• Journal of Bio-Environment Control
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• v.9 no.4
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• pp.201-206
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• 2000

A certain system to overcome high temperature should be introduced for the stable year-round cultivation in greenhouses. There are efficient methods to overcome high temperature such as ventilation system with shading screen, fan and pad system with screen, and fog system with screen. This study was carried out to find a means to determine the capacity of such system. Heat balance equations for each system were established and verified by experimental results. The calculated ventilation rates from heat balance equations showed a good agreement with the measured ones. The evapotranspiration coefficient was the most important parameter affecting the ventilation requirement among input parameter affecting the ventilation requirement among input parameters except weather data. When the evaportanspiration coefficient increased 1%, the ventilation requirement decreased 1.3%. Therefore the data of evapotranspiration coefficient should be accumulated by various experiments, and then design standards and selection guidelines should be provided. The simulation results for same design conditions shown that air exchanges requirement and evaporating water of fan and pad system were 5.1∼7.7% and 6.8∼9.3% larger than those of fog system, respectively.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.445-450
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• 2012

At the limited space, the air conditioning may have difficult to control temperature or humidity for home use. Nowdays, the people reponse to temperature or humidity sensitively. This becomes the Indoor Air Quality (IAQ) is an important factor for comfortably. Heat recovery ventilator (HRV) is used for the solution of inconsistency between IAQ and power-saving. Also, the thermoelectric element is applied to HRV and compared with temperature efficiency and verifying the capacity of the system. To improve the temperature efficiency a single motor and thermoelectric element with the conductive guide vane is experimented. The results shows that it can save 23 W by using the single motor. The developed system of 250 CMH capacities with the thermoelectric element reveals the temperature efficiency improvement of 4.01% in cooling period and 2.98% in heating period compared to the conventional system.

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.1-7
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• 2011

The objective of the present study is to identify the applicability of a low pressure fogging system for cooling commercial tomato greenhouse. In particular, the cooling system in this experiment utilizes low pressure spray nozzles which were developed in Korea recently. The experimental result that the temperature in fog-cooled greenhouse was lower than the non-cooled greenhouse showed the cooling effect by the low pressure fogging system. But because the relative humidity in fog-cooled greenhouse was comparatively low, the satisfactory cooling effect could be acquired by narrowing the space of fog nozzles and extending fogging time to supply more fog spray quantity. The variation of temperature distribution in fog-cooled greenhouse along timelag was insignificant during short time, but that was great during long period of day. This result showed the variation of temperature along timelag was slight by fog cooling but great by other factors like radiation, ventilation, air flow, etc. The advanced operation technology of fog system was required to reduce the variation of temperature along time lag. We plan to suggest the advanced installation and operation technology of low pressure fogging system for cooling commercial tomato greenhouse by further experiments in near future.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.2
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• pp.47-54
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• 2024

The global decrease in traditional energy resources has prompted increasing energy demand, necessitating efforts to replace and optimize energy sources. This study focuses on enhancing energy efficiency in manufacturing plants, known for their high energy consumption. Through simulations and analyses, the study proposes a temperature-based control system for HVAC (Heating, Ventilating, and Air Conditioning) operations, utilizing machine learning algorithms to predict and optimize factory temperatures. The results indicate that this approach, particularly the prediction-based free cooling algorithm, can achieve over 10% energy savings compared to existing systems. This paper presents that implementing an efficient HVAC control system can significantly reduce overall factory energy consumption, with plans to apply it to real factories in the future.

• Journal of Bio-Environment Control
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• v.6 no.1
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• pp.48-54
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• 1997

Among the various vegetables eggplant and gourd family can stand against high temperature environmental condition, about 35$^{\circ}C$. However, most of greenhouse farmers are giving up crop cultivation during hot summer season due to extreme temperature, 4$0^{\circ}C$ or above, condition of greenhouse interior. To improve this inferior crop growth condition, for nozzle system was installed in the pet greenhouse and the effect of fog system was investigated in order to determine fog water amount and the required fog nozzle numbers according to house volumes. MEE fog nozzle was selected for this Investigation which can produce water particle size of 27${\mu}{\textrm}{m}$ with water amount of 100$m\ell$ at pumping pressure of 70kg/$\textrm{cm}^2$. House cooling test was conducted in the pet greenhouse with one minute fogging and one minute air ventilation without stopping. It maintained 32$^{\circ}C$ at the house interior when the atmosphere and the house temperature were 35 and 4$0^{\circ}C$, respectively. And, an experimental equation was developed through calculating the changes of relative humidity and temperature with psychrometric equation which revealed the moisture transfer pattern between the house air and fog system. It showed that the required water fogging amounts to reduce 1$0^{\circ}C$, 40 to 3$0^{\circ}C$, needs 80.7$\ell$ for 1-2W(8,350㎥) and 99.9$\ell$ for 3-2G-3S(10,330㎥) type greenhouse with particle size of 27${\mu}{\textrm}{m}$.