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A Study on the Hull Form Design and Ice Resistance & Propulsion Performance of a Platform Support Vessel (PSV) Operated in the Arctic Ocean (극지해역 운용 해양작업지원선(PSV)의 선형설계와 빙 저항추진 성능 연구)

  • Yum, Jong-Gil;Kang, Kuk-Jin;Jang, Jin-ho;Jeong, Seong-Yeob
    • Journal of the Society of Naval Architects of Korea
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    • v.55 no.6
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    • pp.497-504
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    • 2018
  • Platform Support Vessels operated in the Arctic Ocean support diverse operations of offshore plant in the sea, and the PSV is also needed to support works to exploit the oil and gas in the Arctic Ocean. Both of the ice breaking and the open sea performance have been considered together to secure the enhanced operational performance at the harsh environment in the Arctic Ocean and the open sea as well. In this study, One of the design requirements of a PSV is to guarantee continuous icebreaking performance with 3 knots at 1 m thickness of level ice, where the design draft is 7.5m and the engine power is 13 MW. Three hull forms were designed, and the ice resistance based on empirical formulas was estimated to select the initial hull form having an outstanding performance. The full scale performance of the designed hull forms was predicted by the ice model test conducted in the ice model basin of Korea Research Institute of Ships & Ocean Engineering(KRISO). The analysed results show that the selected hull form satisfies the above design requirement.

Study on Equivalent Consumption Minimization Strategy Application in PTI-PTO Mode of Diesel-Electric Hybrid Propulsion System for Ships

  • Lee, Dae-Hong;Kim, Jong-Su;Yoon, Kyoung-Kuk;Hur, Jae-Jung
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.3
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    • pp.451-458
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    • 2022
  • In Korea, five major ports have been designated as sulfur oxide emission control areas to reduce air pollutant emissions, in accordance with Article 10 of the "Special Act on Port Air Quality" and Article 32 of the "Ship Pollution Prevention Regulations". As regulations against vessel-originated air pollutants (such as PM, CO2, NOx, and SOx) have been strengthened, the Ministry of Oceans and Fisheries(MOF) enacted rules that newly built public ships should adopt eco-friendly propulsion systems. However, particularly in diesel-electric hybrid propulsion systems,the demand for precise control schemes continues to grow as the fuel saving rate significantly varies depending on the control strategy applied. The conventional Power Take In-Power Take Off(PTI - PTO) mode control adopts a rule-based strategy, but this strategy is applied only in the low-load range and PTI mode; thus, an additional method is required to determine the optimal fuel consumption point. The proposed control method is designed to optimize fuel consumption by applying the equivalent consumption minimization strategy(ECMS) to the PTI - PTO mode by considering the characteristics of the specific fuel oil consumption(SFOC) of the engine in a diesel-electric hybrid propulsion system. To apply this method, a specific fishing vessel model operating on the Korean coast was selected to simulate the load operation environment of the ship. In this study, a 10.2% reduction was achieved in the MATLAB/SimDrive and SimElectric simulation by comparing the fuel consumption and CO2 emissions of the ship to which the conventional rule-based strategy was applied and that to which the ECMS was applied.

A study on the emission characteristics of greenhouse gases according to the vehicle technology, fuel oil type and test mode (차량기술, 연료 유종 및 시험모드 특성에 따른 온실가스의 배출특성 연구)

