• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.39 no.12
• /
• pp.30-35
• /
• 2010

• Proceedings of the SAREK Conference
• /
• 2007.11a
• /
• pp.216-221
• /
• 2007

An experiment was carried out to investigate the effect of a coolant circuit arrangement on the heat transfer and air pressure drop of a fin-tube sensible heat exchanger with the corrugated fin surface. The air inlet temperature was set to $23^{\circ}C$,the relative humidity to 50% and the air inlet flow rate to 20, 22, $25m^3/min$, respectively. while the coolant temperature was set to $7^{\circ}C$, and the coolant mass flow rate to 10, 16, 22kg/min, respectively. Experiment showed that the exchanger having a diameter of 12.7mm with parallel circuit does better performance in sensible heat transfer and air pressure drop than those three of diameter of 12.7mm with a series circuit and that with diameter of 15.88mm with a parallel circuit.

• 한국연소학회:학술대회논문집
• /
• 2004.06a
• /
• pp.269-275
• /
• 2004

콘덴싱보일러는 배기가스중의 수증기를 콘덴싱방식이라는 열교환 기술을 통해 2개의 열교환기에서 응축시키면서 생기는 응축잠열을 보일러에 더하여 줌으로써 기존보일러 대비 15 $^{\sim}$ 20% 이상 열효율이 높이는 첨단기술이 사용된 보일러로 콘덴싱보일러의 개발현황, 에너지 절감 효과 그리고 환경친화적 효과를 소개하고자 합니다.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.402-407
• /
• 2008

This study is performed to investigate heat transfer characteristics for thermal performance of fin-and-tube sensible heat exchangers under the low air flowrate according to fin geometry combination and coolant flowrate control. Fins and tubes of samples were separated between front row and rear row. Experiment results are plotted heat transfer rate of each row, heat transfer coefficient and sensible heat ratio against water flowrate control of each row. It is observed that thermal performance can be enhanced by fin geometry combination and water flowrate control of each row under the low air flowrate.

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

• Proceedings of the SAREK Conference
• /
• 2005.06a
• /
• pp.82-82
• /
• 2005

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1996.10b
• /
• pp.77-80
• /
• 1996

우리나라에서 피크부하용으로 사용하는 복합발전이 하계시에서 외기온도가 상승함에 따라 실제로는 정격출력을 내지 못하고 있다. 따라서 본 연구에서는 연료(LNG)의 냉열을 이용하여 가스터빈의 연소용공기를 냉각시킬 경우, 복합발전 시스템의 성능변화를 분석하기 위하여 시뮬레이션을 수행하였다. 그 결과 LNG의 냉열을 이용하여 연소용공기를 원하는 온도까지 냉각시킬 수 있음을 확인할 수 있었다. 또한 연소기로 연료를 투입하기전에 설계온도까지 예열시키는 열교환기를 통해 배기가스에 함유된 현열을 더욱 많이 회수하면서, 가스터빈 투입연료의 온도를 상승시킬 수 있어, 시스템효율이 더욱 상승함을 알 수 있었다. 결론적으로 외기온도가 변하는 경우에, 본 시스템의 도입을 위해서는 경제성분석과 더불어 열교환기 시스템의 최적합성이 추후 진행되어야 할 것이며, 이를 통해 최적의 발전시스템을 구성할 수 있으리라 생각된다.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.10 no.4
• /
• pp.1-7
• /
• 2014

This paper is performed to investigate of cooling effect and total enthalpy variation on EAHES(Earth-to-Air Heat Exchanger System) that is buried 3m depth and 60m length. Using EAHES, the reduction of the sensible heat is obviously but latent heat is showed increased trend. Although the outdoor average latent heat accounts for 53.2% of total enthalpy, latent heat of the exit air from EAHES was raised as 58%. For improving cooling effect of EAHES, it has to considered that how to remove the latent heat from EAHES.

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

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.21 no.5
• /
• pp.589-601
• /
• 1997

A computer simulation program of a high efficiency condensing heat exchanger is developed. The flue gas flows outside bare tube bundles both in strong cross flow and in weak counter flow and the cooling water inside the tubes. Condensing heat exchangers achieve high efficiency by reducing flue-gas temperatures to a level at which most of the water vapor in the flue gas is condensed and the latent heat associated with phase change of the water is recovered. The computer model has been verified by comparison with measured data. To verify the model, heat transfer coefficient was adjusted, along with the mass transfer diffusion coefficient and pressure drop coefficient, to achieve agreement between predicted and measured data. The efficiencies of heat exchanger increase 2.3 ~ 8.1% by condensations of 6.3 ~ 62.6% of the water vapor in the flue gas.