• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.4
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• pp.347-354
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• 2005

This paper compared vertical temperature distribution between the existing balcony model without ventilator facilities and the improved balcony model with ventilator facilities using differential equation. As the air inside of balcony is heated by solar radiation this heated air is not exhausted in the existing balcony, remaining stagnant. The air temperature distribution was $26.7{\sim}29.3^{\circ}C$ in balcony without natural ventilator system. This heated air affected the rising air temperature of adjacent spaces such as living room and bedroom in the existing balcony. But, as the heated air inside of the improved balcony model is exhausted through natural ventilator facilities in summer, the air temperature in balcony has fallen. The air temperature distribution in improved balcony was $24.8{\sim}26.7^{\circ}C$ for the inlet air speed of 1 m/s and $24.6{\sim}26.7^{\circ}C$ for the inlet air speed of 3 m/s. The energy consumption of the improved balcony is 2.5 times less than of the existing balcony. The improved balcony with the closed damper makes a roll as the existing balcony in the aspect of the heating effect. When the heated air in the improved balcony is supplied, the air temperature is raised and the ventilation effect in adjacent spaces was improved.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.231-232
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• 2006

The purpose of this study is to measure and evaluate the thermal conditions of large cruiser's cabin. As the result of this study, followings are cleared. The air volume supplied to the 2 types of cabins is quite diffenrent. Temperature differences in the Room A which is located A deck and supplied enough air volume is stable all around the cabin. But Room B which is located B deck and supplied comparatively small air volume has temperature distribution problems, like time-dependent differences, vertical differences. To serve more comfort and productivity of Room B, it is strongly recommended to do a T.A.B.(Testing, Adjusting and Balancing) for more air volume and/or to design new air flow path to make air stay longer.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.484-491
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• 1997

In this paper, an approach to determine the in-ordinal condition of a room, which is based on multi variable analysis, is proposed. According to this approach, the distance of a state from the ordinal condition is thought to be evaluated by the Mahalanobis' distance. The temperature changes of a room were measured and their statistical characteristics such as distribution type, the mean value and the standard deviation are studied. The applicability of the method for the fire detection is also investigated.

• Journal of Ocean Engineering and Technology
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• v.13 no.3B
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• pp.29-37
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• 1999

Ventilation of the marine engine room is very important for the health of the workers as well as the normal operation of machines. To find proper ventilation conditions of this engine room, numerical simulation with standard k-${\epsilon}$ model was carried out. In the present study, the marine engine room is separated to two floors with porus horizontal partition and considered as a closed space with a heat source and forced ventilation ducts. The porosity of horizontal partition is found to be important. For the engine room with 2 supply ports & 2 exhaust ports, the increasing of the porosity of horizontal partition is effective to reduce the recirculation flow zone in the second floor. When the engine room is ventilated with three supply air ports & one exhaust port, the increasing of the porosity of horizontal partition is effective to reduce the recirculating flow zone in the exhaust air area, but there is a possibility of local extreme heating at the lower side of engine near bottom.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.2
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• pp.83-91
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• 2018

A datacenter is a high energy consuming facility whose cooling energy consumption rate is 10~20 times larger than general office buildings. The higher the temperature of supply air from a CRAC (computer room air-conditioner) is supplied, the more energy efficient cooling is possible because of improving the COP of a chiller and advanced range of outdoor air temperature available for the economizer cycles. However, because the temperature of cold air flowing into server computers varies depending on air mixing configurations in a computer room, the proper supply air temperature must be considered based on the investigation of air mixing and heat dissipation. By these, this study aims to understand the effects of variation of the supply air temperature on the air flow distributions, temperature distributions and rack cooling efficiencies. Computational fluid dynamics (CFD) aided in conducting the investigation. As a result, the variation of the supply air temperature does not affect the air flow distributions. However, it mainly affects the temperature distribution. From the results of CFD simulations, Rack cooling indices (RCIHI and RCILO) were evaluated and showed the ideal state set at $19^{\circ}C$ of the supply air temperature.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.74-80
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• 2020

The ocher jjimjilbang for a single-person household that will be studied in this study is 2.1 ㎡ in size, and this study was conducted to implement well-being room heating that is beneficial to health by supplying radiant heat provided by hot water during room heating by embedding hot water panels in the walls of the ocher jjimjilbang to configure a hot water circulating system. In addition, the ocher bed and the ocher walls, which have been verified through many study findings and reference materials, were constructed so that the living life with a bed and the ocher jjimjilbang would be implemented simultaneously. As the mass flow rate of the hot water increased, the magnitude of the wall temperature rise thanks to the hot water increased, and as the flow rate of the hot water increased, the transfer rate of the heat transferred from the wall of the ocher jjimjilbang to the air inside the wall of the ocher jjimjilbang increased.

