Assessing Suburban Air Quality Constraints on Free Cooling in an Irish City

TL;DR

This study analyzes how outdoor air quality constraints in Cork, Ireland, impact the feasibility of using free outdoor air cooling strategies in buildings, highlighting pollutants that limit natural ventilation options.

Contribution

It provides a novel assessment of outdoor air quality constraints on free cooling potential in Irish suburban environments, linking air pollution data with cooling strategy viability.

Findings

NO2 and PM2.5 exceed thresholds in suburbs

Air quality barriers restrict natural ventilation cooling

Indoor-outdoor pollutant ratios are crucial for design

Abstract

Temperate climates are expected to have an expansion of the number of hours where ventilative cooling is needed and where potential is available even under climate change scenarios. Further to this, the use of free cooling in the form of untreated outdoor air has the potential to be a renewable energy source that adds flexibility to national electricity grids if used appropriately and is critical in decarbonising cooling more generally, particularly where coupled with significant thermal mass in buildings. The following study utilises external air quality measurements from the PASSESPARTOUT project and were collected from unique external air quality systems located in Cork in Ireland. The study characterises this data according to constraints based on control limits for cooling systems and for individual external air quality parameters. While the work aims to demonstrate the barriers to cooling potential that may exist due to poor external air quality, it also offers insights into where good urban air quality supports diurnal ventilative cooling strategies that are best suited given these limitations. The findings show that out of seven outdoor pollutants investigated, NO2 and PM2.5 were consistently above recommended threshold limits in suburban areas and present a barrier to the use of indoor-outdoor direct airflow coupling using natural ventilation strsategies for ventilative cooling purposes. Indoor concentration levels within the surrounding areas to those investigated should be evaluated to develop Indoor-Outdoor ratios for designers for barrier pollutants.