• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.33 no.3
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• pp.50-57
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• 2004

This article reviews absorption cooling R＆D in Europe from the viewpoint of fundamentals, cycle development and applications. The review contains information on R＆D, predominantly of public projects in the field of sorption cooling. We report on research which is performed in Europe with some stress on Germany. There is progress in fundamentals, thermodynamic cycle design, and also applications. In the fundamentals part the discussion about thermodynamics, working pairs, and heat and mass transfer is reflected. Today's discussion on thermodynamic cycles is not very strong. Main focus is on special solid sorption cycles, compression­sorption hybrids, and open cycles, In the applications part the chilling business is the main issue. Some interest is given to the improvement of efficiency on and the adaptation to low temperature waste heat use, but the stress is on the use of solar energy as heat source. The area of heat pumping for heating purposes is less prominent but not at all negligible. Finally, industrial heat pumping involves the reverse cycle (heat transformer, heat pump type Ⅱ) also, but there is no significant activity.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.20 no.2
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• pp.24-36
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• 2024

This study analyzed the feasibility of the air source heat pump in residential buildings based on operational performance and carbon emissions. The operational performance and carbon emissions were compared between a gas boiler and an air source heat pump by calculating the annual heating and hot water load based on the 21A and 36A models for actual residential buildings. For the operational performance of the air source heat pump, the lowest (2.3) and highest COP (5.9) were attained during the winter and summer seasons, respectively. The carbon emissions depend on the amount of energy consumed during operations. An air source heat pump consumed 65.10% and 65.4% less energy per year in the 21A and 36A models, respectively compared to the existing gas boiler. Consequently, for air source heat pump carbon emissions were also reduced by 13.3% and 15.1% per year for the 21A and 36A models, respectively. It shows the effectiveness of applying an air source heat pump compared to an existing gas boiler.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.833-837
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• 2008

GSHP(Ground Source Heat Pump) has been extensively disseminated due to the recent increasing demand over new and renewable energy. In this study, the operating performance of rain water and ground source heat pump system (RW-GSHP) was compared with GSHP during the heating test. Leaving load temperature(LLT) was $50^{\circ}C$, $53^{\circ}C$, $56^{\circ}C$, respectively and rain water tank temperature(RWT) was $13^{\circ}C$, $15^{\circ}C$, $17^{\circ}C$ in this heating test. The experiment was focused on comparison of the system operating performance depending on leaving load temperature (LLT) and rain water tank temperature (RWT). The results showed that rain water and ground source heat pump system (RW-GSHP) was higher heating performance and COPh than those of GSHP.

• Journal of Energy Engineering
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• v.15 no.4 s.48
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• pp.284-290
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• 2006

The improvement of energy recovery is mandatory to decrease consumption of fossil fuels and to minimize negative impacts on the environment which originates from large cooling and heating demand. The absorption heat pump technology has a large potential for energy saving in this respect. Absorption heat pump is a means to upgrade waste heat without addition of extra thermal energy. In this study, resorption heat pump for energy recovery has been investigated using methanol-glycerine. The simulated calculation of theoretical thermal efficiency was performed based on the thermodynamic properties of the working fluid over various operating conditions. The thermal efficiency of higher than 0.4 was obtained by raising industrial waste heat, $70{\sim}80^{\circ}C$, by $40^{\circ}C$ in this system.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.2
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• pp.9-15
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• 2012

The objective of this study is to investigate the influence on the heating performance for a water-to-water 10RT ground source heat pump by using the water switching and refrigerant switching method. The test of water-to-water ground source heat pump was measured by varying the compressor speed, load side inlet temperature, and ground heat source side temperature. The heating capacity and COP of the heat pump increased with increasing ground heat source temperature. As a result, compared to a refrigerant switching method, the water switching method with counter flow improves the heating capacity and COP by approximately 5% in average, respectively.

• Solar Energy
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• v.20 no.3
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• pp.61-73
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• 2000

Heat losses from receivers for a dish-type solar energy collecting system are numerically investigated. The analytical method for predicting conductive heat loss from a cavity receiver is used. The Stine and McDonald Model is used to estimate convective heat loss. Two kinds of techniques for the radiation analysis are used. The Net Radiation Method that is based on the radiation heat balance on the surface is used to calculate the radiation heat transfer rate from the inside surface of the cavity receiver to the environment. The Monte-Carlo Method that is the statistical approach is adopted to predict the radiation heat transfer rate from the reflector to the receiver. Based on the heat loss analysis, the performance of two different receivers for multifaceted parabolic solar collectors with several flat facets can be estimated, and the optimal facet size is obtained.

• The Korea Energy Engineers Association Reports
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• no.68
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• pp.1-20
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• 2007

지부소식/이달의 ISSUE/서울지부 운영위원, 이판욱 기관장/귀뚜라미그룹 김규원 총괄사장/2007 대한민국 에너지대전/제8회 ESCO Mart 성료/ZOOM IN/보일러 Q&A/

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.1
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• pp.64-70
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• 2015

Organic Rankine cycle (ORC) is an useful cycle for power generation system with low temperature heat sources ($80{\sim}400^{\circ}C$). Since the boiling point of operating fluid is low, the system is used to recover the low temperature heat source of waste heat energy. In this study, a ORC with R134a is applied to recover the waste energy of condenser of coal fired power plant. A system model is developed via Thermolib$^{(R)}$ under Simulink/MATLAB environment. The model is composed of a refrigerant heat exchanger for heat recovery from coal fired condenser, a drum, turbine, heat exchanger for ORC heat rejection, storage tank, water recirculation pump and water drip pump. System analysis parameters were heat recovery capacity, type of refrigerants, and types of turbines. The simulation model is used to analyze the heat recovery capacity of ORC power system. As a result, increasing the overall heat transfer coefficient to become the largest of turbine power is the most economical.

• Journal of computational fluids engineering
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• v.21 no.1
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• pp.19-29
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• 2016

A Prototype Gen-IV Sodium-cooled Fast Reactor which is one of the $4^{th}$ generation nuclear reactors is in development by Korea Atomic Energy Research Institute. The reactor is composed of four main fluid systems which are categorized by its functions, i.e., Primary Heat Transport System, Intermediate Heat Transport System, Decay Heat Removal System and Sodium-Water Reaction Pressure Relief System. The coolant of the reactor is liquid sodium and sodium-to-sodium heat exchangers are installed at the interfaces between two fluid systems, Intermediate Heat Exchangers between the Primary Heat Transport System and the Intermediate Heat Transport System and Decay Heat Exchangers between the Primary Heat Transport System and the Decay Heat Removal System. For the design and performance analysis of the Intermediate Heat Exchanger and the Decay Heat Exchanger, a computer code was written during previous step of research. In this work, the computer code named "SHXSA" has been validated preliminarily by computational fluid dynamics simulations.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.782-787
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• 2008

The Kalina cycle simulation study was carried out for a preliminary design of a geothermal power generation system. The Kalina cycle system can be used for the utilization of a low-temperature heat sources such as geothermal and industrial waste heat that are not hot enough to produce steam. The sea/river water can be considered as a cooling media. A steady-state simulation model was developed to analyze and optimize its performance. The model contains a turbine, a pump, an expansion valve and heat exchangers. The turbine and pump were modelled by an isentropic efficiency, while a condenser, an evaporator and a regenerative heat exchanger were modeled by UA-LMTD method with a counter-flow assumption. The simulation results show that the power generation efficiency over 10% is expected when a heat source and sink inlet temperatures are $100^{\circ}C$ and $10^{\circ}C$ respectively.