Smart building automation technologies: thermal comfort assessment and improvements

Thermal comfort is of great importance in today's buildings, especially as it was proven that we spend on average more than 20 hours per day indoors. In order to keep occupants healthy and productive, maintaining thermal comfort conditions is necessary and achieving these conditions requires big amounts of energy. This research focuses on office and university buildings, as they are places with a high frequency of people on daily basis. These buildings are designed for people who need to accomplish a specific task and so they need to provide the occupants with comfortable indoor environmental conditions for the sake of their health, safety and productivity. Therefore, two new approaches which could potentially improve thermal comfort and simplify its assessment for achieving and maintaining such conditions are investigated and presented in this work. First one deals with real time people counting, as occupancy was identified as one of the most important factors for thermal comfort and non-excessive energy use. Lack of a low-cost and accurate solution for people counting inspired the development of a mechatronic sensor based on near infrared depth imaging device and a bio-inspired water filling algorithm, which overcomes most of the issues recognized by other people counting approaches. Second developed solution is oriented towards a complex issue of occupant's thermal comfort assessment. Traditional methods require many parameters that can be hard or expensive to measure, while some of them often need to be estimated. Thus, following an extensive literature review, a new approach for thermal comfort assessment is presented and evaluated in this work. Assessment of thermal comfort is done by non-invasively reading one's forehead skin temperature via a table-top sensor equipped with a miniature thermal camera. The device was developed and evaluated in two separate climate chambers with precisely controlled environmental parameters. Tests were performed on human subjects whose forehead temperature was measured and thermal votes collected via written questionnaires. The results were evaluated and recorded temperature and its rate of change were proven to be a valid indicator of thermal sensation and comfort. Findings allowed to underline that the forehead temperature can be exploited to detect thermal sensation variation and identify potential discomfort issues.