Exhaust ventilation performance in residential washrooms for bioaerosol particle removal after water closet flushing

2016 ◽  
Vol 38 (1) ◽  
pp. 32-46 ◽  
Author(s):  
KW Mui ◽  
LT Wong ◽  
HC Yu ◽  
CT Cheung ◽  
N Li
Keyword(s):  
Exhaust System ◽  
Infection Risk ◽  
Emission Source ◽  
Particle Removal ◽  
Practical Application ◽  
Change Rate ◽  
Exhaust Ventilation ◽  
Air Change Rate ◽  
Water Closet ◽  
Ventilation Performance

Potential bioaerosol infection risk associated with toilet flushing has not been sufficiently addressed in the design of residential washroom exhaust system. This study evaluates the performance of exhaust ventilation for residential washrooms in terms of air change rate, washroom size, washroom geometry, and locations of door louver, exhaust and water closet. Three bioaerosol species namely Escherichia coli (ATCC 10536), Serratia marcescens (ATCC 6911), and Cladosporium cladosporioides (ATCC 16022) are included in the simulations. By shortening the distance between the locations of exhaust and emission source (i.e. water closet), the fractional counts of bioaerosol particles exhausted can be increased. An increased air change rate and a louvered door can also improve the exhaust ventilation performance, yet with a longer time to steady state. This study should provide a useful source of reference for washroom exhaust designers to minimize bioaerosol infection risk. Practical application: This paper shows for residential washroom with an exhaust fan installed, the ventilation performance can be improved by an increased air change rate, and by shortening the distance between the locations of exhaust and emission source.

scholarly journals Comparison of Downdraught and Up Draft Passive Air Conduction Systems (PACS) in a Winery Building

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 259
Author(s):  
Ádám László Katona ◽  
István Ervin Háber ◽  
István Kistelegdi
Keyword(s):  
Air Conditioning ◽  
Natural Ventilation ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
General Applicability ◽  
Change Rate ◽  
Air Change Rate ◽  
Simulation Based ◽  
Ventilation Performance ◽  
Air Conduction

A huge portion of energy consumption in buildings comes from heating, ventilation, and air conditioning. Numerous previous works assessed the potential of natural ventilation compared to mechanical ventilation and proved their justification on the field. Nevertheless, it is a major difficulty to collect enough information from the literature to make decisions between different natural ventilation solutions with a given situation and boundary conditions. The current study tests the passive air conduction system (PACS) variations in the design phase of a medium-sized new winery’s cellar and production hall in Villány, Hungary. A computational fluid dynamics simulation based comparative analysis enabled to determine the differences in updraft (UD) and downdraught (DD) PACS, whereby the latter was found to be more efficient. While the DD PACS performed an air change range of 1.02 h−1 to 5.98 h−1, the UD PACS delivered −0.25 h−1 to 12.82 h−1 air change rate. The ventilation performance of the DD version possessed lower amplitudes, but the distribution was more balanced under different wind incident angles, thus this version was chosen for construction. It could be concluded that the DD PACS provides a more general applicability for natural ventilation in moderate climates and in small to medium scale industry hall domains with one in- and one outlet.

Numerical investigation of wind-driven natural ventilation performance in a multi-storey hospital by coupling indoor and outdoor airflow

2016 ◽  
Vol 25 (8) ◽  
pp. 1226-1247 ◽  
Author(s):  
Ruiqiu Jin ◽  
Jian Hang ◽  
Shanshan Liu ◽  
Jianjian Wei ◽  
Yang Liu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Ventilation ◽  
Tracer Gas ◽  
Indoor Airflow ◽  
Change Rate ◽  
Air Change Rate ◽  
Airflow Field ◽  
Ventilation Performance ◽  
Dynamics Simulations

This study employed two ventilation indexes: local mean age of air and air change rate per hour, to investigate wind-induced natural ventilation of 260 wards of a multi-storey hospital building in suburb of Guangzhou using computational fluid dynamics simulations. Using the surface-grid extrusion technique, high-quality hexahedral grid cells were generated for the coupled outdoor and indoor airflow field. Turbulence was solved by the renormalisation group k-ɛ model validated against experimental data with grid independence studies. Homogeneous tracer gas emission was adopted to predict room age of air. The air change rate of cross ventilation and single-sided ventilation can reach 30–160 h−1 and 0.5–7 h−1, respectively. Due to different locations of room openings on the balconies, natural ventilation of a room can be greatly better than its neighbouring room. The wind-induced cross ventilation highly depends on the distance from the room opening to the stagnation point and on the resulting pressure distribution on the target building surface. Furthermore, it is significantly influenced by the upstream buildings, the bent shape of the target building, and the prevailing wind directions. The coupled computational fluid dynamics methodologies with integrated ventilation indexes are useful for assessing the natural ventilation performance in other complex built environments.

scholarly journals Estimation of a room ventilation air change rate using a stochastic grey-box modelling approach

Measurement ◽  
2018 ◽  
Vol 124 ◽  
pp. 539-548 ◽  
Author(s):  
Marcel Macarulla ◽  
Miquel Casals ◽  
Núria Forcada ◽  
Marta Gangolells ◽  
Alberto Giretti
Keyword(s):  
Change Rate ◽  
Room Ventilation ◽  
Air Change Rate ◽  
Modelling Approach

scholarly journals Quality of life control by selected methods of air exchange in a typical apartment building

2021 ◽  
Author(s):  
Iveta Bullová ◽  
Peter Kapalo ◽  
Dušan Katunský
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Allergic Diseases ◽  
Well Being ◽  
Indoor Climate ◽  
Apartment Building ◽  
Change Rate ◽  
Air Change Rate ◽  
Negative Effect

Air change rate is an important parameter for quantification of ventilation heat losses and also affects the indoor climate of buildings. Indoor air quality is significantly associated with ventilation. If air change isn't sufficient, trapped allergens, pollutants and irritants can degrade the indoor air quality and affect the well-being of a building's occupants. Many studies on ventilation and health have concluded that lower air change rates can have a negative effect on people’s health and low ventilation may result in an increase in allergic diseases. Quantification of air change rate is complicated, since it is affected by a number of parameters, of which the one of the most variable is the air-wind flow. This study aims to determination and comparison of values of the air change rate in two methods - by quantifying of aerodynamic coefficient Cp = Cpe - Cpi – so called aerodynamic quantification of the building and the methodology based on experimental measurements of carbon dioxide in the selected reference room in apartment building.

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