소각로 배열회수용 열교환기의 최적설계를 위한 열전달 및 압력강하 특성 분석

고지운(Ji-Woon Ko),권오경(Oh Kyung Kwon),배경진(Kyung Jin Bae),전동순(Dong-Soon Jeon) 대한기계학회 2022 大韓機械學會論文集B Vol.46 No.5

본 논문에서는 소각로에 적용하기 위한 배열회수용 열교환기의 설계조건 및 형상인자에 따른 열전달 및 압력강하 특성에 대하여 분석하였다. 배기가스의 입구상태는 실제 운영중인 소각시설의 공정분석 결과를 바탕으로 선정하였다. 배기가스를 통하여 회수 요구되는 목표 열전달량 및 냉각수 출구온도는 각각 550 kW 및 55°C 이상이다. 그리고 관내 및 외측 압력강하량은 열교환기 설계 시 적합한 최소값을 제안하였다. 1차 분석을 통하여 설계조건 및 형상인자가 반응값(열전달량, 냉각수 출구온도, 배기가스 및 냉각수측 압력강하량)에 미치는 영향을 알아보았으며, 선정된 주요인자는 냉각수 유량, 전열관 수직 및 수평방향 간격이다. 2차 분석에서는 열교환기의 최적설계를 수행하였으며, 이때 열전달량 및 냉각수 출구온도는 각각 550.1 kW 및 55.9°C이다. 또한, 관내 및 외측 압력강하량은 각각 7.4 kPa 및 32.7 Pa이다. 따라서 목표한 반응값을 만족하는 최적의 열교환기 형상을 제안하였다. In this paper, heat transfer and pressure drop characteristics of heat exchanger for heat recovery were analyzed according to design parameters. The heat transfer rate and coolant outlet temperature required for recovery through the heat exchanger were 550 kW and 55°C or greater, respectively. For internal and external pressure drop, appropriate minimum values were suggested when designing a heat exchanger. In the 1st analysis, the design parameters affecting the response value (that is, heat transfer rate, temperature of coolant outlet, and pressure drop of gas and coolant) were analyzed; subsequently, the coolant mass flow rate, and the vertical and horizontal spacing of the tubes were selected as main factors. In the 2nd analysis, an optimized design of the heat exchanger was performed. As a result, the heat transfer rate and coolant outlet temperature of the optimally designed heat exchanger were 550.1 kW and 55.9°C, respectively. Additionally, the internal and external pressure drops were 7.4 kPa and 32.7 Pa, respectively. Therefore, the optimal shape of the heat exchanger that satisfied the target response value was presented.

가스엔진 삼중열병합 발전시스템 에너지 및 엑서지 분석

김영민,박현욱,김창업,오승묵 한국에너지학회 2023 에너지공학 Vol.32 No.4

현재 개발 중인 가스엔진 삼중열병합 발전시스템은 엔진 배기열과 냉각수열을 동시에 활용하여 동절 기에는 난방을 하고, 하절기에는 엔진 배기열 이용 2중 효용 사이클과 엔진 냉각수열 이용 1중 효용 사이클이 결합된 하이브리드 흡수식 냉동기를 통한 냉방을 한다. 가스엔진 삼중열병합 발전시스템에 서는 온도 레벨이 다른 배기열과 냉각수열을 이용하여 난방수, 냉방수, 급탕수와 같이 다양한 목적으 로 활용하게 되는데, 에너지 분석 뿐만 아니라 엑서지 분석을 통해 각 과정의 효율성과 비가역성을 평 가할 필요가 있다. 동절기에 배기열을 최대한 회수하여 난방열로 활용하기 위해서 고온의 배기열을 그 대로 난방열로 활용하지 않고 흡수식 히트펌프를 구동하여 생산된 냉수를 이용하여 배기열에 포함된 잠열을 최대한 회수할 수 있다. 본 연구에서는 100kW급 가스엔진 삼중열병합 발전시스템의 냉난방 모 드 및 고효율 잠열회수 모드에 대한 에너지 및 엑서지 분석을 실시하여 결과를 비교하였다. In the gas engine trigeneration system under development, a heating mode for winter season is used by direct utilising both engine exhaust and coolant and a cooling mode for summer season is used by hybrid absorption chiller with a double effect cycle by engine exhaust and a single effect cycle by engine coolant. Since in the gas engine trigeneration system space heating and cooling and water heating can be achieved by using the different levels of temperatures of engine exhaust and coolant, exergy analysis can be helpful to evaluate efficiencies and irreversibilities of the processes as well as energy analysis. The high temperature of exhaust gas can not be used for space heating directly but be used to produce cold water by absorption heat pump, which is used for maximum latent heat recovery from the exhaust gas. In this study, the energy and exergy analysis of the 100kW gas engine trigeneration system was performed and compared according to the modes of basic heating and cooling and enhanced heating by latent heat recovery.

