• Title/Summary/Keyword: the plate waste

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Design and Construction of a Bottoming Organic Rankine Cycle System for an Natural Gas Engine (가스엔진용 유기랭킨사이클의 설계 및 제작)

  • Lee, Minseog;Baek, Seungdong;Sung, Taehong;Kim, Hyun Dong;Chae, Jung Min;Cho, Young Ah;Kim, Hyoungtae;Kim, Kyung Chun
    • Journal of the Korean Institute of Gas
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    • v.20 no.6
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    • pp.65-72
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    • 2016
  • ORC system was designed and constructed for utilizing the heat of the exhaust gas and coolant released from the gas engine which was modified to use natural gas as a fuel. In this paper the components of the ORC system were designed and manufactured based on measured data of the gas engine. The components are composed of two plate heat exchanger, the 5kW-class expander and multi stage centrifugal pump. The thermodynamic performance of the ORC system was analyzed by using the electric heater. Also, the developed ORC system was implemented to modified natural gas engine. Two gas engines were used to supply heat to the ORC system. As a result of test bench, when the heat source temperature is $110^{\circ}C$ expander shaft power, the pressure ratio and cycle efficiency is 5.22kW, 7.41, 9.09%. As a result of field test, when the heat source temperature is $86^{\circ}C$ expander shaft power, the pressure ratio and cycle efficiency is 2kW, 3.75, 6.45%.

Assessment of Foodservice management practices and Nutritional adequacy of foods served in child-care centers (보육시설 급식소의 운영현황 및 급식실태 조사)

  • Kwak, Tong-Kyung;Lee, Hye-Sang;Jang, Mi-Ra;Hong, Wan-Soo;Yoon, Gae-Soon;Lyu, Eun-Soon;Kim, Eun-Kyung;Choi, Eun-Hui;Lee, Kyung-Eun
    • Journal of the Korean Society of Food Culture
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    • v.11 no.2
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    • pp.243-253
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    • 1996
  • The purpose of this study was to evaluate the foodservice management practices in child-care centers in order to provide basic information for the development of a model of a centralized food service information center. This approach was achieved using a variety of qualitative and quantitative information including general foodservice management practices and plate waste. A self-completed questionnaire survey of 651 child-care centers in Korea was undertaken and detailed information was carefully collected at 6 representative child-care centers. The results of the empirical survey were as follows: 1. Child-care centers categorized by location were in large cities (59.9%), medium cities (27.6%) and in provincial areas (12.5). 2. Private sector of child-care centers was 46.4% of the total followed by National/public (44.2%) and licensed home day-care programs (9.4%). 3. Total average number of children in child-care centers was $63.3{\pm}43.1$ with a very significant difference (p<0.001) in types of child-care centers. 4. The average space of kitchen and dining room was $5.0{\pm}3.8\;and\;10.8{\pm}11.0$ pyung ($1pyung=3.3058\;cm^2$). 5. The average cost of interim snack in morning and afternoon in child-care centers were $345.9{\pm}459.3$ won and $359.3{\pm}226.6$ won respectively. The average cost of lunch was $644.0{\pm}481.1$ won. There was a significant difference (p<0.001) by types of child-care centers with a highest cost of 863.9 won in licensed home day-care programs. 6. Only a limited number of dietitian were employed, therefore most of food service management practice was not conducted by professional personnel. 7. The result of nutritional analysis of the food revealed that the level of energy and nutrients contained in the food was below the recommeded level (RDA/3).

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Isolation of Cadmium-Tolerant Bacteria and Characterization of Cadmium Accumulation into the Bacteria Cell (카드뮴 내성균(耐性菌)의 분리(分離), 동정(同定)및 균체내(菌體內) 카드뮴 축적(蓄積) 특성(特性))

