## 6 Results and Analysis
System 2 provides a remarkable satisfaction rating of 100%, indicating that all individuals occupying the space had thermal conditions that fell within the ideal Predicted Mean Vote (PMV) range. The observed level of satisfaction is significant and suggests that System 2 is highly proficient in maintaining an optimal thermal environment. Figure 10: PMV index measurements for the analyzed systems. System 3 had a commendable performance, with a satisfaction percentage of 94.1%. The substantial proportion mentioned indicates that a large majority of individuals were situated inside the desirable range of the Predicted Mean Vote (PMV), hence suggesting the efficient management of temperature conditions. In a similar vein, it is worth noting that System 4 demonstrated a satisfaction rate of 92.2%, thereby reinforcing the effectiveness of these ventilation systems in delivering thermal comfort. In comparison, it can be observed that Systems 3 and 4 exhibit marginally lower satisfaction rates in contrast to System 2, yet they consistently uphold elevated levels of thermal comfort. The observation that the satisfaction rates of all systems, except for System 1, surpassed 90% suggests a notable level of success across the board. In conclusion, each of the four systems exhibits a notable capacity to effectively maintain optimal thermal comfort, since there have been no documented occurrences of air drafts. The impact of air drafts on perceived thermal comfort is a critical element to consider. The observed high levels of satisfaction across all systems serve to underscore their effectiveness in establishing and sustaining a pleasant and stable indoor thermal environment, a crucial factor in promoting the well-being and productivity of occupants. The control of noise levels is a crucial feature of the design and operation of decentralized ventilation systems, especially in environments, such as schools or offices. HVAC systems, by their nature, can generate noise, which if not adequately controlled, can become a source of distraction or discomfort. If not effectively managed, this noise can potentially lead to distractions or discomfort. In such circumstances, the prescribed standards for permissible noise levels generally advocate a maximum threshold of 35 dB(A). The purpose of establishing this threshold is to guarantee that the background noise generated by the ventilation system does not disrupt the main functions of the area, such as educational activities in classrooms or concentrated work in offices. For decentralized systems, their inherent advantages in terms of flexibility and energy economy necessitate meticulous design considerations to mitigate noise. This includes the careful selection of equipment that fulfills low-noise standards, the strategic placement of this equipment to minimize sound transmission, and the potential integration of sound-dampening materials or designs. The challenge is to balance the acoustic comfort with the system's effectiveness in air circulation and quality. Surpassing the established standard of 35 dB(A) can result in heightened levels of tension, diminished ability to concentrate, and a general decline in pleasure with the interior environment. Hence, while considering the design and execution of decentralized HVAC systems, it is imperative to recognize that acoustic performance holds equal significance to factors, such as thermal comfort and air quality. It is imperative to maintain the prescribed noise levels to establish an indoor atmosphere that is conducive to comfort, well-being, and productivity. Measurements of acoustic levels were measured for all four systems at different scenarios (e.g., maximum air flow or different air flow stages) using a class 1--sound meter SVANTEK 970. The measurements were realized during the night to minimize the background noise. For all measurements, the background noise was recorded and subtracted for the results. The measurement of data was performed based on the frequency (31.5 Hz to 8000 Hz).