• Title/Summary/Keyword: Heat recovery mode

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The Performance of a Simultaneous Heat and Cooling Heat Pump at Various Charging Conditions (동시냉난방 히트펌프의 냉매 충전량과 운전모드 변화에 따른 성능특성에 관한 연구)

  • Song, In-Sik;Choi, Jong-Min;Joo, Young-Ju;Chung, Hyun-Joon;Kang, Hoon;Kim, Yong-Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.7
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    • pp.492-499
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    • 2008
  • The cooling load in winter is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. The development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the performance of a multi-heat pump with 3-piping system was investigated as a function of refrigerant charge and its performance was analyzed in cooling mode, heating mode, and heat recovery mode. COP in the heating or cooling mode showed little dependence on refrigerant charge at overcharge conditions, while those were strongly dependent on refrigerant charge at undercharge conditions and outdoor inlet temperature. In the heat recovery mode, the performance of the system was very sensitive to charge amount at all conditions. Optimum charge amount in the heat recovery mode was 14% lower than that in the cooling mode at the standard condition because the refrigerant only passed the indoor units. It is required to store the excessive refrigerant charge in a storage tank to optimize the system performance at operating modes.

Experimental Study on the Performance of a Simultaneous Heating and Cooling Heat Pump in the Heat Recovery Mode (동시냉난방 열펌프의 전열회수 성능 특성에 관한 연구)

  • Choi, Jong-Min;Chung, Hyun-Joon;Joo, Young-Ju;Kang, Hoon;Kim, Yong-Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.11
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    • pp.718-726
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    • 2008
  • The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Hence, the development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the performance of a simultaneous heating and cooling heat pump was investigated in the heat recovery mode (HR mode). The system adopted a variable speed compressor using R410A with four indoor units and one outdoor unit. In the HR mode, the capacity and COP were improved as compared with those in the cooling or heating mode because the waste heat in the outdoor unit was utilized as useful heat in the indoor units. However, energy imbalance between heating and cooling capacity of each indoor unit was observed in the 2H-1C HR mode. Therefore, the performance of the system in the 2H-1C HR mode was enhanced by controlling refrigerant flow rate through the outdoor unit.

The performance of a heat pump with 3-piping system at various charging conditions (3관식 시스템 히트펌프의 충전량 변화에 따른 성능 특성에 관한 연구)

  • Song, In-Sik;Choi, Jong-Min;Joo, Young-Ju;Chung, Hyun-Joon;Kang, Hoon;Kim, Yong-Chan
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.288-293
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    • 2008
  • The cooling load in winter is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. The development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the performance of a multi-heat pump with 3-piping system was investigated as a function of refrigerant charge and its performance was analyzed in cooling mode, heating mode, and heat recovery mode. COP in the heating or cooling mode showed little dependence on refrigerant charge at overcharge conditions, while those were strongly dependent on refrigerant charge at undercharge conditions and outdoor inlet temperature. In the heat recovery mode, the performance of the system was very sensitive to charge amount at all conditions. Optimum charge amount in the heat recovery mode was 14% lower than that in the cooling mode at the standard condition because the refrigerant only passed the indoor units. It is required to store the excessive refrigerant charge in a storage tank to optimize the system performance at operating modes.

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An Experimental Study on Performance of Paper Heat Exchangers for Exhaust Heat Recovery Ventilation System (폐열회수 환기시스템에 사용된 종이 열교환기의 성능에 관한 실험적 연구)

  • Chung, Min-Ho;Oh, Byung-Kil
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.3
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    • pp.240-246
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    • 2012
  • The supply and use of exhaust heat recovery ventilation system as effective energy saving equipment has been increasing steadily. The exhaust heat recovery ventilation system can be installed at ceiling of balcony or emergency space. However, ventilation system can not be installed at emergency space because where have to remain as empty space by law. Therefore, the proper installation space of ventilation system is needed. In this study, to install heat recovery ventilation system in the light weight wall, thickness of heat exchanger was assembled below 140 mm. One or two paper heat exchangers were installed in the ventilation system. The efficiency of heat recovery was analyzed through performance experiment on case of cooling and heating mode.

An Experimental Study on Performance Improvement for Exhaust Heat Recovery Ventilation System in a Lightweight Wall (벽체매립형 폐열회수 환기시스템의 열회수 성능 향상에 관한 실험적 연구)

  • Chung, Min-Ho;Oh, Byung-Kil
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.2
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    • pp.61-66
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    • 2014
  • Exhaust heat recovery ventilation systems conserve energy through enthalpy recovery between air intake and exhaust, and they are being increasingly used. An exhaust heat recovery ventilation system can be installed in the ceiling of a balcony or emergency evacuation space. However, in the case of fire, the emergency evacuation space has to by law remain as empty space, and therefore, a ventilation system can't be installed in an emergency evacuation space. Therefore, the need for a proper installation space for a ventilation system is emphasized. In this study, to install a heat recovery ventilation system in a lightweight wall, a heat exchanger was assembled of thickness below 140 mm. The efficiency of heat recovery was analyzed through performance experiment, in the case of the cooling and heating mode. The heat recovery efficiency increases when the surface area is increased, by using closer channel spacing in the heat exchanger, or by increasing the size of the heat exchanger.

