• Title/Summary/Keyword: Heat pump

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A Study on the Operating Characteristics of the Heat Pump System using the Municipal Waste Water as Heat Source (생活廢水熱源 熱펌프시스템 運轉特性 考察)

  • 신현준;박준택
    • Journal of Energy Engineering
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    • v.4 no.2
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    • pp.270-277
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    • 1995
  • 생활수준의 향상으로 따라 민생용 에너지의 소비량이 급격히 증가함에 따라 일상생활에서 발생되는 폐수의 양과 온도가 높아지면서 이들은 주요 에너지자원의 대상으로 부각되고 있다. 즉, 폐수열은 열원으로서의 경제성이 향상되어 에너지자원으로서의 잠재력이 높아지고 있으며, 또한 화석에너지의 과다 사용을 인한 환경오염이 심각한 사회문제로 부각되면서 이들 에너지의 유효이용에 대한 관심이 높아지고 있다. 본 연구는 일상생활에서 발생되는 생활폐수를 대상으로 냉·난방에너지원으로서의 활용 가치를 평가히기 위한 열특성을 파악하고, 이 폐수열을 열원으로 하는 熱펌프시스템을 제작·설치하여 운전 성능을 파악하므로서 장차의 에너지수요에 대응하기 위한 기초자료를 제시하는데 목적이 있다. 이를 위해 아파트 단지를 대상으로 폐수열의 계절별 온도분포를 측정하고, 열원의 특성에 적합한 폐수열교환기, 세척장치 등 요소기기의 구조를 도출하였으며 이를 이용한 熱펌프시스템을 제작하여 성능실험을 수행하였다. 실험결과 난방기의 성적계수(COP)h를 3.5이상으로 유지할 수 있는 비교적 경제성이 높은 熱펌프시스템의 구성이 가능한 것으로 나타났다.

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Analysis of Thermal Performance in Roof Evaporative Cooling System (지붕 증발냉각시스템의 열성능 해석)

  • Shin, U.C.
    • Journal of the Korean Solar Energy Society
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    • v.21 no.3
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    • pp.9-18
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    • 2001
  • This paper reports on an theoretical study of heat transfer from evaporative cooling system by the flow of recirculated water over the roof. In this system tile water is distributed at the top of the pitched roof, collected at the bottom by a gutter and recirculated by a pump. To analysis the system, the energy balance equations are developed and solved using a finite difference method. The calculation results show a good agreement with the measured ones obtained from our experiment. Based on the results, it was seen that the roof-evaporative cooling system reduced the heat flux significantly compared with the conventional roof structure even in the hot-humid summer climate of Korea.

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A Study on Effect of Flow Characteristics for Turbine Impeller Shape (Turbine Impeller 형상이 유동특성에 미치는 영향에 관한 연구)

  • Jeon, Eon-Chan;Youn, Gi-Ho;Kang, Chang-Hun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.4
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    • pp.36-43
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    • 2014
  • Recently, research has been conducted to develop the ORC (organic Rankine cycle), to recover waste heat from facilities such as industrial plants ultimately to create mechanical or electrical energy. The ORC system consists of a heat exchange, a condenser, a pump and a boiler. In this paper, 84 flow analyses were conducted with 21 cases and three variables, i.e., a number of large wings, a number of small wings, and RPMs. R245fa was used as a refrigerant. The flow cavitation phenomenon was investigated through a flow analysis, and a flow stream analysis was conducted.

Characteristics of flow rate according to design parameters of a shroud in outdoor unit (실외기 shroud 설계 인자에 따른 유량 특성)

  • Ryu, Ki-Jung;Kim, Min-Soo;Cha, Woo-Ho;Lee, Kwan-Soo
    • Proceedings of the SAREK Conference
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    • 2008.11a
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    • pp.244-249
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    • 2008
  • In this study, the characteristics of flow in outdoor unit were numerically analyzed. Parametric studies were performed to compare the effect of bell mouth height, fan height and fan width concerned with flow rate. The result indicated that the flow rate was dependent on the bell mouth height, while it was negligibly affected by the fan height and fan width. The fan width was found to affect the velocity distribution at heat exchanger face.

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Analysis of Thermodynamic Design Data of Double-Effect Absorption System for Heating using LiCl-water for Evaporator Heating Source of Solar Energy (흡수식 2중효용 시스템의 증발기 열원으로 태양열을 이용하는 LiCl 수용액 난방시스템 해석)

  • Won, Seung-Ho
    • Journal of the Korean Solar Energy Society
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    • v.24 no.3
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    • pp.39-46
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    • 2004
  • In this paper, thermodynamic design data for heating of double-effect absorption system using LiCl-water for evaporator heating source of sofar energy are investigated for the water-LiCl pair and a comparative study of the water-LiCl pair with the water-LiBr pair is given used for the computer simulation. The computer simulation is based on mass, material and heat balance equations for each part of the system. Coefficients of performance and flow ratios for effects of different operating temperatures are investigated. It is found that the heating COP is higher for the water -LiCl pair than for the water-LiBr pair, and FR is lower for the water-LiCl pair than for the water LiBr pair.

A study on the spray combustion characteristics in a cylinder of a D.I.diesel engine with the electronically controlled injector (전자제어식 직접분사 디젤 엔진 연소실내의 분무연소 특성에 관한 연구)

  • 정재우;김성중;이기형;선우명호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.2
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    • pp.50-56
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    • 2000
  • It is well known that the combustion phenomenon of diesel engine is an unsteady turbulent diffusion combustion. Therefore, the combustion performance of diesel engine is related to a complex phenomenon which involves the various factors of combustion, such as a injection pressure, injection timing, injection rate, and operation conditions of engine. In this study, the spray and the flame development processes in a single cylinder D.I. diesel visualization engine which uses the electronically controlled injection system were visualized to interpret the complicated combustion phenomenon by using high speed CCD camera. In addition, the cylinder pressure and heat release rate were also obtained in order to analyze the diesel combustion characteristics under several engine conditions.

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Water-Cooling System of HVDC System (HVDC 시스템의 수냉식 냉각 시스템)

  • 김찬기
    • The Transactions of the Korean Institute of Power Electronics
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    • v.4 no.3
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    • pp.257-267
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    • 1999
  • This paper deals with the water cooling system of HVDC(High Voltage Direct CUlTentJ. It is generally accepted that water is a veη effective medium to remove heat losses from any type of equipment. Because of this benefits the water cooling method is used in HVDC. The water cooling system consists of a heat exchanger, circulation pump and a connecting pipe. According to thYI1stor temperature level. thyristor junction temperature is controlled by controlling the f fan of exchanger. In this paper. the water cooling system of HVDC system is analyzed and estimated.

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Analysis of the Gravity Effect on the Distribution of Refrigerant Flow in a Multi-circuit Condenser (다분지 응축기의 냉매유량 분배에 미치는 중력의 영향을 고려한 해석방법)

  • Lee Jangho;Kim Moo Hwan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.12
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    • pp.1167-1174
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    • 2004
  • The method to consider gravity effect on the performance of a condenser is developed, and a simple condenser having 'nU' type two circuits is analyzed. Each circuit has the same length and inlet air-side operational conditions. The only difference between two circuits is the direction of refrigerant flow, which is exactly opposite each other between the upper 'n' type circuit and the lower 'U' type circuit. It is shown that the gravity makes the distribution of refrigerant flow uneven in the two circuits at lower refrigerant flow rates; heat transfer rate also becomes uneven. Moreover, much of the refrigerant exists as liquid state in the circuit having low refrigerant flow rate, which will make the cycle balance unstable in the refrigeration cycle system like a heat pump.