Effect of air density variations on greenhouse temperature model

Basically, a greenhouse temperature model is determined based on the balances of mass and energy. In most of the available models, the air density is considered constant. This fact limits the model because of the natural existing relationship between the air density and air humidity. In this work a way to include the effect of air density variation in a greenhouse temperature model is proposed. Through the proposed model it is possible to obtain a better sensibility of the temperature when variations in the air density are present. The pertinence of the proposed extension is analysed via simulations. The results show that the temperature calculus in the greenhouse can be improved when the air density variations effect is considered. As a consequence, strong humidity variations, such as the use of nebulizers inside the greenhouse will affect the prediction calculus of the temperature, which is why they must be taken into consideration. (c) 2007 Elsevier Ltd. All rights reserved.