Numerical evaluation of passive strategies for nocturnal climate optimization in a greenhouse designed for rose production (Rosa spp.)

Abstract

In passive plastic greenhouses that do not have heating systems, the phenomenon of thermal inversion occurs, which means that the temperature inside the greenhouse is lower than the outdoor environment; therefore, the plants are exposed to thermal conditions that are unsuitable for production. The aim of this work was to evaluate passive air climatization alternatives seeking to optimize the nocturnal microclimate of a multi-tunnel Gothic greenhouse projected for rose production in Bogota savannah. The experimental approach included the use of a CFD-2D simulation model successfully validated by recording and archive of temperature data in a greenhouse. A total of 24 steady-state simulations were developed that included 3 nighttime temperature values, 2 sky conditions and 4 greenhouse configurations. The results showed that under the clear sky condition there was a thermal inversion with a value of -0.53 and -1.11 °C for the standard night-time greenhouse configuration. The installation of a thermal screen and porous mesh in the fixed roof vents allowed to control the presence of thermal inversion under clear sky conditions and optimizing the indoor temperature value in the greenhouse under cloudy sky conditions.