Numerical Evaluation of Ventilation Efficiency of Window Type Ventilation Systems

2019 ◽  
Vol 27 (03) ◽  
pp. 1950027
Author(s):  
Young Kwon Yang ◽  
Min Young Kim ◽  
Jin Woo Moon ◽  
Jin Chul Park
Keyword(s):  
Mechanical Ventilation ◽  
Indoor Air ◽  
Numerical Evaluation ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Adverse Pressure Gradient ◽  
Building Energy ◽  
Window Opening ◽  
Ventilation Efficiency ◽  
Air Purifier

Ventilation in buildings is the simplest and most convenient way to purify indoor air. However, when the ventilation is not enough due to natural ventilation, it should be cleaned by mechanical ventilation or air purifier. This process requires building energy. Therefore, it is possible to save the energy of the building by merely increasing the natural ventilation efficiency. This study conducted airflow analysis simulations to investigate the effects of changes in the shape of ventilation openings and louvers on the ventilation efficiency of a window ventilation system. The streamlined window opening exhibited a greater increase in airflow (41.3%) than did the conventional window (24.3%) for the ventilation model with four openings. It was also observed that flow separation and wakes were generated by the adverse pressure gradient arising from the increased airflow speed when a louver was employed. Based on these results, it can be concluded that using a louver as a wind augmentation device is an obstacle to improving the airflow in a window ventilation system.

scholarly journals Indoor air quality in natural-ventilated bedrooms in renovated Norwegian houses

2021 ◽  
Vol 246 ◽  
pp. 01001
Author(s):  
Vegard Heide ◽  
Silje Skyttern ◽  
Laurent Georges
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Indoor Environment ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Opening Angle ◽  
Single Family ◽  
Night Time ◽  
Window Opening

The objective of this work is to investigate the indoor environment in bedrooms ventilated by window opening during night-time. How window opening behaviour affects indoor air quality (IAQ), and how window opening behaviour and IAQ is influenced by external factors, are important questions. The context is renovation of detached wooden houses in Norway. To motivate building owners to renovate their ventilation system, it is important to know the typical indoor environment in bedrooms of existing buildings with natural ventilation. Ten bedrooms in six case houses were investigated by measuring temperature, relative humidity, CO2, particulate matter, formaldehyde and TVOC. The window opening angle was also logged with an accelerometer. The measurements were conducted over 2 to 3 weeks, during March and April. The dwellings were renovated single-family and terraced houses from 1950 – 80, in Trondheim. All the bedrooms had natural ventilation, and the occupants stated they used to open bedroom windows at night. Participants answered a questionnaire about motivations and habits regarding window opening. The most common reason given for not opening was low outdoor temperatures. The window opening behaviour was both predictable and continuous. Windows were open every night in most of the bedrooms, and most of the windows were opened to the same position every night. High CO2 levels during night were found in two bedrooms. In the other bedrooms, the CO2 concentration was satisfying during night-time, although higher concentrations were found in some bedrooms during daytime. Finally, indoor temperature measurements confirmed that many occupants prefer a low bedroom temperature.

scholarly journals RESEARCH OF APARTMENT BUILDINGS‘VENTILATION SYSTEMS AND ANALYSIS OF SYSTEM RENEWAL OPTIONS / DAUGIABUČIŲ GYVENAMŲJŲ NAMŲ VĖDINIMO TYRIMAI IR SISTEMŲ ATNAUJINIMO GALIMYBIŲ ANALIZĖ

2015 ◽  
Vol 7 (4) ◽  
pp. 484-492 ◽  
Author(s):  
Kęstutis Valančius ◽  
Sabina Paulauskaitė ◽  
Violeta Motuzienė
Keyword(s):  
Experimental Study ◽  
Mechanical Ventilation ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Heating Season ◽  
Apartment Buildings ◽  
Air Ventilation ◽  
Hygienic Conditions ◽  
Ventilation Systems

