• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.55-61
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• 2007

This paper has been conducted to estimate cooling capacity of the dehumidification tower using hot water from a solar water heating system as a energy source of regeneration process when the dehumidification and drying system is applied to room cooling. A solar water heating system was operated and indoor temperature distributions were simulated according to weather conditions when the concerned solution was used to dehumidify room air in the dehumidification tower. Through this simulation researches we found th following results ; It was found that air velocity through supply and return diffusers should be controlled because it can cause uncomfort in dwelling area. It was found that in the sunny morning temperatures of dwelling area 1 and 2 are higher than those of dwelling area 3 and 4. In this research all the calculation results of heating and cooling system supported by solar water heater have confirmed that its cooling capacity could not reach PMV 0, thermal comfort.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.18 no.4
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• pp.33-44
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• 2022

In this study, we analyze the existing heating and cooling operation method for an office-type complex building with a central heating and cooling system, and examine the effects of applying various EMS that can be applied according to the load size to save energy in the building. For this purpose, simulation analysis was performed. As a control method, reset control of chilled water, hot water, cooling water and supply air temperatures, optimal start/stop of heat source, and number of heat source control were applied according to the load size, and energy consumption was analyzed accordingly. In addition, when all of these control methods were applied, the overlapping energy saving effect was finally confirmed. As a result, it was possible to confirm the energy saving effect when EMS for reset control and heat source control were applied compared to the existing control method of the heating and cooling system, and the effect for the case of using all these control methods in combination was also confirmed.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.569-572
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• 1999

As the industry has been growing rapidly, the problem of environmental pollution has been on the rise seriously. In this paper, we used solar cells at the power supply unit of the equipment, which has been sold at present, for measuring the quality of water in order to complement the problem. Also, to get rid of the inconvenience that the examiners must go to the job site, check and collect the polluted water we set the goal at designing the water pollution alarm system which measures the quality of water automatically using one-chip microprocessor and materializing the program.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.7
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• pp.549-555
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• 2006

In the present study, sterilizing and antibacterial performance tests of Polybutylene pipe with nano-silver were carried out in the testing bench of water supply facilities. Experimental results show that the average sterilizing and antibacterial rate of two micro-biological samples such as E. coli and S. aureus is about 90% in case of stillness experimental condition and 99% in case of flowing experimental condition, when elapsed time is 120 hours and 3 hours, respectively. Experimental results also show that the supply water velocity in nano-silver Polybutylene pipe varies from 1 m/s to 1.5 m/s, the elapsed time needed sterilizing rate reach to 100% decreases.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.488-490
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• 2001

A dispered power system means a little bit of small power generation equipment located near the power-damend areas. Due to no power supply line, such a power source is very favorable for the decrease in loss of electric power supply, in comparison to the giantly focused power source, Because of small power source, this power source also corresponds promptly to the variation of power demend. On the basis of energy saving, environmental reservation, and utilization of natural or unused energy, solar power plants can be introduced into the residence section of cities and small water or wind-power plants near the urban areas. In case of Korea, some wind farm have been introduced into Cheju island, Condensed introduction of several small power sources into an used distribution line may, however, result in a big problem, it is, therefore, necessary that protective-cooporative plans between power quality and distribution line should be introduced for efficient utilization of KEPCO distribution system.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.763-770
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• 2024

Currently, land-based fish farms utilizing seawater have introduced and are utilizing various equipment such as real-time water quality monitoring systems, facility automation systems, and automated dissolved oxygen supply devices. Furthermore, data collected from various equipment in these fish farms produce structured and unstructured big data related to water quality environment, facility operations, and workplace visual information. The big data generated in the operational environment of fish farms aims to improve operational and production efficiency through the development and application of various methods. This study aims to develop a system for effectively analyzing and visualizing big data produced from land-based fish farms. It proposes a data visualization process suitable for use in a fish farm big data analysis system, develops big data visualization tools, and compares the results. Additionally, it presents intuitive visualization models for exploring and comparing big data with time-series characteristics.

