• Title/Summary/Keyword: dryer

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Analysis of Drying Efficiency for Circulating and Falling Movements on Indirected Drying Process of Food Waste (음식물류폐기물 간접건조과정에서의 순환 및 낙하이동에 따른 건조효율 평가)

  • Kim, Byung Tae
    • Journal of the Korea Organic Resources Recycling Association
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    • v.20 no.4
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    • pp.106-117
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    • 2012
  • Indirected heating dryer is used as one of the food waste treatment technologies for the production of the drier material supplied to the recycling facilities or end user. This study investigated the effect on drying efficiency for the operation of rotating screw with the circulating and falling movements on indirected drying process of food waste. The screw operating condition showed higher drying efficiency despite of the shorter drying time compared to the screw non-operating condition. The moisture content decreased to 14.4% from the initial moisture content of 77.1% after drying 5 hours in the screw operating condition. On the other hand, in the screw non-operating condition, the moisture content decreased slightly to 35.6% after drying 16 hours. During the drying process, variations of the water evaporation rate and particle size showed different tendencies depending on the moisture content regions. In the higher moisture content region above the glue zone(moisture content of about 50%-60%), the particle size increased and the water evaporation rate reached the highest peak. In the range of glue zone, the particle size maximized while the water evaporation rate decreased sharply. In the lower moisture content region below the glue zone, the water evaporation rate and particle size both decreased at the same time. The particle size distribution was widely ranged from 25.0mm to 0.25mm in the screw operating condition while it was narrowly distributed in the screw non-operating condition from 25.0mm to 3.56mm, especially highly concentrated to 25.0mm. It was regarded that the hygroscopic, capillary and gravitational water evaporated more easily from the intra-particle during the circulating and falling movement caused by the rotating of the screw and the difference of the cohesional force of water within intra-particle depending on the moisture content regions. Comparing the effect of the circulating and falling movement on drying efficiency, the water evaporation rates per time and per weight of dry solid in the screw operating condition were higher about 364% and 356%, respectively, than those of the screw non-operating condition.

Study of Sulfur Dioxide Contents in Various Fresh Vegetables During the Drying Process (건조에 따른 채소류 중의 이산화황함량 분석)

  • Ha, Sung-Yong;Kim, Hyun-Jung;Woo, Sung-Min;Lee, Jun-Bae;Cho, Yu-Jin;Kim, Yang-Sun;Bahn, Kyeong-Nyeo;Park, Jong-Seok;Kim, Hee-Yun;Jang, Young-Mi;Kim, Mee-Hye
    • Journal of Food Hygiene and Safety
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    • v.25 no.4
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    • pp.303-309
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    • 2010
  • This study was planned to monitor the change in the content of sulfur dioxide during the drying process of fresh vegetables. The analysis of sulfur dioxide was conducted by the Optimized Monier-Williams Method based on the Korea Food Code. The samples were kinds of vegetables which consisted of naturally-originated sulfur compounds (green onion, onion, cabbage, garlic, radish leaves, radish). Fresh vegetables (n = 182) and dried vegetables (n = 41) purchased from different local areas were investigated for the content of sulfur dioxide. The fresh vegetables were dried at 50~$60^{\circ}C$ using hot-air dryer. The moisture contents of dried samples were adjusted to keep 10 percents. The contents of sulfur dioxide in self-dried vegetables were 104.6 mg/kg in green onion, 75.4 mg/kg in onion, 129.1 mg/kg in cabbage, 197.6 mg/kg in garlic, 23.0 mg/kg in radish leaves and 52.5 mg/kg in radish, respectively. The increase of sulfur dioxide content according to the moisture content reduction was different from the expected. It means that the contents of sulfur dioxide can be altered by other factors except moisture contents. This results can be utilized as materials for the safe management of sulfites of dried vegetables.

Studies on Food Preservation by Controlling Water Activity III. Quality Changes of Fish Meat during Drying and Storage (식품보장과 수분활성에 관한 연구 3. 어육의 건조 및 저장중의 품질)

