Natural ventilation may not improve indoor air quality

AccessScience ◽  
2020 ◽  
Author(s):  
Farhang Tahmasebi ◽  
Yan Wang ◽  
Elizabeth Cooper ◽  
Daniel Godoy Shimizu ◽  
Samuel Stamp ◽  
...  

The Covid-19 outbreak has resulted in new patterns of home occupancy, the implications of which for indoor air quality (IAQ) and energy use are not well-known. In this context, the present study investigates 8 flats in London to uncover if during a lockdown, (a) IAQ in the monitored flats deteriorated, (b) the patterns of window operation by occupants changed, and (c) more effective ventilation patterns could enhance IAQ without significant increases in heating energy demand. To this end, one-year’s worth of monitored data on indoor and outdoor environment along with occupant use of windows has been used to analyse the impact of lockdown on IAQ and infer probabilistic models of window operation behaviour. Moreover, using on-site CO2 data, monitored occupancy and operation of windows, the team has calibrated a thermal performance model of one of the flats to investigate the implications of alternative ventilation strategies. The results suggest that despite the extended occupancy during lockdown, occupants relied less on natural ventilation, which led to an increase of median CO2 concentration by up to 300 ppm. However, simple natural ventilation patterns or use of mechanical ventilation with heat recovery proves to be very effective to maintain acceptable IAQ. Practical application: This study provides evidence on the deterioration of indoor air quality resulting from homeworking during imposed lockdowns. It also tests and recommends specific ventilation strategies to maintain acceptable indoor air quality at home despite the extended occupancy hours.


2018 ◽  
Vol 7 (3.9) ◽  
pp. 42
Author(s):  
Norsafiah Norazman ◽  
Adi Irfan Che Ani ◽  
Nor Haslina Ja’afar ◽  
Muhamad Azry Khoiry

Indoor Air Quality (IAQ) is an essential matter in achieving students’ satisfaction for the learning process. Building’s orientation is a factor that may encourage sufficient natural ventilation for the classroom occupants. Inadequate ventilation is an issue for most existing classrooms. The purpose of this paper is to analyze the accuracy of natural ventilation in classrooms. Therefore, experimental on 20 classrooms has been conducted by using Multipurpose Meter at secondary school buildings in Malaysia. The findings indicated that the accuracy of natural ventilation testing was below the permissible limits throughout the hours monitored, thus this may cause potential health hazards to the students. Temperature and air flow rates were lower than 23 °C and 0.15 m/s respectively, it fulfilled the basic requirements as a standard learning environment. However, measurements taken showed the overall relative humidity (RH) in the classrooms can be categorized as acceptable with 40% to 70% range. On the basis of these findings, it is evident that naturally ventilated classrooms are important especially due to energy efficiency, whereas mechanical ventilation should only be installed as an alternative under extremely hot weather conditions.   


Author(s):  
M. F. Mohamed ◽  
M. Behnia ◽  
S. King ◽  
D. Prasad

Cross ventilation is a more effective ventilation strategy in comparison to single-sided ventilation. In the NSW Residential Flat Design Code1 (RFDC) the majority of apartments are required to adopt cross ventilation. However, in the case of studio and one-bedroom apartments, it is acknowledged that single-sided ventilation may prevail. Deep plan studio and one-bedroom apartments may achieve lower amenity of summer thermal comfort and indoor air quality where mechanical ventilation is not provided by air conditioning. Since compliance with the code may allow up to 40% of apartments in a development in Sydney to be single sided, it is important to understand the natural ventilation performance of such apartments. The objective of this paper is to investigate the natural ventilation potential in single-sided ventilated apartments to improve indoor air quality and thermal comfort. This investigation includes simulating various facade treatments involving multiple opening and balcony configurations. Balcony configurations are included in this study because, in Sydney, a balcony is a compulsory architectural element in any apartment building. The study uses computational fluid dynamics (CFD) software to simulate and predict the ventilation performance of each apartment configuration. This study suggests that properly configured balconies and openings can significantly improve indoor ventilation performance for enhanced indoor air quality and thermal comfort, by optimizing the available prevailing wind. However, it is important to note that inappropriately designed fac¸ade treatments also could diminish natural ventilation performance.


