On the development of a thermal comfort control for classroom conditioned by split-type systems

Thermal comfort conditions may vary substantially within an air-conditioned room equipped by split-type systems. In this work, the comfort conditions in a classroom were evaluated experimentally based on the PMV index, according to ISO 7730 Standard that defines the thermal satisfaction in occupied environments. The experiment was carried out at three different supply airflows (high, medium and low) and three set-point temperatures (23, 24 and 25oC). The results showed that there is a considerable variation in the air velocity field in the room as well as in the PMV values for three different supply airflows, consequently there is a considerable variation of the thermal comfort indices. Several curves were adjusted aiming to express the values of PMV, obtaining a Comfort Index for Split systems (ICS). The purpose of this adjustment is to obtain an equation that provides the value of the comfort index at any condition of use in summer. Thus, for a certain condition of use, one can predict what will be the value of PMV in an occupied environment, enabling the implementation of a control system of the comfort according to this new index (ICS). The variables considered in obtaining the curve were the air temperature (Tar) and the air velocity (Var), since these two variables can be controlled directly by the split-type system. The general purpose of this work is to obtain experimental data and a simple device to control and validate the use of split airflow rates coupled to the air temperature and velocity of air, to automatically control thermal comfort in a space conditioned by a split-type system through a single and representative point within the classroom.