  • HAN Bong-Ho;LEE Jong-Gab;BAE Tae-Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.16 no.3
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    • pp.181-189
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    • 1983
  • A study on the qualify changes of fish meat during drying and storage has been carried out with filefish meat. Filefish meat was dried in a forced air dryer at 40 and $55\%$ for 20 hours with an air velocity of 0.4 m/sec under different conditions of relative air humidities in the range of 10 to $50\%$. The dried fish meat was stored at $30^{\circ}C$ in chambers with constant relative humidities controlled by the use of conditioned air stream passing through the saturated salt solutions. The qualify of filefish meat was evaluated with the brown color densities developed by lipid oxidation and Maillard reaction. Changes of viable cell count during drying and storage were also discussed. The predominant reaction for the brown color developed during the study period was the lipid oxidation. The lipid oxidation rate during drying at constant temperature was appreciably affected by water activities at the drying surfaces of filefish meat during the falling drying rate period. The lipid oxidation rate was the slowest under the condition of the relative air humidity of around $30\%$. In samples stored at water activity of 0.33, the lipid oxidation rate was retarded remarkably in comparison with the samples with lower or higher water activities. The addition of $1\%$ table salt, $1.5\%$ D-sorbitol and $6\%$ sucrose slightly lowered the water activity with the slowest lipid oxidation rate. Such additives resulted the increase of the water soluble brown color densities, which seemed due to the increase of mobility of the water soluble substances by the result of the increase of equilibrium water content. Microflora of the samples immediately after drying consisted of ca. $30\%$ of coccus types, ca. $65\%$ of rod types and ca. $5\%$ of molds and yeasts. During the storage of the samples with a water activity of 0.76, the ratio of the coccus types to the total microflora was increased remarkably while that of the Gram negative non-spore rod types was decreased. The ratios of the Gram positive rod types, molds and yeasts during the storage were nearly constant.

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Study on the Classification and Improvement of Dehydrated Skin under Warm Air Heating Condition (온풍 조건에서 수분 탈락 정도에 따른 피부 분류 및 개선 방안에 대한 연구)

  • Kwon, Oh Sun;Kang, Hyun Jong;Han, Seu ng Min;Yoon, Ji Seon;Cho, Woong Hee;Oh, Joo You ng;Lim, Jun Man;Song, Young Sook;Park, Sun Gyoo
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.46 no.2
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    • pp.179-184
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    • 2020
  • Elasticity and softness of the skin depend on the level of moisture present in the stratum corneum, which is known to be affected by various environmental changes, such as cold and hot winds and dry environments. However, not many studies have been conducted on changes in skin moisture and the degree of recovery due to individual skin differences. In the present study, we aimed to investigate the effect of warm air heating on skin hydration levels and develop moisturizing formulas to improve lowered skin hydration levels. In order to deliver warm air heating condition, heating dryer (40 ℃, 6 m/s, 30 cm apart from forearm) was applied into inner forearm of healthy subjects (male: 10, female: 39, age: 25 - 63) Among 49 subjects, 26 subjects showed significantly lowered skin hydration levels until 30 min after warm air heating exposure (lowered group). In addition, moisturizing cream with high water holding capacity was applied to forearm of 10 subjects in lowered group for 3 weeks and skin hydration levels after warm air heating were significantly improved at the levels of before application of warm air heating. From this study, we found out that there is a skin type that skin hydration levels are significantly decreased under warm air heating condition (dehydrated skin) and this dehydrated skin can be improved by moisturizing formulas with high water holding capacity.

Effect of Low Temperature Vacuum Dried Mackerel Intake on Lipid Profiles and Fatty Acid Compositions in Serum, Heart, Kidney and Adipose Tissue in Mice (저온 진공 건조기를 이용하여 건조된 고등어의 투여가 마우스 혈청과 조직의 지질 및 지방산 조성에 미치는 영향)

  • Choi, Hyung-Ju;Kim, Chang-Bok;Kim, Kyung-Kun;Lim, Sun-Young
    • Journal of Marine Bioscience and Biotechnology
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    • v.1 no.3
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    • pp.198-205
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    • 2006
  • This study was designed to investigate the possibility of the use of dried mackerel, which is enriched with docosahexaenoic (22:6n-3, DHA) and eicosapentaenoic (20:5n-3, EPA) acids, as a means of increasing the intake of these n-3 polyunsaturated fatty acids, and to investigate the effect of the consumption of mackerel on tissue triglyceride, cholesterol contents and fatty acid compositions. Twenty male mice were fed on 5% palm oil (control group) and 5% dried mackerel (mackerel group) diets for four weeks. Total triglyceride, cholesterol and LDL-cholesterol levels tended to decrease in serum, heart and kidney of the mackerel group compared to the control group, while HDL-cholesterol levels were increased with the intake of mackerel. In fatty acid compositions of serum and heart, the mackerel group showed increased percentages of n-3 fatty acids, especially DHA and EPA, and decreased percentages of arachidonic (20:4n-6, AA) and docosapentaenoic (22:5n-6, DPAn-6) acids compared to the control group (p<0.05). There was a similar tendency in kidney and adipose tissue but AA levels were not significantly different between the control and mackerel groups. These results indicate that intake of dried mackerel as the n-3 vehicle for increasing tissue n-3 fatty acids may be associated with improvement in lipid metabolism.

