Experimental Verification of Control Logic for Operation of a Fog Cooling System for a Naturally Ventilated Greenhouse

Handarto,; Hayashi, Makio; Gotō, Eiji; Kozai, Toyoki

doi:10.2525/ecb.45.47

Cited by 14 publications

(4 citation statements)

References 6 publications

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“…Cooling is used as temperature control in the summer, using fogging (Handarto et al, 2006(Handarto et al, , 2007 and fan -and-pad (Al-Mulla et al, 2018;Lopez et al, 2010) systems. These systems operate with low energy costs as they use heat from water vaporization, but they have more difficulty to control temperature and humidity adequately.…”

Section: Introductionmentioning

confidence: 99%

Local Temperature Control in Greenhouse Vegetable Production

Kawasaki

Yoneda

2019

Hortic J

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Uniform temperature throughout a greenhouse is recommended, as the present climate control method and many other studies have shown that the temperature gradient decreases vertically and horizontally in a greenhouse. However, recent research revealed that roots, fruits, flowers, and shoot-tips are more sensitive to temperature changes than leaves and stems, indicating that uniform temperature control may not be necessary. In addition, energy-saving techniques that do not lead to yield loss are desirable to reduce energy costs and ensure sustainable greenhouse production. In this paper, we review current studies on local temperature control methods in greenhouse vegetable production, primarily focusing on the tomato, and compare them with novel climate-control techniques. Roots, fruits, shoot-tips, and flowers are sensitive to temperature changes, showing negative symptoms under extreme temperature conditions. Therefore, the temperature of these plant organs should be controlled locally. Root zone temperature control enhances root growth and its associated physiological activities, promoting uptake of water and mineral nutrients. This subsequently leads to enhanced growth of shoots. Fruit temperature control may not be effective for tomato plants, but it promotes fruit growth and fruit sugar accumulation in melons and watermelons. Shoot-tip temperature control promotes the differentiation of leaf and flower buds. Flower temperature control enhances pollen viability and promotes fruit set. The combination of shoot-tip and flower heating enables low energy consumption compared with conventional heating, without loss of yield. Local temperature control techniques (except roots) have been studied in recent years; however, there is a distinct lack of research on the physiological mechanisms and practical approaches to develop a better local temperature control system. Thus, further studies are required on this area in the future.

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Section: Introductionmentioning

confidence: 99%

Local Temperature Control in Greenhouse Vegetable Production

Kawasaki

Yoneda

2019

Hortic J

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“…However, the hardware of the computers used for controlling the environment was not open source, which means that if the vendor stopped the supply of the devices, it would be difficult to recreate the system with the same logic. Data logging systems have been installed and programmed for controlling devices (Handarto et al, 2006;Handarto et al, 2007), and high-performance data logging systems (e.g., the CR1000 or CR10X provided by Campbell Scientific, North Logan, UT, USA) are adequate to test complicated algorithms. However, the programs must be specifically designed for the controlling devices using non-open-source and machine-dependent programing languages.…”

Section: Resultsmentioning

confidence: 99%

“…Although commercial computer systems have highly user-friendly interfaces and the ability to precisely control various kinds of device (e.g., heaters, ventilators, shading curtains, irrigation systems, fogging systems), the control logic in these commercial systems is sometimes inflexible, and it is sometimes impossible to modify the original complicated control logic. Modifying the original control logic frequently requires users to choose dedicated hardware and develop new software to operate it (Handarto et al, 2006;2007). This inflexibility restricts the spread of this type of computer system, and because development of specialized programs is necessary in the case of controlling simple logic, it is not very user-friendly.…”

Section: Introductionmentioning

confidence: 99%

Development of Program Library Using an Open-source Hardware for Implementation of Low-cost Greenhouse Environmental Control System

Yasuba

Kurosaki

Hoshi

et al. 2018

Environmental Control in Biology

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A program library for use on open-source hardware was developed in order to construct a low-cost environmental control system for greenhouses. The library facilitated the development of environmental sensing and control devices that conform to the protocols of the Ubiquitous Environment Control System (UECS). The open-source hardware used was the "Arduino Ethernet" and the "Arduino Mega 2560 with Ethernet Shield" microcontroller boards. UECS is a system for controlling greenhouse environments that communicates information via a local area network, and devices utilizing the library that we developed can perform the UECS defined communication tasks automatically. With the help of this library, device developers no longer need to program the communications aspects of the device and can concentrate on programming setting and control logic of the device. The library occupies about 29 kilobytes of the read only memory area of the target board. The library and associated open-source microcontroller boards are powerful tools for developing low-cost environmental control systems.

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“…The average diameter of the fog droplets was 10-20 µm. We estimated the required fogging rate according to the environmental conditions (solar radiation, dry and wet bulb temperatures, and ventilation rate) Handarto et al, 2007), and the fogging rate was changed within 0-0.24 g m -2 s -1 by controlling the number of fogging nozzles. The fogging rate was calculated at 30-s intervals.…”

Section: Methodsmentioning

confidence: 99%

Analysis of the Aerial Environment of a Tomato Greenhouse Equipped with Different Fog Cooling Systems

Ishigami

Tetsuka

Gotō

2014

J. Agric. Meteorol.

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Fog cooling systems with natural ventilation are a type of evaporative cooling technique that is widely used in Japan. One drawback of these systems is that it is difficult to maintain the greenhouse air temperature at its optimum range in summer using the conventional single-fluid nozzle system because it has a low cooling efficiency and produces a high risk of pathogen invasion due to excessive wetting of the plant foliage. Therefore, we introduced a twin-fluid nozzle system as an alternative fogging system. This system affords a higher evaporation ratio and a lower degree of plant foliage wetting because it generates fog droplets with diameters smaller than those generated by single-fluid nozzles. We installed these two types of fogging systems in tomato greenhouses and investigated the different aerial environments that they produced. We observed that the twin-fluid nozzle system maintained the air temperature at the same level as that maintained by the single-fluid nozzle system. We also observed that the single-fluid nozzle system significantly inhibited the evapotranspiration in the tomato plants due to wetting of the plant foliage, whereas the evapotranspiration rate when using the twin-fluid nozzle system was 70-100 % higher.

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Experimental Verification of Control Logic for Operation of a Fog Cooling System for a Naturally Ventilated Greenhouse

Cited by 14 publications

References 6 publications

Local Temperature Control in Greenhouse Vegetable Production

Local Temperature Control in Greenhouse Vegetable Production

Development of Program Library Using an Open-source Hardware for Implementation of Low-cost Greenhouse Environmental Control System

Analysis of the Aerial Environment of a Tomato Greenhouse Equipped with Different Fog Cooling Systems

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