Computational Analysis of a Lecture Room Ventilation System

Abayomi Layeni,Olaolu Folorunsho,Kasali Adedeji,Folashade Oniyide,Olawale Onabanjo,Jacob Adebayo,Olusegun Samuel,Jagun Zaid Oluwadurotimi,Olalekan Olamide,Oluwasegun Alabi,Solomon Giwa,Samuel Tongo,Olabode Olanipekun,Taiwo Samuel,Collins Nwaokocha

doi:10.5772/intechopen.92725

Abstract

The level of Indoor Air Quality (IAQ) has become a big topic of research, and improving it using passive ventilation methods is imperative due to the cost saving potentials. Designing lecture buildings to use less energy or Zero Energy (ZE) has become more important, and analysing buildings before construction can save money in design changes. This research analyses the performance (thermal comfort [TC]) of a lecture room, investigate the use of passive ventilation methods and determine the energy-saving potential of the proposed passive ventilation method using Computational Fluid Dynamics (CFD). Results obtained showed that air change per hour at a wind velocity of 0.05 m/s was 3.10, which was below standards. Therefore, the lecture hall needs external passive ventilation systems (Solar Chimney [SC]) for improved indoor air quality at minimum cost. Also, it was observed that the proposed passive ventilation (SC) system with the size between 1 and 100 m3, made an improvement upon the natural ventilation in the room. There was a 66.69% increase after 10 years in the saving of energy and cost using Solar Chimney as compared to Fans, which depicts that truly energy and cost were saved using passive ventilation systems rather than mechanical ventilation systems.

Highlights

Indoor Air Quality (IAQ) and energy consumption in lecture rooms is an important issue and of great concern during the last few years
Thermal comfort is very important to humans; using computational fluid dynamics analysis, ventilation performance of a room is determined with or without passive ventilation systems
The results obtained fall short of the ASHRAE standard [42, 43], which proposed an average air change per hour of between 4 and 6 in a lecture room with an average wind velocity ranging from 0.12–0.5 m/s

Summary

Introduction

Indoor Air Quality (IAQ) and energy consumption in lecture rooms is an important issue and of great concern during the last few years. A temperature analysis at NASA’s Goddard Institute for Space Studies (GISS) noted that the average global Earth temperature has increased approximately by 0.8°C (1.4°F) since 1880, where most of the warming occurred in the last few decades at a rate of 0.2°C per decade since 1970 [4] Another concern is the level of indoor air quality in lecture rooms which has been confirmed to cause discomfort among students in a class and may induce sleep and affect learning. It is essential to maintain good indoor air quality in buildings, which is achieved by providing sufficient ventilation to ensure the removal of stale air and the supply of fresh air for the occupants using several methods These methods include mechanical ventilation (using fans and ducts to move huge volumes of air with or without heating/cooling the air); air-conditioning (in which the temperature and humidity of the air supplied through fans and ducts are fully controlled); and natural ventilation (which makes use of the naturally occurring driving forces of wind and buoyancy). A hybrid approach has been used in practice, which combines both natural forces and mechanical devices, usually fans, to provide adequate ventilation [9–10]

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Results

Conclusion