• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4723-4728
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• 2014

In this study, a thermoelectric module (TEM) and a diesel engine were modeled using 1-D commercial software AMESim, and the performance of the TEM was evaluated when the engine was operated under the NEDC driving cycle. The goal of TEM modeling was to investigate not only the waste heat recovery (WHR) rate and energy converting efficiency, but also the heat transfer rate by taking the materials characteristics into account. In addition, a diesel oxidation catalyst (DOC) was designed, and it was found that the waste heat recovery with TEM affects the activation of DOC and alters engine exhaust composition. The simulation indicated that the WHR using TEM is beneficial for decreasing the fuel consumption of vehicles, but the reduction in the exhaust temperature affects the activation of DOC, resulting in an approximately 14% increase in CO and HC emissions. Therefore, the effect of waste heat recovery on the automotive emission characteristics must be considered in the development of automotive engine WHR systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1022-1026
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• 2013

Recently, the waste heat recovery technique using thermoelectric generator (TEG) in automotive engine has emerged to improve thermal efficiency in commercial vehicle. It is not difficult to recognize the numerous attempts that have been made to develop the TEG simulation model, but it is hard to find the model in conjunction with a particular heat engine system. In this study, 1-D commercial software AMESim was used to develop a computational model that can assess waste heat recovery from a diesel engine exhaust using TEG. The developed TEG simulation model can be used for evaluating the TEG performance of various types of TE module, and the diesel engine model can simulate any type of on and off-road diesel engines. The simulation results demonstrated that approximately 544.75W could be recovered from the engine exhaust and 40.4W could be directly converted into electricity using one TE module. The models developed in this study can be easily coupled with each other in the same computational program; thus, the models are expected to provide a viable tool for developing and optimizing a TEG waste heat recovery system in an automotive diesel engine.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.50-63
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• 2018

The issue of global warming and environmental pollutant has become an international concern due to the widespread use of fossil fuels, and thus waste heat recovery technologies has become important to improve energy utilization. The global market of power generation system using industrial waste heat is rapidly growing at an average rate of 5% due to its advantage of increasing energy efficiency. In order to design an optimal waste heat recovery system, it is necessary to develop a program that offers economic evaluation of each power generating technology according to the heat source conditions. In this paper, the economic analysis module to calculate LCOE is developed and verified the reliability against NETL economic analysis results. As a result of the verification, the error rate is about 6 ~ 7%, which satisfy the accuracy for business feasibility evaluation. In order to enhance the reliability, the module was improved by applying the levelization method used by NETL. As a result of the verification of reliability, the error rate is less than 1% and the accuracy is improved.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.5
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• pp.533-540
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• 2014

Recently, latent heat thermal energy storage system (LHTES) has gained attention in order to utilize middle temperature (373~573 K) waste heat from biomass gasification. This paper has investigated thermo-physical properties of erythritol [$CH_2OHCHOH$ $CHOHCH_2OH$], mannitol [$CH_2OH$ $(CHOH)_4CH_2OH$] and their compounds as phase change materials (PCMs). The differential scanning calorimetry (DSC) was applied to measure the melting point and latent heat of these PCMs. Also the melting and solidification characteristics of these PCMs were observed in a glass tube with a digital camera. In the DSC measurement, when the amount of mannitol content was more than 40 mass%, the melting point of these compounds show two melting points. The experimental results showed that the velocity of melting and solidification were different for every mixture ratio of compounds. These compounds had the super-cooling phenomenon during the solidification process.

• Journal of the Korean Solar Energy Society
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• v.33 no.6
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• pp.39-46
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• 2013

This work introduces a simple one-reactor adsorption desalination system that harnesses low temperature heat sources (solar energy, waste heat), which has been experimentally studied to elicit the most suitable design parameters and operating conditions. The design process of the system was divided into three parts to reflect the operating principle of desalination technology with application of adsorption processes. First, the evaporator for the vaporization of saline water was designed, then the reactor for the adsorption and release of the steam, followed by the condenser for condensation of the fresh water. The specific water yield is measured experimentally with respect to the time while controlling parameters such as heat source temperatures, coolant temperatures, system switching and half-cycle operational times. The present system well demonstrates the applicability of silica gel in relation to adsorption technologies that utilize low temperature heat sources ranging from 60 to $80^{\circ}C$, such as solar energy and waste heat.

• 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.14 no.4
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• pp.53-60
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• 2018

This study was conducted for analysis of a heat pump system using waste heat in an enclosed space such as a green house. The model was developed with mathematical equations in literature and Engineering Equation Solver (EES) was used to get the solution of the developed equations. The simulation results have 5% of reliability comparing the results with actual test data of heat pump system's dynamic operation. The operating performance of the system was calculated with variation of working fluid temperature in the thermal storage tank such as $25^{\circ}C$, $35^{\circ}C$, $45^{\circ}C$ and $55^{\circ}C$. As a result, the system's the highest total heating capacity shows 280 kWh and the storage tank's operating time decreased as the starting storage tank's temperature was high.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.22 no.1
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• pp.1-7
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• 2024

In this research, a detailed analysis of the decay heat contributions of both actinides and non-actinides (fission fragments) from spent nuclear fuel (SNF) was made after 50 GWd·tHM^-1 burnup of fresh uranium fuel with 4.5% enrichment lasted for 1,350 days. The calculations were made for a long storage period of 300 years divided into four sections 1, 10, 100, and 300 years so that we could study the decay heat and physical disposal ratios of radioactive waste in medium- and long-term storage periods. Fresh fuel burnup calculations were made using the code MCNP, while isotopic content and then decay heat were calculated using the built-in stiff equation solver in the MATLAB code. It is noted that only around 12 isotopes contribute more than 90% of the decay heat at all times. It is also noted that the contribution of actinides persists and is the dominant ether despite decreasing decay heat, while the effect of fission products decreases at a very rapid rate after about 40 years of storage.

• International Journal of Air-Conditioning and Refrigeration
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• v.6
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• pp.168-176
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• 1998

A simulation study was conducted to use city-water which is thermally regulated by unused energy as a heat source for urban dwellings. This study utilized multiple heat pump system using the city-water as a heat source and suggested a method of reducing the heat load of hot water supply. The simulation was done to calculate the energy savings at a dwelling for a year. The relation between the controlled temperature of city-water. and electric energy in all seasons was also investigated. Furthermore, it has been found that the controlled water system can lead to considerable energy savings and decrease environmental load such as sensible waste heat which otherwise would form heat islands.

• JOURNAL OF ELECTRICAL WORLD
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• no.11 s.119
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• pp.40-45
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• 1986