• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.10
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• pp.515-529
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• 2017

EnergyPlus, which is widely used in various fields, provides Simple Window Model, a window model that can be used practically. However, the results of building load using the model are different from those of the standard model. The main cause of the deviation by Simple Window Model was analyzed to be due to the assumption that all windows were considered as single layer. The purpose of this study is to propose a window model that improves the cause of deviation by Simple Window Model and can be easily calculated from the algebraic relations. The proposed window model solved the heat balance equation algebraically by using seven window characteristic coefficients. The coefficient relationships consisted of the heat transmission coefficient and solar heat gain coefficient as input parameters make practical use and calculation possible. As a result of comparing the deviation between each window model by implementing the dynamic analysis method, the proposed window model showed that the deviation of the total heating/cooling energy consumption was reduced to 1/3 compared to Simple Window Model for one year. Although the maximum energy consumption did not show any significant improvement, the indoor temperature evaluation showed significantly reduced deviation.

• The KSFM Journal of Fluid Machinery
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• v.5 no.4 s.17
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• pp.26-31
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• 2002

The heat produced by the fission in the fuel of HANARO, 30 MW of research reactor, was transferred from the primary cooling water to the secondary cooling water through heat exchangers. The secondary cooling water absorbing the heat was circulated by secondary cooling pumps and cooled through 33 MW of cooling tower. Each capacity of the three secondary cooling pumps was fifty percent ($50\%$) of full load. The two pumps were normally operated and the other pump was standby. One of the secondary cooling pumps has often made troubles by high vibration. To release these troubles the pump shaft has been re-aligned, the pump bearing has been replaced with new one, the shaft sleeve has been replaced with new one, the shaft and the impeller have been re-balanced representatively and/or the vibration of motor has been tested by disconnecting the shaft of pump. But the high vibration of pump cannot be cleared. We find out the weight balance trouble of the assembly in which the impeller is installed in the shaft. After clearing the trouble, the high vibration is relieved and the pump is operated smoothly. In this paper, the trouble solution shooting method of secondary cooling pump is described including the reason of high vibration

• Journal of Oriental Neuropsychiatry
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• v.16 no.2
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• pp.125-133
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• 2005

Object : This paper is designed to inquire into the influence of eating habits on the emotion of modem people. Method : The methodology is used that searches for materials such as books and treatises on the relationship between eating habits and emotion. Result : Meat used for fast food comes from cows that are fed the feed containing growth hormone and antibiotic. Growth hormone extremely supplements fire or yang within the body while antibiotics undermines the process of yin, leading to an accumulation of damp-heat and inflammation of ministerial fire. Additives contained in instant foods also impinge on the process of yin, leading to poor digestion, damp-heat toxins and ministerial fire. Excessive consumption of meat results in incomplete combustion of fat and hinders the formation of essence. Subsequently, ministerial fire becomes hyperactive as a result of the lack of yin energy. Increased meat consumption in the human diet is coupled with unhealthy eating pattern in which people eat too much for dinner and too quickly. Eating too much disturbs digestion, making it slow and incomplete, leading to excess damp-heat conditions, insufficient amount of vital essence and eventually hyperactive ministerial fire. Milk is considered a catalyst of faster growth, making it suitable for calves. Milk intake rapidly increases the balance of yang and eventually cause hyperactivity of ministerial fire. Conclusion : It is estimated that the eating habits of modern people cause the process of yang, making them feel restless, impatient and aggressive.

• KIEAE Journal
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• v.16 no.2
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• pp.33-41
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• 2016

Purpose: The window energy rating system was developed in early 1990's and various kind of rating system has been implemented in advanced country such as Europe, Australia, Canada and the US since 2000. In Korea, the Energy Consumption Efficiency Rating Indication System has been implemented to promote supply of high efficiency window since July 2012. Normally, the window energy rating system based on heat balance which considers both thermal losses and solar heat gain is used and applied only to residential buildings. However, the system used nationally only considers thermal losses and is applied to every building regardless of its usage. Therefore, in this study, we indicated problems of domestic window energy rating system and looked for improvements. Method: We analyzed thermal performance of various windows through dynamic simulation applied to detached house and compared results with those of domestic and foreign rating system. Result : Thermal performance of south windows is more affected by SHGC than U-value, and that of north windows is also affected by SHGC a lot. The difference between the results of our study and current system is statistically significant. As a result, appropriate evaluation criteria which considers solar heat gain is required.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.2
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• pp.209-218
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• 2002

The temperature field of a counterflow non-premixed flame is investigated using thermocouples of two sizes. A thermal balance is performed on the thermocouple in order to calculate the magnitude of the radiation corrections involved. Both the thermocouple wire and bead are separately considered to be the relevant thermal surface to which convective heat transfer takes place, and from which radiation lasses occur. The flame is also simulated by using a detailed chemical kinetic mechanism in a previously developed computer code. The local thermo-physical properties of the gas mixture, required to calculate the corrections, are determined both from the simulation, and by approximating the properties of the mixture as those of molecular nitrogen at the measured temperatures. It is concluded that the thermocouple wire is the appropriate thermal surface to which radiation corrections apply, in the absence of information about the gas mixture, its properties can be reasonably approximated by those of nitrogen rm ($N_2$), and the radiation corrections are very sensitive to misalignments in the temperature and velocity fields.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.4
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• pp.307-312
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• 2003

