• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.10
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• pp.956-964
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• 2005

In order to control indoor air quality and save energy, it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery The purpose of this research is to find the factors affecting the performance of paper heat exchanger for exhaust heat recovery, which can be applied directly to the conventional ventilation unit, air-purifier, and air-conditioning system. In this study, thermal performance and pressure loss of the paper heat exchanger are measured and compared at various operating conditions. The effectiveness of sensible, latent and total heat at the face velocity of 0.75 m/s are $77\%,\;47\%\;and\;57\%$ in the cooling condition and $77\%,\;59\%,\;and\;\%$ in the heating condition, respectively. The effectiveness for sensible heat is only affected by velocity. On the other hand, the effectiveness for latent heat is affected. by temperature and relative humidity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.37-43
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• 2015

Evaporative cooling is a very effective way for exhaust heat recovery that uses both latent heat and sensible heat. This study investigated the performance of a heat recovery system using evaporative cooling. The experimental apparatus comprised a plastic heat exchanger, a water spray nozzle, an air blowing fan, a water circulation pump, and measuring sensors for the temperature, humidity, and flow rate. The effectiveness of the sensible heat recovery without evaporation was measured and compared with that of the total heat recovery with evaporation. The effectiveness of the sensible and total heat recoveries decreased as the air flow rate increased, and a much higher effectiveness was obtained with the counterflow arrangement in both cases. For total heat recovery, the effectiveness increased with the water flow rate, and the parallel flow arrangement was found to be more sensitive to the water flow rate than the counterflow arrangement.

• Journal of the KSME
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• v.18 no.3
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• pp.18-24
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• 1978

열고환기에는 boiler와 같이 다량의 열 energy를 취급하는 것을 비롯하여 가정용 냉장고, 냉방기 기와 같이 비교적 적은 양의 열 energy를 취급하는것, 가종 고온 gas-gas 열교환기, 초전도송전 등의 초저온기기에 부속되는 저온열교환기 혹은 배열회수, 태양열이용을 위한 장치에 포함되는 열교환기등이 있으며, 그 종류와 내용에 있어서 다양하다. 따라서 새 형식의 열교환기 혹은 우수 한 전열특성을 갖는 표면, 형상을 갖는 전열관의 연구, 개발은 한층더 절실하게 요망된다. 최근주 목을 받고 있는 열교환기용전열관중에는 관축방향을 따라 표면을 파상으로 가공한 것(corrugate 식)과 축과 평형이 되게 만든 좁은 흠을 갖는 관(fluted tube)등이 있는데 이들에 있어서는 다같 이 표면의 요철에 의한 면부근의 난동을 촉진시켜서 우수한 대류열전달의 특성을 갖도록 하고 있다. 한편 응축과 비등등의 상변화를 동반하는 열전달에 대해서는 세구, 기공질금속층, 세공등을 갖는 면에 관해서 새로운 관심이 집중되고 있다. 이 후자의 전열면은 유축열전달에서는 평활면보 다 약10배의 높은 열전달율을 가지며 불등열전달에서는 벽면과 액의 온도차는 평활면의 경우보다 약1/5의 값을 갖는다. 동시에 한계열유속은 5활이상으로 증가시킬 수 있음이 알려져 있다. 따라서 본론에서는 후자의 전열면중에서 최근에 알려진 비약적으로 높은 전열성능을 갖는 전열면에 관해 서 소개하기로 한다.

• Journal of the Korean Wood Science and Technology
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• v.37 no.1
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• pp.94-104
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• 2009

It is urgently required to develop the production of fermentation-heat energy from the waste agricultural and forest biomass and its effective heat exchanging system for the supply of warm water to rural households and greenhouses. In this study 3 helical-type and 1 plate-type heat exchangers using 3 different waste biomasses [e.g. hardwood (HW) sawdust (100%), softwood (SW) sawdust : HW sawdust (50 : 50) and HW sawdust : grass (90 : 10)] were applied in order to find out the best heat recovery system. The heat exchanger was basically considered to improve the overall heat recovery efficiency, to minimize heat loss and to simplify manufacturing, assembling and breaking up the fermenting beds. The helical-type heat exchanger (HX-H3) installed in fermenting bed of HW sawdust : grass (90 : 10) showed relatively higher temperature profiles, in particular mid- and upper-parts than lower and surface parts during 45-day fermentation process. The maximum temperature was ranged from $40^{\circ}C$ to $65^{\circ}C$ with average $60^{\circ}C$. The water temperature of tank outlet was ranged to $33{\sim}48^{\circ}C$ during whole measuring periods. By the way plate-type one (HX-P) installed in same biomass compositional fermenting bed showed $64.5{\sim}76.5^{\circ}C$ at center part, and $43{\sim}56^{\circ}C$ and $42{\sim}58^{\circ}C$, water tank and tank outlet temperatures, respectively, during 100 day measurement. It could be concluded that the plate-type heat exchanger (HX-P) provides not only the effective heating for the rural households and greenhouses, but also having the best heat recovery performance, easy manufacturing, assembling and breaking up the systems.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.294-299
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• 2005

