• Food Science and Preservation
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• v.9 no.2
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• pp.137-143
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• 2002

Temperature and humidity are the most important factors and should be effectively controlled for the cold storage of graius. Fuzzy logic can be easily implemented to the MIMO(Multi-Input Multi-Output) control systems. For the cold storage in grain bin, fuzzy logic was applied to an air conditioning system. The capacities of the grain bin and the air conditioner are 80 tons and 30㎾, respectively. Also, the target values of temperature and relative humidity in outlet duct of the air conditioner were 8$\^{C}$ and 75%, respectively. In order to control temperature and relative humidity of air, a damper in inlet duct was manipulated for temperature control and a heater was used for humidity control. Temperature deviation and change of temperature deviation were used as input parameters for the fuzzy system. Humidity was only considered as a load. The experimental results showed that the controlled temperature of exhausted air was maintained at 8$\pm$2$\^{C}$. Relative humidity of the air was also controlled at the target relative humidity of 50∼80%.

• Journal of the Korean Society of Tobacco Science
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• v.13 no.1
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• pp.13-18
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• 1991

This experiment carried out to review influence of relative humidity, temperature and net weight on cigarette hardness for the uniformal control of cigarette quality. Obtained results are as follows: 1. The difference in the cigarette physical properties of constant hardness control is considerably lower than that of constant net weight control. 2. Contribution rate for cigarette hardness is relative humidity > net weight > temperature. 3. The multiple regression equation of cigarette hardness related with relative humidity, temperature and net weight is calculated as follows.

• Food Science and Preservation
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• v.4 no.2
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• pp.101-113
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• 1997

Temperature, relative humidity and ventilation are closely related one another, and they are the main factors to be controlled for the environmental control system of a storage facility. Conventional environmental control systems do not consider the interrelationship between temperature, relative humidity and ventilation, which results in low performance and high energy consumption. To overcome the inefficiency of the conventional ones, it was developed an on-off control system based on the interrelationship between the factors. The usefulness of the system was illustrated with the results produced by a set of experiments in a real world.

• Journal of Conservation Science
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• v.29 no.4
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• pp.311-320
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• 2013

The showcase has insufficient temperature control, but it has excellent humidity control. The annual average temperature and relative humidity inside the showcase was $18.8^{\circ}C$ and 60.3%, respectively, and the showcase showed lower temperature and higher humidity than the exhibition room. The temperature inside the showcase appeared with high variation according to the seasons, while relative humidity was ranging from 59% to 61% regardless of the seasons. The showcase showed high temperature and humidity likewise the exhibition room in summer. In addition, lowering of temperature was elevated relative humidity according to the operation of air conditioner in summer. A moisture problem occurred because the temperature and humidity differences between the exhibition room and showcase were large according to the operation of air conditioner in winter. PI for temperature and relative humidity inside the showcase is 18.0%, and it means conservation environment for exhibition is unsuitable. In particular, continuous management of temperature and humidity inside the showcase is required because PI in the summer and winter is less than 1.0%.

• Journal of the Korean Solar Energy Society
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• v.36 no.5
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• pp.31-50
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• 2016

To develope a greenhouse fog cooling system to control the temperature and relative humidity simultaneously to the target value, a theoretical analysis and experiments were done. The control process includes the measuring of environmental variables, setting and coding of the water and heat balance equations to maintain the target temperature and relative humidity in greenhouse, calculating of the open level of the greenhouse roof window that governs the natural ventilation and spray water quantity, and operating of the motor to open/close the roof window and pump to spray for water. The study results were shown to be very good because the average air temperature in the greenhouse was kept to be about $28.2^{\circ}C$ with the standard deviation of about $0.37^{\circ}C$ compared to the target temperature of $28^{\circ}C$ and the average relative humidity was about 75.2% compared to the target relative humidity was 75% during the experiments. The average outside relative humidity was about 41.0% and the average outside temperature was $27.2^{\circ}C$ with the standard deviation of about $0.54^{\circ}C$. The average solar intensity in the greenhouse was 712.9 W. The wind velocity of outside greenhouse was 0.558 m/s with the standard deviation of 0.46 m/s.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.39-40
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• 2017

