## 3 Literature Review  
A literature review on the topic of energy consumption, energy-saving measures, and comfort conditions in sports buildings typically explores the following research areas [41]:  
* Energy consumption Sports buildings, such as stadiums, arenas, gyms, and swimming pools, often have high energy demands due to their size, usage patterns, and the need for specialized equipment [42]. The literature frequently examines energy intensity while quantifying energy consumption by comparing it with other building types [15]. While exploring the consumption of energy in these buildings, it is very important to make a difference between various operational phases, such as regular training sessions, events, and maintenance periods that significantly influence energy consumption [16]. The literature highlights how event-specific peaks, such as during large games or concerts, can lead to short-term spikes in energy use [43]. All of these activities of players and spectators were taken under consideration while simulating energy performance. * Energy-saving measures Research in this area focuses on strategies to reduce energy consumption while maintaining or improving users' comfort [44]. Key measures include the transition from traditional lighting systems to energy-efficient LEDs [44]; advanced HVAC systems with variable-speed drives, smart controls, and energy-recovery systems [5]; and measures concerning building envelope, insulation, window glazing, and shading devices in minimizing thermal losses [45]. The literature often emphasizes the importance of Renewable Energy Integration, such as solar panels and geothermal systems [46; 47; 48]. * Comfort conditions  
Maintaining comfort conditions is crucial in sports buildings to ensure the well-being of athletes and spectators. The literature explores thermal comfort, Predicted Mean Vote (PMV), and Predicted Percentage Dissatisfied (PPD) [49]. Research suggests that maintaining a stable indoor temperature and humidity level is key to ensuring comfort, especially in spaces with high occupant density as sports centers [49]; it also explores air quality where proper ventilation systems are essential to maintain healthy air quality, particularly in enclosed spaces where activities may generate high levels of CO\({}_{2}\) or other pollutants [50], as well as acoustic comfort, which is vital in sports facilities [51], where noise levels can be high. Studies examine the use of sound-absorbing materials and acoustic design to minimize disturbances [52]. The literature also identifies challenges in improving energy efficiency in sports buildings, such as the complexity of retrofitting existing structures and the need for more comprehensive data on energy use [53]. Future research directions may include the development of advanced energy monitoring systems, the exploration of new materials and technologies, and the investigation of user behavior's impact on energy consumption [54; 55; 56]. In summary, the literature review underscores the significant energy demands of sports buildings and the various measures available to reduce consumption while ensuring comfort. It highlights the importance of a holistic approach, integrating energy efficiency with sustainable design and operation practices [57]. Table 1 gives an overview of the possible implementation of the Serbian (RS) and international legislation in energy retrofitting of the sports facilities according to the defined research areas: energy consumption, energy-saving measures, and comfort conditions: