• Title/Summary/Keyword: Heat pump

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Analytical Study on the Heating Performance Improvement of a CO2 Heat Pump Using Vapor Injection (가스인젝션을 적용한 이산화탄소 열펌프의 난방성능 향상에 관한 해석적 연구)

  • Jung, Jongho;Baek, Changhyun;Heo, Jaehyeok;Kim, Yongchan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.11
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    • pp.767-776
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    • 2012
  • In this study, a simulation model for a $CO_2$ heat pump using vapor injection was developed and validated. It was used to predict the improvement of the heating performance of the $CO_2$ heat pump at various operating conditions. The simulation results showed consistent results with the measured data. The heating performances of the vapor injection and non-injection heat pumps were compared by varying the outdoor temperature and compressor frequency. The heating capacity of the vapor injection heat pump was 40% higher than that of the non-injection heat pump at the outdoor temperature of $-8^{\circ}C$. The performance of the vapor injection heat pump was consistently higher than that of the non-injection heat pump even when the compressor frequency was reduced to 35 Hz at the outdoor temperature of $-3^{\circ}C$.

A Study on Optimal Operation of Summer Season Cooling System with Numbers of Heat Pumps (다수의 히트펌프로 구성된 냉난방시스템에서 하절기 히트펌프의 최적운전에 관한 연구)

  • Shin, Kwan-Woo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.55 no.1
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    • pp.35-40
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    • 2006
  • Heat-pump system has a special feature that provides heating operation in winter season and cooling operation in summer season with a single system. It also has a merit that absorbs and makes use of wastewater heat, terrestrial heat, and heat energy from the air. Because heat-pump system uses midnight electric power, it decreases power peak load and is very economical as a result. By using the property that energy source is converted to low temperature when losing the heat, high temperature energy source is used to provide heating water and low temperature energy source is used to provide cooling water simultaneously in summer season. This study made up a heat-pump system with 4 air heat sources and a water heat source and implemented the optimal operation algorithm that works with numbers of heat pumps to operate them efficiently. With the heat-pump system, we applied it to cooling and heating operation in summer season operation mode in a real building.

Cyclic performance of residential air-to-air unitary heat pump (주택용 열펌프의 단속운전성능)

  • Min, Man-Ki
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.12 no.4
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    • pp.219-226
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    • 1983
  • Cyclic heating performance of 3 ton air-to-air unitary heat pump installed in a residence in the Washington, D.C. area was determined by applying the bin method to field test result. Cyclic degradation coefficient Cn of heat pump may be expressed in terms of heating load factor HLF as the following : $$C_D=\frac{1-HLF^m}{1-HLF}$$ where $$C_D{\ge}m$$ The less is the value of exponent m, the better is, the performance of a heat pump, depending upon the heat pump design.

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Performance Characteristics of Water-to-Air Heat Pump under Partial Load Heating Operation (물-공기 히트펌프 시스템의 부분부하 난방운전 특성)

  • Cho, Yong;Lee, Nam Young;Kim, Yong Yeol;Kim, Dea Geun;Jung, Eung Tai
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.170.1-170.1
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    • 2010
  • Performance of water-to-air heat pump using raw water has been analyzed under part load heating operation in March, 2010. The water source heat pump of 30 RT was installed for 24 hours cooling and heating ventilation, and the gravity inflow water from Daechung dam is used as the heat source. The daily averaged water and air temperatures are $5.7^{\circ}C$ and $9.9^{\circ}C$ respectively, and the heat pump is operated under part load condition for 7.5 hours in 24 hours. The daily averaged heat pump COP calculated with heat transferred from the brine water is 2.49 and the monthly averaged COP is 2.25 in March. Based on the database of the California Energy Commission, the monthly averaged COPs of air source heat pumps installed in U.S.A. are 1.97 in March and 2.03 in April. Therefore it is confirmed again that the performance of the heat pump using raw water is better than that of air source heat pumps.

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Development of Heat Pump System for High Efficiency Engine Vehicle (고효율엔진 차량 히트펌프 시스템 개발)

  • Park, Byung-Duck;Won, Jong-Phil;Lee, Won-Suk
    • Journal of the Korean Society of Industry Convergence
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    • v.10 no.1
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    • pp.21-26
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    • 2007
  • As DDI or GDI engine discharges very low heat due to its high thermal efficiency, the heat source is not enough for heating the passenger compartment in cold climate condition. To remedy the heating problem, the conventional HFC-134a automotive air-conditioning system has been attempted to run as a heat pump mode. Futhermore, an auxiliary electric heater of new type was equipped to the heat pump air-conditioning loop as a new approach. Hence, a proto-type heat pump air conditioner has been made and tested to investigate the feasibility of the HFC-134a automobile air-conditioning system that could be worked as a heat pump. The experiment results showed that the sufficient heating capacity could be obtained by adding a heat pump with an new electric type auxiliary heater into the conventional heat core in low temperature condition.