  • Lee, Jung-Cheon;Lee, Min-Ho;Kim, Ki-Ho;Park, An-Young
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.4
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    • pp.962-973
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    • 2017
  • Concerns about an air pollution are gradually increasing at home and abroad. The automotive and fuel researchers are trying to reduce emissions and greenhouse gases of vehicles through a research on new engine designs and innovative after-treatment systems using clean fuels (eco-alternative fuel) and fuel quality improvements. In this paper, we stduy the emission characteristics of greenhouse gases on seven vehicles using gasoline, diesel, and LPG by legal test mode in domestic and abroad.(Urban mode, Highway mode, rapidly acceleration and deceleration, using air conditioner, low temperature condition) Regardless of fuels, most of the greenhouse gases tend to show the worst results in cold FTP-75 mode. In the case of A vehicles (2.0 MPI) and B vehicles (2.4 GDI) using a gasoline fuel, the factors that increase greenhouse gases are in order of a rapidly acceleration and deceleration, using air conditioner, low temperature condition. But G vehicles(LPLi) have different emission characteristics from another vehicles. In the case of A vehicles (2.0 w/o DPF) and B vehicles (2.2 with DPF) using a diesel fuel, the factors that increase greenhouse gases are in order of a rapidly acceleration and deceleration, using air conditioner, low temperature condition. However, the factor of F vehicles are in order of low temperature condition, using air conditioner, rapidly acceleration and deceleration. In conclusion, it will be an effective method to apply different technologies of emission reduction for each fuel.

A Study on the Thermal Stability of Long-Term Fuel Storage and Lifetime Estimation of Rubber O-ring in Contacted with Fuel (장기 저장연료의 열안정성 및 연료접촉 고무오링의 수명예측 연구)

  • Chung, K.W.;Hong, J.S.;Kim, Y.W.;Han, J.S.;Jeong, B.H.;Kwon, T.S.;Suh, D.O.;Sung, M.J.;Kwon, Y.I.
    • Tribology and Lubricants
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    • v.34 no.5
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    • pp.197-207
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    • 2018
  • Thermal deterioration of fuel due to long-term storage influences engine performance and causes malfunctions. Fuel stability is usually evaluated via heat resistance and thermal stability during a brief heat shock at high temperature; storage stability in this scenario means that there is very little change in the quality of the fuel during long-term storage. In addition, rubber-based products such as oil seals, O-rings, and rubber hoses can influence the quality of the fuel. When these rubber products are in contact with fuel, they can swell, mechanically weaken, and occasionally crack, thus leaking low molar weight rubber and additives including plasticizer and antioxidant into the fuel to degrade its properties and shorten its useful lifetime. This study determines the thermal stabilities of three kinds of synthetic fuels by evaluating their low temperature kinematic viscosities, chemical composition changes via GC analyses, gross heat of combustion, and color changes. We evaluate the compression set of O-rings by immersing one NBR and two FKM rubber O-rings in the three synthetic fuel samples in airtight containers at variable storage temperatures for six months; from this, we estimate the lifetimes of the O-rings using the Power law model. There were very little changes in the chemical compositions and gross heat of combustion after six months of the experiment. The lifetimes are thus dependent on the materials of the rubber products, and in particular, the FKM O-ring was calculated to have a theoretical lifetime of 200 to 5,700 years. These results indicate that the synthetic fuels maintain their physical properties even after long-term storage at high temperatures, and the FKM O-ring is suitable for long-term sealing of these fuels.

Shape Optimization of Three-Way Reversing Valve for Cavitation Reduction (3 방향 절환밸브의 공동현상 저감을 위한 형상최적화)

  • Lee, Myeong Gon;Lim, Cha Suk;Han, Seung Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.11
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    • pp.1123-1129
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    • 2015
  • A pair of two-way valves typically is used in automotive washing machines, where the water flow direction is frequently reversed and highly pressurized clean water is sprayed to remove the oil and dirt remaining on machined engine and transmission blocks. Although this valve system has been widely used because of its competitive price, its application is sometimes restricted by surging effects, such as pressure ripples occurring in rapid changes in water flow caused by inaccurate valve control. As an alternative, one three-way reversing valve can replace the valve system because it provides rapid and accurate changes to the water flow direction without any precise control device. However, a cavitation effect occurs because of the complicated bottom plug shape of the valve. In this study, the cavitation index and percent of cavitation (POC) were introduced to numerically evaluate fluid flows via computational fluid dynamics (CFD) analysis. To reduce the cavitation effect generated by the bottom plug, the optimal shape design was carried out through a parametric study, in which a simple computer-aided engineering (CAE) model was applied to avoid time-consuming CFD analysis and difficulties in achieving convergence. The optimal shape design process using full factorial design of experiments (DOEs) and an artificial neural network meta-model yielded the optimal waist and tail length of the bottom plug with a POC value of less than 30%, which meets the requirement of no cavitation occurrence. The optimal waist length, tail length and POC value were found to 6.42 mm, 6.96 mm and 27%, respectively.

