• Title/Summary/Keyword: 성적계수

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Load Analysis and Economical Estimation of Hot Water Driven Absorption Chiller (온수구동 흡수식 냉동기 부하분석과 경제성 평가)

  • Kim, Gi-Soo;Chung, Bong-Chul;Shin, Jeong-Kwan;Cheon, Ho-Jun
    • Proceedings of the SAREK Conference
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    • pp.115-119
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    • 2008
  • 지구 자원고갈과 환경오염으로 인한 에너지 절약에 대한 관심은 최근 국제유가 상승에 의해서 국가의 사활을 건 정책으로 반영되고 있다. 하루 중 부하변동이 심하지 않으면서 각실 제어가 필요하지 않은 조건을 갖춘 공간에는 지역난방공사로부터 온수를 공급받아 건물을 냉방하는 방식이 일반적으로 보급되어 있다. 최근 에너지의 유효이용 측면에서 온수 온도차를 늘려 냉방 에너지 보급용량의 확대 및 설비비용을 절감하려는 움직임이 진행되고 있다. 에너지 절약 측면에서 접근하여 볼 때 효율을 상승시키는 방법과 이용열원의 극대화가 동시에 검토되어야 하며 각각의 장점이 있는 현장에 맞추어 다양한 방식이 적용되어야 할 것이다.

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Design of Predictive Controller for Effective Superheat Control of Variable Speed Refrigeration System (가변속냉동시스템의 효율적인 과열도제어를 위한 예측제어기 설계)

  • Choi, Jeong-Pil;Hua, Li;Jeong, Seok-Kwon
    • Proceedings of the SAREK Conference
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    • pp.9-15
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    • 2008
  • In this paper, we suggest PI control with a predictive controller to progress both energy saving and coefficient of performance(COP) in a variable speed refrigeration system. The capacity and superheat are controlled simultaneously and independently by an inverter and an electronic expansion valve respectively for saving energy and improving COP in the system. The refrigeration system has long dead time in superheat inherently. The dead time makes the system difficult to achieve the satisfactory quick control response, especially superheat control response. In order to solve this problem, we designed a predictive controller based on PI control to progress superheat control performance. The control performance was investigated through some experiments to verify the effectiveness of the predictive controller.

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Experimental Study for Investigating the Optimum Operating Conditions of a Seawater Ice Machine (해수제빙장치의 최적 운전 조건 탐색을 위한 실험적 연구)

  • Li, H.;Joo, W.J.;Jeong, S.K.
    • Journal of Power System Engineering
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    • v.14 no.5
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    • pp.76-82
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    • 2010
  • This paper investigates the optimum operating conditions to construct total automatic control system with high energy efficiency of a newly developed seawater ice machine. The machine has an electronic expansion valve(EEV) and a variable speed rotating drum with an evaporator installed inside. The coefficient of performance(COP) was used as an index to evaluate energy efficiency of the machine. At first, the opening angle of EEV was adjusted to obtain COP of the machine at a constant speed of the drum. Then, we checked seawater ice product versus opening angles of the EEV. Finally, effect of drum's rotating speed in response to product of seawater ice and seawater ice temperature were considered.

Analysis of Performance and Economical Efficiency through Cycle Simulation for Power Saving BIP(Block Ice Plant) (절전형 제빙시설 사이클 모사를 통한 성능 및 경제성 해석)

  • 강종호;김남진;이재용;김종보
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.6
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    • pp.455-461
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    • 2001
  • Domestic ice making companies make effort to obtain products and neglect to introduce low cost product improvements with energy savings. The work presented here is an implementation of ice making method to improve both energy efficiency and productivity. In this present investigation, several ice making cycles are proposed for higher efficiency in the system. COP(Coefficient of Performance), ice making time and electric energy consumption are evaluated and compared with the conventional system. Results shows that COP is improved with more efficient use of time for ice making and electric consumption. Therefore, this can offer an opportunity for more efficient use of energy and higher productivity in ice making.

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A Study on the Characteristics of the Refrigerator Using a Refrigerant Injection Type Expansion Device (냉매분사식 팽창장치를 적용한 냉동기의 특성에 관한 연구)

  • 조병옥
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.10
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    • pp.925-931
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    • 2000
  • Refrigerating ability of vapor compression refrigerator is decided by the harmonic work of it's components such as compressor, condenser, evaporator, expansion device, and so on. In this study, choosing refrigerant injectors as a new one of expansion device, temperature change of the cold room, ice freezing ability, and power consumption on flowrate of injector and refrigerant charging condition are evaluated experimentally. As the results of this study, it is verified that the spray injection type refrigeration system has some merits according to the flowrate and spray pattern of injector and charging quantum of refrigerant. And there are some design factors such as spray pattern and shape of spray chamber to utilize and fabricate this refrigerant injection type refrigerator.