The paper presents experimental study of apartment buildings' ventilation parameters which was carried out during the heating season. The results show that the existing apartment buildings often don‘t guarantee the hygienic conditions that are directly related to the indoor air ventilation. Also article contains an analysis of possibilities to upgrade the ventilation systems of apartment buildings. Four ventilation systems‘ upgrade options were examined. The economic analysis showed that according to the economic aspect the best solution for mechanical ventilation in the typical apartment houses is a centralized ventilation system which operates in combination with ground heat pump when supply ducts are mounted on the building facade, and extraction takes place at existing natural ventilation system channels. Straipsnyje pateikiami daugiabučių gyvenamųjų namų vėdinimo parametrų eksperimentiniai tyrimai, kurie buvo atlikti šildymo sezono metu. Tyrimų rezultatai rodo, kad esamuose daugiabučiuose namuose dažniausiai nėra užtikrinamos higieninės sąlygos, kurios yra tiesiogiai susijusios su šių namų vėdinimu. Taip pat straipsnyje pateikiama daugiabučio vėdinimo sistemų atnaujinimo galimybių analizė. Ekonomiškai išnagrinėti keturi vėdinimo sistemų atnaujinimo variantai. Atlikus ekonominę analizę, nustatyta, jog ekonominiu aspektu geriausias mechaninio vėdinimo sprendimas tipiniame daugiabučiame name yra centralizuota vėdinimo sistema, veikianti kombinuotai su gruntiniu šilumos siurbliu, kai tiekiamieji ortakiai montuojami ant pastato fasadų, o ištraukimas vyksta esamais natūralios vėdinimo sistemos kanalais.

Simulation Study on Indoor Air Ventilation Efficiency Based on Computational Fluid Dynamics

2012 ◽  
Vol 466-467 ◽  
pp. 1104-1108
Author(s):  
Jian Qing Min ◽  
Zi Bin Xu
Keyword(s):  
Fluid Dynamics ◽  
Mechanical Ventilation ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Navier Stokes ◽  
Displacement Ventilation ◽  
Navier Stokes Equation ◽  
Air Convection ◽  
Ventilation Efficiency ◽  
Air Ventilation

A numerical investigation is presented of the structure of a displacement ventilation convection by using the Reynolds averaged Navier-Stokes equation and K-ε turbulence model. Numerical results are reported for the effect of Gr/Re2 on structure of indoor air convection and ventilation efficiency. The results show that the structure of indoor air convection changes from mechanical ventilation to natural ventilation, and the curves of ventilation efficiency are like “M” with Gr/Re2 increasing.

An Attempt to Improve Air Quality in Primary Schools

2017 ◽  
Author(s):  
Marek Telejko ◽  
Ewa Zender-Swiercz
Keyword(s):  
Air Quality ◽  
Primary School ◽  
Indoor Air ◽  
Primary Schools ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Co2 Concentration ◽  
School Buildings ◽  
Maximum Value

Most primary school buildings in Poland rely on natural ventilation. This fact is attributed to the age of these buildings constructed more than dozen or even several tens of years ago. Few of them were fitted with a mechanical ventilation system allowing for the adjustment of microclimate parameters. The national requirements for gravity ventilation provide general guidelines, specifying strict description only for the airtightness of windows and doors and the minimum airflow to be supplied to the rooms. The minimum airflow supplied is independent of the number of occupants and purpose of the room. Low indoor air quality (IAQ) can impact occupants’ health and lead to poor productivity or low academic performance. Therefore the provision of good IAQ in classrooms and laboratories is very important. This paper presents the results of the investigation devoted to the quality of indoor air in classrooms of selected Polish primary school. Six primary school in a town with a population of 200 000 inhabitants were involved in the investigations. The participating school buildings were built between 1976 and 1994 and had gravity ventilation systems. The variability of basic IAQ parameters, i.e., temperature, relative humidity and carbon dioxide level, was analysed and the assessment of the classrooms in terms of microbiological purity was performed. The outcomes confirmed the low quality of the indoor air in these buildings. The maximum value of CO2 concentration amounted to more than 4000 ppm. Certain modifications aimed at improving IAQ were proposed during the investigations. Two solutions were implemented. The results of this study indicate that the proposed solution offers the potential to improve IAQ within classrooms.

