• Title/Summary/Keyword: Sub-cooler

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Performance Characteristics of a Vapor Injection Heat Pump System with Different Sub-cooler Capacity (과냉각 열교환기 용량 변화에 따른 인젝션 히트펌프의 성능 특성)

  • Choi, Jong Min;Park, Yong-Jung;Kang, Shin-Hyung
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.10 no.3
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    • pp.17-23
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    • 2014
  • One major breakthrough in the field of heating, ventilation and air conditioning has been the development of heat pumps. Heat pump systems offer economic alternatives for recovering heat from different sources for use in various industrial, commercial and residential applications. In recent years, the heat pump has been tipped to have a very good potential for hot water production. This paper investigated the performance of a vapor injection heat pump with the variation of sub-cooler capacity at heating mode. The heating capacity of the vapor injection heat pump slightly increased with an increment of sub-cooler capacity, while COP didn't increase continuously. The 20% capacity of sub-cooler comparing with system capacity could be used as a standard to select sub-cooler capacity.

Cryogenic Systems for HTS Power Cables

  • Yeom, Han-Kil;Koh, Deuk-Yong;Lee, Bong-Kyu;Kim, Ig-Seang
    • Progress in Superconductivity and Cryogenics
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    • v.5 no.1
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    • pp.133-135
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    • 2003
  • Cryogenic systems are requirement for the operation of HTS power cables. In general, HTS power cables require temperature below 77K, a temperature that can be achieved from the liquid nitrogen at latm or sub-cooled LN2 above latm. HTS power cable needs sufficient refrigeration to overcome its low temperature heat loading. This loading typically cones in two forms : (1) heat leaks from the surroundings and (2) internal heat generation. This paper explains the cooling test system of 10m HTS power cable. This system is composed of storage dewar, auto fill system, core cryostat and cold-box. Storage dewar is a LN2 storage tank and auto fill system is a LN2 supply device to the sub-cooler, Core cryostat is a LN2 flow line. Cold box is a control unit of temperature and flow rate. It is composed of control valve, flow meter, sub-cooler and circulation pump, etc..

Heating Performance Characteristics of a Heat Pump with a Variable Speed Injection Scroll Compressor (인젝션형 가변속 스크롤 압축기를 적용한 히트펌프의 난방성능 특성에 관한 연구)

  • Ko, Suk-Bin;Heo, Jae-Hyeok;Cho, Il-Yong;Kim, Yong-Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.5
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    • pp.377-384
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    • 2012
  • Vapor injection technique has been applied to prevent performance degrdation of a heat pump at low ambient temperatures. In this study, the heating performance of a heat pump with a variable speed injection scroll compressor using R-410A was investigated by applying sub-cooler vapor injection(SCVI) and flash tank vapor injection(FTVI). The heating performance of the heat pump was measured by varying compressor frequency and outdoor temperature. The heating capacity of the FTVI system was 8~10% higher than that of the SCVI system at all operating conditions. On the other hand, the heating performance improvement with the increase in the compressor frequency was more prominent in the SCVI system than in the FTVI system.

Basic Study on Sub-cooling System using Ice storage tank (빙축열조를 이용한 냉매과냉각 시스템 기초연구)

  • Lee, Eun-Ji;Lee, Dong-Won;Kim, Yong-Chan
    • Proceedings of the SAREK Conference
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    • pp.990-995
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    • 2009
  • Experimental basic study was performed to understand the characteristics of sub-cooled refrigerant using a cold heat storage system. This system was made up general vapor-compression refrigeration cycle added sub-cooler and ice storage tank. The purpose of this study are to application use of cold-heat storage systems multiplicity of fields and to understand of sub-cooling system. At the condition using ice storage system, the ice making process was operated during night time by electric power. And then, the refrigerant was sub-cooled using stored cold-heat after being discharged from the air cooling condenser during the day time. Comparing the result at general operation with the operation using sub-cooling system. This study showed the effects of the sub-cooled degree. The cooling performance was increased owing to the sub-cooling of refrigerant during day time, and the compressor consume power was a little decreased. Thus the COP was also increased owing to the sub-cooling of refrigerant.

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