A Study on Analysis of Maritime Industry Structure on Chungnam Province (충남지역 해양산업 구조 분석 연구)

  • Kim, Un Soo;Choi, Kyoung Hoon;Kim, Hwa Young
    • Journal of Korea Port Economic Association
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    • v.34 no.2
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    • pp.1-16
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    • 2018
  • Maritime industry is recognized as a new value-adding and growth engine industry. It provides high value by creating clusters centering on ports. Advanced international ports are also clashing ahead to create clusters, boost profits, and strengthen competitiveness. The Korean government enacted policies for the establishment and upbringing of maritime industrial clusters in 2015. It is very important to understand which maritime industry has a comparative advantage in each region and to establish an integration strategy through maritime industrial clusters. This study analyzes the structure of the maritime industry in the Chungnam province, which is expected to deal with raw materials(mainly oil products), container throughput, and opening of ferry route with China's port. The study analyzed the existing literature on the maritime industry and classified the industry into 5 major categories, 21 sub-categories, and 84 sub-categories in shipping and logistics, shipbuilding, fishery, marine tourism industry, and other industries. Based on the reclassified maritime industry, the structure of the maritime industry in the Chungnam province was analyzed by using location quotient(LQ) and Shift-Share analysis. The study found that the fisheries industry showed the highest value(1.718) in the analysis of LQ, followed by the marine tourism industry(1.092), shipbuilding industry(0.823) and shipping and logistics industry(0.789). The total effect of the maritime industry in Chungnam province was 36,315 and the net growth effect, excluding the national growth effect, was estimated to be 21,321. Based on these results, we classify the maritime industry in the Chungnam province as comparative advantage and comparative disadvantage. The results of this study can be used as basic data for formulating strategies for the construction of the maritime industry cluster in the Chungnam province in the future.

Proposal on Active Self Charging and Operation of Autonomous Vehicle Using Solar Energy (태양광을 이용한 자율주행 자동차의 능동적 자가 충전 및 운행 제안)

  • Hur, Hyun-Woo
    • The Journal of the Korea Contents Association
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    • v.22 no.9
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    • pp.85-94
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    • 2022
  • In modern society, environmental and energy problems have caused to replace cars with environment friendly energy. Vehicles with internal combustion engine which use petroleum are one of the factors that influence global pollution due to environment problems such as fine dust and ozone layer destruction. In addition use of energies for automobile making resources to become depleted. To solve this limited oil energy problem by using other energy sources. To the problem using electric energy and green energy as alternative for a solution. Among environment friendly energies this paper studies the possibility of drive service for autonomous vehicles that self-charges using only solar energy and whether they can be used as pollution free and alternative energy for automobiles. Studies was researched based on published literature review, data from ministry of transportation and automobile companies. Also case of electric vehicle and prototype automobile using only solar energy and the theory of near future technologies. Many automakers are using electric cars as alternative energy. Also making efforts to use solar energy as an substitute energy source and as a way to supplement electricity. Results show that there is a potential on operating autonomous vehicle using only solar energy. Furthermore, it will be possible to use automobiles actively, also use and supply solar energy. This paper suggest the possibility of contributing to the future of the automotive industry.

