• 대한기계학회논문집B
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• 제32권8호
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• pp.629-635
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• 2008

Recently, microturbines have received attention as a small-scale distributed power generator. Since the exhaust gas carries all of the heat release, the microturbine CHP (combined heat and power) system is relatively compact and easy to maintain. Generating hot water or steam is usual method of heat recovery from the microturbine. In this work, a heat recovery unit producing hot water was installed at the exhaust side of a 30 kW class microturbine and its performance characteristics following microturbine power variation was investigated. Heat recovery performance has been compared for different operating conditions such as constant hot water temperature and constant water flow rate. In particular, the influence of water flow rate and hot water temperature on the recovered heat was analyzed.

• 대한기계학회논문집B
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• 제40권2호
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• pp.69-73
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• 2016

최근 자동차 엔지니어들은 자동차 엔진의 열효율을 향상시키기 위한 수단으로 폐열 회수 기술에 많은 관심을 기울이고 있다. 배기량이 큰 가솔린 엔진은 대체로 V형인데, 열 회수를 위해 두 개의 슈퍼히터를 각각의 배기 다기관 가까이에 설치하는 것은 비용 면에서 효율적이지 않다. 하나의 슈퍼히터를 한쪽 배기 다기관에 최대한 가깝게 부착하면 좀 더 높은 열교환 효율을 얻을 수 있으나 폐열회수를 위한 배기가스의 유량은 절반이 된다. 반면에, 배기가스의 유량을 전부 이용하기 위하여 두 배기관이 합류된 지점에 슈퍼히터를 설치하면 배기가스의 온도는 많이 감소된다. 이 사실을 바탕으로 슈퍼히터의 최적 위치를 조사하기 위하여 상용프로그램인 AMESim을 이용해 해석을 수행하였다. 이 때, 배기가스 유량 중 절반만을 사용하더라도 슈퍼히터를 배기 다기관과 최대한 가까이 부착하는 것이 엔진의 배기가스로부터 3.8 kW의 열을 더 회수할 수 있는 것으로 나타났다. 이 결과를 바탕으로 최적의 폐열 회수 모델을 도출하고 제안하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1306-1311
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• 2009

In recent semiconductor manufacturing clean rooms, in order to improve clean room air quality, air washers are used to remove airborne gaseous contaminants such as $NH_3$, SOx and organic gases from the outdoor air introduced into clean room. Meanwhile, there is a large amount of exhaust air from a clean room. From an energy conservation point of view, heat recovery is therefore useful for reducing the outdoor air conditioning load for a clean room. Therefore it is desirable to recover heat from the exhaust air and use it to reheat the outdoor air. In the present study, numerical analysis and experiment was conducted to simulate the amount of energy reduction of exhaust air heat recovery type air washer system. The present numerical results showed good agreement with the results of the experimental data.

• 에너지공학
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• 제21권4호
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• pp.393-397
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• 2012

본 연구에서는 산업용 가스 엔진의 배기 폐열을 회수하여 발전하는 유기랭킨사이클을 구성하고 시스템 성능 분석 실험을 수행하였다. 엔진 배기가스 열을 작동유체(냉매 R134a)에 흡수시키기 위해 Shell & Tube 방식 열교환기를 엔진 배기 매니폴드 후단에 장착하였다. 엔진출력 60 kW인 조건에서 약 63 kW의 배기가스 열을 배출하였으며, 열교환기를 통해 작동유체에 흡수된 열량은 43~46 kW로서 배기가스 열회수율은 68~73%, 최대출력은 4.6 kW로서 배기가스 열량에 대한 최대출력의 비는 7.3%을 나타내었다.

• 대한기계학회논문집B
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• 제25권12호
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• pp.1776-1783
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• 2001

Heat recovery from boiler exhaust gas with multi-stage water-fluidized-bed heat exchanger is analyzed in this study. The recovered energy here is not only sensible heat but also latent heat contained in the exhaust gas. In this system direct contact heat transfer occurs while exhaust gas passes through water bed and the thermal energy recovered this way is again delivered to the water circulating through heat exchanging pipes within the bed. Thus the thermal energy of exhaust gas can be recovered as a clean hot water. A computer program developed in this study can predict the heat transfer performance of the system. The results of experiments performed in this study agree well with the calculated ones. The heat and mass transfer coefficients can be fecund through these experiments. The performance increases as the number of stage increases. However at large number of stages the increasing rate becomes very low.

