English

The COVID-19 pandemic has raised concerns about indoor ventilation conditions worldwide. Monitoring CO2 concentrations in rooms has been widely used, but its relationship with outdoor air ventilation rates and ventilation performance is uncertain. Several uncertainties must be quantified, including the location and rate of CO2 sources, sensor locations, and the dynamics of the surroundings, as well as limitations of existing simulation models, such as well-mixing assumptions.

An approach has previously been developed to estimate space-specific carbon dioxide (CO2) levels that can serve as metrics for the adequacy of outdoor ventilation rates. These metrics are based on the CO2 concentration expected in a space given its intended or expected ventilation rate, volume, and occupant information (i.e., the number of occupants, their CO2 generation rates, and duration of occupancy).

Low energy buildings are highly insulated and airtight and therefore subject to overheating risks, where Ventilative Cooling (VC) could be a relevant solution in both existing and new buildings - being both a sustainable and energy efficient solution to improve indoor well-being, hereunder thermal comfort (State-of-the-art-review, Kolokotroni et al., 2015).
VC is widely used as a key element when designing buildings to cope with overheating to assist improving thermal comfort, but can also improve the Indoor Air Quality due to higher ventilation rates in the cooling season.

To achieve future-proof buildings, it is crucial to design buildings and systems that can withstand to shocks (like heat waves and power outages) and reduce the impact of shocks on thermal comfort in a building. This is known as resilience to overheating.

Overheating in school buildings is likely to lead to a negative learning performance experience for occupants in these settings. In Ireland, school buildings are primarily naturally ventilated, given the relative increases in external mean temperatures that are projected to have negative effects on the potential of natural ventilative cooling going forward, it is important to assess what the current overheating status is in these buildings. Existing work has already highlighted the lack of measurement data on overheating in low energy school buildings.

A Danish office building designed with a hybrid ventilation system has been compared to a full mechanical ventilation system in the same building. The comparisons include a life cycle analysis (LCA) focussing on CO2 equivalents (CO2equiv.) and life cycle cost (LCC) of the two ventilation solutions. The LCA includes embodied carbon form the ventilation components and operational energy due to heating and electricity. A potential reduction of 32% in the total global warming potential (GWP) was found when using a hybrid ventilation solution instead of a mechanical ventilation solution.

Embedding robust yet accessible frameworks to evaluate ventilative cooling potential during the early/concept design stages for building practitioners can help in reducing the performance gap as well as avoiding vulnerability “lock-in” from design decisions that are based on poor or inadequate information. The challenge is to develop performance based evaluation methods that recognise the tacit approach to design in practice. Often design is iterative, non-linear and multi-agent.

The growing challenges of climate change, urbanization, and increased energy demand have underscored the critical need for sustainable and resilient cooling solutions in buildings. In response to this pressing global issue, the International Energy Agency's Energy in Buildings and Communities (IEA EBC) Annex 80 was initiated to address the multifaceted aspects of resilient cooling in the built environment. Annex 80 seeks to provide valuable insights into resilient cooling systems and their indicators, offering a pathway towards a more sustainable and adaptable future...

Smart ventilation which provides air renewal thanks to its variable airflows adjusted on the needs can improve both indoor air quality (IAQ) and energy performance of buildings. However, such performance gains should be quantified with performance-based approaches. In this paper, we propose to extend the performance-based approach with a robust methodology to rank the ventilation systems performance. Such a methodology could be used in a decision-making tool at the design stage of buildings.

Metal Oxide Semiconductor (MOS) sensors measuring Volatile Organic Compounds (VOC) seem to be an obvious step towards broadly available Demand Controlled Ventilation (DCV). The previous research shows that MOS VOC sensors can detect high pollution events such as cleaning, painting, or high occupation density. These abilities seem to make MOS VOC sensors suitable to complement ventilation control systems, especially concerning residential ventilation.