• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.9
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• pp.424-433
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• 2014

The purpose of this study is to evaluate the effectiveness in the lighting performance of mixed type light-shelf, by comparing and analyzing the internal light-shelf, external light-shelf, and mixed-type light-shelf. The performance of light-shelf was evaluated according to the angle of light-shelf at summer solstice, winter solstice, vernal equinox, and autumn equinox. The comparative analysis between the internal light-shelf, external light-shelf, and mixed-type light-shelf was carried out using the performance evaluation and analysis method. The result of performance evaluation is shown as follows. The mixed type light-shelf showed the highest lighting performance all at summer solstice, winter solstice, vernal equinox, and autumn equinox, followed by the external light-shelf and the internal light-shelf in the same order. The mixed type light-shelf was the most favorable for bringing daylight to indoors by adjusting the angle of light-shelf, and it also showed the highest lighting performance in terms of uniformity ratio of illumination which indicates the quality of light.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.137-139
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• 2006

The Continental shelf is important part of the coastal states' jurisdiction at sea, because there are many natural resources in continental shelf. This paper examines the concept and legal status of the continental shelf, the limit of the continental shelf, and expecially the rights and duties of the coastal state relating to its continental shelf.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.48-62
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• 1998

Seasonal volume transport on the Texas-Louisiana continental shelf is investigated in terms of objectively fitted transport streamfunction fields based on the current meter data of the Texas­Louisiana Shelf Circulation and Transport Processes Study. Adopted here for the objective mapping is a method employing a two-dimensional truncated Fourier representation of the streamfunction over a domain, with the amplitudes determined by least square fit of the observation. The fitting was done with depth-averaged flow rather than depth-integrated flow to reduce the root-mean-square error. The fitting process filters out $11\%$ of the kinetic energy in the monthly mean transport fields. The shelf-wide pattern of streamfunction fields is similar to that of near-surface velocity fields over the region. The nearshore transport, about 0.1 to 0.3 Sv $(1 Sv= 10^6\;m^3/sec)$, is well correlated with the seasonal signal of along-shelf wind stress. The spring transport is weak compared to other seasons in the inner shelf region. The transport along the shelf break is large and variable. In the southwestern shelf break, transport amounts up to 4.7 Sv, which is associated with the activities of the encroaching of energetic anticyclonic eddies originated in Loop Current of the eastern Gulf of Mexico. The first empirical orthogonal function (EOF) of streamfunction variability contains $67.3\%$ of the variance and shows a simple, shelf-wide, along-shelf pattern of transport. The amplitude evolution of the first EOF is highly correlated (correlation coefficient: 0.88) with the evolution of the along-shelf wind stress. This provides strong evidence that the large portion of seasonal variation of the shelf transport is wind-forced. The second EOF contains $23.7\%$ of the variance and shows eddy activities at the southwestern shelf break. The correlation coefficient between the amplitudes of the second EOF and wind stress is 0.42. We assume that this mode is coupled a periodic inner shelf process with a non-periodic eddy process on the shelf break. The third EOF (accounting for $7.2\% of the variance) shows several cell structures near the shelf break associated with the variability of the Loop Current Eddies. The amplitude time series of the third EOF show little correlation with the along-shelf wind.

• KIEAE Journal
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• v.16 no.5
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• pp.57-64
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• 2016

Purpose: Recently, lighting energy consumption in buildings has been gradually increasing and more studies are being carried out in order to solve this problem. Especially, the efficiency of the light-shelf system, which is a natural lighting system, has been recognized as a potential solution in addressing this problem and so various studies regarding the light-shelf system are being conducted. However, if high luminance material is used for the light-shelf system, glaring may occur in certain circumstances even though such material increases efficiency, and there are also difficulties related to maintenance and management in the case of an external light-shelf system. Therefore, the purpose of this study is to suggest modifications in relation to the reflectivity of the light-shelf system and introduce a rolling type light-shelf system with built-in cleaning equipment. In addition, a performance evaluation technique was established to verify its effectiveness. Method: In this study, we reviewed previous studies related to the light-shelf system and its performance. Then a testbed was established to assess the performance of the rolling-type light-shelf system suggested in this study. Also, the performance of the rolling-type light-shelf system suggested in this study was compared and analyzed with that of existent light-shelf systems in order to better verify the performance, and the uniformity ratio of illumination and lighting energy consumption were calculated for this purpose. Result: The results of the performance evaluation are as follows. 1) The performance evaluation result of the light-shelf system on the day of the summer solstice shows that $30^{\circ}$ is appropriate for the angle of light-shelf system, and the depth of the incoming natural light also increases as the angle of the light shelf increases. 2) It is possible to improve the uniformity ratio of illumination by increasing the reflectivity of the light shelf, and the reason for this is the increase in the amount of incoming light entering indoors due to the increased reflectivity of the light shelf. 3) The rolling type light-shelf system suggested in this study enables energy saving in comparison with existent light-shelf systems, and when the external illuminance decreases to 60,000 lx and 40,000 lx during the summer solstice due to factors such as the weather, the suggested light-shelf system can save energy by 12.1% and 5.1% respectively. Thus the light-shelf system proposed in this study is deemed to be effective in reducing energy costs.