  • Cho, Ju-Sik;Han, Mun-Gyu;Heo, Jong-Soo
    • Korean Journal of Environmental Agriculture
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    • v.11 no.1
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    • pp.77-85
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    • 1992
  • Of the cadmium-tolerant 162 bacterial strains isolated from soils, river waters or active sludges of waste-water disposal plants in the Gyeongnam province a strain C1, which showed considerably higher growth rate in the agar plate containing 2000 ppm than any other strains isolated, was identified as a Pseudomonas putida or its similar strain when analyzed by taxonomical characteristics. Optimum pH and temperature for the growth of the P, putida were 7.0 and $30^{\circ}C$, respectively. This strain was resistant to antibiotics(ampicillin, chloramphenicol and streptomycin), and heavy metals(lithium, cupper, lead and zinc). This strain utilized salicylate, naphthalene or xylene as a sole carbon source. The rate of cadmium accumulation in P. putida cell was enhanced at low concentration of Cd in the growth media. The maximum cadmium absorption by this strain grown in 1 and l0ppm of Cd was respectively 78% and 60% 24 hrs after culture, but in 100 ppm Cd, 40% 48 hrs after culture. Addition of a non-ionic surfactant Triton X-100(0.1%) to the medium enhanced the accumulation of cadmium in the P. putida up to approximately 37%.

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A Study on Seafood Dishes in Military Standard Menu (군대급식 표준식단중 수산물 이용 메뉴 분석 연구)

  • Lee, Wook-Jin;Min, Sung-Hee;Lee, Young-Mee
    • Journal of the Korean Society of Food Culture
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    • v.18 no.3
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    • pp.261-269
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    • 2003
  • This was preliminary study that was to find out the developing point in military meal service to focus on seafood dishes that recently increased plate waste. This study was conducted to analyze menu patterns in military meal service. The result of this study was using to develop new seafood dishes in military meal service. On the basis of some findings, several developing points how to plan meals include many kinds of seafood dishes and to modify taste and cooking method that was more highly prefered by young military persons were suggested. This preliminary study findings were as follows: 1. Each meal was served cooked rice and 4 kinds of dishes(soup or stew, main dish, side dish and kimchi) 2. The seafood dishes was served as 28.6% in soup or stew, 35.0% in main dish and 36.4% in side dish of total serving of seafood dishes. 3. All of raw materials of seafood were supplied by frozen, several items were supplied dried material. Supplying seafood items were limited. Numbers of using seafood items were using 2.7 times per day. Laver and squid was most frequently used. 4. Seafood dishes were frequently serving in breakfast, especially seasoned & toasted laver was served 28.8% of seafood menu in breakfast because of convenience. 5. The nutrients contents of each dishes were as follows, the soup was $86.5{\pm}3.2kcal$ and $10.9{\pm}8.9g$ of animal protein, stew was $165.3{\pm}70.2kcal$ and $13.3{\pm}7.9g$ of animal protein. Nutrients content of other main dish and side dishes was different from 108.1kcal (in steaming dish) to 412.4kcal (in deep-fat frying dish) according to different cooking method. The highest animal protein dish that contented $18.9{\pm}5.1g$ of protein was pan-frying dish or grilling dish. Lowest one was $8.4{\pm}4.9g$ in braising dish. 6. Major cooking method of seafood was stew and the next was deep fat frying, stirfrying and braising. Pan-frying or grilling was seldomly used in military menu because of limitation of kitchen facilities and cooking utensils. On the basis of these findings, newely developing military seafood menus were focused on combination dish(such as seafood cooked rice or seafood fried rice) and many kinds of sauce that was applied to deep-fat frying dishes.

A basic study on development of high-pressure compact steam unit applied hybrid heat exchanger (하이브리드 열교환기 적용 고압 컴팩트 스팀 유닛 개발에 관한 기초 연구)

  • Kim, Jeung-Hoon;Lim, Gye-Hun;Kim, Seung-Hyun;Jin, Chul-Kyu;Park, Jae-Hong;Cho, Sung-Youl;Hong, In-Ki;Lee, Sang-Rae
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.6
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    • pp.453-457
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    • 2016
  • In various industrial plants such as power generation plants, petrochemical plants, and unit factories, there is an increasing demand for a system that generates hot water using waste or surplus steam. Compact steam unit (CSU), which produces hot water by using steam, is a good solution considering energy reuse. In this study, as a basic study to develop a high-pressure CSU, heat transfer characteristics of a hybrid heat exchanger were investigated through experiments, in order to use the hybrid heat exchanger instead of a conventional plate heat exchanger as the core component of CSU. The experimental results are the followings. Heat balance between the hot side and cold side was satisfied within ${\pm}5%$. Overall heat transfer coefficient increased linearly as the Reynolds number increased and exceeded $5,524W/m^2K$ when the flow velocity was above 0.5 m/s. In addition, pressure drop also increased as the Reynolds number increased, and pressure drop per unit length was below 50 kPa/m.