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The Performance Test and the Feasibility Study for a Dual-Source Heat Pump System Using the Air and Ground Heat Source (공기 및 지열 이용 Dual-Source 히트펌프 시스템의 성능실험 및 경제성 분석)

  • Nam, Yujin;Chae, Ho-Byung
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.5
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    • pp.212-217
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    • 2014
  • Recently, the use of renewable energy has been increased due to growing concern on the energy-saving at buildings and the reduction of $CO_2$ emission. In the field of architecture, to reduce the energy consumption of heating, cooling and hot water supply, heat pump systems with renewable energy has been developed and used in various applications. However, there have been many of researches on the large-scale commercial heat pump systems, but the research and the field application of a compact heat pump system is rare. Therefore, in order to develop the compact heat pump for the small-scale residential building, this study conducted the performance test and feasibility study for a hybrid heat pump using the heat source of air, solar and ground. In the results of experiments through a trial product, the average COP of cooling mode with ground heat source was 4.75, and it of heating mode was 4.03. Furthermore, the average COP of cooling mode with air heat source was 2.60, and it of heating mode was 2.92. Finally, payback period of the system was calculated as 9.2 years.

Temperature monitoring and seasonal borehole heat exchange rate characteristics of a geothermal heat pump system (지열 히트펌프 시스템의 계절별 지중 열교환 특성 및 지반내 온도 변화)

  • Shim, Byoung-Ohan
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.452-455
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    • 2007
  • The geothermal heat pump system is designed for cooling and heating for three stories building (2,435 $m^2$) includes total 79 heat pumps. Therefore, the monitoring system is installed for each floor and the data is automatically transmitted to the monitoring system. Heat exchange rate and temperature of a geothermal heat pump system have been monitored for a long period. The seasonal operation of geothermal heat pump shows the different shape of heat exchange rate for cooling and heating. Ground water flow can influence on heat exchange rate and thermal storage of the system. In order to define the hydraulic characteristics and groundwater temperature variation, the relationships among air temperatures, groundwater temperatures, water table, and precipitation are analysed.

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An Experimental Study on the Part-Load Performance of a River Water Source 2-Stage Heat Pump (하천수 열원 2단 압축 열펌프시스템의 부분부하 운전특성에 관한 실험적 연구)

  • Kim, Ji-Young;Baik, Young-Jin;Lee, Young-Soo;Ra, Ho-Sang
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.1964-1968
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    • 2007
  • The river water heat source heat pump has the advantage in the performance compared to air source heat pump. Although its better performance, the large temperature difference between load and source makes system performance worse by nature. In this study, 2-stage compression is considered as the solution of this problem. Generally, heat pump is designed for maximum capacity rate, but it actually operates at part load condition in many cases. Therefore, an information on the part-load character is very important in view of the system overall performance. In this study, part-load performance tests of a R134a 2-stage compression heat pump were carried out over the river water and supply heating water temperature changes. The experimental results show that the system performance is influenced by the part load rates, river water temperature, load temperature, etc.

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Performance Evaluation of Open-Loop Ground Water Heat Pump system (개방형 지열히트펌프 시스템의 성능평가)

  • Kim, Tae-Won
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.11a
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    • pp.9-14
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    • 2006
  • Open loop or ground water heat pump systems are the oldest of ground-source systems. Standing column wells can be used as highly efficient ground heat exchanger in geo-thermal heat pump systems, where hydrological and geological conditions are suitable. These systems require some careful considerations for well design, ground water flow, heat exchanger selection etc This paper describes 9round water temperature variations, performances in heat ins and cool ing mode and the results of ground water analysis.

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Development of Heating Technology for Greenhouse by Use of Ground Filtration Water Source Heat Pump (여과수열원 히트펌프를 이용한 온실난방기술 개발)

  • Moon, J.P.;Lee, S.H.;Kang, Y.K.;Lee, S.J.;Kim, K.W.
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.172.2-172.2
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    • 2010
  • This study was carried out in order to reduce the installation expense of heating system for greenhouse comparing to geothermal heat pump and develope the coefficient of performance (COP) for a heat pump. For getting plenty of heat flux from geothermal energy. Surface water in river channel was used for getting a lots of geothermal heat by penetrating water through underground soil layer of the river bank that make heat transmission to passing water. The range of water temperature after the process of Ground filtration is 13~18 degrees celsius which is very similar to low heat source of geothermal heat pump system and the plenty amount of heat source from that make the number of geothermal heat exchanging hole and the expense for geothermal heat exchanger construction reduced. Drainage well is also used for returning filtration water to the aquifer that keep the water good recirculation from losing geothermal heat and water resource. For the COP improvement of Heat pump, thermal storage tank with separating insulation plate according to the temperature difference make the COP of Heat pump that is similar to thermal storage tank with diffuser. Developed thermal storage tank make construction expense cheaper than customarily used one's. and that sand filter and oxidation sand (FELOX) are going to be used for improving ground filtration water quality that make heat exchanger efficiency better. All above developed component skill are going to be set on the Ground filtration water source heat pump system and applied for medium, large scale for protected greenhouse in riverside area and on-site experiment is going to do for optimizing the heating system function and overcome the problem happening in the process of on-site application afterward.

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