## 4 Personal Climatization Systems
### Combined Personal Climate Actuators (Ventilation and Radiation)  
As discovered by [PERSON] et al. [29], using combined personal user-controlled climate actuators significantly improves the satisfaction of individuals with their thermal environment (100%) and perceived air quality (94%), when compared to mixing ventilation. The combination of personal ceiling fans, seat fans and table fans improves thermal comfort and prevents cross-infections within office rooms according to [PERSON] et al. [86]. As stated by the researchers, the performance of a seat fan is robust against any movement of the seat and enables energy savings up to 14.87% compared to the use of a single ceiling fan. [PERSON] et al. [104] showed that a combination of personal HVAC systems that consists of a ventilation systems for the face region (air velocity 1.28 m s\({}^{-1}\)) and a conductive underarm cooling system (water temperature 22.7 \({}^{\circ}\)C) facilitates thermal comfort at ambient temperatures of up to 32.3 \({}^{\circ}\)C (Table A5-39). According to [PERSON] et al. [114], heating the back and thigh region provides thermal acceptance at values bigger than 80 % and ambient temperatures of up to 23 \({}^{\circ}\)C. Additional radiant heating of the legs and contact heating via heated seats causes thermal acceptance values higher than 85% at ambient temperatures down to 17 \({}^{\circ}\)C (Table A5-43). Backrest heating combined with a heated floor pad causes a global temperature effect equivalent to an increase in global air temperature of 5.9 K. The concept, however, requires additional air movement [92]. [PERSON] et al. [95] investigated a combined personal heating system consisting of a heated seat, desk- and floor pad (maximum energy demand 163 W). The combination of the different systems was shown to provide better overall thermal comfort than each of the used actuators could provide in single mode. Nevertheless, the use of conditioned seats has the highest energy efficiency. As shown in Table A5-38, this actuator combination ensures thermal comfort down to ambient temperatures of 17.9 \({}^{\circ}\)C independent of the applied control strategy. The user-controlled personal HVAC system implemented by [PERSON] and [PERSON] [115] comprises thermal actuators for face ventilation, under-desk ventilation, heated chairs and under-desk heating panels. It ensures a high thermal acceptance and good perceived air quality at temperature ranges between 20 \({}^{\circ}\)C and 26 \({}^{\circ}\)C (Table A5-42). According to [PERSON] et al. [116], the combined application of temperature-controlled seats and table fans within a temperature range of 18 \({}^{\circ}\)C to 29 \({}^{\circ}\)C leads to a thermal dissatisfaction below 10 %. The study results of [PERSON] et al. [117], [PERSON] et al. [118] reveal that the combination of personal cooling (hand-cooling, face-ventilation) and heating (hand-warmer, foot-warmer) system extends the comfortable ambient temperature range up to values between 18 \({}^{\circ}\)C and 30 \({}^{\circ}\)C. This, however, facilitates energy savings of up to 40%. A temperature range between 20 \({}^{\circ}\)C and 28 \({}^{\circ}\)C would save about 30% of HVAC energy.