Assessing heating and cooling needs of hydroponic sheltered system in mediterranean climate: A case study sustainable fodder production

Abstract

Supplying the heating and cooling needs of a soilless vertical farming system for an intensive and sheltered fodder production system is explored. This paper describes a full system consisting of a Hydroponic Greenhouse (HG), a freshwater tank, and a Multi-Level Pipes Exchanger System (ML_PESys). The ML_PESys warrants the conditioning of the HG and operates in two modes: summer mode during hot periods and winter mode during cold periods, by activating the optimal number of layers. In this work, a dynamic modeling and experimental approach are followed to examine the thermo-energetic setting of the hydroponic greenhouse. Furthermore, an energetic balance is performed to substantiate the chosen model and uphold its validation. The hydroponic greenhouse is heated via a solar water system composed mainly of two evacuated tube solar collectors and cooled with freshwater. An experimental case study is conducted to examine the effect of conditioning on the greenhouse microclimate and its effects on forage growth and productivity. An HGH-Sim model was also used to substantiate the ML_PESys performance in both summer and winter. After validating the model, the numerical results showed an increase in nighttime temperature of between 5 and 6 °C during the test period and a diurnal temperature drop of about 6 °C throughout the warm period. The cooling process was only done in the daytime. The benefit of this application is to increase plant height and get more yield. Compared to traditional feed, hydroponic fodder improves health and reduces feed requirements for livestock. The novelty of this research refers to presenting a new approach aiming to ensure the energy supply of a hydroponic greenhouse for forage crops including a new methodology and new observation. This study brings out the effect of implementing the innovative environmentally friendly conditioning system not only in ensuring the energy supply of a hydroponic greenhouse but also in improving the feed length and the harvest yield.