## 3 Thermal Aspects for Improving Energy Performance
### Maintenance of the Greenhouse Environment
#### 3.1.5 Maintenance of Carbon Dioxide \(CO_{2}\) and Light
This system allows for more precise regulation of \(CO_{2}\) concentrations, automatically adjusting to the specific needs of the plants and the environmental conditions of the greenhouse [183]. Advanced technologies in \(CO_{2}\) control include \(CO_{2}\) recovery systems from industrial exhaust gases or fermentation processes. These systems filter and purify \(CO_{2}\) before its introduction into the greenhouse, representing a sustainable approach by reusing \(CO_{2}\) that would otherwise be emitted into the atmosphere [183; 184]. The implementation of Wireless Sensor Networks (WSN) and artificial intelligence techniques, such as neural networks, significantly improves the monitoring and control of \(CO_{2}\) concentration, allowing real-time adjustments to optimize growing conditions [185; 186; 187; 188]. Biomass-based systems also offer a sustainable solution for generating heat and \(CO_{2}\), using agricultural waste as fuel [189]. The development and integration of \(CO_{2}\) maintenance systems in greenhouses, from conventional methods to innovative solutions, are fundamental to creating an ideal growing environment. This diversity of systems allows flexible applications adapted to different needs and operational conditions, promoting photosynthetic efficiency, improving crop quality and contributing to more sustainable agricultural practices [190]. Effective implementation of these systems can vary based on greenhouse type, climate, and crop type. The choice of the type of artificial lighting for greenhouses will also depend on the type of cultivation, the light needs of the plants, the energy cost and the availability of energy in the region [75]. Sodium vapor lamps (\(N_{a}\)) are often used in greenhouses due to their high light efficiency and low operating costs, but in some crops, such as those that produce flowers and fruits, lighting with LEDs can be more efficient [191]. Additionally, the use of light sensors can help optimize lighting time and minimize energy consumption. Importantly, excessive lighting can negatively affect plant growth and increase energy consumption; therefore, the efficient use of artificial lighting is essential to ensure healthy plant growth and reduce operating costs. Lighting in agricultural greenhouses is crucial to crop production efficiency and performance. [PERSON]. [192] investigated the sustainability of photovoltaic greenhouses in Europe, analyzing agricultural production in greenhouses with different solar panel coverages and concluding that a 25% coverage is ideal for most crops, while low-light crops can tolerate up to 100% coverage with innovative cultivation systems. [PERSON] et al. [174] studied the transition from high-pressure sodium lighting to LEDs in greenhouses, observing energy savings of between 10% and 25%, depending on the energy previously used for lighting. [PERSON] and [PERSON] [175] and [PERSON] et al. [193] addressed the manipulation of light quality with LEDs to optimize plant growth and photomorphogenesis, highlighting the benefits of LEDs over conventional light sources and their potential to improve production in controlled environments. [PERSON] et al. [75] developed a supervisory control strategy based on artificial intelligence to improve energy efficiency in artificial lighting systems, demonstrating a significant reduction in energy consumption and improvement in crop yields. Together, this research reveals the significant impact of advanced greenhouse lighting on the efficiency and sustainability of agricultural production. The main limitations in the use of carbon dioxide (\(CO_{2}\)) and light maintenance systems in greenhouses include the complexity of maintaining optimal concentrations of \(CO_{2}\) due to its dynamic and delayed interaction with temperature, humidity, and light intensity, among others. This results in frequently suboptimal or excessive \(CO_{2}\) concentrations, making it difficult to maximize crop productivity and quality.