• Journal of the Korean housing association
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• v.20 no.4
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• pp.19-29
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• 2009

The purpose of this study is to evaluate the air diffusion performance of a range of indoor units for room airconditioners; the wall-mounted type, floor-standing type, and ceiling-mounted type. These types of units, which have been widely used in housing spaces, will be studied with respect to thermal comfort and the energy performance using CFD analysis. In this study, current air conditioning status and related problems in housing spaces are examined, and a CFD analysis is performed in order to compare and analyze the thermal comfort and energy efficiency across each type of indoor-unit using the PMV, ADPI, EUC and FCEI indexes. The analysis results collectively considering thermal comfort and energy performance indicated that the ceiling-mounted type 4-way indoor unit showed the best diffusion performance in terms of thermal comfort, and had the second best diffusion performance in terms of energy performance after the wall-mounted type under certain conditions.

• Journal of the Semiconductor & Display Technology
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• v.11 no.2
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• pp.59-62
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• 2012

This test method covers a procedure for measuring particle removal characteristic of equipment fan filter unit(EFFU) installed inside of semiconductor process equipments, FPD manufacturing equipments and so on. Since EFFU is a combination of air filter and the assembly of fan, motor and frame, the integrity of these parts is very important for the performance of EFFU. So a conventional particle removal test method for air filters is not suitable for EFFU particle removal performance. This test method defines an evaluation method for EFFU which is installed inside an enclosed space to remove particles that are generated inside process equipment. The particle removal performance of EFFUs is usually depending on the performance of filter media and air flow rate. To understand a performance of an EFFU, the filter media characteristic, air flow rate and the integrity of EFFU parts should be considered simultaneously. This test method is intended to demonstrate the system performance of an EFFU and successfully evaluated EFFU performance characteristics.

• Solar Energy
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• v.18 no.4
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• pp.11-22
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• 1998

Floor panel heating system using hot water is the primary heating system of domestic residential building. This paper presents the results of performance analysis of the heat pump system with air source evaporator and single unit dual sink(SUDSk) condenser. The heat exchanger combines two separated condensers into a single condenser and the object of the SUDSk condenser is to release energy to dual sinks, i.e. air for air heating system and water for panel heating system in one single unit. Simulation program is developed for single unit dual source(SUDS) SUDSk heat pump system and some experimental data are obtained and compared with simulation results. Differences of heating capacity and COP in dual source operating mode are 7% and 8% respectively. Simulation results are in good agreement with test results. Therefore, developed program is effectively used for design and performance prediction of dual source dual sink heat pump system with SUDS evaporator and SUDSk condenser.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.5
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• pp.427-435
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• 2005

This paper investigates the thermal storage performance of the office building which has adopted an air conditioning system with its slab structure as a regenerator. Four cases of the thermal storage performance experiment were conducted. Room air temperatures, floor slab temperatures, temperatures around the air conditioning unit were logged and analyzed. The load handling capacity of the air conditioning unit and the amount of heat stored in the slab were decided from those experiments. Several efficiencies were investigated to evaluate the performance of the thermal storage. The results concluded that the slab as a regenerator is very effective in cutting down peak loads of the office building.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.1
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• pp.44-54
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• 1993

This is an experimental study to identify the performance of air-to-air rotary heat exchanger with polyurethane foam matrix. The experimental apparatus including heating AHU(Air Handling Unit), cooling AHU, sensor chamber, and heat exchanger testing unit was designed and manufactured in this study. The performance of heat exchanger with porous polyurethane foam matrix was tested with variations of the density and the thickness of matrix, regulating the wind velocity and the rotational speed of matrix. The actual heat recovery effectiveness, air leakage rate, and pressure drop of heat exchanger were measured and analyzed.

• Journal of Environmental Health Sciences
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• v.2 no.1
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• pp.25-28
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• 1975

The main purpose of the aeration units in activated sludge process is to enable micro-organisms to metabolize the constituents of the waste effectively by supplying sufficient oxygen for their respiration. Normally, aeration is achieved by bringing the mixture of waste and sludge into intimate contact with air. The main type of aeration unit is diffused air unit in which air is injected into the liquid in the form of bubbles. The object of these laboratory studies is to compare the performance of three laboratory scale aeration systems at various depths of submergence, aerating water with and without the addition of a surface active agent.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.420-422
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• 1998

All Fault Detection and Diagnosis(FDD) methods utilize classification techniques. The objective of this study was to demonstrate the application of classification techniques to the problem of diagnosing faults in data generated by a variable-air-volume(VAV) air-handling unit(AHU) simulation model and to describe the characteristics of the techniques considered. Artificial neural network classifier and fuzzy clustering classifier were considered for fault diagnostics.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.312-317
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• 2005

Electric Multiple Unit is one of the major mass public transportation systems and passengers are under the influence of indoor air quality such as air temperature, relative humidity and concentration of CO2 gas. Therefore ventilation system of Electric Multiple Unit should be designed for both healthy and comfortable environments. We survey the optimal ventilation rate and the permissible CO2 concentration in the saloon with the consideration of the cooling and heating capacity and fresh air induced from tunnel.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.10a
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• pp.5-10
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• 1991

This study was performed to find out the effect about the spacing factor and durability factor to evaluate the durability of concrete in high-strength concrete with freezing and thawing as following each condition, 1) unit cement content : 500kg/$\textrm{m}^3$, 550kg/$\textrm{m}^3$ 2) water/cement ratio : 25%, 30%, 35% 3) air content : below 1.5%, 1.6~3.5%, 4~6%, over 7% From the results tested, a variation of air content was more effective to the durability of concrete than that of water/cement ratio and unit cement content.

• Journal of the Korean Solar Energy Society
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• v.25 no.1
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• pp.45-55
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• 2005

In the summer, the irradiated solar heat gain through the roof has an effect on the thermal environment of the top floor units of apartment houses. This paper investigated the differences of the indoor air temperature, globe temperature and thermal comfort index between the top floor unit and the middle floor unit by measuring them at the sample units on the condition that all the openings of the units are opened. The purpose of this paper is to provide quantitative data about the irradiated solar heat gain during the summertime through the roof of an apartment house and these data to be the source to reevaluate the appropriate roof insulation efficiency. From this study, we obtained three brief results as follows. Indoor air temperature difference between the two sample units shifts a day. Indoor air temperature at the top floor unit is $0{\sim}1.8^{\circ}C$ higher than that of the middle floor unit from 12:00 p.m. to 12:00 a.m. and $0{\sim}2.8^{\circ}C$ lower from 12:00 a.m. to 12:00 p.m. The evaluation of the indoor thermal comfort index and the globe temperature shows similar results as the indoor air temperature measuring. Results of this experiment verified the actual existence of indoor air temperature difference between the top floor unit and the middle one and this difference comes from the heat storage of the roof.