Indoor air modelling and infection risk assessment in a naturally ventilated patient room

Sufficient ventilation in clinics is critical for diluting virus concentrations and lowering subsequent doses inhaled by the occupants. Several advanced simulation methods and tools for building physics and indoor air fluid dynamics are currently available in research and industry. However, in naturally ventilated buildings, indoor air distribution depends strongly on local and dynamically changing conditions, e.g., opening sizes and time, exhaust shaft location, and climatic and weather conditions.

What can CO2 measurements tell us about ventilation and infection risk in classrooms?

Indoor air quality in schools is of critical importance for the health and well-being of pupils and staff. The COVID-19 pandemic highlighted the essential role that ventilation systems play in limiting the spread of airborne diseases and consumer CO2 monitors were deployed in UK classrooms as a cost-effective tool to help manage the ventilation supply. In such settings, which are occupied for long periods by the same group of people, CO2 measurements have also been used to infer the risk of far-field airborne infection.

Thermal comfort and risk of draught with natural ventilation - assessment methods, experiences and solutions

The majority of research and hence the assessment methods and tools for thermal comfort assessment of ventilation systems are not based on findings for natural ventilation solutions and do not take into account the specific characteristics of natural ventilation. This has created a lack of suitable methods for the assessment and performance evaluation of natural ventilation. This paper will focus on the evaluation of assessment methods related to estimating the risk of draught for natural ventilation systems.

Ventilation reliability: A pilot study on window opening behaviour in a primary school

Most New Zealand schools are designed to be naturally ventilated, using openable windows (Ministry of Education Design Quality Standard Guidelines). Furthermore, they must meet the New Zealand Building Code Clause G4 - Ventilation. Clause G4 requires the “net openable area of windows in a classroom to be no less than 5% of the combined habitable floor area to achieve sufficient ventilation”. Although they are designed to code, there is no end-user operational or systems requirement for them to be opened.

A methodology for evaluating the ventilative cooling potential in early-stage building design

As a result of the new initiatives and regulations towards nearly zero energy buildings, designers are more frequently exploiting the cooling potential of the climate to reduce overheating and improve indoor well-being of people. At early stage of design, climate analysis is particularly useful for determining the most cost-effective passive cooling methods, such as ventilative cooling. However, besides the external climate conditions, building energy uses are characterized by occupancy pattern and needs, envelope characteristics and internal loads.

Lessons Learned from Irish Schools: Early-stage Insights on 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.

Ventilation behaviour of occupants driven by outdoor temperature: 12 case studies

This paper presents the results of an Indoor Environment Quality (IEQ) monitoring study (including relative humidity, temperature and IAQ in terms of indoor CO₂) in naturally ventilated dwellings (mainly based on vertical shafts and infiltrations) and the analysis of the data obtained. The aim of the study is to identify patterns that relate occupants’ ventilation behaviour to outdoor temperature and to increase knowledge of occupant’s perceptions of IEQ. The results could be used to improve ventilation models and building regulations.

Method for Evaluating an Air-Conditioning System with Natural Ventilation by Coupled Analysis of a Building Energy Simulation Tool and Computational Fluid Dynamics

In office buildings, an air-conditioning system with natural ventilation can reduce cooling loads and create a comfortable indoor environment. However, it is difficult to predict the performance of such systems and there is concern that the natural ventilation will create an uneven indoor thermal environment. In this paper, we propose a method for evaluating the performance of a natural-ventilation air-conditioning system by coupling a building energy simulation tool and computational fluid dynamics.

Wind Tunnel Experiment of Wind-Induced Single-sided Ventilation under Generic Sheltered Urban Area

The utilization of natural ventilation helps to reduce building energy consumption and improve indoor air quality. In the urban area, the performance of the natural ventilation is very sensitive to surrounding building density. However, the influence of surrounding buildings on ventilation rate was not well investigated in previous research. This paper presents a wind tunnel experiment to assess the influence of urban density on the wind-induced ventilation rate of single-sided ventilation.

Reflections on alternative modelling approaches regarding occupants' window operation behaviour

Computational predictions of buildings' indoor-environmental conditions and energy performance would presumably benefit from the inclusion of models that could reliably capture occupants' window operation behaviour. Frequently, models derived from empirical data have a black-box character. However, the utility of window operation models could be conceivably improved, if the model derivation process is preceded by specific hypotheses regarding the variables that are assumed to influence the frequency and timing of window operation actions.