전기차용 7kW급 고전압 히터 유로 형상 설계를 위한 열유동 시뮬레이션

손권중 한국융합학회 2022 한국융합학회논문지 Vol.13 No.3

Unlike an international combustion engine car, a battery-powered electric vehicle requires an additional heat source for its heating system. A high-voltage coolant heater has the advantages of high efficiency and a wide operating temperature range. In its development, the geometry design of the coolant flow path is essential. This paper presents the thermal flow simulations of a 7kW high-voltage heater with symmetric serpentine flow channels arranged parallelly. The heater performance was evaluated from the simulation results in terms of the pressure and temperature differences and the flow uniformity. The proposed design showed a greater flow resistance and similar heat exchanging capability than the existing parallel serpentine design. It has the advantage of a relatively wide low-temperature surface area, where the control circuit board susceptible to high temperatures can be located. 내연기관 자동차 히터는 연소과정 중에 발생하는 엔진 열을 이용하므로 열원이 추가로 필요치 않지만, 배터리로부터 동력원을 얻는 전기자동차용 히터는 별도의 전열 장치가 요구된다. 지금까지 개발된 전기차용 히터 중에서 냉매를 이용하는 고전압 히터는 효율이 높고 작동 온도 범위가 넓은 장점이 있다. 고전압 히터 내부의 냉각수 유로의 형상은 열교환 성능을 크게 좌우하므로 히터 개발 시 유로 설계는 기술적으로 매우 중요하다. 본 논문에서는 대칭형 서펜타인 유로를 갖는 7kW급 고전압 히터의 유로 형상 설계를 위해 고전압 열유동 시뮬레이션을 수행하였다. 해석 결과로부터 입출구간 차압과 차온 및 유로에서의 유동 균일도를 계산하여 히터의 성능을 평가하였다. 도출된 대칭형 서펜타인 유로 설계안은 기존 평행 서펜타인 비해 차압은 높지만, 열교환 성능은 비등하며 저온부가 비교적 넓게 존재하여 제어 회로의 설치 공간으로 활용할 수 있다는 장점이 있다.

전기자동차용 CNT 히터의 난방 성능 평가

이현석(Hyunseok Lee),배석정(Sukjung Bae),허형석(Hyungseok Heo),이호성(Hoseong Lee),이병호(Byongho Lee) 한국자동차공학회 2020 한국자동차공학회 학술대회 및 전시회 Vol.2020 No.11

One of the most important factors in an electric vehicle is the mileage it can drive on a single charge. Many studies are being conducted on the effects on electric vehicle-mile. When the electric cabin heater is operated in the winter season, power consumption increases and vehicle-mile is significantly reduced. Development of heaters with low power consumption and high heating efficiency is needed. In this study, the performance of conventional positive temperature constant(PTC) heater was compared to a heater with carbon nanotube(CNT) material. Cabin heater was installed in the performance assessment equipment and the performance assessment was performed by simulating the winter season driving environment. Compared to conventional PTC heater, heat capacity of the CNT heater was greater. Pressure drop of CNT heater was high compared to the conventional PTC heater, but the difference was relatively small. CNT heater improved the heat-up rate by 34.2% over the conventional PTC heater.