2017 ◽  
Vol 595 ◽  
pp. 894-902 ◽  
Author(s):  
Luca Stabile ◽  
Marco Dell'Isola ◽  
Aldo Russi ◽  
Angelamaria Massimo ◽  
Giorgio Buonanno

2016 ◽  
Vol 98 ◽  
pp. 180-189 ◽  
Author(s):  
Luca Stabile ◽  
Marco Dell’Isola ◽  
Andrea Frattolillo ◽  
Angelamaria Massimo ◽  
Aldo Russi

2011 ◽  
Vol 6 (3) ◽  
pp. 168-180 ◽  
Author(s):  
Alireza Khaleghi ◽  
Karen Bartlett ◽  
Murray Hodgson

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’.


Jurnal IPTEK ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 150-160
Author(s):  
Fuad Rizal

ABSTRACT Quality of natural ventilation in low rise public housing in Jakarta tends to be low. Situation mentioned above presumably caused by several case, among other form and unadequate opening placement, unadequate furniture placement, form and orientation of public housing mass and minimum building protection from sun radiation. Whereas natural ventilation have an importent role in increasing indoor air quality, increasing occupant healthy and help increasing electricity consumption eficiency. The objective of this research is attempt solving natural ventilation problems in low rise public housing architecturally through designs that could used for occupant activity precisely and presenting good natural ventilation simultaneously so it can support occupant activity in public housing as efficiently, comfortable, healthy and secure. Research begins with conduct an observation towards existing public housing in Jakarta through interview, documentation of existing public housing condition and studying public housing designs through working documents and related standards. Collecting climate data especially wind velocity conducted to get illustration of condition that take place in definite period. Those data then analyzed to produce a model formula of public housing building that tested later with computer. The result of research show that the problems of natural ventilation in low rise public housing can be solved by accurately building design that can adapt with surrounding nature. Quite significant positive change occurs after modification does to the existing unit. Hopefully government through certain official can produce public housing design which more optimal, especially in natural ventilation. People also could knowing the caused of natural ventilation problems inside the room also could solving it by simply, efficiently and accurately through the result of this research. Some advantages occupant could gained are good and prevalent airflow inside the room, reducing air conditioning equipment utilization frequency, less maintenance cost and can it can works all the time.  Keywords: natural ventilation, sun radiation, electricity consumption efficiency, indoor air quality, low rise public housing, wind velocity


2020 ◽  
pp. 1-19
Author(s):  
Cezary Kulis ◽  
Jarosław Müller

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.


2021 ◽  
Vol 2069 (1) ◽  
pp. 012182
Author(s):  
S F Díaz-Calderón ◽  
J A Castillo ◽  
G Huelsz

Abstract Natural ventilation (NV) is a strategy of bioclimatic design to promote hygrothermal comfort and indoor air quality (IAQ). Nowadays, COVID-19 pandemic highlights the review of ventilation standards. In Mexico, the IAQ standard states a minimum of 6 ACH for educational buildings. ACH considers NV as an ideal piston flow and does not provide information of indoor airflow distribution. In this work, new age of air associated parameters are proposed, considering the indoor airflow distribution: the air renovation per hour (ARH) and the renovation parameter R. An isolated educational building located in a rural region is studied. Four window configurations of cross-ventilation are considered. All configurations have one windward window located at bottom. The configurations axial and upward have one leeward window at bottom and top, respectively. While, configurations corner and upward corner have one lateral side window at bottom and top, respectively. A CFD model of the educational building is validated with experiments. The axial configuration has the best performance according to ACH, nevertheless has the worst performance according to ARH and R. The results show that NV evaluation using ACH can lead to wrong decisions. An improvement of NV standard with the age of air associated parameters is recommended.


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