scholarly journals Identifying mechanical ventilation issues in classrooms

2018 ◽  
Vol 44 ◽  
pp. 00055
Author(s):  
Julia Janiga ◽  
Joanna Krzempka ◽  
Aleksandra Szczerbińska
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Operating Time ◽  
Mechanically Ventilated ◽  
Ventilation Systems

This article focuses on the issues of indoor air quality in mechanically ventilated classrooms. The aim of the study was to determine the reasons for inadequate air quality reported by occupants. Two different ventilation systems were assessed by measuring CO2 and VOC concentrations in classrooms during operating time. Results showed that in both cases, CO2 levels in the air, even though mostly acceptable, were exceeded throughout the measuring periods on occasion. Based on obtained data, in both cases probable causes for reported ventilation system malfunctions were proposed.

scholarly journals The Applicability of Coanda Effect Hysteresis for Designing Unsteady Ventilation Systems

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 34
Author(s):  
Aldona Skotnicka-Siepsiak
Keyword(s):  
Mechanical Ventilation ◽  
Energy Efficiency ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Coanda Effect ◽  
Air Jet ◽  
Coandǎ Effect ◽  
Ventilation Systems

Energy-saving ventilation systems are designed to improve the energy efficiency of buildings. Low energy efficiency in buildings poses a considerable problem that needs to be addressed. Mechanical ventilation with heat recovery has gained increased popularity in recent years. Mechanical ventilation has numerous advantages, including easy adjustment and control, high indoor air quality and elimination of indoor pollutants. Mixing ventilation is the most popular type of mechanical ventilation, in particular in residential buildings. Unsteady ventilation is a type of mixing ventilation that involves stronger mixing effects and smaller vertical temperature gradients to improve indoor air quality (IAQ) and minimize energy consumption. This study examines the possibility of controlling and modifying Coanda effect hysteresis (CEH) to generate unsteady flow and simulate the conditions of unsteady mixing ventilation. The experiment was performed on a self-designed test bench at the University of Warmia and Mazury in Olsztyn. It demonstrated that an auxiliary nozzle can be applied at the diffuser outlet to control CEH and the angles at which the air jet becomes attached to and separated from the flat plate positioned directly behind the nozzle. The study proposes an innovative mixing ventilation system that relies on CEH. The potential of the discussed concept has not been recognized or deployed in practice to date. This is the first study to confirm that an auxiliary nozzle by the diffuser outlet can be operated in both injection and suction mode to control CEH. In the future, the results can be used to design a new type of nozzles for unsteady ventilation systems that are based on CEH control.

Indoor air quality impacts of residential mechanical ventilation system retrofits in existing homes in Chicago, IL

2022 ◽  
Vol 804 ◽  
pp. 150129
Author(s):  
Insung Kang ◽  
Anna McCreery ◽  
Parham Azimi ◽  
Amanda Gramigna ◽  
Griselda Baca ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System

scholarly journals Feasibility of a Passive Ventilation System with a Thermal Damper - Simulations and measurement results of an experimental house in a mild region of Japan -

2019 ◽  
Vol 111 ◽  
pp. 06047
Author(s):  
Motoya Hayashi ◽  
Hoon kim ◽  
Yoshinori Honma ◽  
Junichiro Matsunaga
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Indoor Environments ◽  
Air Supply ◽  
Measurement Results ◽  
Simulation Results ◽  
Ventilation Rates ◽  
Ventilation Systems

In order to retain good indoor air quality through the year in detached houses with passive ventilation systems, the authors investigated a mechanical control air-supply method. Firstly, indoor environments in houses with passive ventilation systems with thermal dampers, were examined using a simulation program (Fresh). Secondly, a passive ventilation system with a thermal damper, an under-floorheating system with a heat pump and were installed in an airtight house at Maebashi in Japan and measurements on its ventilation characteristics and indoor air quality were made. The simulation results showed that if the thermal damper is well tuned, this mechanically controlled air-supply opening keeps ventilation rates adequate through the year especially in airtight houses. The measurement results showed that the ventilation rates were kept above the required level through the year and the TVOC concentration decreases from 3000 to 200 μg/m3 in 5 months after the construction.

scholarly journals Indoor air quality and control methods for mechanical ventilation systems inside large passive objects

2020 ◽  
pp. 1-8
Author(s):  
Nina Szczepanik-Ścisło
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Test Object ◽  
Control Methods ◽  
And Control ◽  
Sanitary Conditions ◽  
Ventilation Systems