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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 2013 (설비공학 분야의 최근 연구 동향 : 2013년 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.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. 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 fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (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 for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

Quality Characteristics of Rough Rice during Low Temperature Drying (저온건조 중 벼의 품질 특성)

  • Kim, Hoon;Han, Jae-Woong
    • Food Science and Preservation
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    • v.16 no.5
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    • pp.650-655
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    • 2009
  • This study was conducted to measure the quality characteristics of rough rice during low temperature drying by using an experimental dryer and heat pump with a capacity of 150kg at four temperature levels of 20, 30, 40, and $50^{\circ}C$. The quality and proper drying temperature of rough rice was investigated by measuring variations in moisture content, crack rates, germination rates and cooked rice. Temperatures over $40^{\circ}C$ is considered a high-temperature area, and below $40^{\circ}C$ is considered a low-temperature area. The drying rates were 0.3, 0.6, 0.9, and 1.3%/hr, and the crack ratios were 0, 1.6, 6.8, and 24.2% at the drying temperatures of 20, 30, 40, and $50^{\circ}C$, respectively, which showed that the higher the drying temperature was, the higher the drying rate and crack rate was. Therefore, 20 and $30^{\circ}C$ were found to be appropriate drying temperatures for avoiding crack formation, and $50^{\circ}C$ was inappropriate. At $40^{\circ}C$, the operation methods needed to be modified to limit cracking, such as increasing the tempering time. Also, as the drying temperature increased, the germination rate decreased. Germination rates at 20 and $30^{\circ}C$ were suitable for using the rough rice as a seed, and those at 40 and $50^{\circ}C$ were over 80%, which is the minimum allowable percentage. In the sensory evaluation of cooked rice, the quality of appearance, taste, and texture varied as a function of drying temperature. When considering these factors, the cooked rice that was dried at 20 and $30^{\circ}C$ was better than the cooked rice dried at high-temperature. Consequently, in view of drying temperature and rates, the best conditions for drying rough rice were below $30^{\circ}C$ and below 0.6%/hr.

Effects of Diffused Light Materials on Marketable Yield and Quality of Sunlight Dried Red Pepper (Capsicum annuum L.) in Plastic Film House (비닐하우스 이용 태양초 생산시 산광 재료가 상품 수량과 품질에 미치는 영향)

  • Lee, Guang-Jae;Song, Myung-Gyu;Kim, Si-Dong;Nam, Sang-Young;Lee, Ki-Yeol;Kim, Tae-Jung;Kim, Dong-Eok;Yoon, Jung-Beom;Choi, Kyu-Hong
    • Korean Journal of Plant Resources
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    • v.27 no.1
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    • pp.102-109
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    • 2014
  • This study was carried out to investigate the effects of diffused light materials on marketable yield and quality of sunlight dried red pepper in plastic film house. The after ripening methods were composed of 3 treatments; using electric bulk dryer (Bulk), sealing house (House), and PE sealing. The diffused light materials were control, tent, shading 35% (Shading net), white polypropylene (PP (white)), and black polypropylene (PP (Black)). The marketable yield was high in order of Bulk as 300 g, House as 275 g, and PE sealing as 112 g. The redness of PE sealing was the highest as 17.85 and that of Bulk was the lowest as 10.65. There was significant difference in redness among the treatments. The moisture content of red pepper was the most rapidly reduced in control, and was the most slowly reduced in Shading net treatment. The marketable yield index was the higher in PP (white) as 114% than control. The redness had a significant difference in PP (Black) and tent compared to the other treatments. The capsaicin content showed the highest as $160mg{\cdot}100g^{-1}$ in PP (white) treatment. Conclusively, the most effective method for sunlight drying red pepper was House with PP (White) treatment. It delayed drying for 2 days but increased marketable yield at 114% than control when sunlight dried red pepper in plastic house. Our results also provided an optimized method for improvement of drying red pepper with sunlight, and will be useful for further drying red pepper research.