히터 용융물 궤적 검사를 통한 설치상태 식별에 관한 사례연구

박주희,허수정,이다은,신용현,노희인,김희숙,최기옥,이승훈 한국화재조사학회 2022 한국화재조사학회 학술대회 Vol.2022 No.06

대부분의 가연물에 점화원으로 작용할 만큼 고온 상태인 전기히터는 사용상의 주의 사항을 준수하지 않았을 때 화재가 발생할 위험이 높다. 사용자의 과실 또는 오용으로 화재 사고가 발생하였을 때, 사용자들은 자기 잘못을 감추기 위해 사실을 말하지 않는 경우가 많으며 화재조사관들은 사용자들의 과실을 증명하기 어렵다. 연구자들은 화재 현장의 석영관 히터 반사판에 부착된 용융물의 궤적을 분석해서, 사용자가 히터의 전 도 안전 스위치를 무력화하고 옆으로 눕혀 사용하였던 정황을 증명하였다. 이와 같은 사용은 히터가 쓰러져도 전원이 차단되지 않아 화재 발생의 위험이 높다. 유체의 흔적 분석은 사건 재구성에서 가치가 높고 유용하지만 화재 조사 분야에서 자주 사용되지 않아 왔으며 참고할 만한 화재감식 관련 참고문헌을 발견할 수 없었다. 흔적 분석의 효용성에 대하여 고찰한, 본 연구를 통해 관심을 갖고 화재감식 기법의 다양성이 확장 되길 기대한다. A heat of an electric heater is high enough to be a ignition source for the most of combustible material. So if the precautions are not followed, it has a high risk of fire. When a fire occurs due to their negligence or misuse, users often do not tell the truth to hide their fault. and It is difficult for fire investigators to prove users' fault. The researchers analyzed the traces of the melted material on the reflector of the quartz heater at the fire scene, and proved the situation in which the user disabled the safety switch on heater and was laid and operated on its side. Such usage is considered to have a high risk of fire because the heater does not automatically turn off even if it falls down. Although analyzing the trace of fluid has a high value and useful in fire reconstruction, but it is not frequently used in the field of fire investigation, and also there is references about it. We expect many fire investigators will be interested in and use the analysis through this study that considered the effectiveness of the trace analysis.

전기자동차용 탄소나노튜브 필름 히터의 성능 평가

배석정(Sukjung Bae),허형석(Hyungseok Heo),이현석(Hyunseok Lee),이병호(Byungho Lee),김영삼(Youngsam Kim) 한국자동차공학회 2019 한국자동차공학회 학술대회 및 전시회 Vol.2019 No.11

Efficient thermal management system of electric vehicle is a crucial issue in views of energy consumption and balance in that its electric cabin heater reduces the charging range by 20 to 50 percent in the winter season. Carbon material is employed to develop a highly efficient cabin heater for electric vehicle, which is never been attempted at home and abroad. With its high thermal conductivity, carbon nanutube(CNT) heater can improve heat-up rate and reduce power consumption compared to conventional positive temperature constant(PTC). Carbon nanotube heater is superior in terms of reduced power consumption, stable heating, rapid heating rate to improve indoor comfort and winter defrosting function, weight reduction, durability and reliability. In this study, various carbon film heater patterns has been designed and tested in order to grasp the heat-up behaviors and search the optimal pattern design. Performance assessment of heating-up of carbon heating film has been carried out in comparison with conventional PTC stone for cabin heater. Carbon nanotube film presented prominent heat-up performance than the conventional heater element to a certain temperature criterion.

