Experimental investigation of the air flow in naturally ventilated classrooms (original) (raw)
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Energy Efficiency, 2016
Indoor environmental conditions in classrooms, in particular temperature and indoor air quality, influence students' health, attitude and performance. In recent years several studies regarding indoor environmental quality of classrooms were published and natural ventilation proved to have great potential, particularly in southern European climate. This research aimed to evaluate indoor environmental conditions in 8 schools and to assess their improvement potential by simple natural ventilation strategies. Temperature, relative humidity and carbon dioxide concentration were measured in 32 classrooms. Ventilation performance of the classrooms was deeply characterized, first by fan pressurization measurements of the air permeability and later by tracer gas measurements of the air change rate assuming different envelope conditions. A total of 110 tracer gas measurements were made and the results validated ventilation protocols that were tested afterward. The results of the ventilation protocol implementation were encouraging and, overall, a decrease on the CO2 concentration was observed without modifying the comfort conditions.
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The paper presents the results of the investigations into the indoor climate in classrooms with different ventilation systems. Carbon dioxide is one of the best indicators of air quality in buildings. Therefore the current study is mostly concentrated on the investigation into CO2 levels in classrooms. There is a certain correlation between the air change rate and the changes of carbon dioxide concentration in rooms. The results of the study show the measured values of the CO2 level and indoor air quality in classrooms with different ventilation systems. A new solution of mechanical ventilation is the arrangement of air change in classrooms with mini air handling units (AHU) with heat recovery. The new arrangement might become as revolutionary technology when considering retrofitting smaller schools.
Natural Ventilation Characterization in a Classroom under Different Scenarios
International Journal of Environmental Research and Public Health, 2021
The COVID-19 pandemic has pointed to the need to increase our knowledge in fields related to human breathing. In the present study, temperature, relative humidity, carbon dioxide (CO2) concentration, and median particle size diameter measurements were taken into account. These parameters were analyzed in a computer classroom with 15 subjects during a normal 90-minute class; all the subjects wore surgical masks. For measurements, Arduino YUN, Arduino UNO, and APS-3321 devices were used. Natural ventilation efficiency was checked in two different ventilation scenarios: only windows open and windows and doors open. The results show how ventilation affects the temperature, CO2 concentration, and median particle diameter size parameters. By contrast, the relative humidity depends more on the outdoor meteorological conditions. Both ventilation scenarios tend to create the same room conditions in terms of temperature, humidity, CO2 concentration, and particle size. Additionally, the evolut...
The Effect of Ventilation Strategies on Indoor Air Quality and Energy Consumptions in Classrooms
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Most of the school buildings in Italy are high energy-demanding buildings with no ad-hoc ventilation systems (i.e., naturally-ventilated buildings). Therefore, reducing the heat losses of schools represent the main aspect to be dealt with. Nonetheless, the indoor air quality of the building should be simultaneously considered. Indeed, to date, energy consumptions and air quality are considered as incompatible aspects especially in naturally-ventilated buildings. The aim of the present paper is to evaluate the effect of different ventilation and airing strategies on both indoor air quality and energy consumptions in high energy-demanding naturally-ventilated classrooms. To this purpose, an Italian test-classroom, characterized in terms of air permeability and thermophysical parameters of the envelope, was investigated by means of experimental analyses and simulations through CO2 mass balance equation during the heating season. The air quality was assessed in terms of indoor CO2 conce...
Natural Ventilation and Indoor Air Quality in Education Buildings
Research on indoor air quality and natural ventilation ascertained the causality between poor air quality inside the classroom and poor school performance and even the high incidence of respiratory diseases at children. Therefore possibilities to improve indoor air quality in these areas are more and more searched for. In the present case study it is emphasized a rate of unorganized ventilation in the classroom, far below the present standard. In consequence, there are necessary measures to increase the frequency of air exchange through windows on the first stage, so that in next stage, there are provided ventilation channels and holes with automatically opening, which is scheduled according to the required ventilation rate in those areas.
More than a well-being, providing a good Indoor Climate Quality (ICQ) in education buildings is necessary for students’ health and in order to maximize academic results. In the context of a research focusing on hybrid ventilation strategies, this paper presents the results of a first survey on thermal comfort and indoor air quality in high school classrooms; the results will be subsequently used to develop strategies on mixed mode ventilated classrooms. The objects of the study are the classrooms of ESTP, a civil engineering school located in Cachan, a suburban city in southern of Paris, France. The survey lasted one month during the mid-season. The classrooms are equipped with a mechanical ventilation system and with windows, so that various solutions can be tested based on natural, mechanical and hybrid ventilation. After a first period of monitoring and an analysis of initial conditions, ICQ was analyzed in different conditions according to the schedule and the occupancy of the i...
Ventilation rates and thermal comfort assessment in a naturally ventilated classroom
2016
Ventilation systems are meant (i) to guarantee good indoor air quality (IAQ) by providing and distributing fresh air to the occupied/breathing zone and (ii) to dilute and remove pollutants emitted by indoor sources. On the other hand, inadequate ventilation rates can induce discomfort issues and excessive energy consumption. This study focuses on the performance assessment of natural ventilation strategies in university classrooms, which are characterized by a high occupancy level and the necessity to provide high levels of comfort to perform intellectual work. The high occupancy level creates challenging conditions both in terms of internal gains and CO2 concentration. This paper presents an experimental performance assessment of four natural ventilation strategies applied to a university classroom: single side ventilation, cross ventilation, stack ventilation with and without window supply. Each strategy is evaluated in terms of thermal comfort and air change rate measurements. Th...
E3S Web of Conference, 2019
Indoor air quality (IAQ) inside educational institutions is an important topic in the field of building and health research. School absenteeism and educational performance have been linked to poor air quality inside classrooms. A numerical simulation software has been used to test 5 different scenarios of natural ventilation during summer and winter. CO2 levels, air relative humidity, operative temperature and PMV were used as indoor air quality and thermal comfort indicators. Results have shown high CO2 and humidity levels when all windows are closed, and a variable improvement when different natural ventilations strategies are employed. A detailed procedure for the numerical simulation has been presented.