A Study on Operating Method by Energy Evaluation and Performance Evaluation of Heat Recovery Ventilator According to Outdoor Conditions (전열교환 환기시스템의 외기변화에 따른 성능평가 및 에너지평가를 통한 운전방안에 관한 연구)

  • Kim, Kwang-Hyun;Yee, Jurng-Jae
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.1
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    • pp.57-64
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    • 2008
  • Recently, regulation of ventilator installation and its details has been revised and the establishment of heat recovery ventilator in newly built apartments has been obligated. This study was done to offer the method of operation and design of heat recovery ventilator to save energy by measuring its efficiency and comparing with the results of experiment. This paper confirmed that it is desirable to operate heat recovery ventilator by using "by-pass mode" within $60{\sim}80%$ scope of the difference indoor absolute humidity in spring and autumn and outdoor absolute humidity and heat recovery ventilator of energy saving effect is better than constant air volume system.

A study on performance test of water heat storage type heat-pump system using cooling tower heat source (냉각탑을 이용한 축열식 히트펌프시스템의 성능측정에 관한 연구)

  • Lee, Sang-Hoon;Park, Hyo-Sik;Han, Woo-Yong;Kim, Uk-Jung
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1099-1104
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    • 2008
  • Recent year, mean energy consumptions of a people are higher than other country. And international oil price became over 120 dollar. This energy environment as well as energy war. Maybe, the Meteorological Administration is going to enforce scorching heatwave special report system from that come summer. Besides, 2008 summer, maximum demand power is expected by 64,240,000kW. The electric power equipment reserve rate appeared in to keep 12.5% level. Chilled water storage system witch is one of electric load administration system. Heat pump system used cooling tower heat recovery is advantage that use is possible to summer in small a public bath building. In this paper, we suggest that heat pump system by heat recovery using cooling tower when it is heating operation of ambient air temperature. To apply cooling tower heat recovery heat pump to chilled water heat storage type and achieved performance evaluation about operation. As a result, performance of heat pump system that about 121% in cooling mode, 138% in heating mode higher than KEPCO standard. And heating operation possible to ambient air temperature about $23^{\circ}C$, which of appear cooling tower outlet temperature about $13^{\circ}C$.

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Study on Performance Evaluation of Oscillating Heat Pipe Heat Exchanger for Low Temperature Waste Heat Recovery (저온 폐열 회수용 진동형 히트 파이프 열교환기의 성능 평가에 관한 연구)

  • 안영태;이욱현;김정훈;김종수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.5
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    • pp.368-376
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    • 2001
  • Performance of heat exchanger was evaluated to heat exchanger using oscillating heat pipe for waste heat recovery of low temperature. Oscillating heat pipe used in this study was formed to the closed loop of serpentine shapes using copper tubes. Heat exchanger was formed to shell and tube type and composed of low finned tube. R-22 and R-141b were used to the working fluids of tube side and their charging ratio was 40%. And, water was used to the working fluid of shell side. As the experimental parameters, the inlet temperature difference of heating and cooling part of secondary fluid and the mass velocity of secondary fluid were used. The mass velocity of secondary fluid was changed from 90 kg/$m^2s\; to\;190 kg/m^2$s from the experimental results, heat recovery rate was linearly increased to the increment of the mass velocity of secondary fluid and the inlet temperature difference of secondary fluid. Finally, the performance of heat exchanger was evaluated by using $\varepsilon$-NTU method. It was found that NTU was about 1.5 when effectiveness was decided to 80%.

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A Study on the Release Characteristics of VOCs from Heat Recovery Ventilation System (폐열회수형 환기장치의 휘발성유기화함물 배출 특성에 관한 연구)

  • Kwak, Kyung-Min;Bai, Cheol-Ho;Kim, Jee-Yong;Chu, Euy-Sung
    • Clean Technology
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    • v.13 no.4
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    • pp.281-286
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    • 2007
  • VOCs from the heat recovery ventilation system (total heat exchanger) are measured in this study. Two different types of element (L and M type) from heat recovery ventilating system are tested to study the intial release characteristics of VOCs under KS cooling and heating standard conditions. VOCs are measured for the various flow rates and different operating times. Considering errors in the test method and the measuring instrument, the tested heat recovery ventilating systems was found to release 6 major VOCs, such as acetic acid, 2-butanone (MEK), 2-(methylthio )ethylamine, toluene, styrene, and x-acids (Ion 57). The concentrations of released VOCs are not quite much affected by operating conditions. The results show much larger VOCs concentrations in the cooling mode than in the heating mode, due to the high operating temperatures.

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