Introduction:

The ability to manipulate environmental conditions within a greenhouse allows production control; however, technological constraints still persist in these systems.

Objective:

To model the environment of a zenith greenhouse cultivated with tomato using computational fluid dynamics (CFD), to propose environmental management alternatives and to estimate the energy expenditure and economic cost of using fans.

Methodology:

The energy expenditure (kW·h-1) and cost (MXN) of using natural and mechanical ventilation in greenhouses were estimated based on climate data from municipalities in San Luis Potosí and the State of Mexico. The analysis inside the greenhouse was carried out with CFD and climatological normals. In addition, the ventilation rate and thermal gradients were estimated to infer a local climatic potential as a function of optimum tomato temperatures. In addition, the ventilation rate and thermal gradients were estimated to infer a local climatic potential as a function of optimum tomato temperatures.

Results:

It was observed that in regions with mild summers, the use of mechanical ventilation combined with natural ventilation is a viable alternative by reducing temperature and energy costs. The 3D simulations carried out made it possible to have a detailed view of the spatial distribution of temperature and airflow inside the greenhouse.

Study limitations:

The model only considers wind speed and temperature. To include other variables, it must be calibrated.

Originality:

Ventilation rates (n = 35) and thermal gradients (3 K) were estimated using CFD to infer a regional climatic potential as a function of optimum tomato temperatures.

Conclusions:

Combined ventilation reduces problems due to high temperatures in hours of maximum radiation, with no significant impact on production costs.

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