Sustainable insulation solutions for hydroponic greenhouses: The effects of textile waste reinforcement on thermal microclimate

Abstract

Recycling waste into construction materials represents an adequate solution to both the problem of energy shortage and environmental pollution problem. This study investigated the impact of incorporating textile waste in cementitious blocks to improve the microclimate of greenhouses. The study involved a year-long experimental investigation of a transparent greenhouse (Ref_Gh) and a thermally insulated hydroponic greenhouse (THP_Gh), followed by the development of a numerical model to assess the thermal environment of a hydroponic greenhouse (TRC_Gh) built with cement blocks made by replacing 30% of the sand volume with textile fibers. The results showed that the daytime temperature variation inside the TRC_Gh was 2 °C higher than in the THP_Gh, but still much lower than that in the Ref_Gh. However, the reference greenhouse showed the lowest temperature values at night. The TRC_Gh showed a significant heat demand at night, higher than the demand for the THP_Gh but still lower than the demand for transparent shelter, peaking at 90 W/m2 in December. The study concluded that a hydroponic greenhouse built with textile-reinforced cement blocks offers better thermal performance than a greenhouse made with Plexiglas, but thermal-panel greenhouses still offer the best thermal performance. However, an economic analysis showed that a TRC_Gh has a 1.3-year shorter payback period than a THP_Gh. Overall, this study highlights the benefits of recycling textiles into construction insulation materials. The novelty of this work lies in its approach to improving the microclimate of hydroponic greenhouses by integrating a new insulation material in an efficient and environmentally friendly way.