• Journal of the Korean Solar Energy Society
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• v.25 no.3
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• pp.1-9
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• 2005

The purpose of this paper was to analyze the influence of radiation and convection component separated from surface heat combined transfer coefficient on dynamic Heat load simulation. In general, it was not considered the mutual radiation of walls that heat load simulation calculated by surface combined heat transfer coefficient. In order to solve this problem, we had developed new simulation program to calculate radiation heat transfer and convection heat transfer respectively, and verified the influence of radiation component with this new program, in indoor heat transfer process.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.3
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• pp.130-142
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• 2018

We use heat pumps with thermal storage system to reduce peak usage of electric power during winters and summers. A heat pump stores thermal energy in a thermal storage tank during the night, to meet load requirements during the day. This system stabilizes the supply and demand of electric power; moreover by utilizing the inexpensive midnight electric power, thus making it cost effective. In this study, we propose a system wherein the thermal storage tank and heat pump are modeled using the TRNSYS, whereas the control simulations are performed by (i) conventional control methods (i.e., thermal storage priority method and heat pump priority method); (ii) region control method, which operates at the optimal part load ratio of the heat pump; (iii) load response control method, which minimizes operating cost responding to load; and (iv) dynamic programming method, which runs the system by following the minimum cost path. We observed that the electricity cost using the region control method, load response control approach, and dynamic programing method was lower compared to using conventional control techniques. According to the annual simulation results, the electricity cost utilizing the load response control method is 43% and 4.4% lower than those obtained by the conventional techniques. We can note that the result related to the power cost was similar to that obtained by the dynamic programming method based on the load prediction. We can, therefore, conclude that the load response control method turned out to be more advantageous when compared to the conventional techniques regarding power consumption and electricity costs.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1135-1144
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• 2024

With the increasing ratio of renewables in the grid, a low-carbon and stable base load source that also is capable of load tracking is in demand. Sodium cooled fast reactors (SFRs) coupled to thermal heat storage system (THS) is a strong candidate for the need. This research focuses on the designing and performance validation of a two-tank THS based on molten salt to integrate with a 280 MW_th sodium cooled fast reactor. Designing of the THS includes the vital component, sodium-to-salt heat exchanger which is a technology gap that needs to be filled, and designing and parameter selection of the tanks and related pumps. Modeling of the designed THS is conducted followed by the description of operation strategies and control logics of the THS. Finally, the dynamic simulation of the designed THS is conducted based on Fortran. Results show, the proposed power system meets the need of the design requirements to store heat for 18 h during a day and provide 500 MW_th for peak demand for the rest of the day.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.847-852
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• 2001

A thorough understanding of the transient behavior during load following and start-up is essential in the design and operation of an heat recovery steam generator(HRSG). During this period of time, material that is exposed to high temperature and experiences a large temperature variation is subject to high thermal stress. APESS(Advanced Plant Engineering & Simulation System) is a dynamic simulation software for power plant which is under being developed by Doosan Heavy Industries & Construction Co., Ltd. This paper present the introduction of APESS and the result of simulation for an heat recovery steam generator.

• KIEAE Journal
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• v.15 no.3
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• pp.57-63
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• 2015

Purpose: Ground source heat pump system has been attracted in the horticulture industry for the reduction of energy costs and the increasing of farm income. Even though it has higher initial costs, if it uses in combination with heat storage, it is able to reduce the initial costs and operate efficiently. In order to have significant effect of heat storage type ground source heat pump system, it is required to design the capacity considering various conditions such as energy load pattern and operating schedule. Method: In this study, we have designed heat storage type ground source heat pump system in 5 cases by the operating schedule, and examined the system to find the most economic and having superb performance regarding the system COP(Coefficient of Performance) and energy consumption, using dynamic energy simulation, TRNSYS 17. Result: Conventional ground source heat pump system has lower energy consumption than heat storage type, but following the result of LCC(Life Cycle Cost) analysis, the heat storage type was more economic due to the initial costs. In addition, it has the most efficient performance and energy costs in the case of the smallest heat storage time.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.869-872
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• 2008

On this study, the Control of Temperature is specified on the view of indoor comfort and building energy consumption. It is estimated by Dynamic heat load simulation which has the factors of insulation method and the soil thickness of the green roof system. The fact that the model which has no insulation has the greatest effect of dropping high temperature and the cooling load decrease is confirmed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.4 s.235
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• pp.477-484
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• 2005

Model fer the dynamic simulation of dynamic behaviors of a solid oxide fuel cell (SOFC) is provided. This model is based upon (1) coupled mass and heat transfer characteristics and (2) important chemical reactions such as electrochemical and reforming reactions in high temperature fuel cells such as SOFC. It is found that the thermal inertia of solid materials in SOFC plays an important role to the dynamic behavior of cell temperature. Dynamic characteristics of cell voltage, power, and chemical compositions with different levels of load change are investigated.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.873-876
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• 2008

The purpose of this study was to investigate Green Roof System's thermal performance using dynamic heat load simulation programs related to architectural environment. In results, it is found out that the thermal performance of Green Roof System is stabler than that of roof slab system which means that it is possible to create pleasant indoor environment and save the heating and cooling load.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.207-210
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• 2006

Behavior of dynamic/static recrystallization during hot deformation of Cast alloy 718 was investigated. For this purpose, hot compression test and FE-simulation were conducted via Thermecmaster-Z and DEFORM-3D, respectively. The microstructural evolution during hot compression and post heat-treatment was investigated and deformation mechanism were analyzed by stress-strain curve, FE-simulation and microstructure. FE-simulation results show that the temperature difference between top-die and billet has considerable influence on the final shape of compressed specimen. The relation between applied load and processing time was predicted by the FE-simulation.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1652-1657
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• 2004

Model for the dynamic simulation of dynamic behaviors of a solid oxide fuel cell (SOFC) is provided. This model is based upon (1) coupled mass and heat transfer characteristics and (2) important chemical reactions such as electrochemical and reforming reaction in high temperature fuel cells such as SOFC. It is found that the thermal inertia of solid materials in SOFC plays an important role to the dynamic behavior of cell temperature. Dynamic characteristics of cell voltage, power and chemical compositions with different levels of load changes are investigated.