• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.22-29
• /
• 2008

In order to improve the efficiency of a main transformer in a tilting train, the optimal operation of a cooling system is necessary. For the development of optimal control algorithms of a cooling system, mathematical models of a main transformer cooling system were developed. These include dynamic models of a main transformer, an oil pump, an oil cooler, a blower, and a pipe. Control algorithms for a blower and an oil pump were selected in order to identify the effectiveness of dynamic models. A simulation program was developed by using the developed dynamic models and the selected control algorithms. Simulation results showed good predictions of dynamic behaviors of a main transformer cooling system. Therefore, dynamic models, which were developed in this study, may be effectively used to develop control algorithms of a main transformer cooling system.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.955-960
• /
• 2009

In order to improve the efficiency of the main transformer in a tilting train, the optimal operation of a cooling system is necessary. Mathematical models of a main transformer cooling system were developed. These include models for the main transformer, the oil pump, the oil cooler, and the blower. The optimal oil temperature algorithm was also developed. This consists of the optimal setpoint algorithm and the control algorithm. A simulation program was developed by using mathematical models and the optimal oil temperature algorithm. Simulation results showed that the dynamic behavior of a main transformer cooling system was predicted well by mathematical models and a main transformer cooling system was controlled effectively by the optimal oil temperature algorithm.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.387-392
• /
• 2008

In order to improve the efficiency of the main transformer in a tilting train, the optimal operation of a cooling system is necessary. For the development of the optimal control algorithm of a cooling system, the mathematical model of a main transformer cooling system was developed. This includes the dynamic model of a main transformer, an oil pump, an oil cooler and a blower. The system algorithm of a cooling system, which consists of the temperature setpoint algorithm and the temperature control algorithm, was developed. Optimal oil temperatures of the inlet and the outlet of the main transformer were obtained by considering the total electric power consumption of the system. The oil inlet temperature was controlled by the blower and the oil outlet temperature was controlled by the oil pump. A simulation program was developed by using the mathematical model and the system algorithm. Simulation results showed that the system algorithm developed from this study may be effectively used to control the main transformer cooling system in a tilting train.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.2
• /
• pp.70-77
• /
• 2010

In order to improve the efficiency of a main transformer in a train, the optimal operation of a cooling system is necessary. For the development of optimal control algorithms of a cooling system, mathematical models of a main transformer cooling system were developed. These include static and dynamic models of a main transformer, an oil pump, an oil cooler, and a blower. Static models were used to find optimal oil temperatures of the inlet and the outlet of a transformer. Dynamic models were used to predict transient performances of control algorithms of a blower and an oil pump. Simulation results showed good predictions of the static and the dynamic behavior of a main transformer cooling system. Therefore, mathematical models developed in this study may be effectively used for the development of control algorithms of a main transformer cooling system.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.3
• /
• pp.329-334
• /
• 2011

The cooling water circulation plates had been used to drop the temperature of refractory outside shell of common cooling system by using cooling plate or stave type. When they are attacked by surrounding gas, they are corroded and the water flows in the refractory due to leakage of water. So, the life of refractory material is shortened and changed due to the worse conditions of cooling system. The automatic sensing device for water leakage of cooling plate is developed to check the position of trouble by using the microprocessor system when cooling water leak and gas are flowed into the cooling plate through the leakage position. The flowed gas is detected in the micro-process system which delivers the detected position of cooling plate or stave to main control room through the wireless-radio relay station. This system can be possible to detect the position of cooling plate or stave against the water leakage part immediately and then deliver the signal to main control room by using the microprocessor system and wireless-radio relay station. This system will be developed in changing the working condition from manual system to unmanned auto alarm system.

