Simultaneous Control of inside Air Temperature and Humidity by coupled Heating and Ventilation in a Greenhouse

Abstract

Greenhouse ventilation combined with heating is required to control temperature and moisture levels for a comfort and provide CO₂ for good photosynthesis. The present study focuses on the simulation of a climate in greenhouse during winter. The mathematical model, based on the energy and the water vapor balances inside the greenhouse is used. The main equations of flow are solved with the Fluent^Ò CFD package inside and outside the greenhouse. The external conditions are those of Mediterranean climate and the greenhouse is located in Tizi-Ouzou (Algeria). The study aims at getting a better compromise between flow heating combined with the air exchange rate (a technique used for the dehumidification of the air). After describing the physical phenomena, the equations that govern these phenomena and the method of solving these equations, a program for calculating the inside temperature and humidity was developed and validated by comparison with simulation results. To simulate turbulence inside and outside greenhouse the k-e  Standard turbulence model, which comes out (seems) to be more accurate than the other models, have been preferred. Analytical results are used to determinate optimal conditions of flow heating combined with ventilation rate. 

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