2 kW급 SOFC 시스템에서 Hot BoP의 열분배 시스템과 열적 성능에 대한 실험적 연구

김영배 ( Young-bae Kim ),김은주 ( Eunju Kim ),윤종혁 ( Jonghyuk Yoon ),송형운 ( Hyoung-woon Song ) 한국환경기술학회 2018 한국환경기술학회지 Vol.19 No.2

본 연구에서는 SOFC 시스템에서 배출되는 폐열원을 효과적으로 활용하기 위하여 수치적인 계산과 실험적 검증을 수행하였다. Hot BoP 내 열분배 시스템은 열원의 효율적인 공급을 위한 연소기 및 공기예열과 폐열회수를 위한 열교환기들로 구성되었다. 실험에 사용된 연료는 메탄가스이며 일정한 과잉공기와 합께 예혼합되어 안정적인 희박연소가 가능하게 하였다. 결과로써, SOFC 시스템의 열부하에 따른 열교환기의 전열면적과 열교환율이 반복적 수치 계산을 통하여 분석되었다. 또한 연료의 저위발열량을 기준으로 시스템의 열부하, 열교환기의 효율, 열 손실, 열 회수 성능을 실험적으로 비교 분석하였다. 최종적으로 열분배 시스템은 2 kW급 SOFC 시스템에 상응하는 열 부하에서 약 40 %의 열효율 성능을 나타내었다. In this study, numerical calculation and experimental verification of Hot BoP were conducted to effectively reuse the waste heating gas from SOFC system. For Hot BoP, the well-heated regenerated combustor and three-heat exchangers for pre-heating air, steam generating and economizer were fabricated on the basis of 2 kW SOFC system. CH4 with excess air was used as a fuel and it was possible to burn stably through the pre-mixed combustion. As a results, the required heating area and the thermal efficiency of heat exchanger were estimated through iterative numerical calculation. Also, the system performance such as heat load, thermal efficiency, heat loss and heat recovery were analyzed experimentally. Finally, it was confirmed that Hot BoP has heat recovery rate about 40 % under the full load of 2 kW SOFC system.