• Journal of the Korean housing association
• /
• v.15 no.2
• /
• pp.107-115
• /
• 2004

The objective of this study is to show the system Integrations and control method for operation of the Radiant Floor Cooling. The systems for radiant floor cooling system consist of only using the radiant floor cooling and the radiant floor cooling integrated with a dehumidification system. And the study is suggested control method with composed radiant floor cooling system through simulations. Radiant floor cooling systems compose of four main parts: an existing radiant heating panel, manifold, cooling source and controller, and sensors. If dehumidifying or supplementary cooling is needed, additional equipments such as PAC and AHU are needed. Simulation results show that control method only using radiant floor cooling system can prevent condensation and set room air temperature with the exception of hot and humid periods and control method using the radiant floor cooling integrated with a dehumidification system is comfort thermal environments and can reduce the cooling load quickly, moreover, show comfort control method to meet various cooling operation situations.

• Journal of Advanced Marine Engineering and Technology
• /
• v.31 no.5
• /
• pp.592-598
• /
• 2007

The fuel charge is getting higher in navigation cost. Therefore, shipowners try to find the method for reducing oil consumption. ESS(Energy Saving System) is one of he method. ESS is the system consisted with two inverters, ESS control unit and monitoring system. Two inverters control two main sea water cooling pumps. In the ESS control Unit, the control algorithm finds optimized point to decrease a power consumption of main sea water cooling pumps. Monitoring system observes ESS not to work improperly. ESS is experimented in the laboratory with real condition and analyzed in every view. After experiment, the result of the experiment shows that the control algorithm works correctly and safely. ESS has a plan to be operated in the ship soon. In that case, additional devices are needed to connect ESS with cooling system of the vessel. So the development of addition device is needed and being studied.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.5
• /
• pp.314-320
• /
• 2008

The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the improved wall insulation. Hence, a multi~heat pump is required to cover heating and cooling simultaneously for each indoor unit. In this study, the operating characteristics and performance of a simultaneous heating and cooling heat pump in the cooling-main operating mode were investigated experimentally. The system adopted a variable speed compressor using R410A with four indoor units and one outdoor unit. In the cooling-main mode, the heating capacity decreased due to reduction of flow rate to the indoor unit under heating mode operation. The EEV opening was adjusted to increase flow rate to the indoor unit under heating mode operation. The total capacity and COP in the cooling-main mode increased by 20.5% and 29.2%, respectively, compared with those in the cooling-only mode.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.4
• /
• pp.245-251
• /
• 2008

The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Hence, the development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the operating characteristics and performance of a simultaneous heating and cooling heat pump in the heating-main operating mode were investigated experimentally. The system adopted a variable speed compressor with four indoor units and one outdoor unit with R-410A. In the heating-main mode, the cooling capacity was lower than the design cooling capacity due to the reduction of the flow rate in the indoor unit for the cooling, with the increase of the heating capacity. To solve these problems, the performance characteristics of the simultaneous heating and cooling heat pump in the heating-main mode were investigated by varying the flow rate to the indoor unit for the cooling and the compressor rotating speed. In addition, the adequate control methods were suggested to improve the system efficiency.

• 전자공학회논문지 IE
• /
• v.46 no.4
• /
• pp.25-30
• /
• 2009

The cooling water circulation pipes had been used to drop the temperature of refractory outside shell of blast furnace by cooling plate or stave type. They were attacked by surrounding CO gas and it was the cause that they were corroded and the water inflow in the refractory due to leakage of water. So, the life of refractory material was shorten and changed for the worse the conditions of blast furnace. The automatic sensing device for water leakage of cooling pipe was developed to check the position of trouble by use the micro-process system when cooling water leak and then CO gas will be inflowed into the cooling pipe at the leakage position. The inflowed CO gas will be detected in the micro-process system and delivered the detected position of cooling plate or stave to main control room through the wireless-radio relay station. This system can be possible to detect the position of cooling plate or stave the water leakage part immediately and then deliver the signal to main control room by use the micro-process system and wireless-radio relay station. This system will develop the working condition from manual system to unmanned auto alarm system.