• KIEAE Journal
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• v.17 no.3
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• pp.83-90
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• 2017

Purpose: With the increase in the energy consumption in the building sector, many studies have recently been conducted to address this issue. Due to its efficiency, diverse studies on a light-shelf, which is a natural lighting system, are in progress. However, there has been no research on the external illumination that determines the performance of a light-shelf. Therefore, the present study aimed to prepare the external illumination standard for securing the lighting performance of a light-shelf through the light-shelf performance evaluation based on a 1:1 scale testbed, and to suggest a height-adjustable light-shelf based on an open and closed concept for the case in which the lighting performance of the light-shelf significantly deteriorates, by collecting the external illumination. Method: In this study, a 1:1 scale testbed was established for performance evaluation, and the external illumination standard for securing the performance of the light-shelf was prepared by comparing the lighting performance of the light-shelf depending on the open and closed condition of the light-shelf and the external illumination. Result: 1) In this study, a light-shelf that can be opened or closed depending on the external illumination was suggested. As a result, the prospect right can be secured by creating the condition where there is no light-shelf installation by moving the light-shelf to the top of the window when the lighting performance is not secured. 2) In the summer solstice, the external illuminations appropriate for lighting energy reduction were more than 75,000 lx and 60,000 lx for the light-shelf width of 0.3 m and 0.6 m, respectively. 3) In the intermediate period, the external illumination appropriate for lighting energy reduction was 60,000 lx. In the winter solstice, making the condition where there is no light-shelf installation by closing the light-shelf would be appropriate. 4) Based on the aforementioned results, the external illumination standard for the opening and closing of the height-adjustable light-shelf based on an open and closed concept suggested in this study was 60,000 lx, and the light-shelf with a width of 0.6 m would be advantageous for lighting energy reduction.

• KIEAE Journal
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• v.16 no.5
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• pp.47-55
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• 2016

Purpose: As the energy consumed by buildings increases, there is a growing need for studies and technology development to address this issue. One of the solutions to excessive energy use by buildings is the light-shelf, which is a natural lighting system enabling efficient reduction in light energy, and research in this area has been intensive. However, most of the studies about the light-shelf are limited to the light environment, and thus the application of their findings to an actual environment in the form of a design may be problematic. Therefore, the purpose of the present study is to provide fundamental data for light-shelf design by carrying out a light-shelf performance evaluation on the basis of the light environment and the heating and cooling environment. Method: In the present study, a testbed was established to conduct a light-shelf performance evaluation by measuring the electric power consumption of lighting and heating and cooling devices depending on the existence of a light-shelf and its angle. Result: The findings of the present study are as follows: 1) With respect to the uniformity of the indoor light environment amenity, the optimum angle of a light-shelf was found to be $30^{\circ}$ for the summer solstice and the winter solstice. 2) With respect to the reduction of electric power consumption by indoor lighting devices, the optimum light-shelf angle at the summer solstice is $30^{\circ}$, at which time electric power consumption may be reduced by 10.2% in comparison with when no light-shelf is applied. However, at the winter solstice, a light-shelf may increase the energy consumption for lighting in comparison with when no light-shelf is applied, and this should be taken into account in the design of a light-shelf. 3) In terms of reducing the electric power consumption of heating and cooling devices, the optimum angle of a light-shelf was found to be $30^{\circ}$ for the summer solstice, while a light-shelf is inappropriate for the winter solstice since a light-shelf creates shade and thus increases the heating energy consumption. 4) To summarize the findings above, the optimum angle of a light-shelf is $30^{\circ}$ for the summer solstice, but the installation of a light-shelf may in some circumstances increase the energy consumed by lighting devices as well as by heating and cooling devices. Therefore, more studies and technology development may need to be performed to solve the problem of increased energy consumption at the winter solstice.

• KIEAE Journal
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• v.15 no.3
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• pp.49-56
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• 2015

Purpose: Due to recent increase on energy consumption for light in building, many studies to mitigate this issue have been conducted. Various researches have been carried out to suggest light shelf as one of the solutions, but researches for its reflectivity is very few. In fact, existing research on light shelf shows that utilizing more than 90% of high-illumination materials causes imbalance of glare and illuminance. Method: Therefore this research aimed to evaluate the performance of light shelves depending on reflectivity and to identify proper solution through test-bed. Result: The results are following: 1) Increased reflectivity generally contributed to increase of indoor illuminance but degrade uniformity factor related with indoor comfort of light environment. 2) The $0^{\circ}fixed$ light shelf with 75% of reflectivity and width of 300mm and 40mm appeared to consume more energy than other shelves. Therefore, it is analyzed as unsuitable. 3) This research was conducted by calculating appropriate angle of light shelf around winter and summer solstices and vernal/autumnal equinox. Based on this, performance evaluation was undertaken depending on reflectivity of movable light shelf, which is activated by external sources and can be applied with lower reflectivity than fixed shelf. However, one exception was a movable shelf with width of 600mm that increased light energy consumption when 75% of reflectivity was applied. 4) Performance evaluation of fixed and movable light shelf showed that the shelf with 80% of reflectivity came up with suitable results, but 75% of reflectivity may be applied depending on the width and angle of the shelf. This research is meaningful in that estimation of appropriate reflectivity of light shelf can resolve the glare problem and improve light environment, and further research would be desirable under more diverse conditions to identify proper solution.

