Smart and Solar Greenhouse Covers: Recent Developments and Future Perspectives

Abstract

The examination of recent developments and future perspectives on smart and solar greenhouse covers is significant for commercial agriculture given that traditional greenhouse relied on external energy sources and fossil fuels to facilitate lighting, heating and forced cooling. The aim of this review article was to examine smart and solar materials covering greenhouse. However, the scope was limited to intelligent PhotoVoltaic (PV) systems, optimization of some material properties including smart covers, heat loading and the use of Internet of Things (IoT) to reduce the cost of operating greenhouse. As such, the following thematic areas were expounded in the research; intelligent PV systems, optimization of the Power Conversion Efficiency (PCE), Panel Generator Factor (PGF) and other material properties, heat loading future outlook and perspectives. The intelligent PV section focused on next-generation IoT and Artificial Neural Networks (ANN) systems for greenhouse automation while the optimization of material parameters emphasized quantum dots, semi-transparent organic solar cells, Pb-based and Pb-based PVs and three dimensional (3D) printing. The evaluation translated to better understanding of the future outlook of the energy-independent greenhouse. Greenhouse fitted with transparent PV roofs are a sustainable alternative given that the energy generated was 100% renewable and economical. Conservative estimates further indicated that the replacement of conventional sources of energy with solar would translate to 40–60% energy cost savings. The economic savings were demonstrated by the Levelized cost of energy. A key constraint regarded the limited commercialization of emerging innovations, including transparent and semitransparent PV modules made of Pb-quantum dots, and amorphous tungsten oxide (WO3) films, with desirable electrochromic properties such as reversible color changes. In addition to intelligent energy harvesting, smart IoT-based materials embedded with thermal, humidity, and water sensors improved thermal regulation, frost mitigation and prevention, and the management of pests and disease. In turn, this translated to lower post-harvest losses and better yields and revenues.

Evaluation of the Viability of 3D Printing in Recycling Polymers

“…3D printing has found application in managing agricultural plastic wastes to make useful plastic products for farming applications. Evidence from Maraveas et al [ 88 ] and Maraveas, Bayer, and Bartzanas [ 112 ] consistently shows that 3D-printed Nano-materials exhibit exemplary toughness because they are reinforced and multi-layered for high strength. The examination of the studies [ 88 , 112 ] indicates that the feedstocks used in the 3D printing comprised of clean thermoplastics that were used in the manufacture of greenhouse covers and other agricultural applications such as shade nets and food packaging.…”

“…Evidence from Maraveas et al [ 88 ] and Maraveas, Bayer, and Bartzanas [ 112 ] consistently shows that 3D-printed Nano-materials exhibit exemplary toughness because they are reinforced and multi-layered for high strength. The examination of the studies [ 88 , 112 ] indicates that the feedstocks used in the 3D printing comprised of clean thermoplastics that were used in the manufacture of greenhouse covers and other agricultural applications such as shade nets and food packaging. Additionally, the feedstocks used included PLA and ABS materials that were non-biodegradable polymer filaments [ 112 ].…”

“…Given the adaptability of agricultural plastic waste management in distributed and local recycling, functional agricultural plastic products can also be locally produced through 3D printing using filaments from recycled plastics. Maraveas et al [ 88 ] and Maraveas [ 89 ] agree that increased agricultural plastic waste results from their limited durability. Similarly, a Lifecycle Assessment (LCA) of plastics by Vidakis et al [ 90 ] and Mohammed et al [ 65 ] revealed that less durable plastics contribute to the rapid generation of plastic waste.…”

“…However, the heating or melting process involved reduces the molecular weight of the material, suggesting a high likelihood of defects in 3D printing filaments produced from plastics recycled by HME and FDM. [ 88 ] Experimental study with quantitative and qualitative analysis of properties of 3D printed polymers suitable for greenhouse. HDPE and Nylon 3D printing is used in the production of smart solar and greenhouse covers.…”

Near-Infrared Reflective Greenhouse Covering: A Novel Strategy for Electricity-Free Cooling

“…Polymer substrates, additives, and wall materials all have an impact on the microclimates inside greenhouses. 11 Materials such as photovoltaic power generation and phase change material (PCM) have been used to regulate the greenhouse microclimate and reduce the greenhouse energy demand, 12 but their technical barriers and cost issues may limit their widespread promotion.…”