• Title/Summary/Keyword: CopA3

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Characteristic analysis of air-cooled absorption refrigeration machine (공냉식 흡수식 냉동기의 특성 해석)

  • Kwon Oh-Kyung;Moon Choon-Geun;Yang Young-Myung;Yu Sun-Il;Yoon Jung-In
    • 한국가스학회:학술대회논문집
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    • 1998.09a
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    • pp.249-254
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    • 1998
  • This paper describes the study of developing air-cooled absorption system which uses a new working solution instead of LiBr solution to improve the performance of system. The absorption chiller-heater considered was an air-cooled, double-effect, $H_2O/LiBr+HO(CH_2)_3$ system of parallel flow type. In this study, we found out the characteristic of new working solution through the cycle simulation and compared the result that of LiBr solution to evaluate. The new working fluid has a wider working range with $8\%$ higher crystallization limit at the saturated refrigerant pressure of 0.8kPa. The optimum designs and operating conditions of air-cooled absorption system were suggested based on this cycle simulation analysis. It was demonstrated that new working fluid substantially improves the performance of the absorption refrigeration machine and is expected to increase the COP by as much as $5\%$.

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Discussion on Climate Finance: Issues and Perspectives (유엔기후변화협약 재정 분야 협상 쟁점 및 향후 전망)

  • Jung, Jione;Moon, Jinyoung
    • Journal of Environmental Policy
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    • v.14 no.3
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    • pp.119-136
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    • 2015
  • As the means of implementation, the GCF and scaled-up climate finance compose major elements of a new climate agreement that will be implemented in 2020. The new agreement will be applicable to all parties, implying that developing countries as well as developed countries will be responsible for reducing GHG emissions. Achieving the goal of mobilizing 100 billion dollars will depend on the efforts put forth by developing countries in terms of meaningful mitigation actions and transparent implementation of the mitigation targets. This paper describes a major achievement on the negotiation related to climate finance since the Convention established and addresses the issues and perspectives for the Paris Agreement.

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A Simulation Study on the Annual Heating Performance of the Seawater-Source Screw Heat Pump (해수열원 스크류 히트펌프의 연간 난방운전 성능 모사)

  • Baik, Young-Jin;Kim, Min-Sung;Chang, Ki-Chang;Lee, Young-Soo;Kim, Hyeon-Ju
    • Journal of the Korean Solar Energy Society
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    • v.32 no.3
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    • pp.88-95
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    • 2012
  • In this study, in order to utilize the seawater as a heat source at Gangneung city near the East Sea in Korea, an annual heating performance of a screw heat pump was simulated. For a simulation, the maximum heating capacity of heat pump was assumed at 3.5 MW. An ambient temperature at Gangneung city was calculated from the TMY2 weather data, while the seawater temperature was calculated from the regression equation based on the measurement by the National Fisheries Research and Development Institute of Korea. The heating load was assumed linearly dependent on the ambient temperature, while the maximum heating load was assumed to appear when the ambient temperature is below $-2.4^{\circ}C$, which is the temperature of TAC 2.5% for heating at Gangneung city. A heat pump performance at full-load was calculated from the regression equation, which involves refrigerant's evaporating and condensing temperatures, based on a commercial screw compressor performance map. A heating supply temperature which determines refrigerant's condensing temperature was assumed linearly dependent on the heating load. A performance degradation due to the part-load operation of heat pump was also considered. Simulation results show that an annual heating coefficient of performance ($COP_H$) of a seawater-source screw heat pump is approximately 2.8 and that it is necessary to improve part-load performance to increase an annual performance of the heat pump.

Analysis of Plantar Foot Pressure and Pathway of COP Depending on Inclination of Descending Ramp (내림 경사로의 기울기에 따른 족저압과 압력중심이동경로 분석)

