• 제목/요약/키워드: Heat pump water heater

검색결과 60건 처리시간 0.024초

심야전력을 이용한 Cascade Heat Pump Cycle의 운전결과 분석 (Analysis on Cascade Cycle Heat Pump Application as Night Storage Heater)

  • 정훈;황성욱;이철희
    • 한국기계기술학회지
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    • 제13권1호
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    • pp.113-118
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    • 2011
  • To analyze and verify the effect of replacing thermal storage heater by a cascade cycle heat pump using midnight electricity was installed and tested at a customer's house in Wonju, Korea. The electric night storage heater is consist of 30kW electric heater and 2,700 liters of thermal storage water tank to supply hot water for warming house floor. The power for electric heater was cut off and hot water was only generated by cascade cycle heat pump. Current thermal storage water tank was not eliminated and electric heater wiring was modified. Some operation logic of the heat pump was also modified for proper operation. The required capacity of the heat pump and hot water temperature for given warming condition were estimated. The estimated capacity of heat pump was about 19kW and estimated hot water temperature for proper heating was at least $75^{\circ}C$.

열펌프 가열식 온수기의 동적특성 해석 (Numerical Simulation on Dynamic Characteristics of a Water Heater System Driven by a Heat Pump)

  • 김민성;김민수;백남춘
    • 설비공학논문집
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    • 제14권1호
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    • pp.10-20
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    • 2002
  • A dynamic model of a water heater system heated by a heat pump was developed. The water heater system was composed of heat pump and hot water reservoirs. Finite volume method (FVM) was applied to describe the heat exchangers. A new constraint on electronic expansion valve (EEV) or thermostatic expansion valve (TXV) that can control superheat after the evaporator was developed. Dynamic performances were evaluated for various sizes of the reservoir. In order to compare those performances, time scale was normalized by time constant representing the characteristics of reservoir size. Time constant was determined from quasi steady-state simulation of the system. From the simulation, the size of the water heater reservoir was found to have a large influence on the transient performance of the sys- tem. Therefore, the optimization of the reservoir size is needed in a design process.

저온 외기조건에서 케스케이드 급탕열펌프의 성능특성에 관한 해석적 연구 (Numerical Study of the Performance Characteristics of a Cascade Heat Pump Water Heater at Low Ambient Temperatures)

  • 송재현;정해원;박재우;강훈;김용찬
    • 설비공학논문집
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    • 제25권5호
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    • pp.225-232
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    • 2013
  • Heat pump systems have been widely adopted in buildings for cooling and heating, due to their higher energy efficiency. Recently, the demand for hot water supply from the heat pump system has been increasing. To increase the water supply temperature with higher system efficiency and reliability, a heat pump water heater adopting cascade cycle was investigated in this study. The cascade heat pump water heater consisted of a low-stage cycle using R410A, and a high-stage cycle using R134a. A simulation program for the cascade heat pump water heater was developed, and verified by comparison with experimental data. The performance of the cascade heat pump water heater was optimized, by varying the compressor rotating speeds of the low- and high-stage cycles. At low ambient temperatures, the performance of the cascade cycle was compared with that of the single-stage cycle. The system efficiency of the cascade cycle was higher than that of the single-stage cycle, showing a lower compression ratio and compressor discharge temperature.

히트펌프 온수기 개발을 위한 계측 및 성능평가시스템 구축 (Development of Measurement and Performance Testing System for Heat Pump water Heater)

  • 권성철;양승권
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 D
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    • pp.2310-2312
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    • 2004
  • In Korea Electric Power Corporation (or KEPCO), several Demand-Side Management (or DSM) program have been carried out to effectively meet electric power demand at least costs by modifying customers electricity use patterns. As one of them, KEPCO applies low-priced night thermal-storage power service for heat appliances to facilitate efficient use of power facilities by shifting relatively high daytime demands to night hours to build loads during the off-peak periods. In the market of heat-storage type water-heater, electric water-heater has been mostly used, but it has low energy efficiency and needs high capacity electric equipments. So in order to replace these electric water heaters, 15 HP air-source heat pump water heater is developed in Korea Electric Research Institute (or KEPRI). This paper shows that measurement system for performance testing of heat pump water heater is established and heating capacity and performance is analyzed and measured for out-door environmental change.

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2단 응축 히트펌프 온수시스템의 사이클 해석 및 성능분석 (Performance of Heat Pump Water Heater with Dual Condenser)

  • 유영선;김영중;강금춘;백이;윤진하;강연구;이형모
    • Journal of Biosystems Engineering
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    • 제31권5호
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    • pp.423-429
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    • 2006
  • The heat pump water heater developed in this research consisted of one evaporator, one compressor, 1st condenser, 2nd condenser, one expansion valve, one water tank, one recirculation circuit and etc. The performance of heat pump water heater was tested and analyzed. The quantities of output water changed linearly from 2380 to $660{\ell}/h$, and the output water temperature changed curvedly from 29.9 to $44.5^{\circ}C$ when the opening rate of recirculation valve changed from 0 to 100%. The COP of heat pump water heater increased from 3.0 to 3.8 when the quantities of output water changed from 660 to $2380{\ell}/h$. When the temperature distributions of water tank were measured during 50 minutes after turning on the heat pump, the temperature stratification by the level appeared apparently. When the inlet water temperature changed from 30 to$50^{\circ}C$, the output energy of heat pump hardly changed. The surface area of double pipe heat exchanger changed from 0.429 to $6.254m^2$ when the compressor capacity increased from 1.0 to 50.0 PS.

