## 2 Construction Aspects for Energy Performance Improvement
### Location and Orientation
[16] analyzed the climatic conditions inside a greenhouse with south-facing photovoltaic roofs, where 50% of the roof area was replaced by photovoltaic (PV) modules, resulting in a 64% reduction in the availability of indoor solar radiation compared  
Figure 3: The sun’s daily rays fall on a greenhouse with a north–south orientation. Figure 2: The sun’s daily rays fall on a greenhouse oriented east–west. to a greenhouse without a PV system. This change in the availability of sunlight affected the productivity of crops, specifically tomatoes, even with the use of supplemental lighting powered by the energy generated by the PV system. The study highlighted the importance of considering the impact of shade caused by PV modules on crop yields when integrating photovoltaic systems into agricultural greenhouses. [PERSON] and [PERSON] [38] provided a comprehensive review on shape selection and orientation for greenhouses, emphasizing the importance of these factors in energy efficiency and plant productivity. This article highlights that the proper choice of greenhouse shape and orientation can maximize solar radiation uptake, thereby optimizing the indoor environment for plant growth, as well as reducing the need for additional energy for heating or cooling. The detailed analysis offered by the study helps to understand how these design decisions directly impact the sustainability and operational effectiveness of greenhouses in different climates. Moreover, [PERSON] et al. [39] used a three-dimensional shadow analysis in Auto-CAD to calculate the total solar fraction in greenhouses. The research highlighted that greenhouse orientation is crucial for the distribution of solar radiation and for energy efficiency. The study evaluated how different orientations of the greenhouse affect the amount of solar radiation transmitted to the interior, considering the influence of orientation on the loss and gain of solar radiation during the seasons. The 3D shadow analysis in Auto-CAD allowed an accurate assessment of the total solar fraction, underscoring the importance of correct orientation to maximize solar capture and improve the energy performance of greenhouses. Studies such as Mercan and SEZG'IN [32] have used Multicriteria Decision Analysis (MCDA) and Geographic Information System (GIS) to identify optimal locations in Aydin, Turkey. Five main criteria (topography, soil, climate, water, and economy) and two constraints (land-use capacity and proximity to surface water resources) were considered, based on literature and expert opinions. A total of 160 sites were chosen in existing greenhouse areas through intentional sampling, questioning their suitability. The Analytical Hierarchy Process (AHP) method was used to weight the criteria, revealing that 2.4% of the area was \"most adequate\", 33.4% \"adequate\", 31.4% \"moderately adequate\", 0.7% \"slightly adequate\", 29.6% \"inadequate\", and 2.5% \"outside the evaluation\". Of the sample sites, 1.9% were considered \"most adequate\", 10.1% \"adequate\", 0.6% \"moderately adequate\", and 87.3% \"inadequate\". It was concluded that most of the land was not suitable for greenhouses, mainly due to the distance from water resources and the classification of land use. Recommendations have been made for more effective site selection for greenhouses and other agricultural production areas. [PERSON] et al. [33] highlighted the importance of adapting greenhouse design to local climatic conditions, emphasizing the need for flexible design tools, and concluded that optimizing greenhouse design for the local climate is a key factor in maximizing agricultural productivity. [PERSON] et al. [40] conducted a detailed study on energy conservation strategies to minimize heating costs in greenhouses, addressing solutions such as energy-efficient optimized designs, special roofs, thermal curtains, and advanced heating systems. They emphasized the need to balance energy savings with plant growth requirements, aiming for sustainability and energy efficiency in colder climates.