다중이용업소의 환기방법에 따른 냉·난방에너지 소비량

장소미,고유진,민준기,홍희기 대한설비공학회 2020 설비공학 논문집 Vol.32 No.8

Recently, the pandemic virus COVID-19 causing many infections and cases of infection by from being in the same space with an individual or individuals without direct contact has been alarmingly increasing. Referring to COVID-19’s virulent propagation mechanism, it may be inadequately safe to maintain a distance of 1 to 2 m from an infected person to prevent infection, and frequent, effective ventilation is necessary to remove more virus particles. In this paper, a cafe was selected as a typical multi-use store. TRNSYS18 was used to compare and analyze the heating and cooling load values with the different types of ventilation methods. The analyses were: ventilation not performed, forced ventilation performed at 1500 CMH continuously for 24 hours (simple forced ventilation), forced ventilation according to the concentration of CO2 (reasonable forced ventilation), ventilation using a crossflow plate, and rotary energy recovery ventilation. Compared to the reasonable forced ventilation, the plate and the rotary energy recovery ventilation showed reduction ratios of 6.3% and 20.9% respectively. The heating loads increased by 16.1 times for simple forced ventilation and 6.2 times for reasonable forced ventilation compared to when ventilation was not performed. Conversely, the plate and the rotary energy recovery ventilation showed an increase of approximately two times only. 본 연구에서는 다중이용업소를 대상으로 환기를 하지 않는 경우와 강제환기를 할 경우, 그리고 열회수형 환기장치를 사용하여 환기를 할 경우에 대해 냉․난방에너지 소비량을 산출하여 비교․분석하였다. 결과를 정리하면 다음과 같다. (1) 강제환기량이 증가함에 따라 환기를 하지 않는 경우에 비해 냉․난방부하 모두 증가하였다. 단순 강제 환기의 경우 냉방부하는 2.1배 증가하였으나 난방부하는 16.1배로 크게 증가하였다. 창호를 개방하건 환기팬을 가동하건 일단 금년 여름은 환기량을 확보하는 데 집중하고, 본격적인 난방철이 되기 전에 환기량 확보와 난방에너지 저감을 위해 열회수형 환기장치의 설치를 권고한다. (2) 하계 운전 시 환기를 하지 않는 경우에 비해 현열부하는 별로 달라지지 않는 반면에 잠열부하가 환기량에 따라 크게 증가한다. CO2 농도에 따라 합리적으로 환기량을 제어하는 강제환기에 비해 열회수형 환기장치를 사용하면 판형 6.3%, 회전형 20.9% 냉방부하가 감소한다. 다중이용업소에서 출입구를 개방한 상태에서 냉방하는 경우 에너지 낭비가 매우 크나, 건물 조건에 따라서는 1인당 30 CMH 이하의 환기량이 될 수도 있기 때문에 에너지 절약 및 안정적인 환기량 확보를 위해 열회수형 환기장치의 도입은 필수적이다. (3) 동계 운전 시 환기를 하면 현열부하와 잠열부하가 모두 증가하며, 특히 현열부하가 큰 영향을 받는다. 환기를 하지 않는 경우에 비해 단순 강제환기의 현열부하는 112.0 GJ로 약 15.3배, 합리적 강제환기시(44.3 GJ)에도 6.1배 증가한다. 판형과 회전형 열회수형 환기장치를 도입하면 현열부하는 각각 14.7 GJ, 14.0 GJ로 합리적 강제환기 대비 각각 66.8%, 68.4%의 감소율을 보인다. 환기하지 않는 경우와 비교해도 열회수형 환기장치를 도입하면 난방에너지는 2배 정도 증가하는데 그친다. 다중이용업소와 유사한 환경이 학교와 종교시설 등이다. 앞서 언급한 바와 같이 동절기에는 연속적으로 창문을 열고 난방을 하는 것이 현실적으로 어렵다. 이미 경험한 바와 같이 한두 시간 밀폐된 상태에서 냉난방하고 간헐적으로 창문을 열어 환기하는 것은 대단히 위험하며, 밀폐된 공간에서의 급격한 확산을 피하기 위해서는 연속적인 환기가 전제되어야 한다. 이를 위해 에너지 절약과 연속적이고 안정적인 환기량 확보를 위해 열회수형 환기장치의 도입이 법제화되어야 한다.

열회수 배수장치의 급탕에너지 절감효과 분석

황석호 한국건축친환경설비학회 2021 한국건축친환경설비학회 논문집 Vol.15 No.6

Drain Water Heat Recovery (DWHR) or Waste Water Heat Recovery (WWHR) system is a heat recovery from waste drain water flow and preheat the incoming cold water. This system has been shown to be a viable method of improving the building energy efficiency. This paper investigates the energy saving potential for shower water heat recovery system in residential building. Horizontal system of DWHR was considered because it can be installed under a shower booth and easy access to drain and cold water. The heat energy exchange rate is evaluated using the effectiveness-NTU method. Heat transfer effectiveness was calculated by U-value and area of heat exchanger and drain water flow rate. When a flow rate is 7.5 l/min using heat exchanger has 450 W/m2K U-value and 7 m length, it was possible to save about 20% water heating energy.

