Characteristics of humidity in classrooms with stack ventilation and development of calculation models of humidity based on the experiment

Abstract

The purpose of the paper is to analyse air humidity in classrooms with stack ventilation. Based on experimental research, new humidity models in classrooms were developed. Experimental studies were conducted in five classrooms of the Faculty of Civil and Environmental Engineering at Bialystok University of Technology in north-eastern Poland (23°10′E, 53°08′N). The tests were performed for both unventilated classrooms and those ventilated by opening windows before and between classes. A linear increase in relative humidity during classes was reported in all classrooms. Stack ventilation provides a low, constant flow of air through the room. It should be noted that stack ventilation was equal to about 0.45 air changes per hour (ACH). The increase in relative humidity in rooms of this type depends primarily on the volume of the room and the number of people in the room. The developed models can be used in engineering practice for the design of automatic control systems in ventilation systems. The results indicate a need to control humidity in educational buildings. In this study, the approximate value of the moisture emitted by one class participant was also determined by comparing the moisture balance in the classroom and experimental data.