이다. 극저온 터보 팽창기는 극저온에서 고속으로 회전하면서 고압의 헬륨 혹은 네온 가스를 팽창시켜 온도를 낮추는 역할을 한다. 본 논문에서는 역브레이튼 냉동 사이클을 설계하고, 이에 적합한 극저온 터보 팽창기를 설계하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 동계학술발표대회 논문집
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• pp.88-88
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• 2006

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 하계학술발표대회 논문집
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• pp.24-24
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• 2007

• 한국수소및신에너지학회논문집
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• 제31권5호
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• pp.429-435
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• 2020

This paper describes the experimental study of reverse-Brayton refrigeration system for application to high temperature superconductivity electric devices and LNG re-liquefaction. The reverse-Brayton refrigeration cycle is designed with operating pressure of 0.5 and 1.0 MPa, cooling capacity of 2 kW at 77 K, and neon as a working fluid. The refrigeration system is developed with multi scroll compressor, turbo expander and plate heat exchanger. From experiments, the performance characteristics of used components is measured and discussed for 77-120 K of operating temperature. The developed refrigeration system shows the cooling capacity of 1.23 kW at 77 K and 1.64 kW at 110 K.

• 한국초전도ㆍ저온공학회논문지
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• 제5권2호
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• pp.58-65
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• 2003

The high temperature superconductivity(HTS) cable must be cooled below the nitrogen liquefaction temperature to applicate the cable in power generation and transmi-ssion system under the superconducting state. To obtain superconducting state. a reliable cryocooler system is required. Structural and thermal design have been performed to design cryocooler system operated with reverse Brayton cycle using gas neon as refrigerant. This cryocooler system consists of compressor. recuperator. coldbox. control valves and has 1 kW cooling capacity. Heat loss calculation was conducted for the given cryocooler system by considering the conduction and radiation through the multi-layer insulation(MLI) and high vacuum. The results can be summarized as: conduction heat loss is 7 W in valves and access port and radiation heat loss is 18 W through the surface of cryocooler. The full design specifications were discussed and the results were applied to construct in house HTS cable cooling system.

• 한국기계가공학회지
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• 제14권3호
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• pp.141-148
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• 2015

The cryogenic cooling system should maintain the HTS power cable below 77 K. As the length of HTS power cables has increased, there have been many efforts to develop large capacity cryocoolers. Brayton, Joule-Thomson, and Claude refrigerators were considered for the large capacity cryocooler. Among the various cryocoolers, the Brayton refrigerator is the most competitive in terms of the HTS power cable. At present, it is thought that a 10-kW class refrigerator will be able to be used as a unit cooling system for the commercialization of HTS power cables in the near future. The Brayton refrigerator is composed of recuperative heat exchangers, a compressor, and a cryogenic turbo expander. Among the various components, the cryogenic turbo expander is the part that decreases the temperature, and it is the most significant component that is closely related with overall system efficiency. It rotates at high speed using high-pressure helium or neon gas at cryogenic temperatures. This paper describes the design of a 300-W class Brayton refrigeration cycle and the cryogenic turbo expander as a downscale model for the practical 10-kW class cycle. Flow and structural analyses are performed on the rotating impeller and nozzle to verify the efficiency and the design performance.

• 설비공학논문집
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• 제20권12호
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• pp.775-780
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• 2008

A dynamic model to simulate LNG reliquefaction process has been developed. The model was applied to two candidate cycles for LNG reliquefaction process, which are Reverse Brayton and Claude cycles. The simulation was intended to simulate the pilot plant under construction for operation of the two cycles and evaluate their feasibility. According to the simulation results, both satisfy control requirements for safe operation of brazed aluminum plate-fin type heat exchangers. In view of energy consumption, the Reverse Brayton cycle is more efficient than the Claude cycle. The latter has an expansion valve in addition to the common facilities sharing with the Reverse Brayton cycle. The expansion valve is a main cause to the efficiency loss. It generates a significant amount of entropy associated with its throttling and increases circulation flow rates of the refrigerant and power consumption caused by its leaking resulting in lowered pressure ratio. It is concluded that the Reverse Brayton cycle is more efficient and simpler in control and construction than the Claude cycle.

• 대한안전경영과학회지
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• 제9권4호
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• pp.149-154
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• 2007

The LNG carriers have been propelled by steam turbines and the LNG boil-off(BOG) has been used as fuel or vented. However, as the alternative propulsion systems such as diesel engines are being equipped on the LNG carriers for better fuel efficiency, a need for the LNG BOG re-liquefaction system that liquefies the BOG and sends the liquid BOG back to the LNG cargo has arisen in recent years. This study investigates the design of the BOG re-liquefaction system based on the reverse Brayton refrigeration cycle. The thermodynamic and heat exchanger analysis are carried out and the limitations to the system performance are discussed.

• 한국기계가공학회지
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• 제15권6호
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• pp.129-135
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• 2016

There have been many types of development and commercialization efforts for superconducting power applications with the continuous development of High Temperature Superconducting (HTS) conductors. In particular, HTS power cables are going to be commercialized in real power grids. A cryogenic refrigeration system should be used to keep it below 77 K, and its required cooling capacity continuously increases as the unit length of the HTS power cable increases. Among the many kinds of cryogenic refrigerator, a reverse Brayton refrigerator that uses turbo expanders is a promising refrigerator due to its efficiency and reliability. Among the various components in refrigerators, the cryogenic turbo-expander is the most important part for increasing efficiency and assuring reliability. The design of a 300 W class turbo-expander is described in this paper prior to the development of a 10 kW class turbo expander, which is the required capability for the commercialization of a HTS power cable. The impeller shape and rotation speed are determined based on the cycle analysis. The Eigen frequency and harmonic analysis are conducted with gas bearings at cryogenic temperatures to determine the operational stability.