#### 1.1.6 Temperature Regulation
These sensors provide real-time data to the climate control system, enabling it to make necessary adjustments. * _Heating systems_: Active greenhouses have heating systems to raise temperatures during colder periods. These systems can be fueled by electricity, natural gas, propane, or other energy sources. * _Cooling systems_: Cooling systems are essential for active greenhouses, especially in hot climates. They may include exhaust fans, evaporative cooling pads, or misting systems to reduce the temperature during warmer periods. * _Ventilation_: Active greenhouses have controlled ventilation systems to regulate air exchange and prevent the buildup of excessive heat, humidity, or carbon dioxide. * _Automated irrigation_: Many active greenhouses employ automated irrigation systems to give plants the appropriate amount of water at specific intervals. * _Artificial lighting_: In some cases, active greenhouses use artificial lighting systems to supplement natural sunlight and extend the daily photoperiod for plant growth. An active greenhouse's main advantage is its precise control over the growing environment. By utilizing technology and mechanical systems, growers can create the ideal conditions for various crops and extend the growing season beyond what would be possible outdoors. However, active greenhouses tend to have higher initial setup costs and ongoing operational expenses due to the equipment and energy required to maintain the controlled environment. They are commonly used in commercial agriculture, research facilities, and other settings where crop productivity, quality, and year-round cultivation are essential. Combination of Passive and Active Techniques  
Combining passive and active strategies in greenhouse design makes sense to maximize energy efficiency and establish a more sustainable and regulated environment for plant growth. Passive techniques depend on natural processes, whereas active techniques require technology and external energy sources. By integrating these passive and active techniques, greenhouse operators can create a more sustainable and energy-efficient environment for plant cultivation, optimizing resource utilization and reducing the environmental impact. Passive and active greenhouses are two different types of structures used for plant cultivation. They differ primarily in how they regulate temperature and environmental conditions. Figure 3 illustrates the key differences between passive and active greenhouses, which are explained in the following sections [5; 6; 7]:  
Figure 3: Key aspects used to differentiate passive and active greenhouses. * Temperature regulation  
A passive greenhouse regulates temperature using natural elements like solar radiation, thermal mass, and ventilation. It incorporates design elements such as proper orientation, insulation, and thermal mass materials to manage heat and cold passively. In contrast, an active greenhouse utilizes mechanical systems, including fans, heaters, cooling units, and automated climate control, to actively control temperature and environmental conditions. Active greenhouses offer precise and rapid adjustments to indoor climate, while passive ones rely on natural processes for temperature regulation. * Climate suitability  
Passive and active greenhouses have distinct suitability based on climate conditions. Passive greenhouses are well suited for regions with moderate climates or areas experiencing sufficient sunlight and temperature variations throughout the year. Their reliance on natural processes makes them effective in environments with these elements. In contrast, active greenhouses offer more versatility and can be employed in a broader range of climates, including colder regions. The mechanical systems in active greenhouses provide precise control over temperature and environmental conditions, allowing them to adapt to a wider spectrum of climate variations.