열펌프 온수기의 부하 대응 축열조 제어에 관한 연구 (A Study on Control Method of Thermal Storage Tank for Varying Thermal Load in Heat Pump Water Heater)

  • 남현규;배철호
    • 설비공학논문집
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    • 제24권4호
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    • pp.330-335
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    • 2012
  • A characteristic behavior of the thermal storage tank for varying thermal load in heat pump water heater was studied. The control method was suggested and applied. By measuring the temperature within the storage tank, the heat pump was ON/OFF controlled. The appropriate measuring position and the size of heat exchanger gives the minimized power consumption of heat pump. As the length of heat exchanger increases, the temperature measuring position goes down of the storage tank and the power consumption increases.

전기히터식 및 지열원 히트펌프식 농산물 열풍건조기의 에너지 성능 비교 (Energy Performance Comparison of Electric Heater and Geothermal Source Heat Pump type Agricultural Hot Air Dryers)

  • 양원석;김영일;박승태
    • 한국지열·수열에너지학회논문집
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    • 제14권4호
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    • pp.7-12
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    • 2018
  • Energy performance of electric heater and geothermal source heat pump type hot air dryers are compared in this study. For set temperatures of $30^{\circ}C$, $35^{\circ}C$ and $40^{\circ}C$, radish is dried from initial mass 60 kg until it gets 5 kg, where the difference equals the amount of water removed. As set temperature is increased, drying time is shortened for both electric heater and heat pump types, however energy efficiency is decreased due to increasing electricity consumption. Moisture extraction rate(MER) of electric heater is 2.58~2.84 kg/h, and for heat pump type 2.56~2.71 kg/h, showing little difference between the two types. Specific moisture extraction rate (SMER) of electric heater is 0.94~0.96 kg/kWh, and for heat pump type 1.72~2.21 kg/kWh. SMER of heat pump type is greater by 0.78~1.25 kg/kWh than the electric heater hot air dryer, which is 1.8~2.3 times better in terms of energy efficiency.

태양열과 재열기를 사용한 VI heat pump의 성능 특성에 관한 연구 (Heating Performance Characteristics of Heat Pump with VI cycle using Re-Heater and Solar-Assisted)

  • 이진국;최광환
    • 한국태양에너지학회 논문집
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    • 제35권6호
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    • pp.25-33
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    • 2015
  • In this study, heating performance of the air-cooled heat pump with vapor-injection (VI) cycles, re-heater and solar heat storage tank was investigated experimentally. Devices used in the experiment were comprised of a VI compressor, re-heater, economizer, variable evaporator, flat-plate solar collector for hot water, thermal storage tank, etc. As working fluid, refrigerant R410A for heat pump and propylene glycol (PG) for solar collector were used. In this experiment, heating performance was compared by three cycles, A, B and C. In case of Cycle B, heat exchange was conducted between VI suction refrigerant and inlet refrigerant of condenser by re-heater (Re-heater in Fig. 3, No. 3) (Cycle B), and Cycle A was not use re-heater on the same operating conditions. In case of Cycle C, outlet refrigerant from evaporator go to thermal storage tank for getting a thermal energy from solar thermal storage tank while re-heater also used. As a result, Cycle C reached the target temperature of water in a shorter time than Cycle B and Cycle A. In addition, it was founded that, as for the coefficient of heating performance($COP_h$), the performance in Cycle C was improved by 13.6% higher than the performance of Cycle B shown the average $COP_h$ of 3.0 and by 18.9% higher than the performance of Cycle A shown the average $COP_h$ of 2.86. From this results, It was confirmed that the performance of heat pump system with refrigerant re-heater and VI cycle can be improved by applying solar thermal energy as an auxiliary heat source.

이산화탄소 급탕 열펌프의 운전조건에 따른 성능 특성에 관한 실험적 연구 (Experimental Study on the Performance of a CO2 Heat Pump Water Heater under Various Operating Conditions)

  • 손동진;백창현;허재혁;강훈;김용찬
    • 설비공학논문집
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    • 제23권4호
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    • pp.273-280
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    • 2011
  • In this study, the steady state performance of a $CO_2$ heat pump water heater was measured with a variation of operating conditions such as refrigerant charge amount, compressor frequency, EEV opening, and water mass flow rate. Transient state performance tests were also conducted to investigate major system effects associated with the interaction between the $CO_2$ heat pump water heater and the water tank. Optimum refrigerant charge amount for the system was 1600 g. At compressor frequencies of 50 Hz and 60 Hz, water mass flow rates of 95 kg/h and 105 kg/h, and EEV opening of 8% and 16%, the water heating temperatures were $65^{\circ}C$ and $68^{\circ}C$ and COPs were 3.0 and 2.8, respectively. In the transient condition, the instantaneous COP decreased with an increase in the inlet water temperature.

태양열 온수기 시스템에 적용된 기포펌프의 성능평가에 대한 연구 (A Study on Performance Analysis of the Bubble Pump in Solar Water Heater System)

  • 이광성;이설송;김진화;정효민;정한식
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2310-2315
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    • 2008
  • In this paper, study on performance analysis of bubble pump on the domestic solar water heater system is presented. Device of this experiment is consisted of bubble pump, solar collector and heat exchanger. At the mean time, this system have attached temperature sensors and pressure sensors at bubble pump. In addition, the flow meter was installed at outlet of heat exchanger. And then result of experimental study, average value of the heat exchange amount in heat exchanger was about 7.9kcal/hr, the maximum value of the heat amount in water tank($0.4m^3$) was 489.7kcal/hr and the maximum value of the mass flow rate in bubble pump was about $0.5{\ell}/min$.

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