## 5 Innovative Control System for Personalized Thermal Comfort Prediction  
An automated control of the personal HVAC system that considers thermal comfort must include the real thermal state of an individual. Although advanced HVAC systems comprise several environmental factors such as radiant temperature, air velocity and air temperature, the majority of the HVAC systems in existing buildings is controlled solely based on the measured air temperature. Measuring the skin temperature of the occupant allows the determination of the thermal sensation of the related person. In this way, climate actuators, which are closely positioned to a person's body, can be personalized to ensure optimal thermal comfort for an individual. The skin temperature varies between different body parts and depends on several influencing factors such as metabolic activity and clothing insulation. The distribution of the skin temperature has been investigated by [PERSON] and [PERSON] [58], [PERSON] et al. [60], [PERSON] et al. [144], [PERSON] and [PERSON] [145]. There are temperature differences up to 1.1 K in the face between forehead (highest temperature), chin, and cheek (lowest temperature) [146]. As a result, the thermal sensation also correlates well with the skin temperature. Thermal sensation is strongly correlated with the body core temperature. This is for example shown by [20; 57; 58; 59; 66; 147; 148; 149; 150]. Under decreasing or steady thermal comfort the skin temperature is a highly accurate signal for the current thermal sensation, whereas in the case of an improving thermal comfort from a poor ambient condition, the absolute skin temperature is not well correlated with the current thermal sensation, because positive influences have an anticipatory effect on thermal sensation [57]. However, a finger skin temperature below 30 \({}^{\circ}\)C is usually a signal for dissatisfaction due to cold stress [147]. As shown in Tables 11-16, the overwhelming majority of the studies consider personal HVAC systems without automated control. Among these are user-controlled systems and systems with predefined heating/cooling loads. Single studies compare the thermal performance and energy efficiency between automated and user-controlled personal HVAC systems (Tables 11-15 and 15-18). For instance, [PERSON] et al. [93] investigated a seemingly automated, personalized ventilation system, whose ventilation load profile is based on preceding user-controlled trials in the same thermal environment. The researchers did not find any significant difference between user control and automation with respect to air quality and thermal comfort of the subjects, though they did not develop a transferable hardware-based system. [PERSON] et al. [151] and [PERSON] [152] confirmed the capability of automatically controlled personal HVAC systems by implementing such a heating system with manual adjustment from the researchers, considering the measured fingertip skin temperature. Although there was no significant difference regarding thermal comfort between user-controlled and automatic indoor climate comfort control, the implemented automated system had a higher energy consumption than the user-controlled one. Reasons for the increased energy consumption are the obviously higher heating power during the initial stage of the trial, due to delayed user-controlled heating and a slightly higher average power during the final stage [95]. On one side user control is often mentioned as the solution for assuring thermal comfort in an energy-efficient way, on the other side the received results towards user-controlled and automated control of personal thermal actuators show that there is no perceivable difference between these two systems regarding thermal comfort and perceived individual air quality. The desire for user control of the occupants is confronted with a less predicted productivity in scenarios with user control due to the increased distraction. However, the evaluation of a personal climatization systems inside a laboratory [PERSON] et al.