Trend in Research and Application of Hard Carbon-based Thin Films (탄소계 경질 박막의 연구 및 산업 적용 동향)

  • Lee, Gyeong-Hwang;Park, Jong-Won;Yang, Ji-Hun;Jeong, Jae-In
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2009.05a
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    • pp.111-112
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    • 2009
  • Diamond-like carbon (DLC) is a convenient term to indicate the compositions of the various forms of amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon and tetrahedral amorphous carbon (a-C:H and ta-C:H). The a-C film with disordered graphitic ordering, such as soot, chars, glassy carbon, and evaporated a-C, is shown in the lower left hand corner. If the fraction of sp3 bonding reaches a high degree, such an a-C is denoted as tetrahedral amorphous carbon (ta-C), in order to distinguish it from sp2 a-C [2]. Two hydrocarbon polymers, that is, polyethylene (CH2)n and polyacetylene (CH)n, define the limits of the triangle in the right hand corner beyond which interconnecting C-C networks do not form, and only strait-chain molecules are formed. The DLC films, i.e. a-C, ta-C, a-C:H and ta-C:H, have some extreme properties similar to diamond, such as hardness, elastic modulus and chemical inertness. These films are great advantages for many applications. One of the most important applications of the carbon-based films is the coating for magnetic hard disk recording. The second successful application is wear protective and antireflective films for IR windows. The third application is wear protection of bearings and sliding friction parts. The fourth is precision gages for the automotive industry. Recently, exciting ongoing study [1] tries to deposit a carbon-based protective film on engine parts (e.g. engine cylinders and pistons) taking into account not only low friction and wear, but also self lubricating properties. Reduction of the oil consumption is expected. Currently, for an additional application field, the carbon-based films are extensively studied as excellent candidates for biocompatible films on biomedical implants. The carbon-based films consist of carbon, hydrogen and nitrogen, which are biologically harmless as well as the main elements of human body. Some in vitro and limited in vivo studies on the biological effects of carbon-based films have been studied [$2{\sim}5$].The carbon-based films have great potentials in many fields. However, a few technological issues for carbon-based film are still needed to be studied to improve the applicability. Aisenberg and Chabot [3] firstly prepared an amorphous carbon film on substrates remained at room temperature using a beam of carbon ions produced using argon plasma. Spencer et al. [4] had subsequently developed this field. Many deposition techniques for DLC films have been developed to increase the fraction of sp3 bonding in the films. The a-C films have been prepared by a variety of deposition methods such as ion plating, DC or RF sputtering, RF or DC plasma enhanced chemical vapor deposition (PECVD), electron cyclotron resonance chemical vapor deposition (ECR-CVD), ion implantation, ablation, pulsed laser deposition and cathodic arc deposition, from a variety of carbon target or gaseous sources materials [5]. Sputtering is the most common deposition method for a-C film. Deposited films by these plasma methods, such as plasma enhanced chemical vapor deposition (PECVD) [6], are ranged into the interior of the triangle. Application fields of DLC films investigated from papers. Many papers purposed to apply for tribology due to the carbon-based films of low friction and wear resistance. Figure 1 shows the percentage of DLC research interest for application field. The biggest portion is tribology field. It is occupied 57%. Second, biomedical field hold 14%. Nowadays, biomedical field is took notice in many countries and significantly increased the research papers. DLC films actually applied to many industries in 2005 as shown figure 2. The most applied fields are mold and machinery industries. It took over 50%. The automobile industry is more and more increase application parts. In the near future, automobile industry is expected a big market for DLC coating. Figure 1 Research interests of carbon-based filmsFigure 2 Demand ratio of DLC coating for industry in 2005. In this presentation, I will introduce a trend of carbon-based coating research and applications.

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A Study on Avant-Garde Fine Art during the period of Japanese Colonial Rule of Korea, centering on 'Munjang' (a literary magazine) (일제강점기 '전위미술론'의 전통관 연구 - '문장(文章)' 그룹을 중심으로)

