ventilation

Schools had covered special attention in the last year, due to their importance to organize daily work as well as since most of the children were still not vaccinated. Under this circumstance, the importance of air renewal to reduce the probability of COVID-19 contagion inside buildings was highlighted. 

Throughout history, the human population has experienced major outbreaks of infectious diseases. In December 2019 the previously unknown SARS-CoV-2 virus emerged, which had a huge impact globally. Residents of long-term care facilities (LTCFs) showed to be highly susceptible to infection due to their frailty. Respiratory infectious diseases, such as COVID-19, can spread among others via the airborne transmission route. This is caused by sharing the same indoor environment.

In this study, a sensitivity analysis on the effects of inhabitant behaviour on the performance of ventilation systems is carried out. Inhabitants behave differently in terms of presence at home, window opening, door opening, etc. Relating to the ventilation system, this is reflected in the ventilation demand and consequently the energy consumption, but also in the indoor air quality. Therefore, care should be taken to compare ventilation systems to each other as the inhabitants can be the most determining factor for the performance.

Single-family and low-rise multifamily homes in the United States have become tighter to save energy and enhance comfort. To ensure acceptable indoor air quality (IAQ), mechanical ventilation is also required. As these systems become commonplace in the U.S., various improvements and updates have been made to codes, standards, and voluntary programs such as ASHRAE Standard 62.2, International Mechanical Code, International Residential Code, USEPA Energy Star Home and Indoor Air Plus, and USDOE Zero Energy Ready Homes. 

Calcium Silicate fire protection boards can be used to construct fireproof ductwork for smoke extraction and/or HVAC services. In this paper, the airtightness of the duct system is evaluated. 

Control of HVAC systems may reduce congestion of the electricity grid on district level by shifting energy demand of buildings and increase the self-consumption of local photovoltaic energy. To achieve an optimal control of ventilation, occupant behaviour should be taken into account. To describe occupant behaviour, usually black box models are used and typically need large amounts of high quality training data. Alternatively, use of physical relations allows for a good predictive power requiring less training data.

Within the ventilation principle of buildings, the outdoor air is considered as a source of fresh, "clean" air. However, as we all know, this is not always the case. Although the outdoor air quality in our cities already improved, the concentrations of certain pollutants, especially particulate matter and peak pollutions of ozone (and its precursors nitrogen oxides and volatile organic compounds), remain problematic.

Urban settings change the microclimate around buildings and resulting thermal comfort inside.  This paper presents a method to consider microclimatic conditions, especially the effect of wind variations around the building, which impacts natural ventilation rates and indoor operative temperatures.

This paper touches on historic indicators of good hospital design such as sun, daylight and natural ventilation. Evidence is provided that recent trends in hospital design that lean towards more highly serviced buildings with fixed windows lead to higher levels of Sick Building Syndrome, nosocomial infections and SARS CoV-2 related infections and deaths than in naturally ventilated buildings with opening windows.

As part of the mandated standards for estimating the energy performance of buildings CEN 16798-1 and -2 was developed to provide input for the indoor environment (thermal comfort, air quality/ventilation, lighting, acoustic) to energy calculations and design of buildings with its heating, cooling, ventilation, and lighting systems. A revision of this standard has now been started.