Numerical Investigation of School Stratified Ventilation Systems - A Ventilation Effectiveness Study

Mohammad Reza Adili,Simon Engstfeld,Konstantinos Stergiaropoulos,S.I Tanabe,L Mazzarela,I Nastase,G Cao,J Kurnitski,P Wargocki,C Inard,H Zhang,M.C Gameiro Da Silva

doi:10.1051/e3sconf/201911101022

Abstract

Good indoor air quality is an essential prerequisite for a healthy learning environment. Scientific research has shown that there is a direct correlation between air quality and pupils’ ability to learn. For the same supply air volume flow, stratified ventilation systems lead to an improved quality of breathing air than mixing ventilation systems. The ventilation systems that work on the stratified ventilation principle are therefore particularly suitable for the ventilation of classrooms. The air flow characteristics of these systems in classrooms are, however, not thoroughly investigated. In the context of this work, the air flow parameters of various school ventilation systems with stratified ventilation for a typical classroom will be investigated by means of Computational Fluid Dynamics (CFD). For this purpose, centralized ventilation systems with different air outlets as well as decentralized systems are examined and compared regarding their ventilation effectiveness and thermal comfort.

Highlights

Through the concept of all-day school in Germany, children, adolescents and teachers spend more time in school buildings than previous generations
The evaluation of the results shows that none of the systems fulfils all requirements for category II of thermal comfort according to EN 15251, because the Category II limits are partially exceeded, as shown in Figure and Figure
Different commercially available centralized and decentralized stratified ventilation systems are compared with regard to the ventilation effectiveness and the thermal comfort according to ISO 7730

Summary

Introduction

Through the concept of all-day school in Germany, children, adolescents and teachers spend more time in school buildings than previous generations. In modern classrooms with manual window ventilation, there is reduced air quality, which has a negative impact on the learning ability of the students. Various studies confirm this and identify high CO2 concentrations as the main reason for unhygienic and unhealthy learning environments [1, 2]. The present work investigates the subject of school ventilation systems with stratified ventilation in more detail For this purpose, different systems will be compared with regard to the ventilation effectiveness and the criteria for thermal comfort according to ISO 7730 [4] in a typical German classroom.

Methods

Results

Conclusion