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Study on the Adaptiveness of Using an Injector As an Expansion Device of Refrigerator (냉동기 팽창장치로서 인젝터 사용의 적합성에 관한 연구)

  • Cho, B.O.
    • Journal of ILASS-Korea
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    • v.5 no.3
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    • pp.1-8
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    • 2000
  • Spray as a liquid atomization technique has wide applications of combustion, painting, chemical, medical and agricultural purpose, and so on. Capillary tubes and expansion valves, as an expansion device of vapor compression type refrigerators, has been used from the early time. But there are some problems in practice, the former can't control refrigerant flowrate exactly and the later most of imported are expensive relatively and has some difficulties to install. Choosing an injector as a new concept of expansion device of refrigerator in this study to improve such troubles of the coming expansion device, the refrigerant spray behavior and refrigeration characteristics are evaluated experimentally. It is verified that the injector with a good function of refrigerant atomization plays a desirable role of refrigerant expansion in the actual refrigeration cycle.

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The Analysis of the Effects of Design Parameters on the Energy Efficiency and Performance of TEM Dehumidifiers (열전모듈 제습기의 에너지 효율과 성능에 미치는 설계 인자의 영향 분석)

  • Lee, Tae-Hee
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.16 no.3
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    • pp.1-7
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    • 2020
  • To provide a design direction for high efficiency thermoelectric module(TEM) dehumidifiers, the effects of design factors of TEM dehumidifiers on dehumidification energy efficiency and performance were numerically investigated. The design factors considered in this study are the TEM capacity, the performance of heat exchangers on the heating and cooling surfaces of the TEM. The higher capacity of the TEM results the higher dehumidification energy efficiency and performance at some operating voltage. The enhanced performance of the heat exchanger on heating surface increased the dehumidification energy efficiency and performance at all the operating voltage. The enhanced performance of the heat exchanger on cooling surface decreased the dehumidification energy efficiency and performance at all operating voltage.

Heating and Cooling Performance of a Ground Coupled Heat Pump System with Energy-Slab (에너지슬래브 적용 지열원 열펌프 시스템의 성능 특성에 관한 실증 연구)

  • Choi, Jong-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.2
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    • pp.196-203
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    • 2012
  • Energy foundations and other thermo-active ground structure, energy wells, energy-slab, and pavement heating and cooling represent an innovative technology that contributes to environmental protection and provides substantial long-term cost savings and minimized maintenance. This paper focuses on earth-contact concrete elements that are already required for structural reasons, but which simultaneously work as heat exchangers. Pipes, energy slabs, filled with a heat carrier fluid are installed under conventional structural elements, forming the primary circuit of a geothermal energy system. The natural ground temperature is used as a heat source in winter and a heat sink in summer. The geothermal heat pump system with energy-slab represented very high heating and cooling performance due to the stability of EWT from energy slab. However, the performance of it seemed to be affected by the atmospheric air temperature.

Comparison of Performance Variation between R-22 and R-410A Refrigeration Systems (운전조건 변화에 따른 R-22 냉동사이클과 R-410A 냉동사이클의 성능변화 비교)

  • 박태준;이민규;정지환;장근선
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.3
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    • pp.166-176
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    • 2003
  • Experiments have been conducted in order to make comparisons of a alternative refrigerant (R-410A) cycle characteristic with an existing refrigerant (R-22) cycle characteristic in terms of cooling capacity and coefficient of performance (COP). The parameters examined in the present work include air flow rate, indoor/outdoor air temperatures, and indoor relative humidity. These two refrigeration cycles share all components except compressor, accumulator, oil separator, and piping connecting them. The measurements were made using an air-enthalpy calorimeter. The experimental results show that the R-410A cycle has many advantages over indoor conditions while the R-22 cycle has better performance over outdoor conditions.

Study on the Performance of an ATES Geothermal Heat Pump System and Economic Analysis (ATES 열펌프 시스템 성능 및 경제성 분석에 관한 연구)

  • Oh, Myung-Suk;Choi, Jong-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.4
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    • pp.289-296
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    • 2012
  • The aim of this study is to investigate the performance of a heating and cooling system with aquifer thermal energy storage(ATES heat pump system) known as one of the underground thermal energy storage application systems. The ATES system was composed of heat pump unit and ATES, which was installed in a factory building located in Anseoung. The system represented very high heating and cooling performance, and showed nearly constant COP at each heating and cooling season due to the stability of EWT. The economic analysis about an ATES system and a conventional system was also executed. The conventional system adopted an air-conditioner in the summer season and a LNG boiler in the winter season. The payback period of the ATES system was estimated by 6.62 years.