Acceptance of Vegetable Menus of a School Lunch Program by High School Students in Seoul and its Association with Health and Dietary Behavioral Factors (서울시내 일부 고등학생의 채소 급식 메뉴에 대한 기호도 및 관련 인자의 영향)

  • Hong, Jae-Hee;Cho, Mi-Sook
    • Korean Journal of Food Science and Technology
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    • v.44 no.1
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    • pp.121-134
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    • 2012
  • This study was conducted to investigate the acceptance of vegetable menus by high school students and the factors that influence the acceptability. Second-grade high school students (n=389) in Seoul were asked to assess their acceptability of vegetable menus and plate waste, and answered survey questions concerning their demographic characteristics, health-related attitudes, dietary attitudes, dietary habits, and nutritional knowledge. Overall, the menus containing items that were sweet or familiar to the subjects were preferred. Acceptability was significantly associated with the amount of consumption. The acceptability was correlated with dietary habits, dietary attitudes, nutritional knowledge, and several health-related variables. The vegetable-liking groups showed significantly higher scores concerning dietary habits, dietary attitudes, and nutritional knowledge, but did not exhibit a specific pattern of association with the health-related variables. This result implies that intervention strategies focusing on changes in cognitive and/or hedonic factors, such as nutritional education or flavor-flavor learning, would be beneficial for increasing students' acceptance of vegetable menus.

Advanced Treatment of Sewage and Wastewater Using an Integrated Membrane Separation by Porous Electrode-typed Electrolysis (분리막/다공 전극형 전기분해 조합공정을 이용한 하.폐수의 고도처리)

  • Choi, Yong-Jin;Lee, Kwang-Hyun
    • Membrane Journal
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    • v.22 no.2
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    • pp.95-103
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    • 2012
  • To treat nitrate and non-biodegradable organics effectively in sewage, industrial wastewater and livestock wastewater, the activated sludge process integrated by a membrane separation and a porous electrode- electrolysis was proposed and its efficiency was investigated. The proposed system was consisted of 3 processes; activated sludge, membrane filtration and electrolysis. In the study, the membrane filtration played a role in reducing the load of the electrolysis to operate the proposed process stably. The electrolysis consisted of a porous electrode to increase the efficiency due to the extension of the specific surface area. Additionally, redox reaction in the electrolysis was induced by decomposing influent water as current was applied. As a result, hydrogen free radicals and oxygen radicals as intermediates were produced and they acted as oxidants to play a role in decomposing non-degradable organics. It was environmentally-friendly process because intermediates produced by porous electrode were used to treat waste matters without supplying external reagent. Experimental data showed that the proposed process was more excellent than activated sludge process. SS removal efficiencies of the proposed process, membrane filtration and activated sludge process were about 100%, about 100% and about 90%, respectively. COD removal efficiencies of the proposed system, membrane filtration and activated sludge process were about 92%, about 84% and about 78%, respectively. T-N removal efficiencies of the proposed system, membrane filtration and activated sludge process were about 88%, about 67%, and about 58%, respectively. The SS data showed that SS was efficiently removed in the single of the membrane filtration. The COD/T-N data showed that COD/T-N of membrane hybrid process was treated by removing a little soluble organics and SS, and that COD/T-N of electrolysis hybrid process was treated by oxidize organics with high removal rate.

A Study on Teaching-Learning and Evaluation Methods of Environmental Studies in the Middle School (중학교 "환경" 교과의 교수.학습 및 평가 방법 연구)

