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The solar thermal storage is an important issue for greenhouse applications in winter period. For the reason that greenhouse operations, such as heating and cooling, consume a large amount of energy. The thermal storage is important to minimize the cost of greenhouse production. Surplus air thermal energy (SATE) is available in greenhouses during all the year, even in the cold period, hence its use in greenhouse applications is possible. In this present work, a solar heating cooling system (SHCS) with quartzitic sandstone as thermal storage material to store and use the SATE in greenhouse production was operated for cooling and heating processes and its performance was evaluated during winter period. This system consists of a quartzitic sandstone and including thermal storage blocks and pipes with fans to manage those processes in greenhouse. This system was located in the Souss-Massa region, Morocco. The heating and cooling of inside air by SHCS can improve the greenhouse microclimate and tomato yield. The results show that the air temperature in greenhouse equipped with SHCS exceeds than that of the control one about 3 °C at night and 6 °C lower during day, with fewer fluctuations. Moreover, the relative humidity was 10% lower at night. The SATE stored was varied between 15.68 and 140 MJ/day in plastic greenhouse with an area of 165 m2 during day, and 65% of this heat recovered at night. The SHCS was improved the tomato yield about 1.74 kg/m2 than that of normal production. An economic analysis revealed that this system is very profitable and could generate profits for farmers.

The following paper presents a Computational Fluid Dynamic (CFD) comparative study of the effect of side wall and roofs vents openings on canary greenhouse airflow circulation and climate distribution under different ventilation processes. The investigation was conducted in a one hectare canary greenhouse type, which is the most widespread type in the whole Mediterranean and along the Atlantic coast area of Morocco, especially in souss vally region. The simulations were performed with the commercial code CFD2000 based on the solution of the partial differential equations, which describe the flows, and was obtained by discretizing the space and time and solving the transport equations on the spatial grid as difference equations, used a finite volume discretization. The standard two equations k-ε model was used to describe the turbulent transport. The influence of external factors such the cover temperature, the wind speed, on the flow was simulated by boundary conditions, these values were obtained from experimental results. Simulations were conducted with a fixed wind speed equal 1.05 m/sec, tomato crop rows oriented north-south and the ventilation openings are continuous and equipped with insects screen type 20/10. Results reveal that ventilation opening arrangements strongly affects the greenhouse wind speed, which can generate a heterogeneous climate, especially during daytime. But in the other hand, results confirm that there is no significant effect of the side wall vents opening on canary greenhouse air temperature and humidity fields.

The aim of this paper is to predict in details the distributed nocturnal climate inside a one hectare Moroccan canary type tomato-greenhouse equipped with continuous roof and sidewalls ventilation openings with fine insect screens, by means of 3D CFD (Computational Fluid Dynamics) simulations by using a commercial Software package CFD2000 based on the finite volumes method to solve the mass, momentum and energy conservation equations. The turbulent transfers were described by a k-e model. Likewise, the dynamic influences of insect screens and tomato crop on airflow movement were modeled by means of the concept of porous medium with the Boussinesq assumption. Atmospheric radiations contribution was included in the model by customising the plastic roof cover temperature deducted from its energy balance. Also, the CFD code was customized in order to simulate in each element of the crop cover the sensible and latent heat exchanges between the greenhouse air and tomato crop. Simulations were carried out with a wind prevailing direction perpendicular to the roof openings (west-east direction). Simulations were later validated with respect to temperature and specific humidity field measurements inside the experimental greenhouse. Also, the model was verified respect to global sensible and latent heat transfers. Results show that, generally, greenhouse nocturnal climate distribution is homogeneous along the studies greenhouse area. The insect proof significantly reduced inside airflow wind speed. But there is no significant effect on the inside air temperature and specific humidity respect to outside.