Effects of Side Vents and Span Numbers on Wind-Induced Natural Ventilation of a Gothic Multi-Span Greenhouse

Kaçıra, Murat; Sase, Sadanori; Okushima, Limi

doi:10.6090/jarq.38.227

Cited by 50 publications

(23 citation statements)

References 8 publications

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“…CFD has also been used for the design of more efficient ventilation systems. For instance Kacira et al (2004) and Baeza et al (2009) conducted CFD simulations to investigate the effect of side vents in relation to the number of spans. Both studies showed the importance of side ventilation combined with roof ventilation in large greenhouses.…”

Section: Introductionmentioning

confidence: 99%

Shading screens for the improvement of the night time climate of unheated greenhouses

Montero¹,

Muñoz²,

Sánchez-Guerrero

et al. 2013

Span. j. agric. res.

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The objective of this work was to study the effect of shading screens, normally used during the day for cooling purposes, on the night-time climate of unheated greenhouses. For this purpose, first a number of experimental measurements were taken during cold nights to characterise the greenhouse climate both with and without an aluminised external screen. Secondly a Computational Fluid Dynamic (CFD) model of greenhouse was developed. After validation of the model by comparison with experimental data, the model was used to simulate the greenhouse climate for different sky conditions ranging from cloudless to overcast nights. Simulations were performed for a greenhouse with internal and external shading screens and for the same greenhouse without screens. Experimental results showed the positive effect of an external shading screen, whose use increased night-time temperature and reduced the risk of thermal inversion. Its effect was much stronger under clear sky conditions. The CFD model supported this conclusion and provided a detailed explanation of the temperature behaviour of all the greenhouse types considered. CFD simulations proved that an aluminised screen placed inside the greenhouse at gutter height gave the greatest thermal increase. Therefore, external or internal screens can help to increase the sustainability of greenhouse production in areas with mild winter climates by enhancing the use of solar energy stored in the greenhouse soil during the previous day and released at night-time.

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Section: Introductionmentioning

confidence: 99%

Shading screens for the improvement of the night time climate of unheated greenhouses

Montero¹,

Muñoz²,

Sánchez-Guerrero

et al. 2013

Span. j. agric. res.

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“…Their results provide valuable guidance for ventilation system management; however, they are limited to specific greenhouse structures and local climate conditions. So far, most numerical studies of natural ventilation have focused on greenhouse climate and ventilation performance during the summer (Baeza et al, 2009;Bartzanas et al, 2004;Fatnassi et al, 2003Fatnassi et al, , 2006Hong et al, 2008;Kacira et al, 1998Kacira et al, , 2004Kichah, Bournet, Migeon, & Boulard, 2012;Nebbali et al, 2012;Ould Khaoua et al, 2006;Teitel et al, 2008). Few have examined the effect of vent opening on greenhouse climates during the different seasons of summer and winter when natural ventilation is respectively used for cooling and dehumidification.…”

Section: Introductionmentioning

confidence: 99%

“…In the greenhouse engineering community, many researchers have employed CFD to study the effects of greenhouse design (Bartzanas, Boulard, & Kittas, 2004;, Bournet, Ould Khaoua, Boulard, Migeon, & Chassériaux, 2007Hong et al, 2008;Kacira, Sase, & Okushima, 2004;Kacira, Short, & Stowell, 1998;Kittas and Bartzanas, 2007;Lee, Short, Sase, Okushima, & Qiu, 2000;Ould Khaoua, Bournet, Migeon, Boulard, & Chassériaux, 2006), specific equipment (Baeza et al, 2009;Fatnassi, Boulard, & Bouirden, 2003;Fatnassi, Boulard, Poncet, & Chave, 2006;Montero et al, 2013;Tamimi, Kacira, Choi, & An, 2013) and external weather conditions (Hong et al, 2008;Nebbali, Roy, & Boulard, 2012; Ould 400 K. He et al Khaoua et al, 2006;Teitel, Ziskind, Liran, Dubovsky, & Letan, 2008;Tong et al, 2009) on greenhouse climates. Their results provide valuable guidance for ventilation system management; however, they are limited to specific greenhouse structures and local climate conditions.…”

Section: Introductionmentioning

confidence: 99%

The effect of vent openings on the microclimate inside multi-span greenhouses during summer and winter seasons

Chen

Sun

et al. 2015

Engineering Applications of Computational Fluid Mechanics

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In research literature, little attention has been applied to the effect of vent openings on greenhouse climates during cooling and dehumidification processes with natural ventilation, which would provide guidelines for greenhouse management. To address this problem, a 3D CFD model was successfully designed based on 11-span plastic greenhouses. The model was validated with the measured air temperature and relative humidity, and then used to investigate the effects of vent configuration and opening size on the greenhouse climate. The simulations show that the vent configuration affects greenhouse microclimate patterns and the spatial and temporal variations of the internal climate. Meanwhile, the vent opening size affects greenhouse dehumidification time, air temperature and relative humidity during the dehumidification process. Finally, the assessments of ventilation performance highlight that the roof plus side opening is most suitable for summer cooling, while the roof opening is most suitable for winter dehumidification.

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“…CFD has been used to study the effects of side vent opening size and location on airflow patterns and temperature distribution in naturally ventilated greenhouses (Lee and Short, 2000). Kacira et al (2004) analyzed the effect of wind speed, side ventilators, and span numbers on ventilation rates using the CFD approach, showing that when both side and roof ventilators were used, maximum greenhouse ventilation rates were achieved. Lee et al (2002) used CFD models to study the effect of roof vent opening of fully open-roof style multi-span greenhouses, and validated the output with particle image velocimetry (PIV) data.…”

Section: Simulationmentioning

confidence: 99%

Numerical Modeling of Greenhouse Floor Heating

Reiss¹,

Mears²,

Manning³

et al. 2007

Transactions of the ASABE

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A numerical simulation model of a greenhouse floor heating system was developed and validated using data collected in a research greenhouse located at Cook College, Rutgers University, New Brunswick, New Jersey. The model was then modified and used to evaluate two different heat pipe diameters and spacings that are typical in the greenhouse industry today: 13 mm (0.5 in.) diameter pipe placed on 22.9 cm (9 in.) centers, and 19 mm (0.75 in.) diameter pipe placed on 30.5 cm (12 in.) centers. Two heat pipe elevations within the solid concrete floor system were also simulated, and the effects of the pipe's vertical position, diameter, and spacing on surface heat flux, surface temperature, and surface temperature uniformity were evaluated. The simulation results showed that the smaller diameter pipe placed closer together and at a lower elevation provided the best temperature uniformity without compromising other performance criteria. The model was then further modified to simulate flats with growing media placed on the floor surface. Model simulations were conducted for six different supply water temperatures ranging from 32.2°C (90°F) to 60°C (140°F), while maintaining a target ambient greenhouse air temperature of 15.6°C (60°F). The simulation outputs showed that using the smaller diameter pipe placed closer together resulted in a higher surface heat flux, a higher growing media temperature, and greater temperature uniformity within the growing media, for each supply water temperature simulated.

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Effects of Side Vents and Span Numbers on Wind-Induced Natural Ventilation of a Gothic Multi-Span Greenhouse

Cited by 50 publications

References 8 publications

Shading screens for the improvement of the night time climate of unheated greenhouses

Shading screens for the improvement of the night time climate of unheated greenhouses

The effect of vent openings on the microclimate inside multi-span greenhouses during summer and winter seasons

Numerical Modeling of Greenhouse Floor Heating

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