• Title/Summary/Keyword: Automotive Air Conditioning System

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

Design technology of automobile air conditioning system (자동차용 에어콘의 설계기술)

  • 양시영;송영길
    • Journal of the korean Society of Automotive Engineers
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    • v.18 no.6
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    • pp.46-62
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    • 1996
  • 최근 들어 이념에 따른 적대관계가 무너지고 국제화에 따른 무한경쟁체제에 돌입하게 됨에 따라 단순한 기술도입만으로는 생존할 수 없다는 인식하에 미력하나마 연구개발에 눈을 돌리기 시작하였다. 그런데 에어콘 부품관련 상당부분이 특허에 저촉되있어 이를 회피한 고효율 저소음의 독자 모델 개발에는 상당한 어려움이 뒤따르며 이는 산학연이 일체가 되어 해결해야할 문제로 판단된다. 즉 대학에서는 기초이론 정립, 설계관련 소프트웨어 개발, 기초설계 및 이론 해석쪽에 비중을 두고, 연구소에서는 이를 응용한 최적 및 양산설계를 그리고 산업체에서는 양산성 검토등 생산과 관련된 기술을 체계적이고 지속적으로 발전시켜나가야만이 기술선진국으로 발돋움 할 수 있다. 따라서 필자는 이와관련 선진 기술업체의 현황을 알아보고 제품설계에 필요한 기술등을 간단히 서술하므로써 자동차 에어콘에 관심을 갖고 있는 사람들에게 조금이나마 연구방향에 도움이 되었으면 한다. 본 내용의 대부분은 에어콘 설계 및 생산을 위하여 수집한 자료중에 일부를 발췌하여 기술하였으며 사안에 따라 다소의 차이가 있음을 미리 밝혀둔다.

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An experimental study on the heat transfer characteristics in packed bed (충전층내에서의 열전달특성에 관한 실험적 연구)

  • 신현준;양한주;오수철
    • Journal of the korean Society of Automotive Engineers
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    • v.4 no.3
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    • pp.40-47
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    • 1982
  • Heat transfer on packed bed is considered to be important for the effective designs of chemical reaction equipment, air conditioning system, and storage type heat exchanger, etc. Currently studies are being carried out quite actively in this field in order to increase the heat transfer efficiency. The effect of heat transfer is closely relater to materials, shapes, porosities and packing states of packed bed as well as mutual dimensional relations between particles and the container. Investigation shows that heat transfer results appear to be influenced by such parameters as fluid velocity through packed bed, mass flow, and thermal properties. It is noted that viscosity is also considered to be an important factor in this problem. In this study, effective thermal conductivities on packed bed, effects of thermal conductivity (Ke) and friction factor (Fk) according to change of porosity(.epsilon.) and Reynolds number(Reh(, and pressure loss of the fluid, are experimentally investigated. Results show that the effective thermal conductivity increases and the friction factor decreased, as against the increase of Reynolds number. But as the increase of porosity increase them both.

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Technology Development Trend of Domestic and Foreign Electric Vehicle and Technology Development Strategy of Domestic Electric Vehicle Core Parts (국내외 전기자동차 기술 개발 동향 및 국내 전기자동차 핵심 부품 기술 개발 전략)

  • Son, Younh-Wook;Huh, Gun-Soo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.5
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    • pp.373-381
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    • 2017
  • The electric vehicle market has increased rapidly in recent years. Established global automakers have announced that electric cars will be developed and distributed. Furthermore, current electric cars are not merely breezes, instead, they are the mainstream of automobiles. However, high prices, short mileage, and long charge times are the main obstacles to the spread of electric vehicles. To solve these problems, the competition for technology development for the expansion of electric vehicles worldwide intensifies because of the improvements in mileage, price reduction, and expansion of charging infrastructure. In this paper, the trends in the development of key technologies for electric vehicles in overseas markets and the present strategic goals for the development of key technologies for electric vehicles in Korea will be identified.

Study of Compressor-Performance Improvement in Automotive Air-Conditioning System (자동차용 에어컨 압축기의 성능 향상에 대한 연구)

  • Kim, Young Shin;Yoo, Seong Yeon;Na, Seung Gyu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.9
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    • pp.713-718
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    • 2015
  • The purpose of this study is to realize compressor-performance improvements in the fuel economy of an automotive air-conditioning system. We conduct cooling performance tests in a compressor calorimeter test stand. To improve the cooling performance, we investigate the increase in the suction flow rate and the decrease in the discharge dead volume. Based on the results of the test, we found that the cooling capacity and the coefficient of performance (COP) of the compressors were improved as follows. The cooling performance improved greater at high speeds than low speeds in the case of an increase in the suction flow rate increase, and it improved more at low speeds than at high speed when there was a decrease in the discharge dead volume. When both of the above factors were included, we observed that the improvement effects were generally balanced for both high- and low-speed modes, and there was a significant improvement in the discharge temperature. The improvement was found to be about 3.2% at low speed, 8.3% at high speed during in cooling performance improvement, about 5.8% at low speed and about 6.2% at high speed in COP improvement, and there was a decrease of about $3^{\circ}C$ at low speed and a $5^{\circ}C$ decrease at high speed in discharge temperature.

