Radiometric Characterization, Solar and Thermal Radiation in a Greenhouse as Affected by Shading Configuration in an Arid Climate

Abdel-Ghany, Ahmed M.; Picuno, Pietro; Al-Helal, I.M.; Alsadon, Abdullah A.; Ibrahim, Ahmed A.; Shady, Mohamed

doi:10.3390/en81212404

Cited by 41 publications

(20 citation statements)

References 29 publications

(41 reference statements)

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“…This has led to the rapid expansion of the use of greenhouses for crop protection. The critical challenge facing greenhouse operation under these conditions is the unacceptable increases of the inside greenhouse air temperature, which requires appropriate cooling methods to provide a favorable environment for crop growth [1,2]. Preventing solar heat load from entering the greenhouse is the most appropriate method for cooling greenhouses in arid regions [3].…”

Section: Introductionmentioning

confidence: 99%

“…Preventing solar heat load from entering the greenhouse is the most appropriate method for cooling greenhouses in arid regions [3]. Through this method, solar radiation can be reduced before entering the greenhouse by cutting-off (via absorption or reflection) a portion of the incident radiation on the greenhouse cover [1][2][3]. This can be accomplished by deploying fixed or movable shading nets below or above the roof of the greenhouse [4].…”

Section: Introductionmentioning

confidence: 99%

“…This can be accomplished by deploying fixed or movable shading nets below or above the roof of the greenhouse [4]. In sunny and hot regions, extensive use of plastic nets for shading greenhouses in summer has been recorded because of their positive impacts on the greenhouse microclimate, the productivity of crops, and many other environmental and economical benefits [1][2][3][4]. Plastic nets are also used as standalone covers (net houses) for modifying the microclimate, saving energy and water consumption, and protecting crops against virus-vector insects and birds [5,6].…”

Section: Introductionmentioning

confidence: 99%

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Predicting the Cooling Potential of Different Shading Methods for Greenhouses in Arid Regions

et al. 2019

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Shading greenhouses in a hot and sunny climate is essential to reduce the inside greenhouse air temperature. However, the type and location of nets need to be addressed properly to determine the shading method that provides a better cooling effect on the greenhouse air. This study was conducted to evaluate the effects of five different shading methods on greenhouse microclimates, and to investigate the cooling potential of each method. Four greenhouse models covered with 200-µm thick plastic film were used for the study: one was kept as control (C), one was whitened with slaked lime (L), and two were shaded with white and black nets (50% shading factor) deployed simultaneously at two locations, in contact (WC, BC) and at 20-cm distance from the cladding film (WD, BD). The microclimatic parameters were measured inside and outside the greenhouse models, and the cooling potential (CP) was predicted for each shading method. The results showed that the black net at 20-cm distance (BD) is desirable as it provides high CP with a reasonable solar radiation transmission. The maximum CP was estimated as 8.5 • C, 8 • C, 6 • C, 3.2 • C, and 2.1 • C for L, BD, BC, WD, and WC, respectively. Shading with white nets is not recommended because their cooling potential is very low. Based on these results, we developed correlations for predicting the CP for each shading method as a function of the transmitted solar radiation flux (S i ). These correlations depend on S i . Accordingly, they can be used for small greenhouses, whitewashed with a slaked lime of any concentration, or shaded with a black net having any shading factor.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Predicting the Cooling Potential of Different Shading Methods for Greenhouses in Arid Regions

et al. 2019

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“…Active blind-type shading systems have been investigated widely for building applications [54]. However, such systems have been investigated only rarely for greenhouse applications, although shading control is extremely important in greenhouse cultivations [12]. In the present manuscript, a novel PV blind system specific for greenhouse applications is presented.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, installing PV arrays partially on a greenhouse roof might be preferred if the PV panels are intended as shading materials. Shading is a fundamentally important practice for greenhouse cultivation in high-insolation regions, such as Spain [11] or Saudi Arabia [12]. Previous studies conducted in Japan [13] and in the Mediterranean region [14,15] demonstrated that an adequate level of shading mitigates excessive temperature rises in greenhouses in summer, improving crop growth and quality [16,17].…”

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confidence: 99%

Electrical Energy Producing Greenhouse Shading System with a Semi-Transparent Photovoltaic Blind Based on Micro-Spherical Solar Cells

Yano

Cossu

et al. 2018

Energies

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An increasing population and limited arable land area endanger sufficient and variegated food supplies worldwide. Greenhouse cultivation enables highly intensive plant production and thereby enables the production of abundant fresh vegetables and fruits. The salient benefits of greenhouse cultivation are supported by ingenious management of crop environments, assisted by fossil fuel and grid electricity supplies. To reduce dependence on traditional energy resources, various studies have investigated exploitation of renewable energies for greenhouse environment management. Among them, solar photovoltaic (PV) technologies are anticipated to feed electrical energy to greenhouse appliances for microclimate control. This study proposes a venetian-blind-type shading system consisting of semi-transparent PV modules as blind blades based on micro-spherical solar cell technology to achieve greenhouse shading and electricity production concurrently. In response to the solar irradiance level, the PV blind inclination was altered automatically using a direct current (DC) motor driven by electrical energy generated by the PV blind itself. The PV blind was operated continuously during a five-month test period without outage. Moreover, the PV blind generated surplus electrical energy of 2125 kJ for blind system operations during the test period. The annual surplus energy calculated under the present experimental condition was 7.8 kWh m −2 year −1 , suggesting that application of the PV blind to a greenhouse roof enables sunlight level control and electrical appliance operations in the greenhouse with a diminished fuel and grid electricity supply, particularly in high-insolation regions.Energies 2018, 11, 1681 2 of 23 produces carbon dioxide emissions, the amounts of which should be reduced in the agricultural sector [2]. Under these circumstances, various studies have been conducted to use renewable energy for managing greenhouse crop environments [3,4]. Among them, solar photovoltaics (PVs) are expected to feed electricity to appliances that are used for greenhouse environment management [5].Deploying PV arrays on the sunny ground beside a greenhouse is the simplest and most effective mode of electrical energy generation. For instance, fan and pad cooling systems in Saudi Arabia [6] and in Arizona [7], a fog cooling system in Malaysia [8], and heat pump systems in Italy [9,10] were operated with power from ground-mounted PV arrays. Nevertheless, installing PV arrays partially on a greenhouse roof might be preferred if the PV panels are intended as shading materials. Shading is a fundamentally important practice for greenhouse cultivation in high-insolation regions, such as Spain [11] or Saudi Arabia [12]. Previous studies conducted in Japan [13] and in the Mediterranean region [14,15] demonstrated that an adequate level of shading mitigates excessive temperature rises in greenhouses in summer, improving crop growth and quality [16,17]. Conventionally, nets [14,15,18] and reflective coatings [18,19] have been used as practical ...

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Toward Sustainable Agriculture: Net-Houses Instead of Greenhouses for Saving Energy and Water in Arid Regions

Abdel-Ghany

Al-Helal

2019

Sustaining Resources for Tomorrow

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Radiometric Characterization, Solar and Thermal Radiation in a Greenhouse as Affected by Shading Configuration in an Arid Climate

Cited by 41 publications

References 29 publications

Predicting the Cooling Potential of Different Shading Methods for Greenhouses in Arid Regions

Predicting the Cooling Potential of Different Shading Methods for Greenhouses in Arid Regions

Electrical Energy Producing Greenhouse Shading System with a Semi-Transparent Photovoltaic Blind Based on Micro-Spherical Solar Cells

Toward Sustainable Agriculture: Net-Houses Instead of Greenhouses for Saving Energy and Water in Arid Regions

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