• Title/Summary/Keyword: Low Temperature Heat Source

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Simulation of HFC organic Rankine cycles for geothermal power generation (지열발전을 위한 HFC 유기랭킨 사이클의 시뮬레이션)

  • Baik, Young-Jin;Kim, Min-sung;Chang, Ki-Chang;Yoon, Hyung-Kee;Lee, Young-Soo;Ra, Ho-Sang
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.569-572
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    • 2009
  • In this study, HFC ORCs (Organic Rankine Cycles) are investigated for a low-temperature geothermal power generation by a simulation method. A steady-state simulation model is developed to analyze and optimize cycle's performance. The model contains a turbine, a pump, an expansion valve and heat exchangers. The turbine and pump are modelled by an isentropic efficiency. Simulations were carried out for the given heat source and sink inlet temperatures, and given flow rate that is based on the typical power plant thermal-capacitance-rate ratio. 3 HFC fluids are considered as a candidate for a working fluid of low-temperature ORCs. In this study, all optimized HFC ORCs are shown to yield almost the same performance in terms of power for a low-temperature heat source of about $100^{\circ}C$.

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Performance Analysis of Ammonia-Water Regenerative Rankine Cycles for Use of Low-Temperature Energy Source (저온 열원 활용을 위한 암모니아-물 재생 랭킨 사이클의 성능 해석)

  • Kim, Kyoung-Hoon;Han, Chul-Ho
    • Journal of the Korean Solar Energy Society
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    • v.31 no.1
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    • pp.15-22
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    • 2011
  • It is a great interest to convert more energy in the heat source into the power and to improve the efficiency of power generating processes. Since the efficiency of power generating processes becomes poorer as the temperature of the source decreases, to use an ammonia-water mixture instead of water as working fluid is a possible way to improve the efficiency of the system. In this work performance of ammonia-water regenerative Rankine cycle is investigated for the purpose of extracting maximum power from low-temperature waste heat in the form of sensible energy. Special attention is paid to the effect of system parameters such as mass fraction of ammonia and turbine inlet pressure on the characteristics of system. Results show that the power output increases with the mass fraction of ammonia in the mixture, however workable range of the mass fraction becomes narrower as turbine inlet pressure increases and is able to reach 16.5kW per unit mass flow rate of source air at $180^{\circ}C$.

Feasibility study on district heating Magok area by sewage water heat source (마곡지구 하수열에너지이용 타당성 검토)

  • Lee, Young-Soo
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.357-362
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    • 2009
  • As a unutilized energy, treated sewage water locates widespread near urban areas. From the previous survey, the sewage water is reported to hold energy potential up to 36,000 Tcal/year, which was 2.1% of the total domestic energy consumption and 9.7% of the energy usage in the household and business sector in 2006. Temperature of the sewage water differs locally, but its range is observed in a range of $20{\sim}25^{\circ}C$ in summer and $8{\sim}13^{\circ}C$ in winter. Since the temperature range of the sewage water has a better seasonal distribution about $5{\sim}10^{\circ}C$ compared to ambient air, it is a promising heat sink for summer or heat source for winter. The sewage water is also a high quality heat source from its abundant quantity and uniform temperature. Considering the ambient temperature of Korea is very low in winter, a heat pump system using the sewage water can be an alternative to prevent problems of capacity deficiency and frost formation.

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Comparative Performance Analysis of Ammonia-Water Rankine Cycle and Kalina Cycle for Recovery of Low-Temperature Heat Source (저온 열원 발전을 위한 암모니아-물 랭킨 사이클과 칼리나 사이클의 성능특성의 비교 해석)

  • KIM, KYOUNGHOON;BAE, YOOGEUN;JUNG, YOUNGGUAN;KIM, SEWOONG
    • Transactions of the Korean hydrogen and new energy society
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    • v.29 no.2
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    • pp.148-154
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    • 2018
  • This paper presents a comparative analysis of thermodynamic performance of ammonia-water Rankine cycles with and without regeneration and Kalina cycle for recovery of low-temperature heat source. Special attention is paid to the effect of system parameters such as ammonia mass fraction and turbine inlet pressure on the characteristics of the system. Results show that maximum net power can be obtained in the regenerative Rankine cycle for high turbine inlet pressures. However, Kalina cycle shows better net power and thermal efficiency for low turbine inlet pressures, and the optimum ammonia mass fractions of Kalina cycle are lower than Rankine cycles.

