Heating and CO₂ enrichment systems can improve yields in intensive greenhouse agriculture Combining both techniques, which are currently applied commercially, can potentially enhance their effect. The CO₂ must be separated from the other noxious gases present (such as CO, NO_X, and SO₂) to avoid them becoming part of the supply. The CO₂ is then provided to the greenhouse on demand in the same way as the heating. In this work, we show that an improved food productivity of a pilot-scale greenhouse system combined with CO₂ capture by adsorption using activated carbon and heating with alternative fuel. The proposed system's overall performance was evaluated and optimized. The best values were 46.7 g/kg of CO₂ storage capacity on the adsorbent bed, 99.99 % removal rate harmful gases from the gas supplied to the greenhouse, CO₂ levels of 1851.0 ± 262.8 mg/Nm³ of the CO₂ levels in the greenhouse, and an enrichment time of 2.18 ± 0.92 h/day. The system's effective performance over extended periods (November-February) was confirmed and the productivity of a crop species (tomato) was compared to a control, showing an increment of 18 %. The results indicate that this is a valuable option for increasing the crop yield. By integrating this combined system with advanced climate control strategies, it is possible to maximize the CO₂ provided per day, leading to higher yields. The system proved to be stable under real pilot-scale conditions over winter periods (four months).

Large amounts of crop residue are produced annually in areas such as Almeria (Spain). These residues have elevated moisture and ash contents, and are also very heterogeneous, which hinders their reutilization. With the aim of facilitating biomass utilization in energy recovery-related processes, a model for solar drying was developed. Experiments were performed inside a greenhouse with tomato and pepper residues, following two strategies (hung or stacked residues). The influence of temperature and relative humidity on the residues’ equilibrium moisture was also studied. The results were that a model allowed for determination of the equilibrium moisture as a function of ambient conditions (temperature and relative humidity), with the model’s characteristic parameters being different for each crop residue. Regarding the drying process, the results conform to first-order kinetics, with the values of the kinetic constants varying as a function of the crop residues and their arrangement. The variation in equilibrium moisture as a function of the annual variation in ambient conditions (temperature and relative humidity) in Almería means that it would only be possible to dry crop residues inside greenhouse below a moisture level of 0.43 kg_water/kg_drysolids (30% water content) from April to November.