• The Magazine for Energy Service Companies
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• s.58
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• pp.34-37
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• 2009

'안전시공, 완벽시공, 고객만족'의 슬로건으로 ESCO를 말하는 기업이 있다. 대구에 위치한 (주)동서 기연은 소형열병합발전시스템, 바이오매스(우드칩, 바이오탄)보일러, 열회수환기장치, 태양열, 지열, 시스템냉난방기, 통합자동제어시스템, 진공청소시스템 등 기술력을 보유하고 전문 시공 업체로 전문성을 인정받았다. '더 싼 가격으로 더 큰 효율'을 위한 에너지 신기술로 에너지 분야에서 지속적으로 성정하고 있는 동서기연을 소개한다.

• 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.

• Journal of the KSME
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• v.35 no.9
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• pp.836-847
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• 1995

파울링은 열교환기에 형성되는 열저항으로 에너지 손실에 많은 영향을 미친다. 그러나 파울링은 그 예측이나 감소 또는 제거가 매우 어려운 것으로 인식되어 왔다. 작동유체자체를 철결하게 유지함으로써 파울링을 감소할 수도 있으나 작동유체 자체의 특성 때문에 본질적으로 작동유체를 청결하게 유지할 수 없는 경우가 대부분이다. 즉, 폐열 회수의 대상이 되는 액체가 하천수나 생 활하수인 경우 작동액체를 청결하게 유지함으로써 파을링을 저감시피는 방법은 타당치 않다.일 본의 폐얼회수 프로젝트와 담수화 프로젝트에서 특이한 점은 두 가지 프로젝트에서 열교환기면의 파울링 문제 해경을 전열 촉진의 내용과 거의 비슷한 비중으로 다루고 있다는 점이다. 파울링은 오래 전부터 열시스템설계자의 주요 관심사였으나 큰 진전은 없었다. 그러나 현재는 주변기술이 발달로 더 이상 연구 불가능 영역은 아닐 듯 싶다.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.175-182
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• 2007

The objective of the present study is to investigate the heat storage characteristics of a packed bed according to periodically oscillating flows. Experiments have been performed to measure transient temperature distributions in solid and fluid Phases of the porous media. A simplified analytical model has been developed with intra-particle and dispersion effects neglected, and non-dimensional parameters have been derived. The transient temperature distributions according to the simplified numerical model agree well with the experimental results. Heat storage efficiencies defined in two different ways are obtained for various time periods and face velocities.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1197-1203
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• 2004

This study investigates the air leakage and heat transfer characteristics of a rotary-type air-to-air heat exchanger with a fiber polyester matrix. The leakage airflow rate is measured using a tracer gas method for various ventilation rates and rotational speeds of the matrix wheel. A correlation equation for air leakage is obtained by combining the pressure leakage and the carryover leakage. The pressure leakage is observed to be a function of ventilation airflow rate only, and the carryover leakage is found to be a linear function of rotational speed. The real efficiency of the heat exchanger can be obtained from its apparent efficiencies by taking into account the air leakage ratio. As the ventilation rate increases, the heat recovery efficiency decreases. As the rotational speed of the matrix increases, the efficiency increases initially but reaches a constant value for the rotational speeds over 10 rpm.

• KIEAE Journal
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• v.16 no.6
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• pp.123-128
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• 2016

Purpose: In order to save the energy consumption of buildings, buildings have been constructed with high performance insulation or airtightness. However, high performance insulation or air tightness has led to a poor indoor air quality. Therefore, HRV(Heat Recovery Ventilator) has received attention to save the energy consumption and insure a good air quality. Because existing research is almost about the performance of HRV in residential buildings, This study analyzed the effect of HRV on cooling energy consumption in commercial office building. Method: This study was proceeded at commercial office building in In-cheon. In order to evaluate the energy consumption of HRV, this study proposed two methods: estimating energy consumption of the room installed AHU(Air Handling Unit) system; estimating energy consumption of the room installed HRV system. Therefore, comparison of two methods was proceeded to evaluate energy performance of each method. Result: As the result of comparison between rooms installed AHU and HRV, the experiment showed that energy consumption of the room installed HRV system is about 22% less than the room of AHU system. This conclusion is considered because the room installed HRV system have maintained temperature well at set point temperature $26^{\circ}C$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.2
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• pp.119-128
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• 2008

Thermal assessment of a new CANDU spent fuel disposal system, which improves the retrievability of the spent fuel and enhances the densification factor compared with the Korean Reference disposal System, is carried out in this study. The canisters for CANDU spent fuels are stored for long term and cooled by natural convection in the proposed disposal system for the retrievability. The steady state thermal analyses for proposed CANDU disposal system are carried out with the ANSYS 10.0 CFX code. The thermal analyses are performed through two steps. At the first step, the sensitivity of the disposal tunnel spacing is analysed. The differences of maximum temperatures by several tunnel spacings are calculated at three points in the disposal tunnel. The result shows that the differences of the temperature at the three points are almost negligible because 99% of the decay heat is removed by natural convection. At the second procedure, 60m tunnel spacing with a ventilation system instead of natural convection is considered. The result is applied to the calculation of the canister surface temperature in disposal tunnel as boundary conditions. Consequently, the average and the maximum surface temperature of disposal canisters are $79.9^{\circ}C$ and $119^{\circ}C$, respectively. The inner maximum temperature of a basket in the disposal canister is calculated as $140.9^{\circ}C$. The maximum temperature of the basket meets the thermal requirement for the CANDU spent fuel cladding.

• Journal of Energy Engineering
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• v.21 no.4
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• pp.393-397
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• 2012

In this study, an organic Rankine cycle(ORC) for gas engine waste heat recovery for industry has been constructed and a performance analysis test has been carried out. Shell & tube style heat exchanger has been equipped on an engine exhaust manifold in order to absorb heat of engine exhaust gas into the working fluid(refrigerant R134a). Under 60 kW of engine power output, about 63 kW of engine exhaust gas heat was discharged and the proportion of heat recovered was 68~73% while 43~46 kW of heat was absorbed into working fluid. Consequently rated power output of ORC was 4.6 kW while the ratio of rated power output to engine exhaust gas heat was 7.3%.