• Journal of Hydrogen and New Energy
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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.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.201-204
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• 2015

Recently, energy excessive consumption and environmental pollution are the social issued. The most efficient way to solve both energy excessive consumption and environmental pollution is existing combustion system improved. This study was part of the assume and commercial used existing waste heat recovery condensing boiler to low emission performance for exhaust gas recirculation(EGR) and thermal efficiency rise by applying the condensed water recirculation(CWR) conducted. The researchers applied the EGR and CWR develop a new concept for the condensed water recirculation waste heat recovery condensing boiler. Waste heat recovery condensing boiler applied to the condensed water recirculation thermal efficiency of the same conditions was increased by about 4.8~5.5% and pollution emission also decreased.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.15 no.1
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• pp.97-104
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• 1986

This is to supply the basic data for saving energy and the appropriate way of waste disposal. The amount of waste disposed and its heat after burning is guessed to get conclusions. 1. The amount of disposable waste in 1990 in Seoul area is expected to be 2.2kg per man/day, coal ashes (YONTAN) 0.7kg, non-coal ashes 1.5kg. 2. The amount of waste combustible and heat after burning will be increased, and it is useful when the waste has Less than $70\%$ of water. 3. The method to collect waste should be specially organized, because most of the waste collected In Korea Is wet. 4. As the heat emitted from mass burning is $4\times10^{12}kcal/y$ in 1985, it is considered to be in senses of energy saving and the rationnal way of waste disposal. 5. Special concern is needed because the environment contaminated will be polluted in result of burning.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.2100-2108
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• 1991

A hear transfer model was developed to calculate the temperature distribution in the rotary kiln incinerator of municipal solid waste. The thermo-gravimetric characteristics of waste and the gas-to-waste heat transfer coefficient were determined by comparing the experimental results and model prediction. With this, heat transfer rates by existing heat transfer mechanisms were calculated to be compared each other. The effects of treatment capacity, calorific value of waste, and flow rate and temperature of combustion air on the temperature distribution in the rotary kiln incinerator were predicted by the model developed in this work.

• International Journal of Air-Conditioning and Refrigeration
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• v.9 no.3
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• pp.27-35
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• 2001

Heat transfer characteristics of a heat exchanged for low temperature waste heat recovery using oscillating capillary tube heat pipe (OCHP) were evaluated against the charging ratio variation of working fluid and various working fluids. R-l42b, R-22 and R-290 were used as working a 2.6mm in outside diameter, 1.44mm in inside diameter with 101m length and 140 turns. Charging ratio of working fluid was 40% and 50%. water was used as secondary fluid. Inlet temperature and mass velocity for each secondary fluid were 297 K, 280 K and 9~27 $4kg/m^2s$, respectively. From experimental results, it was found that heat transfer performance of R-22 was higher than those of R-142b and R-290 and it was proportional to Figure of Merit for thermosyphon. As a result, it was thought that R-22 was the most reasonable working fluid of waste heat recovery for low temperature waste heat recovery.

• Journal of Hydrogen and New Energy
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• v.23 no.3
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• pp.236-242
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• 2012

This study has been carried out the experiment for the possibility of biogas reforming using waste heat. The source of this waste heat is the exhaust gas from a small-sized gas engine generator. For recovering the waste heat, Two-stage heat exchanger is manufactured. The two-stage heat exchanger is composed of a heat exchanger for the exhaust gas and a heat exchanger for the water. This two-stage heat exchanger is used for reforming the biogas by means of on-site hydrogen production at the small-sized gas engine generator. The two-stage heat exchanger is coupled with the biogas reformer which is a kind of catalytic reformer. To confirm a heat recovery efficiency of the two-stage heat exchanger, temperature differences of inlet and outlet locations are measured. Also, the variations of syngas concentrations with various biogas flow rates are investigated. As a result using manufactured two-stage heat exchanger, the biogas can be reformed from waste heat recovery. This experiment suggests that the exhaust gas heat exchanger is available for reforming the biogas.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1171-1178
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• 1992

An experiment was performed to describe the heat and mass transfer occurring between hot waste gas and cold water through direct contact in a direct contact heat exchanger. This model was then used to obtain an equation of overall heat transfer coefficent based on heat exchanger volume. The diffusion heat transfer rate is 2-3 times larger than the convection heat transfer rate as results of condensation of the water vapor contained in the waste gas. The boiler efficiency increases over 10%.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.6
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• pp.685-691
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• 2005

In this study, high performance waste heat recovery heat exchanger was developed using the bayonet tube with spiral serrated fins. Especially, heat exchanger of the bayonet tube type was operated well because of double water passes mechanism and characteristics. A cooling water Passes down inner tubes to thimble-form tubes, then flows back up as it boils. The heat exchanger of bayonet tube type was composed of steel tube with 7channels$(I.D_1\;14mm.\;I.D_2\;31.6mm)$ and spiral serrated fins. The performance tests were conducted under the following conditions A cooling water flow rate was 273kg/h and engine l·pm was varied from 750rpm to 3500 rpm. From the experimental result. waste heat recovery was 9.21kW when engine rpm was 3500. and pressure drop was $15\~260mmHg/m^3$ The effectiveness of heat exchanger was about /$0.7\~0.9$. The performance of heat exchanger was evaluated by using the $\varepsilon-NTU$ method. In the study the NTU of the heat exchanger was $1.57\~2.33$.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.3
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• pp.639-646
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• 2014

A heat exchanger using two-phase loop thermosyphons was developed as a waste heat recovery system. An experimental study was carried out on the heat transfer characteristics of two-phase loop thermosyphons heat exchanger and the results from the experiments were used to see the possibility which the two-phase loop thermosyphons could be an alternate solution for waste heat recovery system. In the present work, R134a has been used as the working fluid and the filling rate do working fluid and heat flux have been used as the experimental parameters. The results show that the filling rate of working fluid and heat flux are very important factors for the operation of two-phase loop thermosyphons. The experimental results showed the provisional results as a waste heat recovery system.

• Journal of the Korea Institute of Building Construction
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• v.5 no.1 s.15
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• pp.123-129
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• 2005

This study is as a part of the new disposal and recycling plans of heat-resource waste of Daegu dyeing industrial center we tried to examine applicable possibility of crushed thing(waste aggregate) as aggregates for mortar and concrete. To examine applicable possibility of waste aggregate as a lightweight-aggregate for concrete and mortar, we carried this study by mainly property examination of concrete according to replacement ratio of waste aggregate. We carried slump, unit weight, compressive strength and bending strength test according to replacement ratio of waste aggregate. As the result of that, if we use waste aggregate, lightweight of concrete and mortar will be possible. Specially it shows a strength improvement effect of cement hardening according to using this so it is judged that applicable possibility as aggregate for concrete and mortar is very excellent.