An Applicability Analysis of River Water Source Heat Pump System using EnergyPlus Simulation (에너지플러스 시뮬레이션을 통한 하천수 열원 히트펌프 시스템의 적용 가능성 분석)

  • Sohn, Byonghu
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.18 no.2
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    • pp.10-21
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    • 2022
  • A water source heat pump (WSHP) system is regarded as an energy-efficiency heating and cooling supply system for buildings due to its high energy efficiency and low greenhouse gas emissions. Recently, water sources such as river water, lake water, and raw water are attracting attention as heat sources for a heat pump system in Korea. This paper analyzed the applicability of a river water source heat pump system (RSHP). The river water temperature level was compared with the outdoor air and ground temperature levels to present applicability. In addition, the cooling and heating performance were compared through a simulation approach for the RSHP and a ground source heat pump (GSHP) applied to a large-scale office building. To compare the temperature level, the actual data were applied to the river water and the outdoor air, while the simulation results were applied to the ground circulation water. The results showed that the change in river water temperature throughout the year was similar to the change in outdoor air temperature. However, unlike the outdoor air temperature, the difference between the hourly and daily average river water temperatures was not large. The temperature level of river water was lower during the heating season and somewhat higher during the cooling season than that of the ground circulation water. Finally, the performance of the RSHP system was 13.4% lower than that of the GSHP system on an annual-based.

A Study on Performance Characteristics of A Single Effect LiBr/Water Refrigeration Cycle (단효용 LiBr/물 흡수식 냉동사이클의 성능특성에 관한 연구)

  • 연제문;임삼택;오주원;이경우
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2001.05a
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    • pp.95-99
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    • 2001
  • As a way to use energy effectively, the present study is aimed at investigating the performance characteristics of a Single Effect LiBr/Water Absorption Refrigerator using a low temperature driving heat-source. It was carried out by changing the driving heat-source temperature, the cold water outlet temperature(the refrigeration load), the cooling water inlet temperature, and the weak solution flow rate and this study compares the performance characteristics of refrigerator against the existence and non-existence of the Recirculation of the Weak solution which is used as a method to improve the performance of refrigerator. In case of Recirculation of the weak solution, more improved the Refrigeration Capacity and COP was obtained, and these effects became more larger in the high temperature of driving heat-source and large quantity of solution.

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Study on the Performance of Fuel Cell Driven Compound Source Heat Pump System to a Large Community Building (대형 Community 건물의 연료전지 구동 복합열원 하이브리드 히트펌프 시스템 성능에 관한 해석적 연구)

  • Jeong, Dong-Hwa;Byun, Jae-Ki;Choi, Young-Don;Cho, Sung-Hwan
    • New & Renewable Energy
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    • v.4 no.3
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    • pp.23-35
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    • 2008
  • In the present study, performances of fuel cell driven compound source hybrid heat pump system applied to a large community building are simulated. Among several renewable energy sources, ground, river, sea, and waste water sources are chosen as available alternative energies. The performance and energy cost are varied with the hybrid heat pump sources. The system design and operation process appropriate for the surrounding circumstance guarantee the high benefit of the heat pump system applied to a large community building. Th system is driven by fuel cell system instead of the late-night electricity due to the advantages of the low energy cost and waste heat with high temperature.

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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
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    • v.13 no.3
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    • pp.93-98
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    • 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.

A Study on the Monitoring Methods for Energy Production in Ground Source Heat Pump System (지열원 열펌프 시스템의 에너지 생산량 모니터링 신뢰도 향상 방안 연구)

  • Kang, Shin-Hyung;Lee, Kwang Ho;Do, Sung Lok;Choi, Jong Min
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.15 no.2
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    • pp.10-16
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    • 2019
  • In this study, the present regulation of heat metering for the ground source heat pump was investigated. The ground source heat pump has been adopting the heat metering system used in the district heating system for estimating the heating and cooling energy production amount. The accuracy of the present heat metering systems for a water to water ground source heat pump is low, because the system for district heating has a relatively high temperature range comparing with the ground source heat pump operating conditions. Even though the heat amount for the building side should be measured, the heat absorption and extraction amount from or to the ground was measured for the water to air ground source heat pump due to the difficulty of estimating the air side heating and cooling capacity in the present regulation. It is highly recommended to validate the heat metering system to have reliability for the ground source heat pump and develop the system to be applicable water to air ground source heat pump.

Heating Performance Analysis of Building Integrated Geothermal System (건물일체형 지열히트펌프시스템의 난방 성능 분석)

  • Jin, Shangzhen;Lee, Jin-Uk;Kim, Tae-Yeon;Leigh, Seung-Bok
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.206-210
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    • 2012
  • Ground source heat pump is a central heating and cooling system that pumps heat to or from the ground. Building Integrated Geothermal system used in this experiment is one of the Ground Source Heat Pump Systems which utilize energy pile. The purpose of this study is to evaluate heating performance of the system. The building is a low-energy experiment apartment in Yonsei University Songdo Campus and the subject is one of the energy reduced houses in this apartment. In the experiment, indoor temperature, outdoor temperature and the inlet and outlet temperature of ground heat exchanger and subject model, were measured. Then the heat pump's Coefficient of performance(COP) of the heat pump was calculated. As a result, the COP of heat pump is 4-5. Although the depth of the ground heat exchanger in this experiment is shallower than usual heat exchanger, the result of heating performance of this system was good as well.

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