  • 남상준
    • Hwankyungkyoyuk
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    • v.7 no.1
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    • pp.1-17
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    • 1994
  • This study was performed to determine appropriate teaching-learning and evaluation methods for Environmental Studies. To promote the relevance of our study to the needs of the schools and concerned educational communities of environmental education, we reviewed related literature, conducted questionnaire surveys, interviewed related teachers and administrator, held meetings with experts, and field-tested our findings. For selecting and developing teaching-learning methods of Environmental Studies, findings of educational research in general are considered. moreover, principles of environmental education, general aim of environmental education, orientations of environmental education, and developmental stages of middle school students in educational psychology were attended. In addition, relevance to the purpose of the Environmental Studies curriculum, appropriateness for value inquiry as well as knowledge inquiry, small group centered class organization, social interaction centered teaching-learning process, regional environmental situation, significance of personal environment, evaluation methods of Environmental Studies, multi- and inter-disciplinary contents of the Environmental Studies textbook, suitability to the evaluation methods of Environmental Studies, and emphasis on the social interaction in teaching-learning process were regarded. It was learned the Environmental Studies can be taught most effectively in via of holding discussion sessions, conducting actual investigation, doing experiment-practice, doing games and plate, role-playing and carrying out simulation activities, and doing inquiry. These teaching-learning methods were field-tested and proved appropriate methods for the subject. For selecting and developing evaluation method of Environmental Studies, such principles and characteristics of Environmental Studies as objective domains stated in the Environmental Studies curriculum, diversity of teaching-learning organization, were appreciated. We categorized nine evaluation methods: the teacher may conduct questionnaire surveys, testings, interviews, non-participatory observations; they may evaluate student's experiment-practice performances, reports preparation ability, ability to establish a research project, the teacher may ask the students to conduct a self-evaluation, or reciprocal evaluation. To maximize the effect of these methods, we further developed an application system. It considered three variables, that is, evaluates, evaluation objectives domains, and evaluation agent, and showed how to choose the most appropriate methods and, when necessary, how to combine uses of different methods depending on these variables. A sample evaluation instrument made on the basis of this application system was developed and tested in the classes. The system proved effective. Pilot applications of the teaching-learning methods and evaluation method were made simultaneously; and the results and their implications are as follows. Discussion program was applied in a lesson dealing with the problems of waste disposal, in which students showed active participation and creative thinking. The evaluation method used in this lesson was a multiple-choice written test for knowledge and skills. It was shown that this evaluation method and device are effective in helping students' revision of the lesson and in stimulating their creative interpretations and responces. Pupils showed great interests in the actual investigation program, and this programme was proved to be effective in enhancing students' participation. However, it was also turned out that there must be pre-arranged plans for the objects, contents and procedures of survey if this program is to effective. In this lesson, non-participatory observation methods were used with a focus on the attitudes of students. A scaled reported in general description rather than in grade. Experiment-practice programme was adopted in a lesson for purifying contaminated water and in this lesson, instruction objectives were properly established, the teaching-learning process was clearly specified and students were highly motivated. On the other hand, however, it was difficult to control the class when some groups of students require more times to complete their experiment, and sometimes different results. As regards to evaluation, performance observation test were used for assessing skills and attitudes. If teachers use well-prepared Likert scale, evaluation of all groups within a reasonablely short period of time will be possible. The most effective and successful programme in therms of students' participation and enjoyment, was the 'ah-nah-bah-dah-market' program, which is kind of game of the flea market. For better organized program of this kind, however, are essential, In this program, students appraise their own attitudes and behavior by responding to a written questionnaire. In addition, students were asked to record any anecdotes relating to self-appraisal of changes on one's own attitudes and behaviours. Even after the lesson, students keep recording those changes on letters to herself. Role-playing and simulation game programme was applied to a case of 'NIMBY', in which students should decide where to located a refuse dumping ground. For this kind of programme to e successful, concepts and words used in the script should be appropriate for students' intellectual levels, and students should by adequately introduced into the objective and the procedures of the lessons. Written questionnaire was used to assess individual students' attitudes after the lesson, but in order to acquire information on the changes of students' attitudes and skills, pre-test may have to be made. Doing inquiry programme, in which advantages in which students actually investigated the environmental influence of the areas where school os located, had advantages in developing students' ability to study the environmental problems and to present the results of their studies. For this programme to be more efficient, areas of investigation should be clearly divided and alloted to each group so that repetition or overlap in areas of study and presentation be avoided, and complementary wok between groups bee enhanced. In this programme, teacher assessed students' knowledge and attitudes on the basis of reports prepared by each group. However, there were found some difficults in assessing students' attitudes and behaviours solely on the grounds of written report. Perhaps, using a scaled checklist assessing students' attitudes while their presentation could help to relieve the difficulties.

