CO₂ enrichment in protected agriculture has been extensively studied as a strategy to enhance crop productivity, resource use efficiency, and climate resilience. This systematic review examines the scientific literature on CO₂ enrichment in greenhouses, vertical farms, and controlled environment agriculture (CEA) systems, with a focus on its impact on crop physiology, photosynthesis, agricultural yield, modeling and simulation techniques, injection technologies, and sustainability challenges. A comprehensive bibliometric and systematic search was conducted in the Scopus database using key terms related to CO₂ enrichment and sustainable protected agriculture, following the PRISMA methodology. From an initial set of 212 documents, 171 were selected after removing duplicates, inaccessible articles, and studies not directly relevant to this context. The findings indicate that CO₂ enrichment can significantly improve photosynthetic efficiency, water use efficiency, and crop productivity, although its impact varies depending on species, environmental conditions, and application strategies. Computational models, such as CFD and machine learning, have optimized CO₂ distribution in controlled environments, contributing to more precise and resource-efficient agricultural practices. However, environmental and economic concerns, particularly energy consumption, carbon footprint, and the sustainability of CO₂ sources, remain critical challenges. To ensure the sustainable adoption of CO₂ enrichment, it is essential to integrate renewable energy sources, carbon capture and reuse technologies, and advanced CO₂ injection systems. This review provides a holistic assessment of current knowledge, identifying opportunities and barriers for the development of climate-smart protected agriculture systems that align with global sustainability goals and contribute to food security and environmental stewardship.

This study addresses solar energy applications in protected agriculture, focusing on greenhouses and related technologies. A bibliometric and technical analysis is developed, covering research published between 1976 and 2024, to identify the main trends and challenges in the use of solar energy in controlled environments. The methodology was based on the PRISMA approach, using the Scopus database to retrieve relevant documents. From an initial total of 221 documents, 216 were selected after a filtering and debugging process, ensuring the relevance of the final set. In the analytical phase, the results showed a moderate growth of 3.68% in the annual publication rate, highlighting the impact of research on solar energy’s application to air conditioning and energy efficiency in greenhouses. Most of the studies reviewed feature hybrid systems that combine solar energy with other resources, and we highlight both advances in climate control through artificial intelligence and the implementation of photovoltaic and thermal technologies to improve the energy efficiency of agricultural systems. The results also underline the importance of tomato cultivation in the selected studies, reflecting its global economic impact. The conclusions highlight the need for the further integration of energy storage and desalination technologies, especially in arid regions with high solar irradiation, to ensure the sustainability of greenhouses. It is proposed that future research should address the wider implementation of hybrid systems and advanced climate control technologies, optimizing both the use of energy resources and the performance of crops under cover. In addition, it is recommended that international collaboration be strengthened to address technical and climatic challenges in protected agriculture and to expand the adoption of innovative solutions in different geographical contexts.

In Mexico, there are regions where the temperature drops below the minimum threshold for tomato cultivation (10 °C), requiring the implementation of auxiliary equipment to heat greenhouse air. The objective of this work was to estimate the energy consumption necessary to maintain climate requirements of a greenhouse located in Texcoco, State of Mexico, by using a model of energy balance implemented on Computational Fluid Dynamics (CFD) simulations. The temperature prediction relied on a numerical model based on CFD, proposing a benchmarking on the position and direction of the heater to estimate its effect on the thermal distribution. Results indicated that heater operation on January 2019, a power of 85.56 kW was needed to keep the greenhouse at 12 °C. Also, simulations indicated that electric heater used was not enough to get a homogeneous temperature inside the greenhouse. To achieve well-distributed thermal conditions, it was necessary to consider both the direction and position of heaters. Consequently, airflow direction became more important than height of the heater in order to homogenize the greenhouse area, given that the thermal gradient was reduced due to reverse heat flows.

The present study focuses on the development, thermodynamic evaluation, and economic analysis of a photovoltaic-thermal (PVT)-based automated mixed-mode indirect solar dryer (AMMISD). The developed AMMISD was used for drying five date varieties native to the Aswan area, namely Shamia, Bartamuda, Sakkoti, Malkabii, and Gondaila. The initial and final moisture contents of date varieties ranged between 15.7% and 17.2% and 4.91% and 6.41%, respectively. All date fruit varieties reached equilibrium moisture content after 6 days (60 h) compared with 14 days (140 h) in a traditional indirect solar dryer (SD) and 14–25 days (140–250 h) under open-air sun drying. The energy analysis of both the solar air collector (SAC) and the SD showed that the SAC efficiency and the drying efficiency were in the range of 15.15–63.33% and 4.01–4.41%, respectively. Additionally, the exergy analysis of the SAC and drying room (DR) revealed a maximum efficiency of 27.5% and 96.62%, respectively. The improvement potential (IP) ranged from 4.62 to 13.64 W, the mean value of waste exergy ratio (WER) was 0.84, and the sustainability index (SI) ranged from 1.01 to 1.38. Moreover, the economic analysis showed substantial economic advantages for date fruit drying, yielding annual savings of approximately USD 236.9, with an investment recovery period of about 2.091 years.

This paper examines the essential role of artificial lighting in protected agriculture, a crucial sector in addressing the increasing global food demand and the challenges posed by climate change. It explores how advanced lighting technologies, particularly LED systems, have revolutionized productivity and sustainability in greenhouses and indoor or urban farming systems. These technologies enable precise control over key factors influencing crop growth, optimizing both yield and resource efficiency. The methodology was based on a bibliometric analysis developed in four phases: collection of information in the scientific database Scopus, filtering and selection of relevant documents, quantitative and qualitative analysis of trends, and visualization of the results using tools such as VOSviewer. The study included scientific publications between 1974 and 2024, focusing on keywords related to greenhouse lighting technologies and protected agriculture systems. Key findings identified a significant increase in research over the last two decades, with countries such as the United States, Canada, the Netherlands, and China leading the way in scientific output. The main trends in artificial lighting for protected agriculture include the use of specific light spectra (particularly red and blue) to optimize photosynthesis and morphogenesis, as well as the integration of LED systems with digital sensors and controllers for enhanced precision. However, in developing countries such as Colombia, the adoption of these technologies remains in its early stages, presenting significant opportunities for implementation and expansion. Additionally, this bibliometric analysis provides a robust foundation for identifying key areas for improvement and guiding future research toward more sustainable and efficient agricultural practices.

This study proposed an indicator to calculate the regional thermal potential from the local temperature. A probabilistic function curve generalized as a complementary error function (erfc) was used to assume the temperature curve follows the normal distribution and considered only the portion of the curve where the appropriate temperatures for the crop are located (wi). The Greenhouse Thermal Effectiveness (GTE) index was calculated using (a) the data of measured temperature (outside) and simulated values from inside of the greenhouse, and (b) the normal temperature data from five meteorological stations. Estimations of GTE using average daily temperature (°C) throughout the year indicate that, with an annual mean temperature of around 14 °C, the GTE is 2798 degree units and inside the greenhouse its value goes up to 5800. May is when the highest temperatures occur and when the highest amount of GTE units can be accumulated. The range of temperatures in the analyzed stations were from 13 to 21 °C and the GTE calculated per year was from 2000 to 7000. The perspective will be to calculate if this energy will be enough to grow tomatoes (or other crops) without extra energy for heating or cooling. If more energy may be needed, estimating how much would be the next step.