• Title/Summary/Keyword: Heat pump

Search Result 1,218, Processing Time 0.068 seconds

On-site Performance Test and Simulation of a 10 RT Air Source Heat Pump

  • Baik, Young-Jin;Chang, Young-Soo;Kim, Young-Il
    • International Journal of Air-Conditioning and Refrigeration
    • /
    • v.12 no.2
    • /
    • pp.61-69
    • /
    • 2004
  • In this study, on-site performance test of an air source heat pump which has a rated capacity of 10 RT is carried out. Since indoor and outdoor air conditions can not be controlled to satisfy the standard test conditions, experiments are done with the inlet air conditions as they exist. To estimate the performance of the heat pump for other conditions, the heat pump is modeled with a small number of characteristic parameters. The values of the parameters are determined from the few measurements measured on-site during steady operation. A simulation program is developed to calculate cooling capacity and power consumption at any other arbitrary operating conditions. The simulation results are in good agreement with the experiment. This study provides a method of an on-site performance diagnosis of an air source heat pump.

Optimization of Heat Pump Systems (열펌프의 성능 최적화에 관한 연구)

  • Choi, Jong-Min;Yun, Rin;Kim, Yong-Chan
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 2007.11a
    • /
    • pp.538-541
    • /
    • 2007
  • An expansion device plays an important role in optimizing the heat pumps by controlling refrigerant flow and balancing the system pressures. Conventional expansion devices are being gradually replaced with electronic expansion valves due to increasing focus on comfort, energy conservation, and application of a variable speed compressor. In addition, the amount of refrigerant charge in a heat pump is another primary parameter influencing system performance. In this study, the flow characteristics of the expansion devices are analyzed, and the effects of refrigerant charge amount on the performance of the heat pump are investigated at various operating conditions. Cooling capacity of the heat pump system is strongly dependent on load conditions. The heat pump system is very sensitive with a variation of refrigerant charge amount. But, the performance of it can be optimized by adjusting the flow rate through expansion device to maintain a constant superheat at all test conditions.

  • PDF

A Comparative Study of Heat Pump Drying System Performances (열펌프를 이용한 건조시스템의 성능비교 연구)

  • 김석광;이흥주
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.16 no.8
    • /
    • pp.1595-1602
    • /
    • 1992
  • An energy efficient drying system, utilizing a heat pump to recover the wasted heat with high efficiency is proposed. In conventional drying systems, over-heating occurs through a condenser as the same amount of air is provided into the evaportator and the condenser. In order to prevent the over-heating, part of the outlet air from the drying chamber must be bypassed to increase the rate of vaporization in the drying chamber without release of the heat from the system. Since a part of the heat in the condenser is used to heat the air during the drying process of the proposed system, a high drying efficiency and low SPC(Specific Power Consumption) could be obtained, Comparing the performances between the proposed heat pump and a conventional one, it was found that the drying efficiency of the proposed heat pump is higher than that of the conventional heat pump by an amount of 7-25%.

Drying Performance Simulation for the Basic Design of a Heat Pump Dryer (열펌프 건조기의 기본 설계를 위한 건조 성능 해석)

  • Lee, Kong-Roon;Kim, Ook-Joong
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.31 no.10
    • /
    • pp.860-867
    • /
    • 2007
  • Heat pump drying has a great potential for energy saving due to its high energy efficiency in comparison with conventional air drying. In the present study, the performance simulation for the basic design of a heat pump dryer has been carried out. The simulation includes one-stage heat pump cycle, simple drying process using the drying efficiency. As an example, the heat pump cycle with Refrigerant 134a has been investigated. For the operating conditions such as the average temperature of the condenser, the heat rate released in the condenser, the flow rate of drying air, and drying efficiency, the simulation has been carried out to figure out the performance of the dryer. The parameters considered in the design of the dryer are COP, MER, SMER, the rate of dehumidification, the temperature and humidity of drying air and those parameters are compared for different conditions after carrying out the simulation.

Performance Analysis of Heat Pump System for Greenhouse Cooling (온실 냉방을 위한 히트펌프의 성능 분석)

  • 윤용철;서원명;이석건
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.43 no.6
    • /
    • pp.120-126
    • /
    • 2001
  • This experiment was carried out to analyse on the cooling and dehumidifying effects of greenhouse by air-to-water heat pump system employing the air as cooling source. following results were obtained ; 1. The coefficients of performance (COP) of heat pump itself and total heat pump system were approximately 2.71~2.88 and 1.99~2.22, respectively. 2. The night-time cooling load of experimental greenhouse was 64.9 MJ/h, and the heat absorbed (cooling load) from heat pump system was 816.3~1,004.6 MJ/day. 3. The dehumidified moisture amount from experimental greenhouse was 7.0~15.0 kg/h. 4. The night time temperature of experimental greenhouse cooled by heat pump system could be maintained 4~6$^{\circ}C$ lower than that of control greenhouse which was almost equal to outside air temperature.

  • PDF

Study on the Simulation of Heat Pump Heating and Cooling Systems to Resident Building (숙박업소 건물의 히트펌프 냉난방 시스템 적용을 위한 시뮬레이션 연구)

  • Choi, Young-Don;Han, Seong-Ho;Cho, Sung-Hwan;Kim, Ju-Sung;Um, Chul-Jun
    • Proceedings of the SAREK Conference
    • /
    • 2006.06a
    • /
    • pp.915-920
    • /
    • 2006
  • Recently available heat pump system by using air heat-source is not efficient. Because the mean temperature of korean winter season is low, economy of air heat-source heat pump descend, and COP is below 3.0. This paper was practiced the simulation on evaluation criteria for heat pump heating and cooling systems to resident building. As a result, heating and cooling composition heat pump system apply to the building needed to be provided heat source for 24 hours.