5개 광역시 동계 전기난방기기 보급 및 사용량

김태완 한국자료분석학회 2013 Journal of the Korean Data Analysis Society Vol.15 No.1

A concern for the demand and the variability of electricity is increasing because the peak load was highrocketing for the last 3 years due to the temperature change, especially abnormal coldness. It is therefore needed for investigation for the distribution rate and use behavior of electric heating equipments, and its electricity usage. It surveyed total 1,300 samples within 2.72% allowable error out of 5 metropolitan cities in Korea (550 households, 250 industrial facility, 300 commercial facility, and 200 schools). The important component is the distribution, the distribution rate, and the use behavior of the electricity equipments. The results are: The distributed number of electric mattress is 646 million and that of electricity heater is 142 million. The peak load in the commercial facilities is the highest as 305 million kW. Out of equipments, the peak load of EHP is 161million kW, and that of electric fan heater is 149 million kW. A test of the difference in the peak load of EHP and electric fan heater shows that there is no difference between them either testing by facilities or electric equipments at the 1% significance level. It means that the policy or regulation of electricity demand management should be done targeting both equipments. For the future electricity demand forecasting, an accumulation of the times series data and prediction of the distribution rate of the electric equipments are needed. 최근 이상 한파 등 기상의 변화로 인한 동계 최대전력 급증으로 인하여 전력수요에 영향을 미치는 요인, 즉 전기 난방기기 보급과 사용행태 및 전력사용량에 대한 실태조사의 필요성이 대두되었다. 본 논문은 5개 광역시의 일반, 상업, 산업, 학교시설을 모집단으로 하여 총 1,300개 표본(허용오차 2.72%), 일반가구 550(4.18%), 상업시설 300(5.66%), 산업시설 250(6.20%), 학교 200 (6.93%)을 사용하였다. 조사주요항목은 각 난방기기의 조사 대상의 분포, 난방기기 보급률, 난방기기별 전력사용 행태 등이다. 전기장판이 646만대 이상, 전기히터/난로가 142만대 이상 보급된 것으로 나타났다. 최대전력은 상업시설(305만kW)이 가장 많은 전력을 소비하고 있는 것으로 조사되었으며, 기기별로는 EHP(161만kW), 전기온풍기(149만kW)순으로 가장 소비가 높은 것으로 나타났다. EHP와 전기온풍기의 최대 전력 차이에 대한 시설유형별이나 기기대수별로 검정 시 유의수준 1%에서 귀무가설을 기각하지 않는다. 즉 동일선상에서 두 기기에 대한 동계 전력 정책의 필요성을 논의할 수 있다. 향후 동계전력수요예측에 반영하기 위해서는 주기적이고 신뢰성 있는 통계조사와 난방기기 보급에 관한 시계열 자료 축적, 난방기기별 미래의 보급률 예측 등이 필요하다.

전기히터식 및 지열원 히트펌프식 농산물 열풍건조기의 에너지 성능 비교

양원석,김영일,박승태 한국 지열 · 수열에너지학회 2018 한국지열에너지학회논문집 Vol.14 No.4

Energy performance of electric heater and geothermal source heat pump type hot air dryers arecompared in this study. For set temperatures of 30℃, 35℃ and 40℃, radish is dried from initial mass60 kg until it gets 5 kg, where the difference equals the amount of water removed. As set temperatureis increased, drying time is shortened for both electric heater and heat pump types, however energyefficiency is decreased due to increasing electricity consumption. Moisture extraction rate(MER) ofelectric heater is 2.58~2.84 kg/h, and for heat pump type 2.56~2.71 kg/h, showing little differencebetween the two types. Specific moisture extraction rate (SMER) of electric heater is 0.94~0.96 kg/kWh, and for heat pump type 1.72~2.21 kg/kWh. SMER of heat pump type is greater by 0.78~1.25kg/kWh than the electric heater hot air dryer, which is 1.8~2.3 times better in terms of energy efficiency.

전기차 난방용 CNT 히터의 공기 측 전열 핀 설계

배석정(Sukjung Bae),이준용(Junyong Lee),허형석(Hyungseok Heo),이병호(Byungho Lee),김영삼(Youngsam Kim) 한국자동차공학회 2018 한국자동차공학회 학술대회 및 전시회 Vol.2018 No.11

Cabin heating of electric vehicles is supplied electricity from limited electrical energy as there is no heat source unlike one of conventional internal combustion vehicles. In the winter season with use of electric heaters, the one-time charging range is reduced by 20 to 50 percent, which is a major factor in the delayed expansion of the electric vehicle market. General requirements for electric vehicles should be low energy consumption, rapid heat generation to implement defrosting function, light, compact, etc. In order to develop an innovative cabin heater for electric vehicle, the carbon materials is employed in this study. Carbon film heaters have a stable resistance, and can operate normally except in the area if part of it is open circuit. In this study, the design of the air side heat transfer fins has been carried out for the development of CNT heater. Models based on the fin pitch has been constructed to design the optimum geometry, and the pressure drop characteristics was predicted according to air flow rate.

