• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4253-4259
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• 2015

In this study, the effects of various control methods of outdoor air cooling control system on control characteristics and energy consumption in building are researched by simulation. The system analysis modelling is done by using TRNSYS program package, and the control performances with existing outdoor air cooling methods are compared with the control ones without outdoor air cooling. As a result, appropriate operating temperature conditions of outdoor air cooling system according to outdoor temperature changes are required, and the outdoor air/return air dry bulb temperature comparison control method among the control methods shows best responses in energy savings.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.2
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• pp.34-43
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• 1992

The purpose of this study is to consider the performance and exhaust characteristics in the practical engine according to the cooling water temperature change of engine and to set up the optimum cooling condition and to obtain the optimum operating condition of thermostat in the cooling system. In order to accomplish the purpose of this study, authors have used the following procedure. 1. This study is to investigate the influence of the cooling water temperature on the engine performance and the exhaust gas, authors regulated the cooling water temperature by using the special closing circuit and measured the concentration of exhaust gas by using the exhaust gas measuring system in the exhaust pipe. 2. This study carried out the experiment by regulating the opening degree of throttle valve and engine speed in the dynamometer and by changing the cooling water temperature, at the same time kept air-fuel ratio constant and made the spark ignition time MBT(Minimum spark advance for Best Torque) 3. This study measured the cooling water temperature by using the K-type thermocouple centring around the easy over-heated parts and by installing a special closing circuit. Therefore, in this study, authors intend to examine the influence of the cooling water temperature on the engine performance, exhaust gas and present the basic materials needed in the engine design including the optimum operating time control system for the cooling water temperature.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.4
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• pp.325-332
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• 2017

The engine cooling system is a device that maintains the temperature in the engine room at an appropriate level by driving a cooling fan when the temperature in the engine room generated during the vehicle operation occurs over a certain temperature. In recent years, the vehicle cooling system has changed to an electronic system. Therefore, in this paper, we design and develop a hall sensor based electronic engine cooling system. In this paper, a hall sensor module and an actuator module for engine cooling control system are designed. In order to verify the performance of the designed module, the magnetic field control was verified through the simulation of the diameter and the head of the coil.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.6
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• pp.532-540
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• 2001

The objectives of this study are to analyze the control variables according to condensation occurrence, to find the range in floor surface temperature and frequency of condensation, and to evaluate the control methods through simulations when the radiant heating system is used for cooling. Through the simulation analysis the control methods such as on/off control, variable flow control and outdoor reset with indoor temperature feedback control are evaluated and compared. The results show that the lowest floor surface temperature is around $23^{\circ}C$, the surface condensation can be prevented by controlling indoor humidity within 20g/kg(DA0, and that outdoor reset with indoor temperature feedback control is more appropriate than on/off control and variable flow control with regard to prevention of the condensation and thermal comfort.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.897-900
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• 2005

This paper presents temperature control of aluminum plate using Peltier module. As one of the thermoelectric effect, Peltier effect is heat pumping phenomena by electric energy. So if current is charged to Peltier module, it absorbs heat from low temperature side and emits heat to high temperature side. In this experiment, Peltier module is used to control the temperature of small aluminum plate with heating and cooling ability of Peltier module with current control and fan On/OFF control. And current control of Peltier module was accomplished by PWM method. As a results of experiments, it takes about 125sec to control temperature of aluminium plate between $30^{\circ}C\;and\;70^{\circ}C$ and about 70sec between $40^{\circ}C\;and\;60^{\circ}C$, in ambient temperature $29^{\circ}C$ while operating cooling fan only while cooling duration. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.46-51
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• 2007

The near-optimal control algorithm for central cooling system has been developed for minimizing energy consumption while maintaining the comfort of indoor thermal environment in terms of the environmental variables such as time varying indoor cooling load and outdoor temperatures. The optimal set-points of control parameters with near-optimal control are supply air temperature and chilled water temperature. This study has been done by using LapVIEW program with PID control in order to analyze the central cooling system energy saving.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.5
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• pp.49-55
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• 2012

In order to derive the efficient utilization of low pressure compressed air fogging system, cooling efficiencies with control types were analyzed through cooling experiments in tomato greenhouses. The control types were set up with temperature control, humidity control, temperature and humidity control, and time control. It showed that the cooling effects were 0.7 to $3.3^{\circ}C$ on average and maximum of 4.3 to $7.0^{\circ}C$, the humidification effects were 3.5 to 13.5 % on average and maximum of 14.3 to 24.4 %. Both the cooling and humidification effect were the highest in the time control method. The cooling efficiency of the air fogging system was not high with 8.3 to 27.3 % on average. However, the cooling efficiency of 24.6 to 27.3 % which appears from the time control is similar to the cooling efficiency of high pressure fogging system experimented in Japan. The air fogging system is operated by low pressure, but its efficiency is similar to high pressure. We think because it uses compressed air. From this point of view, we suggest that the air fogging system can get the cooling efficiency of similar levels to that of high pressure fogging system and it will have an advantage from clogging problem of nozzle etc.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.17 no.4
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• pp.68-78
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• 2021

In order to solve the increasing deterioration of the energy shortage problem, ground-source heat pump (GSHP) systems have been widely installed. The control method is a significant component for maintaining the long-term performance and for reducing operation cost of GSHP systems. This paper presents the measurement and analysis results of the cooling performance of a GSHP system using capacity control with outdoor air temperature. For this, we installed monitoring equipments including sensors for measuring temperature, flow rate and power consumption, and then monitored operation parameters from July 9, 2021 to October 2, 2021. From measurement results, we analyze the effect of capacity control with outdoor air temperature on the cooling performance of the system. The average performace factor (PF) of the heat pump was 6.95, while the whole system was 5.54 over the measurement period. Because there was no performance data of the existing GSHP system, it was not possible to directly compare the existing control method and the outdoor air temperature method. However, it is expected that the performance of the entire system will be improved by adjusting the temperature of cold water produced by the heat pump, that is, the temperature of cold water on the load side according to the outside air temperature.

• Journal of Power Electronics
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• v.10 no.2
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• pp.187-193
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• 2010

This paper proposes a cooling system using thermoelectric elements for improving the output of building integrated photovoltaic (BIPV) modules. The temperature characteristics that improve the output of a BIPV system have rarely been studied up to now but some researchers have proposed a method using a ventilator. The efficiency of a ventilator depends mainly on the weather such as wind, irradiation etc. Because this cooling system is so sensitive to the velocity of the wind, it is unable to operate in the nominal operating cell temperature (NOCT) or the standard test condition (STC) which allow it to generate the maximum output. This paper proposes a cooling system using thermoelectric elements to solve such problems. The temperature control of thermoelectric elements can be controlled independently in an outdoor environment because it is performed by a micro-controller. In addition, it can be operated around the NOCT or the STC through an algorithm for temperature control. Therefore, the output of the system is increased and the efficiency is raised. This paper proves the validity of the proposed method by comparing the data obtained through experiments on the cooling systems of BIPV modules using a ventilator and thermoelectric elements.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.233-236
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• 2003

In this Paper, the temperature control error and cooling characteristics of inverter typ coolers are evaluated to predict application validity of coolers under heating pattern and amount The temperature control error of coolers small in 15~70% range of the max. cooling ability. At less than 15% of max. cooling ability has the inverter type cooler a basic temperature control error $\pm0.5^{\circ}C$ and acts as on/off type coolers. The inverter type cooler is unsuitable for precision temperature control under the complex heating pattern. But PID control of cooler including the heating system is an alternative for the case.