• Korean Journal of Community Nutrition
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• v.12 no.3
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• pp.310-321
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• 2007

Effective and systematic sanitation management programs are necessary to prevent foodborne disease outbreaks in school foodservice operations. The purpose of this study was to identify the elements to improve in order to ensure the safety of school food service by evaluating sanitation management practices implemented under HACCP-based programs. The survey was designed to assess the level of hygiene practices of school food service by using an inspection checklist of food hygiene and safety. Fifty-four school foodservice establishments considered as poor sanitation practice groups from two year inspections by Seoul Metropolitan Office of Education were surveyed from September to December in 2005. Inspection checklists consisted of seven categories with 50 checkpoints; facilities and equipment management, personal hygiene, ingredient control, process control, environmental sanitation management, HACCP system and safety management. Surveyed schools scored $68.0{\pm}12.42$ points out of 100 on average. The average score (% of compliance) of each field was 10.7/20 (53.3%) for facilities and equipment management, 7.4/11 (67.2%) for personal hygiene, 7.4/11 (74.1%) for ingredient control, 22.4/32 (69.8%) for process control, 8.9/12 (73.8%) for environmental sanitation management, 4.2/7 (59.7%) for HACCP systems management, and 7.2/8 (89.7%) for safety management, respectively. The field to be improved first was the sanitation control of facilities and equipment. The elements to improve this category were unprofessional consultation for kitchen layout, improper compartment of the kitchen area, lacks of pest control, inadequate water supply, poor ventilation system, and insufficient hand-washing facilities. To elevate the overall performance level of sanitation management, prerequisite programs prior to HACCP plan implementation should be stressed on the school officials, specifically principals, for the integration of the system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.11
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• pp.595-599
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• 2013

The pipes used in buildings are generally categorized into metallic or plastic materials. Metal pipes, such as copper and stainless steel pipes, are mainly used for water and hot water supply, and for the heating system. However, plastic pipes made of polyethylene and cross-linked polyethylene are used for floor heating, water drainage, and air vent systems. Usually, plastic pipes have thermal demerits, such as high linear expansion coefficients and bending phenomenon by hot water, although the pipes have several merits of light weight, low price, low thermal conductivity, and the comparatively high workability of metal pipes. Therefore, if those kind of demerits are overcome, plastic pipes can be easily accepted for hot water systems. This research is aimed to evaluate the applicability for vertical heating pipes of a plastic pipe system consisting of electric fusion fitting of a conductive carbon compound and propylene random glass fiber pipe, through measurement of the expansion rate and leakage in summer and winter seasons, in the apartment construction field.

• The Journal of the Acoustical Society of Korea
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• v.33 no.2
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• pp.111-117
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• 2014

In this paper, the structure-borne noise reduction on electrical equipment is discussed by the experimental analysis. The water cooling system in electrical equipment is the only noise source, so the mock-up was made to measure noise characteristics. Effects of power supply, stiffness, isolation of noise source and natural frequency determined by resilient mounts are investigated using the mock-up. The console prototype was made referring to noise reduction technique by the mock-up. The structure-borne noise level of a console prototype was measured and some experiments to reduce the noise was undertaken. The $1^{st}$ and $4^{th}$ harmonics of operating frequency of cooling fans causes highest structure-borne noise levels. The control of operating speeds of several DC cooling fan groups was tried. Also types and installation layouts of resilient mounts were investigated. To reduce structure-borne noise, followings can be applied: increase of stiffness, isolation of source, decrease of natural frequency of mount, combination of operating speed of fans, selection of mounts, and so on.

• Journal of Biosystems Engineering
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• v.29 no.6 s.107
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• pp.521-530
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• 2004

The solar powered water pump is very ideal equipment because solar power is more intensive when the water is more needed in summer and it is very helpful in the rural area, in which electrical power is not available. The average solar radiation power is $3.488\;kWh/(m^2{\cdot}day)$ in Korea. In this study, the experimental system of the water pump driven by the radiation energy were designed, assembled, tested and analyzed fur realizing the solar powered water pump. Energy conversion ken radiation energy to mechanical energy by using n-pentane as operating material was done and the water pumping cycles were able to be continued. The quantity of the water pumped per cycle ranged from 2 L to 10 L depending on the level of the valve open area far the vapour supply. The average quantity was about 4,366 cc. The thermal efficiency was about $0.018\%$. The pressure level of the n-pentane vapour in flash tank was about $110\~150\;kPa$ and that in the water tank was $93\~130\;kPa$. The pressure in the condenser during cycles was maintained as about 70 kPa. The condensation of the n-pentane vapour in the water tank was increased with the cycles even though the internal and external insulation were done. Air tank performance was better with increasing of the water piston displacement and the water could be pumped with the water piston displacement becoming higher than 6,500 cc.