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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 2009 (설비공학 분야의 최근 연구 동향 : 2009년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Lee, Dae-Young;Kim, Seo Young;Choi, Jong-Min;Baik, Yong-Kyu;Kwon, Young-Chul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.7
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    • pp.492-507
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    • 2010
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2009. 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) Research trends of thermal and fluid engineering have been surveyed as groups of general thermal and fluid flow, fluid machinery and piping, and new and renewable energy. Various topics were covered in the field of general thermal and fluid flow such as an expander, a capillary tube, the flow of micro-channel water blocks, the friction and anti-wear characteristics of nano oils with mixtures of refrigerant oils, etc. Research issues mainly focused on the design of micro-pumps and fans, the heat resistance reliability of axial smoke exhaust fans, and hood systems in the field of fluid machinery and piping. Studies on ground water sources were executed concerning two well type geothermal heat pumps and multi-heat pumps in the field of new and renewable energy. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included the heat transfer in thermoelectric cooling systems, refrigerants, evaporators, dryers, desiccant rotors. In the area of industrial heat exchangers, researches on high temperature ceramic heat exchangers, plate heat exchangers, frosting on fins of heat exchangers were performed. (3) In the field of refrigeration, papers were presented on alternative refrigerants, system improvements, and the utilization of various energy sources. Refrigeration systems with alternative refrigerants such as hydrocarbons, mixed refrigerants, and $CO_2$ were studied. Efforts to improve the performance of refrigeration systems were made applying various ideas of suction line heat exchangers, subcooling bypass lines and gas injection systems. Studies on heat pump systems using unutilized energy sources such as river water, underground water, and waste heat were also reported. (4) Research trend in the field of mechanical building facilities has been found to be mainly focused on field applications rather than performance improvements. In the area of cogeneration systems, papers on energy and economic analysis, LCC analysis and cost estimating were reported. Studies on ventilation and heat recovery systems introduced the effect on fire and smoke control, and energy reduction. Papers on district cooling and heating systems dealt with design capacity evaluation, application plan and field application. Also, the maintenance and management of building service equipments were presented for HVAC systems. (5) In the field of architectural environment, various studies were carried to improve indoor air quality and to analyze the heat load characteristics of buildings by energy simulation. These studies helped to understand the physics related to building load characteristics and to improve the quality of architectural environment where human beings reside in.

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2011 (설비공학 분야의 최근 연구 동향: 2011년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Lee, Dae-Young;Kim, Seo-Young;Choi, Jong-Min;Paik, Yong-Kyoo;Kim, Su-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.6
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    • pp.521-537
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    • 2012
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2011. 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) Research trends of thermal and fluid engineering have been surveyed as groups of fluid machinery and fluid flow, thermodynamic cycle, and new and renewable energy. Various topics were presented in the field of fluid machinery and fluid flow. Research issues mainly focused on the rankine cycle in the field of thermodynamic cycle. In the new and renewable energy area, researches were presented on geothermal energy, fuel cell, biogas, reformer, solar water heating system, and metane hydration. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer, nanofluids and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer above liquid helium surface in a cryostat, methane hydrate formation, heat and mass transfer in a liquid desiccant dehumidifier, thermoelectric air-cooling system, heat transfer in multiple slot impinging jet, and heat transfer enhancement by protrusion-in-dimples. In the area of pool boiling and condensing heat transfer, researches on pool boiling of water in low-fin and turbo-B surfaces, pool boiling of R245a, convective boiling two-phase flow in trapezoidal microchannels, condensing of FC-72 on pin-finned surfaces, and natural circulation vertical evaporator were actively performed. In the area of nanofluids, thermal characteristics of heat pipes using water-based MWCNT nanofluids and the thermal conductivity and viscosity were measured. In the area of industrial heat exchangers, researches on fin-tube heat exchangers for waste gas heat recovery and Chevron type plate heat exchanger were implemented. (3) Refrigeration systems with alternative refrigerants such as $CO_2$, hydrocarbons, and mixed refrigerants were studied. Heating performance improvement of heat pump systems were tried applying supplementary components such as a refrigerant heater or a solar collector. The effects of frost growth were studied on the operation characteristic of refrigeration systems and the energy performance of various defrost methods were evaluated. The current situation of the domestic cold storage facilities was analyzed and the future demand was predicted. (4) In building mechanical system fields, a variety of studies were conducted to achieve effective consumption of heat and maximize efficiency of heat in buildings. Various researches were performed to maximize performance of mechanical devices and optimize the operation of HVAC systems. (5) In the fields of architectural environment and energy, diverse purposes of studies were conducted such as indoor environment, building energy, and renewable energy. In particular, renewable energy and building energy-related researches have mainly been studied as reflecting the global interests. In addition, various researches have been performed for reducing cooling load in a building using spot exhaust air, natural ventilation and energy efficiency systems.