This paper summarises the indoor air quality of a sports hall built in the passive standard. The sanitary conditions within the object were measured and analysed to identify whether the standards were met and if the test object was safe for occupants. This paper summarises the indoor air quality of a sports hall built in the passive standard. The sanitary conditions within the object were measured and analysed to identify whether the standards were met and if the test object was safe for occupants. This paper summarises the indoor air quality of a sports hall built in the passive standard. The sanitary conditions within the object were measured and analysed to identify whether the standards were met and if the test object was safe for occupants. This paper summarises the indoor air quality of a sports hall built in the passive standard. The sanitary conditions within the object were measured and analysed to identify whether the standards were met and if the test object was safe for occupants. This paper summarises the indoor air quality of a sports hall built in the passive standard. The sanitary conditions within the object were measured and analysed to identify whether the standards were met and if the test object was safe for occupants. This paper summarises the indoor air quality of a sports hall built in the passive standard. The sanitary conditions within the object were measured and analysed to identify whether the standards were met and if the test object was safe for occupants. This paper summarises the indoor air quality of a sports hall built in the passive standard. The sanitary conditions within the object were measured and analysed to identify whether the standards were met and if the test object was safe for occupants.

scholarly journals Computational Analysis of a Lecture Room Ventilation System

2020 ◽  
Author(s):  
Abayomi Layeni ◽  
Collins Nwaokocha ◽  
Olalekan Olamide ◽  
Solomon Giwa ◽  
Samuel Tongo ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Minimum Cost ◽  
Solar Chimney ◽  
Lecture Room ◽  
Room Ventilation System ◽  
Ventilation Systems

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.

scholarly journals Analysis of Indoor Air Pollutants and Guidelines for Space and Physical Activities in Multi-Purpose Activity Space of Elementary Schools

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 220
Author(s):  
Yeo-Kyung Lee ◽  
Young Il Kim
Keyword(s):  
Mechanical Ventilation ◽  
Elementary Schools ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Co2 Concentration ◽  
Activity Space ◽  
Optimum Number ◽  
Ventilation Systems

Owing to the recent increase in the number of warning reports and alerts on the dangers of fine dusts, there has been an increasing concern over fine dusts among citizens. In spaces with poor ventilation, the occupants are forced to open the window to initiate natural ventilation via the direct introduction of the outside air; however, this may pose a serious challenge if the external fine-dust concentration is high. The lack of natural ventilation increases the indoor carbon dioxide (CO2) concentration, thus necessitating the installation of mechanical ventilation systems. This study analyzed the frequency of the application of mechanical ventilation systems in the Multi-purpose activity space of elementary schools, which are spaces where children require a higher indoor air quality than adults owing to the rapid increase in the CO2 concentration of the Multi-purpose activity space during activities. In addition, the architectural and equipment factors of the Multi-purpose activity spaces of nine elementary schools were characterized. The results revealed that five out of the nine elementary schools installed mechanical ventilation systems, whereas the remaining four schools installed jet air turnover systems. The indoor air quality of the Multi-purpose activity space of D elementary school, which had the minimum facility volume among the schools investigated in this study (564.2 m3), with up to 32 participants for each activity, was investigated. The results revealed that the ultrafine-dust (PM2.5) concentration of the facility was as high as 4.75 µg/m3 at a height of 1.2 m, and the CO2 concentration was as high as 3183 ppm. The results of the analysis of three elementary schools with different volumes were compared and analyzed using CONTAM simulation. This study determined the required volume per occupant and the optimum number of occupants for a given volume and presented guidelines for the optimum number of occupants, activities, and volume to reduce the high concentration of pollutants in the analyzed Multi-purpose activity space. The guideline proposed in this study is aimed at maintaining the CO2 concentration of the Multi-purpose activity space below 1000 ppm, as prescribed by the Indoor Air Quality Control in Public-Use Facilities, Etc. Act in South Korea.

Numerical and Experimental Modeling of Indoor Air Quality Inside a Conditioned Space with Mechanical Ventilation and DX-Air Conditioner

2020 ◽  
Vol 38 (9A) ◽  
pp. 1257-1275
Author(s):  
Wisam M. Mareed ◽  
Hasanen M. Hussen
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Airflow Rate ◽  
Air Conditioner ◽  
Breathing Zone ◽  
Lecture Room ◽  
Ventilation Performance

 Elevated CO2 rates in a building affect the health of the occupant. This paper deals with an experimental and numerical analysis conducted in a full-scale test room located in the Department of Mechanical Engineering at the University of Technology. The experiments and CFD were conducted for analyzing ventilation performance. It is a study on the effect of the discharge airflow rate of the ceiling type air-conditioner on ventilation performance in the lecture room with the mixing ventilation. Most obtained findings show that database and questionnaires analyzed prefer heights between 0.2 m to 1.2 m in the middle of an occupied zone and breathing zone height of between 0.75 m to 1.8 given in the literature surveyed. It is noticed the mismatch of internal conditions with thermal comfort, and indoor air quality recommended by [ASHRAE Standard 62, ANSI / ASHRAE Standard 55-2010]. CFD simulations have been carried to provide insights on the indoor air quality and comfort conditions throughout the classroom. Particle concentrations, thermal conditions, and modified ventilation system solutions are reported.

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