A review of the corrective power of personal comfort systems in non-neutral ambient environments

This paper discusses a spectrum of systems that cool or heat occupants personally, termed ‘personal comfort systems’ (PCS), in order to quantify their ability to produce comfort in ambient temperatures that are above or below the subjects’ neutral temperatures.The comfort-producing effectiveness may be quantified in terms of a temperature difference, coining the index ‘corrective power’ (CP). CP is defined as difference between two ambient temperatures at which equal thermal sensation is achieved - one with no PCS (the reference condition), and one with PCS in use.  CP represents the degree to which a PCS system may “correct” the ambient temperature toward neutrality. CP can alternatively be expressed in terms of thermal sensation and comfort survey scale units.Published studies of PCS are reviewed to extract their CP values. Cooling CP ranges from -1 to -6K, and heating CP from 2K to 10K.  The physical characteristics of the particular PCS systems are not reported in detail here, but are presented as prototypes of what is possible.  Deeper understanding of PCS will require new physiological and psychological information about comfort in local body segments and subsegments, and about spatial and temporal alliesthesia.  These topics present many opportunities for productive future research

Numerical study of different ceiling-mounted air distribution systems for a virtual classroom environment

This paper presents a comparative numerical study of different ceiling-mounted-localized air distribution systems placed above students in a virtual classroom in summer conditions. The influence of four different ceiling-mounted-localized air distribution systems, using vertical descendent jets, on the thermal comfort, local thermal discomfort, and air quality levels was numerically evaluated. The air distribution index, developed previously, was used for non-uniform environment. This index considers the thermal comfort level, air quality level, effectiveness for heat removal, and effectiveness for contaminant removal. Numerical simulations were conducted for a virtual classroom equipped with one of four different ceiling-mounted-localized air distribution systems and with 6 desks, 6 or 12 students, and 2 upper airflow outlets. Inlet air supply temperature of 20 and 24? and an outdoor air temperature of 28? were used. The simulation results show that the air supply system having a vertical air jet placed at 1.8m above the floor level (Case III), and with an inlet area of 0.01m(2) and a supply air velocity of 3m/s would represent the best option in comparison with other air supply methods. In general, the air distribution index value decreases with an increase in inlet air temperature and the number of occupants. The air distribution index values are highest for Case III representing a classroom with 6 or 12 occupants with an inlet air temperature of 20 or 24?.info:eu-repo/semantics/publishedVersio