• KIEAE Journal
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• v.14 no.6
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• pp.5-13
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• 2014

Various studies on lighting energy savings are conducted, given that lighting energy consumption accounts 23.5% of building energy consumption. Especially, external type light shelf's efficiency is acknowledged; however, its application is limited in Korea, where high rise building ratio is high, due to high wind pressure. This study delves into natural lighting system to cope with wind pressure, and proposes the punching plate-installed light shelf. This study actually draws lighting energy output, according to whether the punching plate is applied through the test-bed, and verifies the effectiveness of the punching plate-installed light shelf. The conclusion is presented below: First) The result of performance evaluation of light shelf with the punching plate in winter solstice showed that the awning area decreased as the opening ratio increased so that the indoor distributed illumination tended to increase, and $-40^{\circ}$ which was advantageous for awning was determined as the proper angle. Second) The light shelf with the punching plate in spring/autumn equinox shows improved lighting according to the angle, and the appropriate angle of light shelf with the punching plate has increased to $15^{\circ}$ and $20^{\circ}$ according to the opening ratio in comparison to $5^{\circ}C$ which is the appropriate angle of light shelf with no punching plate due to the reflection area reduced by the reflecting plate with holes. Third) The result of performance evaluation of light shelf with the punching plate in summer solstice showed that the lighting performance tended to decrease as the opening ratio increased. 4) The light shelf with the punching plate incurs a 50% energy loss in comparison to the light shelf with no punching plate. However, its effectiveness has been proven in the aspects that it can bring a 50% energy saving in comparison to the case with no installation of light shelf and that it can be designed in response to wind pressure on the high floors.

• KIEAE Journal
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• v.17 no.3
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• pp.91-97
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• 2017

Purpose: Various studies on a light shelf are in progress, but it has the problem of glare occurrence. The present study suggested a diffusion film as the method for resolving the glare problem, and aimed to establish light shelf-related basic data by conducting the performance evaluation of a light shelf depending on the installation position of the diffusion film. Method: To carry out the light shelf performance evaluation depending on the diffusion film installation position, three cases were established: no diffusion film installation (Case 1), diffusion film installation on the reflector (Case 2), and diffusion film installation on the upper glass surface of the window for light shelf installation (Case 3); and the energy reduction performance, luminance, and luminance contrast were analyzed based on a testbed. Result: The conclusions of this study are as follows. 1) When the diffusion film was applied, the amount of light introduced through the light shelf decreased, and the average indoor illumination decreased accordingly. 2) For Case 3, the lighting energy reduction performance was identical to the lighting energy reduction efficiency of the existing light shelf; and for Case 2, it was found to be inappropriate as the lighting energy consumption increased compared to that of the existing light shelf. 3) The analysis of the glare for the cases established in this study showed that the luminance contrast was low for Case 3, and thus the glare problem could be minimized. 4) The specific angle of the light shelf could induce the glare problem by increasing the luminance depending on the external condition. 5) Based on the aforementioned contents, the installation position of the diffusion film for improving the lighting performance and glare problem of the light shelf was found to be the upper glass surface of the window for light shelf installation.

• Food Science of Animal Resources
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• v.38 no.6
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• pp.1216-1225
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• 2018

Shelf-life is defined as the amount of time during which a food product retains its desired sensory, chemical, and physical characteristics while remaining safe for consumption. The food industry needs to rapidly obtain the necessary information for determining the shelf life of its products. Here we studied the approaches available for conducting accelerated shelf-life tests. Accelerated shelf-life testing is applied to a variety of products to rapidly estimate change in characteristics with time. The aim of this work was to use accelerated shelf-life testing to study the changes in pH, microbiology, and sensory characteristics of ice cream by the application of a kinetic approach and, based on the observations, to estimate its shelf life. As per the current law, there is no shelf life on ice cream. Our results suggest that the shelf life of an ice cream sample was 24.27 months at $-18^{\circ}C$, 2.29 months at $-6^{\circ}C$, 0.39 months at $-1^{\circ}C$, and 0.15 months at $4^{\circ}C$. Results of this study suggest that a set expiration date on ice cream might also contribute to effective management of ice cream characteristics in the retail chilled chain.