• Clean Technology
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• v.3 no.1
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• pp.82-87
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• 1997

A resorption heat pump for energy recovery leas been investigated using methanol-glycerine. The calculation of the theoretical thermal efficiency for the resorption heat pump was carried out based on the thermodynamic properties of this working pair over various operating conditions for each part of the system. More than 40% of the thermal efficiency can be obtained by raising industrial waste heats ($60{\sim}70^{\circ}C$) by $40^{\circ}C$ using the resorption heat pump cycle.

• Solar Energy
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• v.18 no.3
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• pp.169-175
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• 1998

Metal hydrides can be used for the purpose of heat storage and transportation from the industrial complex which own recoverable waste heats to the neighboring cities by the medium of hydrogen. The properties of metal hydrides, some problems of heat transportation using metal hydrides, and the example of heat transportation system were discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.69-75
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• 2019

The cooling performance of heat pump system for light-duty commercial electric vehicle was evaluated experimentally. The cooling performance characteristics of the heat pump for light-duty commercial electric vehicles were evaluated by varying the temperature, flow rate of chiller coolant, and electric compressor speed, under the exterior air temperature of 35 ℃ and interior air temperature of 25 ℃. Increasing the compressor speeds decreased the cooling system efficiency by 16.4 % on average with the cooling capacity increasing by 8.0 % on average and the compressor work increasing by 27% on average. To use waste heat from the coolant to chill power electronic components, such as the motor and inverter, a chiller was installed to transfer heat between the coolant and refrigerant. Increasing the temperature of the chiller coolant from 35 ℃ to 55 ℃ decreased the efficiency by 18.2 % on average due to higher condensing heat source. Increasing the coolant flow rate from 10 liter/min to 20 liter/min did not affect the cooling capacity of the system due to a similar total condensing heat transfer rate at the chiller and the exterior heat exchanger. In future works, heating performance will be investigated by varying the operating conditions to use the chiller's waste heat with an improvement of heating capacity.

• 한국전산유체공학회:학술대회논문집
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• 2002.10a
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• pp.133-138
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• 2002

A 3-D axisymmetric computer program is developed to predict the NO behavior in SNCR system for the stoker incinerator with the waste treatment capacity, 200ton/day. To this end a turbulent reacting flow field calculation is made using proper assumption and empiricism. The stoker bed is assumed to be a homogeneous waste-volatilized gaseous state. The initial composition or reactants are assumed based on the data of the ultimate analysis. Turbulent is resolved by k-e model and turbulent reaction is handled by eddy-breakup model harmonized with empirical chemistry data for gaseous combustion, NO and urea reaction. The liquid droplet is traced by Lagrangian method incorporated by aerodynamic drag, Coriolis and crntrifugal forces. Radiation is treated by sensible heat loss model. Calculation results are in good agreement with experimental data at the outlet of post combustion chamber in Daejon 4th industrial complex. The flue gas shows the temperature range of $900\sim1000^{\circ}C$, velocity of 5m/s and NO concentration of 140ppm at the exit while the measured temperature, flue gas velocity and NO concentration are $967^{\circ}C$, $3\sim4m/s$ and $100\sim200ppm$respectively. Using the developed computer program a parametric study has been made with the variation of heat content of waste, castable length and SNCR variables for the determination of proper injector location. In general, the calculated results are consistent and physically acceptable.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.573-577
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• 2013

Heat pumps come into wide use because high energy efficiency can be obtained and diverse heat sources like geothermal heat, waste heat and air are available. It is necessary for an air source heat pump to defrost in order to remove frost on the surfaces of an outdoor heat exchanger. It is impossible for continuous heating if reverse cycle operation is used as defrosting method, furthermore it causes the degradation of COP. In this study an fin-tube heat exchanger with three rows was used as an outdoor coil. One row among three rows of the heat exchanger was used like a condenser in order to remove frost on it, the others were used as evaporator to accomplish continuous heating. Each row was switched in order from a condenser to an evaporator in specified time interval. Tests were carried out during minimum 180 minutes at the defrost-heating test condition(dry bulb temperature $2^{\circ}C$, wet bulb temperature $1^{\circ}C$) described in KS C 9306. Time-averaged COP was about 20% higher than that of conventional defrosting method.

• Clean Technology
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• v.23 no.3
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• pp.223-236
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• 2017

As the use of waste and biomass increases in a power generation boiler, high temperature corrosion (HTC) problems of boiler heat exchangers are becoming very important. Chlorine of the low-rank fuels is mainly responsible for the HTC issues, which typically occur in the surface of high temperature heat exchanger like a superheater or reheater. In order to mitigate the problem, various approaches have been proposed in terms of design modification, material improvement, fuel pre-treatment and additive utilization. In this study, the current state of research and development focused on the additive method was investigated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.2
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• pp.120-125
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• 2011

As an effort to secure economically viable heat recovery units, innovative fin shapes for industrial boilers are studied for better performance. In the present study a numerical modeling for the analysis of heat exchanger performance is conducted using a commercial software, ANSYS CFX and the results are compared with the experimental data. Out of several candidate fin shapes curved wavy fin is selected for the present study. Both numerical and experimental data are directly compared for heat transfer rate and pressure drop with the assumed constant surface temperature of $60^{\circ}C$. Exhaust gas is obtained from a test apparatus which supplies variable flow rates. The numerical results show reasonable agreements with the experimental data within 10% in terms of both total heat transfer and pressure loss.

• 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.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.5
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• pp.452-459
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• 2010

This study is aimed to investigate changes of combustion characteristics and heat efficiency when syngas from gasification process using low-rank fuel such as waste and/or biomass is applied partially to an industrial boiler. An experimental study on syngas co-combustion was performed in a 0.7 MW (1 ton steam/hr) water tube boiler using heavy oil as a main fuel. Three kinds of syngas were used as an alternative fuel: mixture gas of pure carbon monoxide and hydrogen, syngas of low calorific value generated from an air-blown gasification process, and syngas of high calorific value produced from an oxygen-blown gasification process. Effects of co-combustion ratio (0~20%) for each syngas on flue gas composition were investigated through syngas injection through the nozzles installed in the side wall of the boiler and measuring $O_2$, $CO_2$, CO and NOx concentrations in the flue gas. When syngas co-combustion was applied, injected syngas was observed to be burned completely and NOx concentration was decreased because nitrogen-containing-heavy oil was partially replaced by the syngas. However, heat efficiency of the boiler was observed to be decreased due to inert compounds in the syngas and the more significant decrease was found when syngas of lower calorific value was used. However, the decrease of the efficiency was under 10% of the heat replacement by syngas.

• Journal of Power System Engineering
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• v.20 no.1
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• pp.11-17
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• 2016

In this study, the simulation for performance comparison between basic single stage organic rankine cycle, multi stage reheater cycle and multi stage reheater & recuperator cycle was carried out. The multi stage reheater cycle and multi stage reheater & recuperator cycle was designed to improve the efficiency for organic rankine cycle using heat source from industrial waste heat and heat sink from deep ocean water. R245fa was selected as a refrigerant for the cycle and system efficiencies were simulated by the variation of the heat sink temperature and the cycle classification. Performance characteristics were simulated by using the Aspen HYSYS. It was confirmed that the system efficiency was decreased by the increase of heat sink temperature. These results can be considered to be applied as geo-ocean thermal energy conversion in where plenty of geothermal or ocean thermal resource exist.