• Journal of Animal Environmental Science
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• v.3 no.2
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• pp.77-85
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• 1997

Recently, local swine producers are rapidly adopting the indoor production system which developed in foreign countries. However, this imported system is reported as not functioning properly because of different climate conditions. The objective of this project was to investigate the environment characteristics of a windowless delivery swine building. The parameters studied were the heating and cooling loads, the daily changes of indoor temperature and relative humidity, the horizontal and the vertical distributions of indoor temperature, and the effect of mist cooling on indoor temperature. From this study, the following are founded : 1. The maximum cooling and heating loads were - 317.0kcal/㎡$.$h and 336.5kal/㎡$.$h in summer and in winter. The large loads seems to be on account of inappropriate operations of ventilating fans. 2. The daily variations of relative humidity in indoor were smaller than those in outside. Those values both in summer and in winter as relative humidities in door was lower than optimum for growing pigs, the additional humidifier might be helpful to increase the relative humidity in indoor. 3. The horizontal distribution of the indoor temperature was found to be uniform in the variation range of 1$^{\circ}C$. 4. The vertical distribution of the indoor temperature was not found to be uniform; the temperature of upper part was higher than that of slot part. 5. Average values of indoor temperature became lower by 3$^{\circ}C$ by mist cooling. But the variation of temperature was found to be larger; The middle part of the room was cooled down, but the corner part of the room was not affected by misting due to uneven nozzle configuration.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.178-185
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• 1995

Warm deep drawing for optimum forming conditions to give the maximum drawing depth is investigated and compared with the results at room temperature. Experiments which draw square cups of STS 304 stainless steel sheet under the constant lubrication condition of teflon film made both in a crank and hydrqulic press for two kinds of specimens . The maximum drawing depth at warm forming condition reaches 1.4 times the drawing depth at room temperature in a crank press, whereas 1.6 times in a hydrqulic press, and also more uniform distribution of thickness in case of warm deep drawn cup is observed. The effects of other factors on formability , such as forming temperature, speed of press and cooling of punch are examinnied and discussed.

• Transactions of Materials Processing
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• v.4 no.4
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• pp.345-352
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• 1995

Warm deep drawing for optimum forming conditions to give the maximum drawing depth is investigated and compared with the results from experiments performed at room temperature. Experiments which draw square cups of STS 304 stainless steel sheet under the constant lubrication condition of teflon film are made both in a crank and hydraulic press for two kinds of specimens. The maximum drawing depth at warm forming condition reaches 1.4 times the drawing depth at room temperature in a crank press, whereas 1.6 times in a hydraulic press, and also more uniform distribution of thickness in case of warm deep drawn cup is observed. The effects of other factors on formability, such as forming temperature, speed of press and cooling of punch are examined and discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.1 no.2
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• pp.116-127
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• 1989

Research on reheating cooling cycle and its practical application have been made to prevent unequalized distribution of temperature and humidity of room due to lack of supply air volume and dewdrops on supply diffusers to be taken place as a result of lower temperature of supply air than that of dew point of room air in cooling cycle of constant air volume, single duct, single zone and draw-through fan type. In view of the fact that human body is insensitive to humidity, it is possible not only to construct the complete non-reheating cooling cycle by increasing the humidity point allowable with the deduction of occupant's sense of pleasantness minimizing, but also to get cooling cycle decreasing the reheating quantity if the humidity exceeds the point allowable. In addition, it is possible to save maximum 8% in electric energy for cooling in cooling system by constructing non-reheating cooling cycle instead of reheating cooling cycle and by increasing the relative humidity of room from 50% to 65% in case efficiency and air pressure of cooling system are low. It is also possible to get an optimum cooling cycle by determining the room humidity in consideration of pleasantness of occupants and conservation rate of electric energy if the cooling capacity, efficiency and total pressure of cooling equipment are fixed.