  • Park, Ca-Rey
    • The Journal of Art Theory & Practice
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    • no.4
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    • pp.57-76
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    • 2006
  • From the late 1920s to the 1930s, Korea's fine art community focused on traditional viewpoints as their main topic. The traditional viewpoints were discussed mainly by Korean students studying in Japan, especially oil painters. Such discussions on tradition can be divided into two separate halves, namely the pre- and post-Sino-Japanese War (1937) periods. Before the war, the modernists among Korea's fine art community tried to gain a fuller understanding of contemporary Western modern art, namely, expressionism, futurism, surrealism, and so forth, on the basis of Orientalism, and borrow from these schools' in order to create their own works. Furthermore, proponents of Joseon's avant-garde fine arts and artists of the pro-fine art school triggered debate on the traditional viewpoints. After the Sino-Japanese War, these artists continued to embrace Western modern art on the basis of Orientalism. However, since Western modern fine art was regressing into Oriental fine art during this period, Korean artists did not need to research Western modern fine art, but sought to study Joseon's classics and create Joseon's own avant- garde fine art in a movement led by the Munjang group. This research reviews the traditional view espoused by the Munjang group, which represented the avant-garde fine art movement of the post-war period. Advocating Joseon's own current of avant-garde fine art through the Munjang literary magazine, Gil Jin - seop, Kim Yong-jun and others accepted the Japanese fine art community's methodology for the restoration of classicism, but refused Orientalism as an ideology, and attempted to renew their perception of Joseon tradition. The advocation of the restoration of classicism by Gil Jin-seop and Kim Yong-jun appears to be similar to that of the Yasuda Yojuro-style restoration of classicism. However, Gil Jin-seop and Kim Yong-jun did not seek their sources of classicism from the Three-Kingdoms and Unified Silla periods, which Japan had promoted as a symbol of unity among the Joseon people; instead they sought classicism from the Joseon fine art which the Japanese had criticized as a hotbed of decadence. It was the Joseon period that the Munjang group chose as classicism when Japan was upholding Fascism as a contemporary extremism, and when Hangeul (Korean writing system) was banned from schools. The group highly evaluated literature written in the style of women, especially women's writings on the royal court, as represented by Hanjungnok (A Story of Sorrowful Days). In the area of fine art, the group renewed the evaluation of not only literary paintings, but also of the authentic landscape paintings refused by, and the values of the Chusa school criticized as decadent by, the colonial bureaucratic artists, there by making great progress in promoting the traditional viewpoint. Kim Yong-jun embraced a painting philosophy based on the painting techniques of Sasaeng (sketching), because he paid keen attention to the tradition of literary paintings, authentic landscape paintings and genre paintings. The literary painting theory of the 20th century, which was highly developed, could naturally shed both the colonial historical viewpoint which regarded Joseon fine art as heteronomical, and the traditional viewpoint which regarded Joseon fine art as decadent. As such, the Munjang group was able to embrace the Joseon period as the source of classicism amid the prevalent colonial historical viewpoint, presumably as it had accumulated first-hand experience in appreciating curios of paintings and calligraphic works, instead of taking a logical approach. Kim Yong-jun, in his fine art theory, defined artistic forms as the expression of mind, and noted that such an artistic mind could be attained by the appreciation of nature and life. This is because, for the Munjang group, the experience of appreciating nature and life begins with the appreciation of curios of paintings and calligraphic works. Furthermore, for the members of the Munjang group, who were purists who valued artistic style, the concept of individuality presumably was an engine that protected them from falling into the then totalitarian world view represented by the Nishita philosophy. Such a 20th century literary painting theory espoused by the Munjang group concurred with the contemporary traditional viewpoint spearheaded by Oh Se-chang in the 1910s. This theory had a great influence on South and North Korea's fine art theories and circles through the Fine Art College of Seoul National University and Pyongyang Fine Art School in the wake of Korea's liberation. In this sense, the significance of the theory should be re-evaluated.

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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 2004 and 2005 - (공기조화, 냉동 분야의 최근 연구 동향 -2004년 및 2005년 학회지 논문에 대한 종합적 고찰-)

  • Choi, Yong-Don;Kang, Yong-Tae;Kim, Nae-Hyun;Kim, Man-Hoe;Park, Kyoung-Kuhn;Park, Byung-Yoon;Park, Jin-Chul;Hong, Hi-Ki
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.19 no.1
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    • pp.94-131
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    • 2007
  • A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.