• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1099-1103
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• 2013

A combat vehicle needs to have an air-conditioning unit. Accordingly, new combat systems have tended to apply an integrated heating, cooling, and ventilating system. The air conditioning unit used depends on the combat vehicle's purpose of use. In this study, we studied an air-conditioning unit for an armored combat vehicle as a special use and military specification and tried to improve the air-conditioning unit's performance.

• KIEAE Journal
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• v.7 no.6
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• pp.17-22
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• 2007

The integration of PV modules into building facades or roof could raise their temperature that results in the reduction of PV system's electrical power generation. Hot air can be extracted from the space between PV modules and building envelope, and used for heating in buildings. The extraction of hot air from the space will enhance the performance of BIPV systems. The solar collector utilizing these two aspects is called PV/T(photovoltaic/thermal) solar collector. This paper compares the experimental performance of two different types of air type PV/T collector units: the base case of a collector unit with 10cm gap for forced ventilation and the other unit with copper pin attached to PV module to enhance its thermal performance. The experimental results shows that the base case unit had the overall efficiency of 41.9% and the improved unit with copper pin attached to PV module had 50.1% efficiency. For these air type PV/T units, the forced ventilation of the air space improved the electrical performance as well as the thermal performance.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.348-353
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• 2006

Autonomous and intelligent resource model (AIR-model) defines a building-block of complex systems to pursue value creation by means of diverse resources, referred to as an AIR-unit, and presents a collaboration model with the AIR-units. An AIR-unit represents a piece of resources, such as machines, labor, raw materials, and other assets, considered individually by a complex system as means to accomplish given tasks. It is defined with its own service capability and a goal, and pursues achieving the goal by means of the capability. Moreover, an Air-unit is equipped with autonomy and intelligence, whereby it makes a decision on its course of action on its own initiative. Air-units collaborate on system operations with each other through goal-oriented negotiations. In this research, distinctive features of the AIR-model are addressed and described in detail. Principal components of the AIR-model are also designed via object-oriented modeling techniques. A prototype system based on the AIR-model is finally presented as an embodiment tool of a fractal manufacturing system (FrMS).

• Particle and aerosol research
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• v.9 no.3
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• pp.139-147
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• 2013

The performances of indoor air cleaners including particle cleaning capacity and collection efficiency are usually tested at the condition of the maximum air flow rate of the air cleaners. However, the power consumption of the air cleaners is highly dependent on the air flow rate of the individual air cleaners. Therefore, there seems to be an optimized air flow rate for the air cleaning capacity considering power consumption. In this study, clean air delivery rate(or standard useful area as suggested room size) and power consumption have been investigated for different maximum air flow rates of 15 air cleaners and then compared those for different air flow rate modes of the individual 5 air cleaners selected from the 15 cleaners. For the maximum air flow rate conditions of 15 air cleansers, the power consumption per unit area was less related to the maximum air flow rate. However, for the different air flow rate modes of the selected 5 air cleaners, the lower power consumption per unit area was corresponding to the lower air flow rate mode of the individual air cleaners. When considering the operation time to the desired particle concentrations, there was an optimized one in the medium air flow rate modes for the individual air cleaners. Therefore, not only the maximum air flow rate but also lower air flow rates of individual air cleaners should be considered for estimating air cleaning capacity based on energy consumption per unit area.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.333-339
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• 2000

This study was performed to investigate the performance of heat recovery device attached to exhaust gas funnel connected to combustion chamber of greenhouse heating system. The experiment heat recovery system is mainly consisted of LPG combustion chamber and two heat recovery units; unit-A is attached directly to the exhaust gas funnel, and unit-B is connected with unit-A. Heat recovery performance was evaluated by estimating total energy amount by using enthalpy difference between two measurement points together with mass flow rate of gas and/or air passing through each heat recovery unit depending on 5 different flow rates controlled by voltage meter. The results of this experimental study, such as heat exchange behavior of supply air pipes and exhaust air passages crossing the pipes, pressure drop between inlet and outlet, heat recovery performance of exchange unit, etc., will be used as fundamental data for designing optimum heat recovery device to be used for fuel saving purpose by reducing heat loss amounts mostly wasted outside of greenhouse through funnels.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1131-1136
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• 2006

In this study, an experimental and numerical analysis on the flow characteristics of heating and cooling unit installed within ceiling with functional modules was carried out. And the flow characteristics of the heating and cooling unit was investigated with the main parameters such as each filter and inside structure. The experimental results show the possibility of medium filter application. And the numerical results show that the effect of improved inside structure of heating-cooling and air-conditioning unit on flow distribution.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.3
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• pp.193-200
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• 2009

The ventilation system of apartments can be divided by supply and exhaust fan, supply fan and exhaust free and supply free and exhaust fan. Recently, the individual ventilation system and central ventilation system which is combined cooling system with duct system are applied to apartment ventilation system. The airflow pattern is affected by location of supply unit and exhaust unit in indoor. This study is to investigate the proper distance between supply unit and exhaust unit using CFD. As a result of this study, the proper distance between supply unit and exhaust unit could be suggested at the interval of 3 m in supply and exhaust fan system and 2.5 m in supply fan and exhaust free.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.3
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• pp.20-24
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• 2006

Air balancer is a conveyance cargo-handling machine, used in assembly and process lines of car and machining industries. This can lift up an object, the weight of which is from 5 to 200 kg, and moves it to a position. As industrial technologies evolve, it is required to move an object and fit it into a specified position with greater accuracy, rather than performing simple tasks such as lifting objects up and down as conventional ones do. There is also a demand to handle an object with one hand, rather than with two hands,. Through designs of manifold unit for an air balancer function, pilot regulator unit to keep pressure constant, hand unit for an accurate load perception function, and air balancer circuit, this study enables everybody to work it with ease and convenience. Experiments and comparisons were conducted for the performance evaluation of the circuit.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2001.02a
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• pp.132-135
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• 2001

Cryogenic air separation unit(ASU) was developed about 100 year ago in Europe. However, because there is not any ability of process design or manufacturing of ASU in Korea, many ASUs come from advanced countries every year. The purpose of this study is the development of cryogenic air separation unit by our own ability, especially cold box for nitrogen production. On this study, we developed the computer program for physical properties of gases and process simulation. We also did process design and manufactured of cold box, including air separation column, liquid air heat exchanger and condenser. The result of cold box test was successful.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.7
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• pp.688-696
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• 2000

A scheme for fault detection on the subsystem level is presented. The method uses analytical redundancy and consists in generating residuals by comparing each measurement with an estimate computed from the reference models. In this study regression neural network models are used as reference models. The regression neural network is memory-based feed forward network that provides estimates of continuous variables. The simulation result demonstrated that the proposed method can effectively detect faults in an air handling unit(AHU). The results show that the regression models are accurate and reliable estimators of the highly nonlinear and complex AHU.