• 설비공학논문집
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• 제15권12호
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• pp.979-986
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• 2003

The performance characteristics of heating and cooling operation for a heat pump system using seawater heat source and exhaust energy are presented. The heat pump system is made of a waste heat recovery system and a vapor compression refrigeration system. The working fluid is R-22. The heat pump system COPs are measured during heating and cooling operation modes, and the resultant COPs were 9.7 and 7.9, respectively, which are three times higher than those of the heat pump itself. Therefore, the performance of the heat pump system using exhaust energy is excellent compared to that of a general heat pump. The experimental data can be effectively used for the design of the high efficient heat pump using a seawater heat source.

• 한국자동차공학회논문집
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• 제20권2호
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• pp.21-29
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• 2012

A dual loop waste heat recovery system with Rankine steam cycles for the improvement of fuel efficiency of gasoline vehicles has been investigated. A high temperature loop (HT loop) only recovers the heat of the exhaust gas. A low temperature loop (LT loop) recovers the residual heat from the HT loop, the coolant heat and the remaining exhaust gas heat. The two separate loops are coupled with a heat exchanger. This paper has dealt with a layout of the dual loop system, the review of the working fluids, and the design of the cycle. The design point and the target heat recovery of the HT boiler, a core part of a HT loop, have been presented. The prototype of the HT boiler was evaluated by experiment. For the performance evaluation of the HT boiler, inlet temperature of the HT boiler working fluid was set equal to the temperature degree of sub-cool of $5^{\circ}C$ at the condensing pressure. The exit condition was the degree of super-heat set at $5^{\circ}C$. The characteristics of the HT boiler such as heat recovery and pressure drops of fluids were evaluated with varying flow rates and inlet temperatures of exhaust gas under various evaporating pressure conditions.

• 설비공학논문집
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• 제20권6호
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• pp.372-380
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• 2008

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 to predict the performance of the paper heat exchanger. Pressure drops at various velocities, and sensible and latent heat transfer rates at various dry-bulb temperatures, relative humidities and specific humidities are measured to derive experimental correlations. The results of prediction using correlations show fairly good agreement with the experimental data obtained in the actual operating conditions.

• 한국안전학회지
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• 제14권4호
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• pp.78-84
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• 1999

A compact air-preheating type heat exchanger was developed and tested for the ultra-high temperature heat recovery applications. For the direct use of exhaust gases up to $1200^{\circ}C$, the heat exchanger adopted a ceramic core with high strength and low thermal expansion coefficient less than $1{\times}10^{-6}^{\circ}C^{-1}$. The ceramic core was fabricated by special extrusion and bonding techniques. To minimize thermal stresses in the core, spring-loaded sealing mechanism was designed and successfully installed. 1-pass air flow scheme was adopted for the compactness and cost-savings. The pressure test for the ceramic core showed no failure under 35 kPa and less than 3% leak under 7 kPa. Flue gas simulation system was developed to investigate the performance of the heat exchanger. The test results showed normal operations of the heat exchanger up to $1200^{\circ}C$ of exhaust gases and relatively high heat recovery efficiencies of 31～39% depending upon exhaust gas temperatures..

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.844-849
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• 2008

In recent semiconductor manufacturing clean rooms, in order to improve clean room air quality, air washers are used to remove airborne gaseous contaminants such as $NH_3$, SOx and organic gases from outdoor air introduced into clean room. Meanwhile, there is a large quantity of exhaust air from clean room. From the energy saving point of view, heat recovery is useful for the reduction of air conditioning energy consumption for clean room. Therefore it is desirable to recover heat from the exhaust air and use it to reheat the outdoor air. However, so far there have not been sufficient studies of analyzing the comparison of the amounts of energy consumption and saving. In the present study, an experiment was conducted to investigate the energy consumption and heat recovery of a fin-coil type air washer system for semiconductor manufacturing clean rooms.