  • Han, Jin-Tae;WhangBo, Gak
    • The Journal of the Korea Contents Association
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    • v.10 no.8
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    • pp.257-265
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    • 2010
  • The purpose of this study was to investigate the effect of different ramp inclination on the maximum plantar foot pressure and pathway of the center of pressure. Fifteen healthy adults who had no musculoskeletal disorders were participated with this study and descended the ramp with different inclination(level, $-5^{\circ}$, $-10^{\circ}$, $-15^{\circ}$). Plantar foot pressures were recorded by the Matscan system(Tekscan, Boston, USA) during level and descending ramp with barefoot. Plantar foot surface was defined as seven regions for pressure measurement; two toe regions, three forefoot regions, one midfoot region, one heel region. Repeated ANOVA was used to compare each region data of foot according to different ramp inclination. As descending ramp inclination became increased, the pressure of hallux region was significantly increased at $-15^{\circ}$ inclination and the pressure of 2-3 metatasal head region were significantly decreased at $-5^{\circ}$, $-10^{\circ}$, $-15^{\circ}$ inclination. The pathway of COP had a tendency to be shifted inside in forefoot and prolonged to great toe as the descending ramp inclination increased. The results indicated that plantar foot pressure could be changed at hallux and forefoot regions with $-5^{\circ}$ ramp inclination and these findings demonstrated that ramp inclination could affect the structure and function of foot.

Analysis of Test Operations Effect of Open-Closed Loops Complex Geothermal System Combined with Groundwater Well (지하수정호 결합 복합지열시스템의 시범운영 효과분석)

  • Song, Jae-Yong;Kim, Ki-Joon;Lee, Geun-Chun;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.28 no.3
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    • pp.475-488
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    • 2018
  • This study evaluates geothermal system efficiency in terms of input power and heat exchange volume on the heat-source and load sides, by applying a combined open-closed type loop system comprising a geothermal system and a groundwater well to a cultivation site. In addition, this study analyzes the effects of heating and cooling for a complex geothermal system, by evaluating the temperatures of an external site and a cultivation site during operation. During cooling operations the heat exchange volume on the heat source side, average 90.0kW/h for an open type system with an input of 235L/minute groundwater, and 40.1kW/h for a closed type system with an input of 85L/minute circulating water, for a total average heat exchange volume of 130.1kW/h. The actual heat exchange volume delivered on the load side averages 110.4kW/h. The average EER by analysis of the geothermal system's cooling efficiency is 5.63. During heating operation analysis, the heat exchange volume on the heat source side, average 60.4kW/h in an open type system with an input of 266L/minute groundwater, and 22.4kW/h in closed type system with an input of 86L/minute circulating water, for a total average heat exchange volume of 82.9kW/h. The actual heat exchange volume delivered on the load side averages 112.0kW/h in our analysis. The average COP determined by analysis of the geothermal system's heating efficiency is 3.92. Aa a result of the tradeoff between the outside temperature and the inside temperature of the production facility and comparing the facility design with a combined well and open-closed loops geothermal(CWG) system, we determine that the 30RT-volume CWG system temperature are lower by $3.4^{\circ}C$, $6.8^{\circ}C$, $10.1^{\circ}C$ and $13.4^{\circ}C$ for ouside temperature is of $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$ and $35^{\circ}C$, respectively. Based on these results, a summer cooling effect of about $10^{\circ}C$ is expected relative to a facility without a CWG system as the outside temperature is generally ${\geq}30^{\circ}C$. Our results suggest that a complex geothermal system provides improvement under a variety of conditions even when heating conditions in winter are considered. Thus It is expected that the heating-cooling tradeoffs of complex geothermal system are improved by using water screen.

Feasibility Study on Thermal Power Plant Condenser Heat Recovery for District Heating and Fuel Line Preheating (발전소 복수기 배열회수의 지역난방 및 연료라인 예열용 활용타당성 검토)

  • Jung, Hoon;Hwang, Gwang-Won
    • New & Renewable Energy
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    • v.5 no.3
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    • pp.40-48
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    • 2009
  • Recovered heat has been considered as a renewable energy in Europe since 2008 because its great effect on energy saving and carbon decreasing in plant process. Energy saving and decreasing green gas are critical issue today, so various technologies to save energy and decrease carbon dioxide in plant process have been applied to many industrial area. In this paper, the feasibility of condenser heat recovery by heat pump in power plant for district heating and fuel line preheating were reviewed by verifying energy (heat) balance and mass balance of power plant model. Some ways to compose proper system to recover heat of condenser are suggested and their possibilities are also reviewed. Limitations on heat recovery in power plant are also reviewed. The results are verified by calculating input/output energy based on actual performance test data of Taean Thermal Power Plant in Korea. There is noticeable improvement of plant performance in some cases which demand low temperature (<100 C) heat like distrcit heating, fuel line heating, and so forth.

