• Title/Summary/Keyword: Heat pump

Search Result 1,218, Processing Time 0.088 seconds

Performance Enhancement of the Heat Pump Using the Refrigerant Subcooling System (냉매 과냉각 시스템을 이용한 열펌프의 성능향상에 관한 연구)

  • 손창효;윤찬일;박승준;이동건;오후규
    • Proceedings of the Korean Society of Marine Engineers Conference
    • /
    • 2001.05a
    • /
    • pp.106-111
    • /
    • 2001
  • The performance characteristics of heat pump system using the new refrigerant subcooling system were investigated. The new heat pump system has the ice storage tank to accumulate the latent heat of the refrigerant during the night-time. The heat is released to subcool the saturated refrigerant liquid at the outlet of a condenser in the daytime. The experimental apparatus is a well-instrumented heat pump which consisted of a refrigerant loop and a coolant loop. The test sections(condenser and evaporator) were made of tube-in-tube heat exchanger with the horizontal copper tube of 12.7[mm] outer diameter and 9.5[mm] inner diameter. The evaporating temperatures ranged from $-5[^{\circ}C]$ to $0[^{\circ}C]$ and the subcooling degrees of the refrigerant varied from $15[^{\circ}C]$ to $25[^{\circ}C]$. The test of the ice storage was carried out at evaporating temperature of $-10[^{\circ}C]$ and the ice storage mode is an ice-on-coil type. The main results were summarized as follows ; The refrigerant mass flow rate and compressor shaft power of the heat pump system were independent of the subcooling degrees. The cooling capacity o the heat pump system increases as the evaporating temperature and subcooling degree increases. The cooling capacity of the heat pump system is about 25 to 30% higher than that of normal heat pump system. The COP of the heat pump system which subcooled the refrigerant liquid at the outlet of the condenser is about 28% higher than that of the normal heat pump system.

  • PDF

A study on the part-load performance of 2-stage water source heat pump (2단 압축 수열원 열펌프 시스템의 부분부하 운전특성에 관한 연구)

  • Lee, Young-Soo;Baik, Young-Jin
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
    • /
    • v.5 no.1
    • /
    • pp.13-17
    • /
    • 2009
  • The river water heat source heat pump has the advantage in the performance compared to air source heat pump. In this study, an experimental study on a 2-stage heat pump, which is designed to utilize a river water heat source, were carried out. Generally, a heat pump is designed for maximum capacity rate, but it actually operates at part load condition in most cases. Therefore, an information on the part-load characteristic 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.

  • PDF

Study on the Performance Characteristics of the Solar Hybrid System with Heat Pump Operating Temperature during Winter Season (겨울철 열펌프 작동온도에 따른 태양열 하이브리드 시스템의 성능특성에 관한 연구)

  • Kim, Won-Seok;Cho, Hong-Hyun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.22 no.12
    • /
    • pp.821-827
    • /
    • 2010
  • Study on the performance characteristics of the solar hybrid system with heat pump operating temperature during winter season has performed by using an experimental test. The system performance and operating characteristics with the heat pump operating temperature, hour and load condition were investigated and analyzed. As a result, the hot water temperature was significantly affected by the heat pump operating temperature at the morning(time 1) and noon(time 2). However, hot water temperature was set by the radiation quality and collecting operation hour at the afternoon(time 3). In addition to the solar fraction was decreased for the high heat pump operating temperature because the heat pump operated with a long operating time and short operating period.

Effect of the Heat Exchange between Low and High Temperature Refrigerant on the Heat Pump Performance (저온측과 고온측 냉매간 열교환이 열펌프의 성능특성에 미치는 영향)

  • 이건중;송현갑
    • Journal of Biosystems Engineering
    • /
    • v.24 no.4
    • /
    • pp.343-350
    • /
    • 1999
  • The ambient air is commonly used as low-temperature heat source for heat pump operation. However, the coefficient of performance(COP) of the air to water heat pump is decreased with the ambient air temperature drop. In this study to solve this problem, the AVACTHE(Automatic Variable Area Capillary Type Heat Exchanger) with 3 levels of heat exchange area(0, 1,495.4, 1,794.5$\textrm{cm}^2$)was installed in the refrigerant circuit of the heat pump. The AVACTHE effect on the performance of heat pump was tested with the ambient air temperature variation. The COP improvement of the heat pump could be achieved by the AVACTHE installation when below -5$^{\circ}C$ of the ambient air temperature.