In order to control indoor air quality and save energy. it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery. Paper heat exchanger can recover $50{\sim}70$ of the enthalpy difference between supply and exhaust air. The purpose of this research is to obtain the experimental correlations for the friction factor, heat transfer coefficient, mass transfer coefficient and permeance of paper heat exchanger, which can be used for the performance prediction of the paper heat exchanger. Pressure drop at various velocities and heat transfer rate at various dry-bulb temperatures, relative humidities, and specific humidities are measured to make experimental correlations. The results of prediction using correlations show fairly good agreement with experimental data.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.328-333
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• 2008

In order to control indoor air quality and save energy, it is needed to install a suitable heat exchanger for heat recovery. A plastic heat exchanger have many advantages and can recover $50{\sim}80%$ of the temperature difference between supply and exhaust air. The purpose of this research is to evaluate the performance of plastic heat exchanger with different shapes. Pressure drop and heat transfer characteristics of plastic heat exchangers are investigated for various velocities.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.245-250
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• 2003

In order to control indoor air quality and save energy, it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery. The purpose of this research is to find the performance of paper heat exchanger for exhaust heat recovery, which exchanges latent heat as well as sensible heat. Experimental apparatus comprises heat exchanger model, constant temperature and humidity chamber, fan and measurement systems for temperature, pressure and flow rate. Thermal performance and pressure loss of the paper heat exchanger are measured and compared at various air velocities and outdoor conditions. Experimental results show that paper heat exchanger can recover $50{\sim}70%$ of the enthalpy difference between supply and exhaust air.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.107.1-107.1
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• 2011

최근 석유, 가스, 석탄을 비롯한 화석연료의 다량 사용으로 기후변화, 대기오염 등의 환경문제 및 자원 고갈의 우려 때문에 바이오매스는 중요한 화석연료 대체 에너지 자원으로써 큰 관심을 받고 있다. 바이오매스 자원을 에너지로 전환하는 방법 중 하나인 급속 열분해 공정은 산소가 없는 상태에서 바이오매스를 열적으로 분해하여 액상 상태의 생성물을 회수하는 공정으로, 증기상의 열분해 가스를 응축하여 회수하게 된다. 바이오매스의 급속 열분해에 관한 연구는 주로 바이오매스의 종류와 열분해 조건에 따라 회수되는 바이오 원유의 수율 및 물리 화학적 특성에 관한 연구가 수행되고 있으나, 열분해 가스의 응축에 관한 연구는 응축에 수반되는 복잡한 물리적 현상 때문에 미진하다. 따라서 본 연구에서는 바이오매스의 급속 열분해를 통해 생성되는 증기상의 열분해 가스의 응축 현상을 모사 할 수 있는 모델링 기법에 대해 연구하였다. 급속 열분해 공정을 통해 생성되는 바이오 원유는 수백개의 화합물로 구성되어 있으며, 동일한 바이오매스를 사용한 경우라도 공정조건에 따라 바이오 원유에 포함된 화합물은 달라진다. 따라서 본 연구에서는 바이오 원유의 주요 화합물인 water, propanal, butanal, pentanal, phenol, guaiacol, coniferyl alcohol, formic acid, acetic acid, propanoic acid, butanoid acid를 대상으로 열분해 가스의 응축을 모사하였다. 본 연구에서는 응축 모델링 기법의 검증을 위해 실험결과와 비교하여 정확성을 검증하였으며, 본 연구의 결과를 활용하여 응축 조건 변화에 따른 급속 열분해 가스의 응축률을 예측하고, 이를 이용한 응축 열교환기 설계에 유용하게 사용될 수 있을 것으로 판단된다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.11a
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• pp.141-146
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• 2002

폐가스-공기 열교환 방식의 열교환기는 각종 산업용 요ㆍ로나 보일러 등에서 배출되는 폐열을 예열공기로 회수하여 연소용공기로 사용하는 에너지 절약방법으로 현재와 같이 고유가가 지속되고, 전 세계적인 공업화에 의한 고도성장과 생활수준의 향상에 따른 에너지 수요 증가, 에너지자원의 매장량의 한계 및 지역적 편중, 산유국이 밀집되어 있는 중동지역의 불투명한 정세를 미루어 볼 매 석유수급, 고유가의 불안요인은 더욱 증가할 것으로 추정된다.(중략)

• Journal of Bio-Environment Control
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• v.9 no.4
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• pp.212-222
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• 2000

This study was performed to investigate the performance of heat recovery device attached to exhaust gas flue connected to combustion chamber of greenhouse heating system. The experimental heat recovery system is mainly consisted of LPG combustion chamber and two heat recovery units; unit-A is attached directly to the exhaust gas flue, and unit-B is connected with unit-A. Heat recovery performance was evaluated by estimating total energy amounts by using enthalpy difference between two measurement points together with mass flow rate of gas and/or air passing through each heat recovery unit depending on 5 different flow rates controlled by voltage meter. The results of this experimental study, such as heat exchange behavior of supply air tubes and exhaust air passages crossing the tubes, pressure drop between inlet and outlet, heat recovery performance of exchange unit, etc., will be used as fundamental data for designing optimum heat recovery device to be used for fuel saving purpose by reducing heat loss amounts mostly wasted outside of greenhouse through flue.