This study aims to evaluate the humidity control performance of low-priced generic ceramic panels that are used to control humidity. Temperature and humidity are monitored by using 'Living Lab' and the change of indoor relative humidity is measured and analyzed. According to the results of the study, the indoor relative humidity of rooms installed with ceramic panels was found to be low compared to that of living rooms by 2.2%RH (test period) and 3.2%RH (daily). In the case of maximum relative humidity, rooms installed with ceramic panels were found to be low by 6.9%RH. The results are attributable to the humidity absorption of ceramic panels. Accordingly, future ceramic panels need the improvement of performance and an appropriate construction area should be derived depending on indoor space.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1065-1068
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• 2008

Concrete is still one most common construction materials even in railway structures. As structures become massive and mega-sized, the importance of early age concrete quality control becomes more significant. Among various factors, relative humidity and temperature are the primary factors governing the early age quality. Temperature raise due to cement hydration causes stress, which can develop to cracking with internal and/or external restraints. Exposure conditions including ambient temperature, humidity and wind also significantly affect the cracking behavior of early age concrete. Among many of studies on the early age concrete behavior, investigation on the variation of temperature and relative humidity internal of concrete is not common. That is in part because the difficulties in measuring the relative humidity and temperature inside the concrete. This study used a digital sensor with an appropriate logger to measure internal temperature and relative humidity. This direct measuring method is expected to provide more reliable and comprehensive data acquisition on the early age behavior of concrete.

• Journal of Biosystems Engineering
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• v.17 no.1
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• pp.55-64
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• 1992

The aim of this study was to develop a phytotron for studying the effects of environmental factors such as temperature and humidity on plant growth. This equipment consists of the growth chamber, and the measurement and control system including control algorithms required for optimum operation. As the first step of the study, a temperature and humidity control system was developed. The results of this study are summarized as follows ; 1. Pt-100 was selected to measure temperature and a linearized op-amp circuit was developed for signal conditioning. 2. Pt-100 wet bulb thermometer based on Asmann's principle was developed to measure relative humidity. 3. Temperature and relative humidity conditions were controlled by ON-OFF and PWM operation using a PID controller. And an autotuning algorithm using the characteristics of step response was developed to determine optimal PID constants which were independent of the size of apparatus and environmental factors. 4. Under the ambient temperature of $20^{\circ}C{\sim}25^{\circ}C$, the temperature was kept within the error of ${\pm}0.3^{\circ}C$ in the range of $10^{\circ}C{\sim}40^{\circ}C$, and the relative humidity was kept within the error of ${\pm}5%$ in the range of ${\pm}50%{\sim}90%$.

• KIEAE Journal
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• v.10 no.6
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• pp.131-137
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• 2010

This study aims to know temperature and humidity handling ability of Hwang-To brick and traditional paper window's in mock-up room test. To achieve these goals, mock-up room test was carried out. The results are as follows. 1) There are no significant differences among specimen in temperature handling capacity. 2) Traditional paper windows are very sensitive when compared with glass window in humidity control. 3) Traditional paper windows have a big handling capacity in humidity control when vapors letting out in mock-up room. 4) Hwang-To brick case is more stable than other cases in relative humidity variances because it has more potential to contain humidity.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.200-207
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• 2009

This study was conducted to analyze the variations of air temperature, relative humidity and pressure in a low pressure chamber for plant growth. The low pressure chamber was composed of an acrylic cylinder, a stainless plate, a mass flow controller, an elastomer pressure controller, a read-out-box, a vacuum pump, and sensors of air temperature, relative humidity, and pressure. The pressure leakage in the low pressure chamber was greatly affected by the material and connection method of tubes. The leakage rate in the low pressure chamber with the welding of the stainless tubes and a plate decreased by $0.21kPa{\cdot}h^{-1}$, whereas the leakage in the low pressure chamber with teflon tube and rubber O-ring was given by $1.03kPa{\cdot}h^{-1}$. Pressure in the low pressure chamber was sensitively fluctuated by the air temperature inside the chamber. An elastomer pressure controller was installed to keep the pressure in the low pressure chamber at a setting value. However, inside relative humidity at dark period increased to saturation level.. Two levels (25 and 50kPa) of pressure and two levels (500 and 1,000sccm) of mass flow rate were provided to investigate the effect of low pressure and mass flow rate on relative humidity inside the chamber. It was concluded that low setting value of pressure and high mass flow rate of mixed gas were the effective methods to control the pressure and to suppress the excessive rise of relative humidity inside the chamber.