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Feasibility Study on Retrofitting Lighting and Heat Source Equipments in Office Buildings (사무소건물 조명기기와 열원기기의 고효율기기로의 교체에 관한 경제성 검토)

  • Lee, Chul-goo;Kim, Jong-dae;Im, Tae-soon
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.12 no.2
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    • pp.13-18
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    • 2016
  • Energy saving has been main concern, thus government supporting policies which are based on Fundamentals of Low-carbon Green Growth Act', 'Green Building Support Act, have been prepared in Korea. The objective of this study is to estimate energy conservation effectiveness and economic advantage assuming that lighting equipments and heat source equipments would be retrofitted. Office building, which has total floor area of $30,000m^2$, was a subject of this study. From the estimations, electric rate will be decreased by 62,886,000 won per year due to lighting equipments retrofit, and gas rate will be decreased 11,141,000 won or 17,332,000 won per year due to heat source equipments retrofit (in case of COP 1.2 or 1.5). Payback period of each case that are calculated by energy saving cost and retrofit cost are estimated 27.9 year, 38.6 year and 29.2 year, thus economic supporting policies is necessary for effective energy saving in buildings. Meanwhile payback period of heat source equipment for new building is estimated 6.1 year and 8.3 year.

Heat Exchanger Design of a Heat Pump System Using the Heated Effluent of Thermal Power Generation Plant as a Heat Source for Greenhouse Heating (화력발전소의 온배수를 열원으로 이용하는 시설원예 난방용 히트펌프 시스템의 열교환기 설계기준 설정)

  • Ryou, Young Sun;Kang, Youn Ku;Jang, Jae Kyung;Kim, Young Hwa;Kim, Jong Goo;Kang, Geum Chun
    • Journal of Bio-Environment Control
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    • v.21 no.4
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    • pp.372-378
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    • 2012
  • This study was carried out in order to determine the optimum length of a roll type PE pipe heat exchanger employed in the water-to-water heat pump system using the waste heat of the heated effluent flowed out from thermal power generation plants as a heat source. And the heat pump system of 30 RT for an experimental test was designed and manufactured. And also PE pipes were employed to recover the waste heat from the heated effluent. The inside diameter of PE pipe heat exchanger was 20 mm, the thickness was 2 mm and the diameter of a roll was 1,000 mm. And from the results of this study, we found that the optimum length of PE pipe heat exchanger was 75 m per the heat pump capacity of 1.0 RT (3.51 kW) and then the heating COP of heat pump system was 3.8.

A Study on Supercooling Repression of TMA-Water Clathrate Compound II (TMA-물계 포접화합물의 과냉각 억제에 대한 연구 II)

  • Kim Chang-Oh;Kim Jin-Heung;Chung Nak-Kyu
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 2006.05a
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    • pp.317-324
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    • 2006
  • This study aims to find out cooling characteristics of TMA(Tri-Methyl-Amine, ($CH_{3})_{3}N$) 25wt%-clathrate compound with ethanol($CH_{3}CH_{2}OH$) such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at $-6{\sim}-8^{\circ}C$, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as $3.8^{\circ}C$ according to cooling source temperature in case that 0.5w% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is $0.9^{\circ}C $ and minimum supercooling is $0.8,\;0.7^{\circ}C$ according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is $3.013{\sim}3.048\;kJ/kgK$ according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol. This can lead to shorten refrigerator operation time of low temperature thermal storage system and improve COP of refrigerator and efficiency of overall system. Therefore energy can be saved and efficiency can be improved much more.

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A Study on the Cooling Characteristics Improvement of TMA-Water Clathrate Compound by Ethanol (에탄올에 의한 TMA-포접화합물의 냉각특성 개선에 대한 연구)

  • Lee, Jong-In;Kim, Chang-Oh
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.1
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    • pp.23-28
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    • 2007
  • This study aims to find out cooling characteristics of TMA(Tri-Methyl-Amine, $(CH_3)_3N$) 25wt%-water clathrate compound with ethanol($CH_3CH_2OH$) such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at $-6{\sim}-8^{\circ}C$, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as $3.8^{\circ}C$ according to cooling source temperature in case that 0.5wt% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is $0.9^{\circ}C$ and minimum supercooling is 0.8, $0.7^{\circ}C$ according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is $3.013{\sim}3.048\;kcal/kg^{\circ}C$ according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol. This can lead to shorten refrigerator operation time of low temperature latent heat storage system and improve COP of refrigerator and efficiency of overall system. Therefore energy can be saved and efficiency can be improved much more.