전기히터식 및 히트펌프식 식품 건조기의 에너지 성능 비교

유영우(Young Woo Yu),김영일(Young Il Kim),박승태(Seungtae Park) 한국지열·수열에너지학회 2015 한국지열에너지학회논문집 Vol.11 No.4

In this study, energy performance of two types of food dryers which are electric heater and heat pump is studied experimentally. With drying chamber temperatures controlled at 45, 50 and 55oC, sliced radish is dried from an initial mass of 90 to final 7 kg. Moisture content, drying time, total power consumption, MER (moisture extraction rate, kg/h) and SMER (specific moisture extraction rate, kg/kWh) are measured and analyzed. As the drying chamber temperature is increased, drying time is shortened but energy efficiency is reduced for both types. For an electric heater dryer, the effect of chamber temperature on drying time is significant but less significant on energy efficiency. For a heat pump dryer, the dependence of chamber temperature on drying time is weak but strong on energy efficiency. Temperature levels have little effect on electric heater dryer performance but strong effect on heat pump dryer which operates on a vapor compression refrigeration cycle. The energy performance of the heat pump dryer is superior with an average SMER of 2.175 kg/kWh which is 2.22 times greater than that of the electric heater dryer with SMER of 1.224 kg/kWh.

전기자동차 주행거리 향상을 위한 바이오에탄올 연소식히터를 적용한 난방시스템 개발

최두열(Duyoul Choi),이원석(Wonsuk Lee),김철민(Chulmin Kim),최이철(Yicheol Choi),심홍록(Hongrok Shim) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5

The main objective of this paper is to develop heating system on battery electric vehicle for range enhancement. In general, PTC heater is widely used on battery electric vehicle. However, according to recent research, the range is reduced by more than 50% due to the amount of power consumption of PTC heater on battery electric vehicle. In order to resolve this problem, additional heating system was adopted in this study. The heating performance, power consumption and range enhancement were analyzed on battery electric vehicle by using bio-ethanol fire-operating heater. This experimental work has done at a low temperature in the wind tunnel. This work gets results that the heating performance is satisfied with target temperature, power consumption is saving 60% and the range is extended up to 53% compared to operating only PTC heater.

전기 히터의 형상에 따른 시뮬레이션 열 해석 연구를 통한 융합 기술 연구

이정호,조재웅 한국융합학회 2015 한국융합학회논문지 Vol.6 No.6

추운 겨울철 실내를 따뜻하게 해주는 발열 및 난방기구들은 필수적인 요소이며, 2000년대부터 이러한 난방기구들의 사용량은 급격하게 증가하고 있다. 하지만, 화재 사고와 화재의 위험성 역시 증가하고 있다. 따라서 본 연구에서는 보다 안전한 난방기구의 설계를 위하여 시중에서 판매되는 세라믹, 카본 및 근적외선 히터들로서의 세 가지 형상의 전기히터들을 참고하여 3D 모델링하였으며, 이들 모델들을 가지고 열 해석을 수행하여 열변형량과 열응력 등에 따른 내구성을 연구하였다. 본 연구에서 도출된 연구 결과들을 바탕으로 각 형상에 따른 전기히터 모델들의 내구성을 예측할 수 있었고, 궁극적으로 보다 안전한 내화성이 있는 새로운 난방기구의 개발에 기여할 수 있었다. 또한 디자인 면에서 융합 기술로의 접목도 가능하여 미적인 감각을 나타낼 수 있다. In cold winter season, the apparatuses of heating and heater which warm up the interior of a room are necessary element and the used amount of these apparatuses from the year 2000 has been increased abruptly. But, the fire accident and the danger of fire are also increased. Therefore, 3D modelling is done by referring three kinds of the electric heaters as the heaters of ceramic, carbon and near infrared ray sold in the city for the design of more safe heating apparatuses in this study. The thermal analyses with these models are carried out and the durabilities due to the thermal deformation and stress are studied. By the background of the study results derived in this study ultimately, the durabilities of electric heater models due to each shape can be anticipated and contributed to the development of new heating apparatus with more safe resistance to fire. And it is possible to be grafted onto the convergence technique at design and show the esthetic sense.