Numerical investigation of radon dispersion and dose assessment for typical ventilation schemes with an air purifier

2020 ◽  
Vol 30 (1) ◽  
pp. 114-128
Author(s):  
Dong Xie ◽  
Chenhua Wang ◽  
Chuck W Yu ◽  
Hanqing Wang
Keyword(s):  
Mechanical Ventilation ◽  
Effective Dose ◽  
Natural Ventilation ◽  
Indoor Radon ◽  
Radioactive Decay ◽  
Dose Assessment ◽  
Radiological Protection ◽  
Ventilation Condition ◽  
Air Supply ◽  
Air Purifier

Radon is a radioactive pollutant that could pose hazards to the surrounding environment and people due to its radioactive decay progenies. In this study, numerical simulations of radon dispersion were conducted under natural and mechanical ventilation with an air-purifier for radon. Factors such as the air supply speed, position and air supply angles of the purifier were considered. Results showed that the increase in the air supply speed from the purifier was an effective solution to reduce indoor radon pollution. The effect was better when the purifier was in the middle of the room. The purification effect was similar when the air supply changed under natural ventilation, while purification function was more effective when the air supply angle was 60° under the mechanical ventilation condition. An effective dose estimation involving typical ventilation schemes with radon purifier was evaluated. Using this approach, the radiation effect on occupants was computed. The calculated effective dose was 0.9 mSv y−1 when the air supply speed of the purifier was 0.2 m s−1 under natural ventilation. As a result, the effective dose calculated was under the annual effective dose limit of 3–10 mSv y−1 recommended by the International Commission on Radiological Protection (ICRP) for public exposure.

scholarly journals Comparison of indoor air pollutants concentration in two Romanian classrooms

2018 ◽  
Vol 32 ◽  
pp. 01023
Author(s):  
Vasilica Vasile ◽  
Alina Dima ◽  
Elena Zorila ◽  
Andrei Istrate ◽  
Tiberiu Catalina
Keyword(s):  
High School ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Pollutants ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Experimental Campaign ◽  
Air Pollutions ◽  
Hybrid Ventilation ◽  
Indoor Air Pollutants

This paper investigates the air pollutions in space ventilated in two High School classrooms. The analysis consists of comparison of one classroom with hybrid ventilation system and another one stander-by classroom with natural ventilation. Several studies regarding indoor air quality during the experimental campaign have been done for VOC, CO2, CO, other pollutants, keeping monitored for humidity and temperature. The experimental demonstrated that the highest value for CO2 in stander-by classroom is 2691 ppm and in classroom with hybrid ventilation is 1897 ppm, while values for CO are 1.1 / 1.1 ppm and VOC 0.14 / 0.06 ppm, better use hybrid ventilation.

scholarly journals FACTORS AFFECTING VENTILATION, INDOOR-AIR QUALITY AND ACOUSTICAL QUALITY IN ‘GREEN’ AND NON-‘GREEN’ BUILDINGS: A PILOT STUDY

2011 ◽  
Vol 6 (3) ◽  
pp. 168-180 ◽  
Author(s):  
Alireza Khaleghi ◽  
Karen Bartlett ◽  
Murray Hodgson
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Sound Pressure ◽  
Low Frequency ◽  
Green Buildings ◽  
Noise Levels ◽  
Ventilation Rates

This paper discusses a pilot project involving the direct monitoring of ventilation, indoor-air quality and the acoustical conditions in selected nominally ‘green’ and non-‘green’ buildings located on a university campus. The objectives were to measure parameters quantifying these three aspects of indoor environmental quality, determine the relationships between them and the building-design concepts, and evaluate the implications of the results for ventilation-system design, especially in ‘green’ buildings. Measurements were made in rooms, with and without acoustical treatment, in buildings with natural ventilation or mechanical (displacement and/or mixed-flow) ventilation systems. Measurements were made of ventilation rates (air changes per hour), indoor air quality (respirable-fibre, total-VOC and ultrafine-particulate concentrations), and the acoustical conditions (noise levels and reverberation times). Correlations between the environmental results, the building concept, the ventilation concept and the building window status were explored. In rooms with natural ventilation, low-frequency noise and total sound-pressure levels were lower; however, the rooms had higher ultrafine-particulate counts and lower ventilation rates. Rooms with mechanical ventilation had higher low-frequency and total sound-pressure levels, higher ventilation rates and fibre concentrations, but lower concentrations of ultrafine particulates. It was concluded that, in general, mechanical ventilation can provide better indoor air-quality, but that HVAC noise is an issue if the system is not properly designed. In ‘green’ buildings, noise levels were acceptable when the windows were closed, but increasing the ventilation rate by opening the windows resulted in higher noise levels. The results suggest that the acceptability of environmental factors in buildings depends on the degree of compliance of the design and its implementation with standards and design guidelines (i.e. for ventilation, air quality, thermal comfort, etc.), whether the original design concept is ‘green’ or non-‘green’.