  • PDF

Performance Characteristics of R134a Supercritical Heat Pump (R134a 냉매용 초임계 히트펌프의 성능 특성)

  • Choi, In-Soo
    • Journal of Power System Engineering
    • /
    • v.18 no.4
    • /
    • pp.60-65
    • /
    • 2014
  • In this paper, cycle performance analysis for heating capacity, compression work and COP of R134a supercritical heat pump is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include superheating degree, pressure and outlet temperature of gas cooler, compressor efficiency and evaporating temperature in the R134a supercritical heat pump system. The main results were summarized as follows : Superheating degree, pressure and outlet temperature of gas cooler, compressor efficiency and evaporating temperature of R134a heat pump system have an effect on the heating capacity, compression work and COP of this system. With a thorough grasp of these effect, it is necessary to design the supercritical heat pump using R134a. The prediction for COP of R134a supercritical heat pump have been proposed through multiple regression analysis.

Simulation for High Efficient Heat Pump System using Seawater Heat Source and Exhaust Energy (해수 열원 및 폐열 이용 고성능 열펌프 시스템 모사)

  • 최광일;오종택;오후규
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.15 no.1
    • /
    • pp.59-66
    • /
    • 2003
  • The purpose of this study is to analyze the characteristics (COP) of the heat pump system for various operating conditions with the use of seawater heat source and exhaust energy. To accomplish the goal, first of all, the computer simulation for heat pump system is carried out. The heat pump system model is made of a waste heat recovery system and a vapor compression refrigeration system, and the working fluid is R-22. The model calculated the change of COP with the variation of temperature and flow rate. The COP and the plate heat exchanger (PHE) area of the heat pump system are considered moderately high in the condensation temperature of $25^{\circ}^C$ and the evaporation temperature of $2^{\circ}^C$ in indoor culture system. The simulation results will be used effectively for the design and the performance prediction of heat pump system using unused energy in a land base aquaculture system.

LCC Analysis of a Heat Pump System Using River Water (하천수 열원 이용 열펌프 시스템의 LCC 분석)

  • Han, Sang-Soo;Park, Cha-Sik;Kim, Yong-Chan
    • Proceedings of the SAREK Conference
    • /
    • 2009.06a
    • /
    • pp.1424-1428
    • /
    • 2009
  • The performance of a heat pump using river water as a heat source was compared with that of a conventional air-conditioner for cooling and a boiler system for heating. The heat pump system using river water considered the 1-stage cycle for cooling and the 2-stage cycle for heating. The COPs of the river water source heat pump were $0.5{\sim}1.1$ higher than those of the conventional system in the cooling season. The LCC of the river water source heat pump system was lower 13.5% and 32.4% than that of the conventional system I and II. In addition, when the initial cost ratios of the river water source heat pump system to the conventional system I and II were less than 1.2 and 1.4, respectively, an acceptable payback was found to be less than 5 years.

  • PDF

Exergy Analysis of On/Off Controlled Heat Pump

  • Jang, Ki-Tae;Nam, Kwan-Woo;Jeong, Sang-Kwon
    • International Journal of Air-Conditioning and Refrigeration
    • /
    • v.7
    • /
    • pp.22-32
    • /
    • 1999
  • A multi-type heat pump controls the mass flow rate of the working fluid to cope with variable heat loads when it is under dynamic load condition. This paper describes the exergy analysis associated with the unsteady response of a heat pump. First, a basic heat pump cycle is examined at a steady state to show the general trends of exergy variations in each process of the cycle. Entropy generation issue for the heat exchangers is discussed to optimize the heat pump cycle. Secondly, the performance of the inverter-driven heat pump is compared to that of the conventional one when the heat load is variable. Thirdly, the exergy destruction rate of the heat pump with On/Off operation is calculated by simulating the thermodynamic states of the working fluid in the condenser and the evaporator. The inefficiency of On/Off operation during the transient period is quantitatively described by the exergy analysis.

  • PDF

Performance Evaluation of Air Source Multi Heat Pump Floor Heating System in Apartment (공동주택 공기열 멀티 히트펌프의 바닥난방 성능 평가)

  • LEE, C.H.;Nah, H.S.;JUNG, H.;Kim, K.S.
    • Journal of the Korean Society of Mechanical Technology
    • /
    • v.13 no.3
    • /
    • pp.93-98
    • /
    • 2011
  • To analyze and evaluate the performance of developing air to water multi heat pump, the heat pump was installed and tested at low energy house in Daejeon, korea. Heating capacity of heat pump is 16.5KW and cooling capacity is 14.0KW. Space heating/cooling, floor heating and hot water is available. The results performance evaluation of heat pump in lab test showed that the coefficient of performance (cop) was 3.75, and heating capacity was 16.0KW in ambient temperature $7^{\circ}C$. Also at ambient temperature $-15^{\circ}C$, the COP was 1.69. At a low energy house, floor heating is controled by a floor heating water temperature and a room temperature. The COP of heat pump is decreased with frequent on/off operation for controlling of floor heating water temperature.

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
    • /
    • v.12 no.4
    • /
    • pp.219-226
    • /
    • 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.

  • PDF