• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1233-1235
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• 2016

It is desirable to place virtual machines for minimizing the number of operational servers in order to save energy in high-density cloud computing environment. However, the compacted servers can incur heat islands. This paper firstly finds out the relationship between the server utilization by the virtual machine placement and the energy consumption of servers and heat from servers. Then, this paper proposes a virtual machine placement algorithm to save energy consumed and avoid heat islands.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.41-48
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• 2008

The required energy for the heat treatment of pine log was evaluated in this study. A proper heat treatment of pine log infected by pinewood nematode (Bursaphelenchus xylophilus) can prevent spreading of the infection by pinewood nematode and make the infected pinewood valuable again. The FAO (Food and Agriculture Organization of the United Nations) heat treatment standard for various types of infected wood for which a heat treatment of the core part of the wood is necessary is 30 minutes at $56^{\circ}C$, taking into account the international standards for phytosanitary measures (ISPM No. 15). In this study, the energy consumption during the heat treatment was separated into two kinds of energy, initial energy for heating kiln drier and to reach set point temperature and relative humidity and the required energy supplementing heat loss. The initial required energy per unit time is greater than that during the treatment. The energy consumption per unit time varied little during the heat treatment. As a result, the set point relative humidity with set dry bulb temperature and density of wood dependent on moisture content are very important factors to change energy consumption in the experiment. The heat treatment at higher temperature and higher humidity levels requires more energy consumption but less treatment time. It is expected that a more effective energy program could be planed for the heat treatment of pine log through this study.

• Fire Science and Engineering
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• v.17 no.4
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• pp.117-123
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• 2003

In this study; the ignition and heat release rate characteristics of rigid polyurethane foam were investigated in accordance with setchkin ignition tester and cone calorimeter which is using oxygen consumption principle. In the ignition temperature study; flash-ignition temperature was $383^{\circ}C$-$390^{\circ}C$, self-ignition temperature was$ 493^{\circ}C$∼495$^{\circ}C$. The self-ignition temperature of rigid polyurethane foam was about $100^{\circ}C$ higher than the flash-ignition temperature. In the cone calorimeter study, the time to ignition of rigid polyurethane foam was faster as the external heat flux increase. In the same heat flux level, the time to ignition was faster as the density of rigid polyurethane foam decrease. Also the heat release rate was the largest value at the heat flux of /$50 ㎾\m^2$ and had a tendency of increase as the heat flux level and density increase. In the standpoint of time to ignition and heat release rate, the fire performance of rigid polyurethane foam was influenced by the applied heat flux level and density and the flashover propensity classified by Petrella's proposal was high.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.193-194
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• 2010

This study classify the every meshes in Busan metropolitan city, based on the heat density and cooling/heating ratio. As the result of evaluations on the heat density and cooling/heating ratio for the 3289 meshes, the number of meshes which needs more than 2.5 Tcal/mesh.year of heat density is 850(25.8%). The meshes that needs more than district and cooling index 1, which is normally and strongly requested to introduce the district cooling and heating system, is 188(5.7%).

• New & Renewable Energy
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• v.3 no.1 s.9
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• pp.27-37
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• 2007

This study is to analyse the feasibility for providing Co-generation plant in Apartment Complex for 4 typical Apartment Complexes located Seoul metropolitan area, The selected complexes are three midium-large size Apartment[nearby 35pyoug of floor area] and one complex of small size Apartment[below 25 pyoung of floor area] for comparison. The necessary data for the study were collected with visitation of each site. The study showed very positive result for the three medium-large size Apartment Complexes of which the average floor area is more than 25 pyoungs, while negative result for the Complex of which average floor area is less than 25 pyoungs. Other than floor size it was found that the electric consumption density also influence the economic feasibility. In study the unit fixed cost of the energy produced from Co-generation plant is one third of the unit variable cost[fuel cost] and it seems better to select high thermal efficiency machine for Co-generation plant even with some higher cost of the plant.

