• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.21-26
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• 2017

In this study, performance tests were conducted to investigate the applicability of a double-tube heat recovery ventilation system. Paper, aluminum, polymer, were investigated as materials for the inner tube using the same exhaust-air volume. In all cases, the temperature exchange efficiency of the aluminum tube was the highest, while the paper tube showed similar results to those of the polymer tube. This probably resulted from the differences in thermal conductivity and thicknesses of the materials. The humidity exchange efficiency was the highest for the paper tubes in all cases, while the aluminum tubes and polymer tubes showed similar results. The total heat exchange efficiency, which includes the values of humidity exchange and temperature exchange, was highest in the case of the paper tube, and the aluminum tube and the polymer tube showed similar results. In the case of the paper tube, sensible heat and latent heat exchange occur at the same time, and the coefficient of energy of the aluminum tube and polymer tube are large values, when to be compared with only applicably sensible heat exchange coefficient of the aluminum tube and the polymer tube of total heat exchange efficiency value. The results of this study could be applied to the design of a ventilation system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.1
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• pp.81-86
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• 2013

Exhaust gas from a small portable electric generator is simply exhausted to the surroundings because the capacity and quality of the waste heat of this gas is generally not sufficient to recover and utilize. We have proposed a seawater distiller utilizing the thermal energy of waste gas from an electric generator. The distiller recovers heat from the waste gas by means of a heat pipe and uses it effectively through a multiple-effect diffusion-type structure. We constructed an experimental apparatus with a vertical single-effect still having a 4-stroke 50 cc generator engine and found that the experimental results for distillate productivity show good agreement with the theoretical predictions. The results show that the distiller can recover 52 W of waste heat from the gas at $171^{\circ}C$, and ~85% of the recovered heat can be utilized for distillation to produce 70 g/h of fresh water. This is equivalent to a productivity of 500 g/h in the case of a 10-effect still. Therefore, the proposed distiller should be useful in remote areas where electricity and water grids are inadequate.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.287-287
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• 2009

연료전지는 전기에너지와 열에너지를 동시에 사용 할 수 있기 때문에 에너지 효율이 높고 유해 배기물이 거의 없으므로 친환경적이다. 따라서 환경문제가 대두되고 있는 오늘날, 고효율 친환경의 연료 전지는 차세대 에너지원으로 각광받고 있다. 보일러와 계통선에서 열과 전기를 공급받는 기존방식에 비해 연료전지 코제너레이션 시스템의 경우 20%이상 에너지 절감율을 향상시킬 수 있다. 기존 10kW이하의 소용량 발전설비의 경우 대형 발전소와 같은 수준인 30%이상의 전기 효율을 기대할 수 없으나 고분자 전해질 연료전지를 적용할 경우 1kW급에서도 35%의 전기 효율을 기대할 수 있으며 열회수까지 고려할 경우 80%에 가까운 열효율을 달성할 수 있다.(4)연료전지 시스템은 연료전지 스택 이외에, 연료변환장치, 급기설비, 열 및 물관리 설비, 전력변환장치 그리고 제어 장치 등으로 구성된다. 연료전지 시스템 성능은 연료전지 스택의 성능에 가장 의존적인데 연료전지 스택의 성능은 같은 스택이라도 운전 및 제어 방법에 따라서 다양하게 변할 수 있다. 실제로 연료전지 스택 자체의 전기 변환 효율은 최대 40% 까지로 매우 높으나, 다양한 운전 조건에 따라 효율이 30~40% 수준에서 변화는 것이 현실이다. 때문에 시스템을 설계할 때에는 종합화된 시스템 측면에서의 운전까지 고려한 설계와 성능 해석이 필요하다. 그간 연료전지를 활용한 가정용 열병합 발전분야에서는 시스템 설계를 위한 시뮬레이션 기반 성능 해석에 관한 연구가 활발히 진행되어왔다. 하지만 연료전지 스택의 경우 간이화된 성능 모델식을 사용하여 이로 인한 성능 예측모델의 오차가 크게 발생하여 전체 시스템 최적화의 저해요인으로 작용하여왔다. 따라서 본 연구에서는 가정용 연료전지 열병합 발전 시스템을 자체적으로 설계 개발하였으며 이 중 연료전지 스택의 성능모델을 실험기반으로 구축하였다. 먼저 가정용 연료전지 열병합 발전 시스템의 설계는 크게 네 단계로 구분되며 이는 1) 시스템 개념 설계, 2) 연료전지 스택 설계, 3) 주변장치 설계, 4) 제어시스템 설계로 이뤄진다. 연료전지 스택의 성능 모델은 고분자연료전지의 성능에 가장 민감하게 영향을 미치는 온도 및 습도의 변화에 따른 다양한 스택 성능을 예측 가능하도록 개발하였으며 이는 간단한 이론 모델의 구조에 실험 데이터를 기반으로 모델 파라미터를 도출하는 기법으로 이뤄졌다.

• Journal of Navigation and Port Research
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• v.36 no.5
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• pp.349-355
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• 2012

In this study, for the purpose of reduction of $CO_2$ gas emission and to increase recovery of waste heat from ships, the ORC(Organic Rankine Cycle) is investigated and offered for the conversion of temperature heat to electricity from waste heat energy from ships. Simulation is performed with waste heat from the exhaust gasse which is relatively high temperature and cooling sea water which is relatively low temperature from ships. The result shows that 1,000kW power generation is available from exhaust gas and 600kW power generation is available from sea water cooling system. Different fluid is used for simulation of the ORC system with variable temperature and flow condition and efficiency of system and output power is compared.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5045-5050
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• 2015

As modern houses are constructed with high-density and high-insulation, there is benefit to reduce energy consumption, but there are many side effects raised from polluted air. To solve the problem, a ventilation system is used to improve a indoor air quality. In this study, we tested the parallel flow type heat exchanger used in a heat exchanger of an automotive air conditioner. And we experimentally estimate ventilation performance of HRV(heat recovery ventilator) with heat-pipe according to working fluid filling quantity and ventilation. The working fluid was R22, which was filled from 40 to 60 (%vol.) by 10(%vol.). Ventilation based on the front velocity was measured from 0.3 m/s to 1.5 m/s by 0.3 m/s intervals. Refrigerant filling quantity with the highest efficiency was found to depend on the ventilation. From this study the optimal refrigerant filling quantity in accordance with the ventilation of the detachable heat pipes was found experimentally.

• Journal of Internet of Things and Convergence
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• v.8 no.1
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• pp.23-29
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• 2022

The product to be developed in this study is a heat recovery device which generates steam or hot water at high temperature and high pressure by heating water using exhaust gas from diesel engine, gas engine, gas turbine, etc. as an exhaust gas boiler off heat boiler(EGB) type for ship and power generation. The steam vapor or the created warm water is used as the power source required for the steerage heating and hot water facility or the HFO heating of the ship, and the turbine drive. The principle of waste heat boilers serves to heat water as high temperature exhaust gas with heat pass through the tube of the boiler. The heated water is a structure that is sent to a cabin or turbine device in the form of steam. In this study, the objective of this study is to maximize the efficiency by increasing the heat transfer surface by replacing the tube which is the heat transfer part of EGB with the plate tube.