  • PDF

Analysis on Economic Feasibility of Electric Night Storage Heat Pump as a Substitution of a Heater (심야전기보일러 대체 Heat Pump의 경제성 분석)

  • JUNG, H.;JO, J.Y.;Lee, C.H.
    • Journal of the Korean Society of Mechanical Technology
    • /
    • v.13 no.3
    • /
    • pp.119-124
    • /
    • 2011
  • Electric night storage heater was introduced and disseminated for power grid balancing and efficient management of power generation facility. But fuel cost for heating has been increased rapidly while the cost of electricity increased slightly. This abnormal rate system caused peak load in winter at last. To solve this problem, application of an air source heat pump was suggested. In the study, the effect of replacing night heater by heat pump and the economics were analysed. In addition the expectation of prospect of heat pump penetration was simulated based on surveyed and investigated data. As a result, fund supporting as well as institutional backing was needed for effective propagation and return of investment.

The Performance Improvement of a Gas Injection Heat Pump with a Flash Tank (기액분리기를 적용한 가스 인젝션 히트펌프의 성능 향상에 관한 실험적 연구)

  • Son, Kilsoo;Kim, Dongwoo;Choi, Sungkyung;Kim, Yongchan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.29 no.6
    • /
    • pp.297-305
    • /
    • 2017
  • Air-source heat pumps are widely used in residential heating systems. However, the decrease in the capacity of the heat pump is unavoidable when operating at very low and high ambient temperatures. The vapor injection technique is considered a promising technology to overcome this problem. Recent research on vapor injection cycles have mainly adopted a scroll compressor with an internal heat exchanger at severe operating conditions. This study measured the COP and EER of a gas injection heat pump using a flash tank with an inverter-driven rotary compressor at severe operating conditions. Compared to non-injection heat pumps, the heating capacity and COP of the gas injection heat pump improved up to 15% and 2.9%, respectively, at outdoor temperatures of $-10^{\circ}C$ to $7^{\circ}C$. The cooling capacity of the gas injection heat pump was 11% higher than the non-injection heat pump at an outdoor temperature of $35^{\circ}C$. At the same time, the EER of the gas injection heat pump was similar to that of the non-injection heat pump.

Greenhouse Heating Characteristics of Heat Pump-Latent Heat Storage System (열펌프-잠열축열 시스템의 온실 난방 특성 연구)

  • 강연구;송현갑
    • Journal of Biosystems Engineering
    • /
    • v.25 no.5
    • /
    • pp.379-384
    • /
    • 2000
  • In order to use the natural thermal energy as much as possible for greenhouse heating, the air-air heat pump system involved PCM(phase change material) latent heat storage system was composed, and three types of greenhouse heating system(greenhouse system, greenhouse-PCM latent heat storage system, greenhouse-PCM latent heat storage-heat pump system) were recomposed from the greenhouse heating units to analyze the heating characteristics. The results could be concluded as follows; 1) In the greenhouse heated by the heat pump under the solar radiation of 406.39W/$m^2$, the maximum PCM temperature in the latent heat storage system was 24$^{\circ}C$ and the accumulated thermal energy stored in PCM mass of 816kg during the daytime was 100,320kJ. In the greenhouse without heat pump under the maximum solar radiation of 452.83W/$m^2$, the maximum PCM temperature in the latent heat storage system was 22$^{\circ}C$ and the accumulated thermal energy stored during the daytime was 52.250kJ. 2) In the greenhouse-PCM system without heat pump the heat stored in soil layers from the surface to 30cm of the soil depth was 450㎉/$m^2$. 3) In all of the greenhouse heating systems, the difference between the air temperature in greenhouse and the ambient temperature was about 20~23$^{\circ}C$ in the daytime. In the greenhouse without heat pump and PCM latent heat storage system the difference between the ambient temperature and the air temperature in the greenhouse was about 6~7$^{\circ}C$ in the nighttime, in the greenhouse with only PCM latent heat storage system the temperature difference about 7~13$^{\circ}C$ in the nighttime and in the greenhouse with the heat pump and PCM latent heat storage system about 9~14$^{\circ}C$ in the nighttime.

  • PDF

Performance Evaluation of a $CO_2$ Heat Pump System for Fuel Cell Vehicles (연료전지 자동차용 이산화탄소 열펌프 시스템의 성능평가)

  • Kim, Sung-Chul;Park, Jong-Chul;Kim, Min-Soo;Won, Jong-Phil
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.16 no.1
    • /
    • pp.37-44
    • /
    • 2008
  • The global warming potential (GWP) of $CO_2$ refrigerant is 1/1300 times lower than that of R134a. Furthermore, the size and weight of the automotive heat pump system can decrease because $CO_2$ operates at high pressure with significantly higher discharge temperature and larger temperature change. The presented $CO_2$ heat pump system was designed for both cooling and heating in fuel cell vehicles. In this study, the performance characteristics of the heat pump system were analyzed for heating, and results for performance were provided for operating conditions when using recovered heat from the stack coolant. The performance of the heat pump system with heater core was compared with that of the conventional heating system with heater core and that of the heat pump system without heater core, and thus the heat pump system with heater core showed the best performance among the selected heating systems. On the other hand, the heating performance of two different types of coolant/air heat pump systems with heater core was compared each other at various coolant inlet temperatures. Furthermore, to use exhausted thermal energy through the radiator, experiments were carried out by changing the arrangement of a radiator and an outdoor evaporator, and quantified the heating effectiveness.