scholarly journals Indoor air quality improvement in natural ventilation using a fuzzy logic controller

2020 ◽  
pp. 1-19
Author(s):  
Cezary Kulis ◽  
Jarosław Müller
Keyword(s):  
Fuzzy Logic ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Optical Sensors ◽  
Natural Ventilation ◽  
Fuzzy Logic Controller ◽  
Ventilation System ◽  
Raspberry Pi ◽  
Physical Parameters

The aim of the research was to design and validate the prototype of a device developed to improve the quality of indoor air by supporting the natural ventilation in building. A CO2 sensor and thermo-hygrometer were used to measure the physical parameters of the indoor air. The developed device is based on the Raspberry Pi single-board-computer (SBC) and optical sensors. The prototype casing was made using 3D printing technology. The software was written using the Python 2.7 programming language. The key algorithm of control uses fuzzy logic. The effectiveness of the developed device has been confirmed. The use of the device enabled improvement of the indoor air quality. The presented device may be a solution to improve the indoor air quality by supporting the ventilation system.

scholarly journals The Determination of Indoor Air Quality and Thermal Comfort with Different Space and Ventilation in the Teracce and Bungalow Houses

2021 ◽  
Vol 16 (3) ◽  
pp. 774-793
Author(s):  
Nur Baitul Izati Rasli ◽  
Nor Azam Ramli ◽  
Mohd Rodzi Ismail
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Physical Parameters ◽  
Air Contaminants ◽  
Code Of Practice ◽  
Air Movement

This study observed the influence of different ventilation, indoor and outdoor activities (i.e., cooking, praying, sweeping, gathering, and exhaust from motorcycle) between a bungalow house (i.e., stack and cross ventilation applications) and a terrace house (i.e., one-sided ventilation application). We appraised the indoor air quality (IAQ) and thermal comfort. We monitored the indoor air contaminants (i.e., TVOC, CO, CH2O, PM10, O3, and CO2) and specific physical parameters (i.e., T, RH, and AS) for four days in the morning (i.e., 6.00 a.m. – 9.00 a.m.), morning-evening (i.e., 11.00 a.m. – 2.00 p.m.), and evening-night (i.e., 5.00 p.m. – 8.00 p.m.) sessions. The results found that cooking activities are the major activities that contributed to the increase of the TVOC, CO, PM10, O3, and CO2 concentrations in the bungalow and terrace houses. However, IAQ exceeded the Industry Code of Practice on IAQ (ICOP) limit in the terrace house. The bungalow house applies stack and cross ventilation, double area, and a long pathway of indoor air contaminants movements. Besides that, the results indicated that cooking activities worsen the ventilation system because CO2 exceeded the ICOP limit on Day 2 at 74.1 % (evening-night session) and Day 3 at 13.2 % (morning session), 11% (morning-evening session), and 50.1 % (evening-night session). Moreover, the combination of mechanical (i.e., opened all fans) and natural ventilation (i.e., opened all doors, windows, and fans) is the best application in the house without a cooking ventilator with lower indoor air movement. Furthermore, the temperatures exceeding the ICOP limit of 23-26 °C for both bungalow and terrace houses could be lower indoor air movement, which is less than the ICOP limit of 0.15-0.5 m/s and high outdoor air temperature. Therefore, it is prudent to have an efficient ventilation system for acceptable indoor air quality and thermal comfort in the family house.

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