Joining thin aluminum alloy is difficult using most welding techniques. Many of problems associated burn-through by the high heat input. Common welding techniques are TIG, MIG, and MIG-PULSE welding. The VP-GMAW provides more control of the heat balance in the welding arc by taking advantage of the different arc characteristics obtained with each of the two polarities. In this paper, we proposed new VP-GMAW method by control DSP 320C32, and the characteristic and experiment result-voltage, current, welding bead, penetration by this method are presented.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2173-2187
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• 2022

A 3D thermo-elasto-hydrodynamic model is developed to analyze the sealing performance of a notched mechanical seal applied in the reactor coolant pump. In the model, the generalized Reynolds equation, the energy equation coupled with notch heat balance equation, the heat conduction equations, and the deformation equations of the sealing rings are iteratively solved by the finite element method. The film pressure and temperature distribution are obtained, and the deformation of the sealing rings is revealed to study the mechanism of the notched mechanical seals. A parameterized study is conducted to analyze the sealing performance under different operating conditions. As a comparison, the sealing performance of non-notched seals is also studied. The results show that the hydrostatic effect is dominant in the load-carrying capacity of the fluid film due to the radial mechanical and thermal deformations. The notch can cool the fluid film and influence the thermal deformation of seal rings. The sealing performance is sensitive to the pressure difference, ambient temperature, and rotational speed. It is suggested to set the notches on the softer sealing rings to acquire the greater hydrodynamic effect. Compared with the non-notched, the notched end face holds a better lubrication performance, especially under lower rotational speed.

• Korean Journal of Remote Sensing
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• v.11 no.1
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• pp.65-80
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• 1995

Remote Sensing data with ancillary ground-based meteorological data provides the capalility of computing threeof the four surface energy balance components(i.e. net radiation, soil heat flux and sensible heat flux) at different spatial and temporal scales. As a result, this enablis the estimation of the remaining term, latent heat flux. One of the practical applications with this approach is to produce evapotranspiration maps over large areas. This results could estimate and reproduce areal evapotranspiration over large area as much as several hundred sequare kilometers. Moreover, some calculating simulations for the effects of the land use change on the surface heat flux has been made by this method, which is able to estimate evapotranspiration under arbitracy presumed condition. From the simulation of land use change, the results suggests that the land use change in study area can be produce the significant changes in surface heat flux. This preliminary research suggests that the future research should involve development of methods to account for the variability of meteorological parameters brought about by changes in surface conditions and improvements in the modeling of sensible heat transfer across the surface atmosphere interface for partical canopy conditions using remote sensing information.

• Atmosphere
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• v.34 no.1
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• pp.69-81
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• 2024

In this paper, Annual flux variations in the Boseong Tall Tower (BTT) from 2016 to 2020 were analyzed using data from three levels (2.5 m, 60 m, and 300 m). BTT was installed in Boseong-gun, Jeollanam-do in February 2014 and continued to conduct energy exchange observations such as CO2, sensible heat, and latent heat using the eddy covariance method until March 2023. The BTT was located in a very flat and uniform paddy field, and flux observations were conducted at four levels: 2.5 m, 60 m, 140 m, and 300 m above ground. Surface energy balance was confirmed from observed data of net radiation flux, soil heat flux, sensible heat flux, and latent heat flux. Additionally, 2.5 m height surface fluxes, which are most influenced by agricultural land, were compared with data from Local Data Assimilation and Prediction System (LDAPS) of the Korea Meteorological Administration to evaluate the accuracy of LDAPS flux data. The correlation coefficient between LDAPS flux data and observed values was 0.95 or higher. Excluding summer latent heat flux data, there was a general tendency for LDAPS data to be higher than observed values. The footprint areas estimated below 60 m height mainly covered agricultural land, and flux observations at 2.5 m and 60 m heights showed typical agricultural characteristics. In contrast, the footprint estimated at 300 m height did not show agricultural characteristics, indicating that observations at this height encompassed a wide range, including mountains, sea, and roads. The analysis results of long-term flux observations can contribute to understanding the energy and carbon dioxide fluxes in agricultural fields. Furthermore, these results can be utilized as essential data for validating and improving numerical models related to such fluxes.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.135-135
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• 2017

Greenhouse have been developed to provide the plants with good environmental conditions for cultivation crop, two major factors of which are the inside air temperature and humidity. The inside temperature are influenced by the heating systems, ventilators and for systems among others, which in turn are geverned by some type of controller. Likewise, humidity environment is the result of complex mass exchanges between the inside air and the several elements of the greenhouse and the outside boundaries. Most of the existing models are based on the energy balance method and heat balance equation for modelling the heat and mass fluxes and generating dynamic elements. However, greenhouse are classified as complex system, and need to make a sophisticated modeling. Furthermore, there is a difficulty in using classical control methods for complex process system due to the process are non linear and multi-output(MIMO) systems. In order to predict the time evolution of conditions in certain greenhouse as a function, we present here to use of recurrent neural networks(RNN) which has been used to implement the direct dynamics of the inside temperature and inside humidity of greenhouse. For the training, we used algorithm of a backpropagation Through Time (BPTT). Because the environmental parameters are shared by all time steps in the network, the gradient at each output depends not only on the calculations of the current time step, but also the previous time steps. The training data was emulated to 13 input variables during March 1 to 7, and the model was tested with database file of March 8. The RMSE of results of the temperature modeling was $0.976^{\circ}C$, and the RMSE of humidity simulation was 4.11%, which will be given to prove the performance of RNN in prediction of the greenhouse environment.