중고온 히트파이프를 이용한 열회수기술에 관한 연구

이영수,김종률,장기창,백영진 대한설비공학회 2004 설비공학 논문집 Vol.16 No.11

The present study has been conducted to develop a heat pipe heat exchanger for middle-high temperature ranged from 300 to 600℃. Heat transfer rate, overall heat transfer coefficient and temperature effectiveness were investigated using a heat pipe heat exchanger with Dowtherm A as working fluid. Theoretical analysis was also conducted, and the followings were obtained: (1) Heat exchange rate increased as waste gas temperature supplied to evaporator and frontal velocity in condenser increased, (2) Overall heat transfer coefficient increased by 3∼7% as frontal velocity in evaporator and condenser increased, (3) Temperature effectiveness was about 30% in evaporator and was about 40% in condenser, (4) Heat recovery rate was about 38%, (5) Pressure drop did not exceed 8 mmH2O under the running condition of 1∼3 Nm/s, (6) Simulation results were corresponded with experimental results.

폐열회수시스템의 열교환기 최적설계조건

성규식(Gyu-Sik Sung),황은빛(Eunbit Hwang),박주헌(Juheon Park),최종성(Jongseong Choi),신기열(Ki-Yeol Shin),배상수(Sang-Su Bae),조경철(Kyung-Chul Cho),권오대(Oh-Dae Kwon) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11

In this study, optimum capacity design of heat exchangers in a waste heat recovery system(WHRS) that recovers a large amount of heat energy from high-temperature exhaust gas which was supplied from a power generation gas engine using biogas produced from organic waste in an industrial complex were performed. The type and size of waste heat recovery system components suitable for engine power capacity according to biogas production volume were designed, and energy recovery efficiency was analyzed. The waste heat recovery system consists of a smoke tube boiler that produces 5 bar pressure and 161°C superheated steam from exhaust gas as heat source, and two economizers that produce preheating of supply water and hot water. Two different gas engine capacities as 100kW and 250kW were analyzed to product a target amount of superheated steam and hot water to maximize efficiency of waste heat recovery system. From the result of heat exchanger performance analysis, the optimum value of heat exchanger capacity ratio was founded as similar range as 0.43 ~ 0.46 even two different capacity of engines.

배기열 회수용 종이 열교환기의 성능에 영향을 미치는 인자에 관한 연구

정민호,유성연 대한설비공학회 2005 설비공학 논문집 Vol.17 No.10

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 0.75m/s are 77%, 47% and 57% in the cooling condition and 77%, 59% and 69% 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.

배기열 회수장치용 열교환기의 수치해석적 성능 평가

이준호 ( Junho Lee ),한상욱 ( Sangwook Han ),김현철 ( Hyunchul Kim ),최안식 ( Ansig Choi ) 한국액체미립화학회 2016 한국액체미립화학회 학술강연회 논문집 Vol.2016 No.-

Energy efficiency of the internal combustion engine for automobile is around 30% that shows its inefficiency. Therefore, various researches to increase the energy efficiency of the internal combustion engine vehicle have been reported. One of promising technology is the exhaust heat recovery system which harvests wasted heat form the exhaust system. In this study, the plate type heat exchanger was designed in order to improve the performance of the exhaust heat recovery system. The plate type heat exchanger for exhaust heat recovery system consists of multiple layers for the high temperature exhaust gas and the low temperature coolant, respectively. The parametric study for the base model(Casel) was carried out and analyzed such as the heat recovery and the pressure drop at each condition. In addition, the shape of exhaust heat recovery system was changed and the optimized heat exchanger model was selected in terms of performance and manufacturability. Heat recovery for the Base model(Case1) was around 4.7Kw at the design opint.

배가스 열회수 히트펌프 시스템 실증을 통한 운전특성 분석

이승호(Seung-Ho Lee),이관수(Kwan-Soo Lee),이길봉(Gil-Bong Lee),이영수(Young-Soo Lee),박상일(Sang-Il Park),고창복(Chang-Bok Ko) 대한설비공학회 2013 대한설비공학회 학술발표대회논문집 Vol.2013 No.6

The performance test of the 15 RT grade heat pump system with flue gas heat recovery was performed in the Korea Institute of Energy Research. The flue gas is exhausted from the 320 RT absorbtion chiller-heater in winter season. Using this flue gas, source water is heated by condensed type heat exchanger in by-pass. And the operating characteristics of the heat recovery heat pump system were analyzed. Based on the results of the experiments, operating maps were obtained and optimum operating range was suggested where the return and heat source water temperature are 51℃ and 31℃, respectively.