• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.108-113
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• 2009

Buildings with multi-complex spaces designed for architectural values and functional requirements give rise to technical challenges in terms of energy efficiency and thermal comfort. Since spaces in such buildings are connected with openings with geometrical complexity, it is hard to define zoning plan and to control heating/cooling loads effectively. This paper presents a case study on the evaluation of operation strategy for a building with multi-complex spaces using computer simulation. The modelling methodology and the results of the simulations are also described.

• 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.

• Journal of environmental and Sanitary engineering
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• v.11 no.1
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• pp.57-61
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• 1996

This study was to decompose carbon tetrachloride and CFC with pyrolytic incineration unit because of prohibition of their usage sooner or later. We have investigated heating value and temperature versus decomposing rate, removal of $Cl_2$ and dust in the flue gas, The results obtained were as follows; 1. In combustion condition to decompose $CCl_4$ heating value was 3,300Kcal/Kg, retention time was 2,0 sec. incinerator exit temperature was $950^{\circ}C$. 2.The removal of HCI and $Cl_2$ in flue gas used NaOH as reagent, then molar ratio o of $Na^+/Cl^-$ was 1.07. 3. NaCI of dust component was more than 90 %, 2 stage venturi scrubber was used to remove dust, then removal rate of dust was 99% over at L/G of $1.7Vm^3$

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.293-296
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• 2002

This paper describes the instantaneous current resultant type load parallel high frequency resonant inverter consisting of three unit half-bridge serial and parallel resonant inverter can be used as power source of induction heating. This proposed inverter can reduce distribution of the switching current because of using the current of serial resonant circuit to the input current of the parallel one. The analysis of the proposed circuit is generally described by using the normalized parameters. Also, the principle of basic operating and the its characteristics are estimated by the parameters such as switching frequency($\mu$), load resistance(λ). Experimental results are presented to verify theoretical discussion. This proposed inverter will can be practically used as a power supply in various fields as induction heating application, DC-DC converter etc.

• Journal of the Korean Society for Railway
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• v.3 no.4
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• pp.177-184
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• 2000

In this paper, a HVAC controller which has a bilinear system is designed to control the air temperature in building room and a saving of energy on the HVAC system. For modeling of the HVAC bilinear system, AHU(Air Handling Unit) is modeled on the control of inside-outside air flow using three dampers in a duct. A heat exchanger and the single room are also modeled by the energy conservation law. Under the modeling of the HVAC bilinear system, the control's law of the bilinear HVAC system is derived by Lyapunov's non-linear theory and Deress's the linear feedback laws for bilinear system. In this paper it was proved that the controller of the HVAC bilinear system is able to control the air temperature with a disturbance in order to get a target of temperature in the building room by the computer simulation when the control inputs regulate the air flow rate and a capacity of the heat exchanger.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.263-268
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• 2008

In a residential complex case, the efficiency of land use are maximized, but a variation of external condition such as load in-equality, the increase in wind velocity and solar radiation by a height causes increasing energy in a building. Besides, because of increasing window size for a lighting and a view, it comes heating load in winter and cooling load in summer. A choice of cooling-system is important for this reason. Recently an internal high-rise residential complex installs an air-cooling system and operates individual heating. However, this study applies water-cooling used one public cooling-tower instead of an air-cooling system, also with an efficiency test of an air and a water-cooling system, consider an internal applicability.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1412-1416
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• 2003

Induction Heaters are commonly used in heating steel strip product, because it can rapidly and efficiently heat steel strip/bar. In this study, a inductive heating model is developed and the predictions are compared with measured temperatures. The temperatures are measured from POSCO thin-slab rolling facility (so called Minimill). Induction heater is installed between reduction unit and holding furnace This induction heater raise the temperature of steel bars from $930^{\circ}C$ to about $1100^{\circ}C$ which gives the required temperature for finishing mill process after holding period at holding furnace. Unlike other simple equation models, this model allows us to predict temperature profiles of sections of steel bars.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.81-88
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• 1998

This paper describes the method decide to optimal sizing and operation scheduling of total cogeneration system which is interconnected with cogeneration unit of utility and auxiliary thermal devices of heating company. Optimal sizing and operation scheduling is established in order to minimize the fuel cost under national viewpoint. Simulations are carried out to show the reliability of method suggested by seasons and kinds. The simulated results can be effectively used as the guideline of operation scheduling between the utility and the heating company.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.339-348
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• 1999

A computer model was developed in order to predict the temperature distribution and the performance of the vertical tube-in-tube ground coil heat exchanger. This model has been validated by experimental results conducted by ORNL. The heat exchanger performance with the variation of the length is calculated and compared. As results, the heat exchanger performance is proportional to the length but the performance per unit length decreases. The minimum performance of 70m - PVC heat exchanger during cyclic operation for a week is obtained 20,054kJ/h for cooling operation and 13,915kJ/h for heating operation. And minimum temperature difference is $4.64^{\circ}C$ for cooling operation and $2.64^{\circ}C$ for heating operation. In each case, it is noted that the temperature difference between the pipe and the far-field occurs within 0.8m from the heat exchanger.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.251-257
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• 2003

In this paper, a new distributed intelligent control module based on LonWorks fieldbus for air handling unit(AHU) of heating, ventilating and air-conditioning(HVAC) is proposed to replace with a conventional direct digital control(DDC) with 32 bit microprocessor. The proposed control architecture has a excellent features such as highly compact and flexible function design, a low priced smart front-end and reliable performance with various functions. This also addresses issues in control network configuration, logical design of field devices by S/W tool, Internet networking and electronic element installation. Experimental results showing the system performance are also included in this paper.