The impact of mechanical ventilation operation strategies on indoor CO2 concentration and air exchange rates in residential buildings

2020 ◽  
pp. 1420326X2096076
Author(s):  
Pedro F. Pereira ◽  
Nuno M. M. Ramos
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Exchange Rates ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Ventilation Strategy ◽  
The Impact ◽  
Mechanical Extraction ◽  
Air Exchange

In Portugal, residential buildings commonly have their ventilation strategy changed after commissioning. This occurs due to the building managers' willingness to reduce shared costs with the electricity needed for fan operation. However, this option is not technically supported, and the effects of such a strategy on indoor air quality-related to human pollutants are yet to be quantified. CO2 was monitored in 15 bedrooms and air exchange rates were calculated for each room. The air exchange rate values ranged from 0.18 to 0.53 h−1 when mechanical extraction ventilation was off, and from 0.45 to 0.90 h−1 when mechanical extraction ventilation was on, which represents an average increase of 119%. With the current intermittent ventilation strategy, all rooms remain above 1500 ppm for a given percentage of time, and 12 rooms presenting CO2 concentrations above 2000 ppm. Simulations of theoretical CO2 concentrations, for a non-interrupted mechanical ventilation strategy show that no rooms would accumulate CO2 concentrations above 2000 ppm, and only 25% would present CO2 concentrations above 1500 ppm. Pearson correlations between the monitored CO2 and human and spatial factors identified two relevant parameters. Those parameters correspond to ratios between CO2 generation and floor area ([Formula: see text]), and airflow with CO2 generation ([Formula: see text]). The proposed ratios could be used as ways to optimise ventilation costs and indoor air quality.

scholarly journals Low-infiltration housing in Rochester, New York: A study of air-exchange rates and indoor air quality

1982 ◽  
Vol 8 (1-6) ◽  
pp. 435-445 ◽  
Author(s):  
F.J. Offermann ◽  
C.D. Hollowell ◽  
W.W. Nazaroff ◽  
G.D. Roseme ◽  
J.R. Rizzuto
Keyword(s):  
New York ◽  
Air Quality ◽  
Exchange Rates ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Exchange

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.

scholarly journals Improving the Indoor Air Quality of Residential Buildings during Bushfire Smoke Events

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 32
Author(s):  
Priyadarsini Rajagopalan ◽  
Nigel Goodman
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Building Envelope ◽  
Air Cleaners ◽  
The Usa ◽  
Design Selection ◽  
The Impact

Exposure to bushfire smoke is associated with acute and chronic health effects such as respiratory and cardiovascular disease. Residential buildings are important places of refuge from bushfire smoke, however the air quality within these locations can become heavily polluted by smoke infiltration. Consequently, some residential buildings may offer limited protection from exposure to poor air quality, especially during extended smoke events. This paper evaluates the impact of bushfire smoke on indoor air quality within residential buildings and proposes strategies and guidance to reduce indoor levels of particulates and other pollutants. The paper explores the different monitoring techniques used to measure air pollutants and assesses the influence of the building envelope, filtration technologies, and portable air cleaners used to improve indoor air quality. The evaluation found that bushfire smoke can substantially increase the levels of pollutants within residential buildings. Notably, some studies reported indoor levels of PM2.5 of approximately 500µg/m3 during bushfire smoke events. Many Australian homes are very leaky (i.e., >15 ACH) compared to those in countries such as the USA. Strategies such as improving the building envelope will help reduce smoke infiltration, however even in airtight homes pollutant levels will eventually increase over time. Therefore, the appropriate design, selection, and operation of household ventilation systems that include particle filtration will be critical to reduce indoor exposures during prolonged smoke events. Future studies of bushfire smoke intrusion in residences could also focus on filtration technologies that can remove gaseous pollutants.

Indoor air quality, air exchange rates, and radioactivity in new built temporary houses following the Great East Japan Earthquake in Minamisoma, Fukushima

Indoor Air ◽  
2013 ◽  
Vol 23 (4) ◽  
pp. 332-341 ◽  
Author(s):  
N. Shinohara ◽  
M. Tokumura ◽  
M. Kazama ◽  
H. Yoshino ◽  
S. Ochiai ◽  
...  
Keyword(s):  
Air Quality ◽  
Exchange Rates ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Great East Japan Earthquake ◽  
Air Exchange

The impact of design ventilation rates on the indoor air quality in residential buildings: An Italian case study

2016 ◽  
Vol 26 (10) ◽  
pp. 1397-1419 ◽  
Author(s):  
Roberta Moschetti ◽  
Salvatore Carlucci
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Ventilation System ◽  
Residential Building ◽  
Limit Values ◽  
Italian Case ◽  
Ventilation Rates ◽  
The Impact

The paper investigates the effects on building indoor air quality (IAQ) resulting from the choice of different design ventilation rates. A reference residential building was analysed by means of the multizone modelling software CONTAM, by monitoring the concentration of two pollutants: occupant-generated carbon dioxide (CO2) and total volatile organic compounds (TVOC) from indoor sources. A demand-controlled ventilation strategy based on building occupancy was implemented and users' presence schedules were defined. Specifically, the evolution of indoor pollutant concentrations was investigated when the design ventilation rates, recommended by two IAQ-related standards (the Italian UNI 10339 and the European EN 15251), were implemented through a mechanical ventilation system. Different results regarding the IAQ level were achieved accordingly to the dissimilar ventilation rates. After a statistical analysis on the distributions of CO2 and TVOC concentrations, EN 15251 outcomes showed overall better results of the analysed statistical metrics, i.e. prevalence, sensitivity and accuracy. Indeed, the EN 15251 design airflows led to indoor conditions that were more often classified either in the correct air quality class or in a higher class. Finally, a better alignment between the national and European IAQ standards is recommended, especially in terms of airflows, air quality classes and pollutant limit values.

scholarly journals Indoor Air Quality in Passivhaus Dwellings: A Literature Review

2020 ◽  
Vol 17 (13) ◽  
pp. 4749 ◽  
Author(s):  
Alejandro Moreno-Rangel ◽  
Tim Sharpe ◽  
Gráinne McGill ◽  
Filbert Musau
Keyword(s):  
Air Quality ◽  
Data Collection ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Well Being ◽  
Future Research ◽  
Design Strategies ◽  
Housing Design ◽  
The Impact

Indoor air quality (IAQ) is a critical consideration in airtight buildings that depend on mechanical ventilation, such as those constructed to the Passivhaus standard. While previous reviews of IAQ on Passivhaus-certified buildings foccused on offices, this study examines residential buildings. A summary of data collection methods and pollutant concentrations is presented, followed by a critical discussion of the impact of Passivhaus design strategies on IAQ. This review indicates that IAQ in Passivhaus-certified dwellings is generally better than in conventional homes, but both occupant behaviour and pollution from outdoor sources play a significant role in indoor concentrations. Moreover, there are differences in data collection and reporting methods. Many of the available studies depend on short-term IAQ monitoring of less than two weeks, making it difficult to determine the longer impact of housing design on IAQ and occupants’ well-being. There is also a lack of studies from non-European countries. Future research should focus on investigating associations between IAQ and Passivhaus design strategies in hot and humid climates, where evidence is particularly lacking. Further effort is also required to investigate potential links between occupant’s perception of IAQ and physical exposure to indoor pollution. Finally, the lack of homogeneous monitoring and reporting methods for IAQ studies needs to be addressed.

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