• Journal of the Korean Wood Science and Technology
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• v.48 no.2
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• pp.217-230
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• 2020

Global warming has increased interest in reducing greenhouse gas emissions. And a policy has effort to reduce energy consumption as a greenhouse gas reduction plan. In Korea, 25% of total energy is consumed in the building sector. In order to reduce energy consumption of buildings, it is possible to expand the utilization of wood as a structural material or thermal insulation materials with low thermal conductivity. It is also reported that when used as an interior finishing material, the energy consumption of the building is reduced by up to 7% by insulation performance. In this study, the heat transfer characteristics and the heat capacity were compared according to the three type of finishing materials(cement, paulownia coreana, medium density fiberboard) normally used as indoor finish materials. Through this study, most of the heat transfer volumes are transferred in the form of radiant heat, and the result was derived from the highest amount of energy and heat transfer in the use of paulownia coreana. When indoor finishing materials are used as wood, it is deemed that energy efficiency inside the building will be improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4679-4684
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• 2013

Compared with internal combustion engine, the electric vehicle has a limitation of low driving range due to low battery capacity due to relatively low energy density. Moreover, the energy consumption rapidly increases up to 30% during winter season with operating electric heater. In this study, electric vehicle performance was evaluated using heat pump having higher energy efficiency rather than electric heater for cabin heating. Electric vehicle system and heat pump system were developed using 1-D simulation software called AMESim, the simulation result indicated that the energy consumption could be reduced approximately 66% when the electric heating system was replaced with the heat pump system. As a result, the driving range is expected to increase the similar value. This study proved the merit of heat pump for cabin heating in electric vehicle, and it could contribute to developing suitable heating method for electric vehicles.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.3
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• pp.85-93
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• 1994

The engine performance and combustion characteristics of diesel oil and fish oil blended with diesel oils were investigated at various blending rate of fish oil in a diesel engine. The maximum pressure showed no significant difference among test fuels at low load, but it was higher as the blending rate of fish oil increases at high load. Increasing the blending rate of fish oil, the rate of heat release and burned fraction were higher than those of diesel oil. The ignition delay became longer than that of diesel oil as the blending rate of fish oil increases, and its differences were larger at different loads. The combustion duration and density of smoke were shorter and lower as the blending rate of fish oil increases. The rate of fuel consumption showed no significant difference between diesel oil and fish blended with diesel oils.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.11
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• pp.812-819
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• 2010

Recently residential buildings are characterized with high-rise and high density. Under this circumstance, achieving comfortable and healthy indoor environment with minimized energy consumption becomes a very challenging engineering and societal issue. Along this the increased size and transparency of window as well as light surface caused by high stories lowers the heat shield efficiency of building. Since glass that constitutes building surface has low heat efficiency, it aggravates heat loss of all building considerably, thereby resulting in extreme heating load and cooling load in the country where temperature varies much in summer and winter. The research will check whether experiment can be effectively done by overcoming the limit of existing artificial solar laboratory constructed in the country and properly adjusting controlled variables with simplified function through construction of this experimental set.

• Safety and Health at Work
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• v.8 no.4
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• pp.327-328
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• 2017

Despite provision of drinking water as the most common method of occupational heat stress prevention, there remains confusion in hydration messaging to workers. During work site interactions in a hot and humid climate, workers commonly report being informed to consume tepid fluids to accelerate rehydration. When questioned on the evidence supporting such advice, workers typically cite that fluid absorption is delayed by ingestion of chilled beverages. Presumably, delayed absorption would be a product of fluid delivery from the gut to the intestines, otherwise known as gastric emptying. Regulation of gastric emptying is multifactorial, with gastric volume and beverage energy density the primary factors. If gastric emptying is temperature dependent, the impact of cooling is modest in both magnitude and duration (${\leq}5$ minutes) due to the warming of fluids upon ingestion, particularly where workers have elevated core temperature. Given that chilled beverages are most preferred by workers, and result in greater consumption than warm fluids during and following physical activity, the resultant increased consumption of chilled fluids would promote gastric emptying through superior gastric volume. Hence, advising workers to avoid cool/cold fluids during rehydration appears to be a misinterpretation of the research. More appropriate messaging to workers would include the thermal benefits of cool/cold fluid consumption in hot and humid conditions, thereby promoting autonomy to trial chilled beverages and determine personal preference. In doing so, temperature-based palatability would be maximized and increase the likelihood of workers maintaining or restoring hydration status during and after their work shift.