Antibacterial Characteristics of Silver Nano-Particles Attached to Activated Carbon Filter (은나노를 부착한 활성탄 필터의 제균특성)

  • Heo, Ju-Yeong;Nam, Sang-Yeob;Kang, Jeong-Hee;Song, Ji-Hyeon;Kang, Byung-Ha;Han, Sung
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.10
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    • pp.583-589
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    • 2009
  • Activated carbon has long been used in purification processes for indoor air quality. However, the bioaerosol removal by activated carbon is not often sufficient to be used in an air control devise. In order to overcome these problems, silver nano-particles have been proposed as an antibacterial agent on the surface of activated carbon. Silver or silver ions have been known for antimicrobial activities. In this study, bioaerosol generated by using an Escherichia coli culture was introduced to a lab-scale column packed with activated carbon (AC) and silver nano-particles attached to activated carbon (Ag-AC). E. coli was almost completely removed in the Ag-AC column, whereas bioaerosol penetrated through the AC column. To determine the antibacterial effect of different filter materials in a full-scale air-handling system, another experiment was conducted using a wind tunnel equipped with a heat exchanger and three filter materials including commercial fabric, AC and Ag-AC. It was found that E. coli proliferated on the surface of the heat exchanger after 5 days, which dramatically increased bioaerosol counts in the effluent air stream. The fabric filter could not control the increased bioaerosol and most of the E. coli penetrated the filter. The bacterial removal efficiency was found to be approximately 45% in the AC filter, while the antibacterial efficiency increased to 70% using the Ag-AC filter. Consequently, the Ag-AC filter can be an effective method to control bioaerosol and improve indoor air quality.

Energy Simulation for Conventional and Thermal-Load Controls in District Heating (지역난방의 일반제어 및 열량제어 에너지 시뮬레이션)

  • Lee, Sung-Wook;Hong, Hiki;Cho, Sung-Hwan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.1
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    • pp.50-56
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    • 2015
  • Korea district heating systems have mainly used setting temperature control and outdoor reset control. Different from such conventional normal methods, a thermal-load control proposed in Sweden can decrease the return temperature and reduce pump power consumptions because the control is able to provide the appropriate amount of required heat. In this study, further improved predictive optimal control in addition to the conventional controls were simulated in order to verify its effect in district heating system using TRNSYS 17. $200m^2$ apartment housing which accounts for 25% in Korea and is used as a calculation model;. the number of households in the simulation was 9. As a result, a higher temperature difference and decreasing flow rate at primary loop were shown when using thermal-load control.

Experimental Study on Drag Reduction Effects of New Non-Ionic Surfactants

  • Tae, Choon-Sub;Cho, Sung-Hwan
    • International Journal of Air-Conditioning and Refrigeration
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    • v.14 no.4
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    • pp.147-155
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    • 2006
  • The drag reduction (DR) and heat transfer efficiency reduction (ER) of non-ionic surfactant were investigated as a function of fluid velocity, temperature, and surfactant concentration. An experimental apparatus consisting of two temperature controlled water storage tanks, pumps, test specimen pipe and the piping network, two flow meters, two pressure gauges, a heat exchanger, and data logging system was built. From the experimental results, it was concluded that existing alkyl ammonium surfactant (CTAC Cethyl Trimethyl Ammonium Chloride) had DR of $0.6{\sim}0.8$ at $1,000{\sim}2,000ppm$ concentration with fluid temperature ranging between $50{\sim}60^{\circ}C$. However, the DR was very low when the fluid temperature was $70{\sim}80^{\circ}C$. The new amine oxide and betaine surfactant(SAOB Stearyl Amine Oxide + Betaine) had lower DR at fluid temperatures ranging between $50{\sim}60^{\circ}C$ compared with CTAC. However, with fluid temperature ranging between $70{\sim}80^{\circ}C$ the DR was $0.6{\sim}0.8$ when the concentration level was $1,000{\sim}2,000ppm$.

Study on the Drag Reduction and Heat Transfer Efficiency Reduction of the Non-Ionic Surfactant (비이온 계면활성제의 마찰 및 열교환효율 저감 특성 연구)

  • Cho, Sung-Hwan;Tae, Choon-Seob
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.2
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    • pp.133-141
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    • 2007
  • The drag reduction (DR) and heat transfer efficiency reduction (HTER) of nonionic surfactant according to the fluid velocity, temperature and surfactant concentration were investigated experimentally. For this study, several kinds of new surfactant which contains amine-oxide and betaine were developed. And experimental apparatus equipped with two water storage tanks temperature controlled, pumps, testing pipe network, two flowmeters, two pressure gauges, heat exchanger, and data logging system was built. Results showed that existing alkyl ammonium surfactant (CTAC) had DR of $0.6{\sim}0.8$ for $1,000{\sim}2,000\;ppm$ in fluid temperature of $50{\sim}60^{\circ}C$ and had very low DR in fluid temperature over $70^{\circ}C$. And new amino oxide and betaine surfactant (SAOB) had lower DR in fluid temperature of $50{\sim}60^{\circ}C$ compared with CTAC but in fluid temperature of $70{\sim}80^{\circ}C$ DR was $0.6{\sim}0.8$ for 1$1,000{\sim}2,000\;ppm$.

CFD Analysis for Spiral-Jacketed Thermal Storage Tank in Solar Heating Systems (태양열 시스템에 적용된 나선재킷형 축열조의 CFD 해석)

  • Nam, Jin-Hyun;Kim, Min-Cheol;Kim, Charn-Jung;Hong, Hi-Ki
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.10
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    • pp.645-653
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    • 2008
  • Spiral-jacketed thermal storage tanks can greatly simplify solar heating systems while maintaining the thermal performance at a similar level as conventional systems with an external heat exchanger. Proper design of the spiral-jacket flow path is essential to make the most of solar energy, and thus to maximize the thermal performance. In the present work, computational fluid dynamics (CFD) analysis was carried out for a spiral-jacketed storage tank installed in a solar heating demonstration system. The results of the CFD analysis showed a good agreement with experimentally determined thermal performance indices such as the acquired heat, collector efficiency, and mixed temperature in the storage tank. This verified CFD modelling approach can be a useful design tool in optimizing the shape of spiral-jacket flow path and the flow rate of circulating fluid for better performance.