Preventive Effects of Rosa rugosa Root Extract on Advanced Glycation End product-Induced Endothelial Dysfunction (해당근 추출물의 항산화 활성 및 최종당화산물에 의한 혈관내피세포 기능장애 억제활성)

  • Nam, Mi-Hyun;Lee, Hyun-Sun;Hong, Chung-Oui;Koo, Yoon-Chang;Seo, Mun-Young;Lee, Kwang-Won
    • Korean Journal of Food Science and Technology
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    • v.42 no.2
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    • pp.210-216
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    • 2010
  • Rosa rugosa has traditionally been used as a folk remedy for diabetes. The objective of this study was therefore to demonstrate the inhibition of endothelial dysfunction activities through antioxidants and the anti-glycation of Rosa rugosa roots. Dried roots of Rosa rugosa were boiled in methanol for three hours, evaporated and lyophilized with a freeze-dryer. The methanolic extract of Rosa rugosa roots (RRE) was tested for antioxidant activities by measuring total polyphenol (TP) content, flavonoid content, 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging activity (DPPH) assay, and ferric-reducing antioxidant power (FRAP) assay. The total TP content, flavonoid content, FRAP value, and $DPPHSC_{50}$ are $345.2\;{\mu}g$ gallic acid equivalents/mg dry matter (DM), $128.1\;{\mu}g$ quercetin equivalents/mg DM, 2.2 mM $FeSO_4$/mg DM and $34.2\;{\mu}g$ DM/mL, respectively. Treatment of RRE significantly lowered fluorescent formation due to advanced glycation reaction. In addition, reactive oxygen species (ROS) scavenging assay, monocyte adherent assay and transendothelial electrical resistance (TEER) assay were performed to investigate the possibility that RRE improves endothelial dysfunction-induced diabetic complications. The adhesion of THP-1 to treated HUVEC with RRE ($100\;{\mu}g/mL$; 33% and $500\;{\mu}g/mL$; 75%) was significantly reduced compared to HUVEC stimulated by glyceraldehydes-AGEs (advanced glycation end product). The TEER value ($88\;{\Omega}{\cdot}cm^2$) of stimulated HUVEC by glyceraldehydes-AGEs was reduced compared to non-stimulation ($113\;{\Omega}{\cdot}cm^2$). However, normalization with RRE increased endothelial permeability in a dose-dependent manner ($100\;{\mu}g/mL$; $102\;{\Omega}{\cdot}cm^2$ and $500\;{\mu}g/mL$; $106\;{\Omega}{\cdot}cm^2$). Thus, these results suggest that Rosa rugosa roots could be a novel candidate for the prevention of diabetic complications through antioxidants and inhibition of advanced glycation end product formation.

Recent Progress in Air Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 (공기조화, 냉동 분야의 최근 연구 동향: 2006년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Shin, Dong-Sin;Choi, Chang-Ho;Lee, Dae-Young;Kim, Seo-Young;Kwon, Yong-Il
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.6
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    • pp.427-446
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    • 2008
  • A review on the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 has been accomplished. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro heat exchanger and siphon cooling device using nano-fluid. Traditional CFD and flow visualization methods were still popular and widely used in research and development. Studies about diffusers and compressors were performed in fluid machinery. Characteristics of flow and heat transfer and piping optimization were studied in piping systems. (2) The papers on heat transfer have been categorized into heat transfer characteristics, heat exchangers, heat pipes, and two-phase heat transfer. The topics on heat transfer characteristics in general include thermal transport in a cryo-chamber, a LCD panel, a dryer, and heat generating electronics. Heat exchangers investigated include pin-tube type, plate type, ventilation air-to-air type, and heat transfer enhancing tubes. The research on a reversible loop heat pipe, the influence of NCG charging mass on heat transport capacity, and the chilling start-up characteristics in a heat pipe were reported. In two-phase heat transfer area, the studies on frost growth, ice slurry formation and liquid spray cooling were presented. The studies on the boiling of R-290 and the application of carbon nanotubes to enhance boiling were noticeable in this research area. (3) Many studies on refrigeration and air conditioning systems were presented on the practical issues of the performance and reliability enhancement. The air conditioning system with multi indoor units caught attention in several research works. The issues on the refrigerant charge and the control algorithm were treated. The systems with alternative refrigerants were also studied. Carbon dioxide, hydrocarbons and their mixtures were considered and the heat transfer correlations were proposed. (4) Due to high oil prices, energy consumption have been attentioned in mechanical building systems. Research works have been reviewed in this field by grouping into the research on heat and cold sources, air conditioning and cleaning research, ventilation and fire research including tunnel ventilation, and piping system research. The papers involve the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies on indoor air quality took a great portion in the field of building environments. Various other subjects such as indoor thermal comfort were also investigated through computer simulation, case study, and field experiment. Studies on energy include not only optimization study and economic analysis of building equipments but also usability of renewable energy in geothermal and solar systems.