energy efficiency

To reduce the carbon footprint of the built environment, a significant overhaul of the existing housing stock is essential. This entails not only ensuring proper insulation and airtightness in residences but also optimizing their ventilation systems. To precisely gauge the impact of an advanced ventilation system, the use of a pressure node model, such as multizone ventilation models like COMIS or TNO's AirMAPs model, is indispensable. However, when dealing with existing dwellings, numerous unknown variables, including interior door usage, can introduce substantial variations in results.

Open offices, where more than one person works, have been used frequently in recent years. However, there are many studies on the efficiency of the indoor air quality of the employees in these offices. It has also been shown that the risk of cross-contamination is higher in such offices during the COVID period, but this risk can be reduced by increasing the amount of fresh air.

The Performance 2 project (2020-2024) is a French national research project that aims to evaluate the durability of Humidity-based Demand Controlled Ventilation (DCV) systems installed in two multi-family social housing buildings (Paris and Villeurbanne) over than 10 years ago. This evaluation includes the analysis of continuous measurements performed on the ventilation system (sensors located close to the air terminal devices) and two additional Indoor Air Quality (IAQ) campaigns including two other monitors placed in the “dry” rooms conducted in 13 dwellings.

The materials that compose the built environment have a key role in the resulting energy demand since their thermal properties affect the heat transfer processes. The use of cool materials aims at increasing the albedo of the urban surfaces and decreasing the heat absorbed by them. Cool materials can decrease roof temperatures, reduce energy needs for cooling and improve indoor comfort for spaces that are not air conditioned.

Green buildings incorporate several features to improve energy efficiency, indoor environmental conditions, and occupant satisfaction. However, studies have indicated that green-certified buildings do not always provide occupants with an acceptable level of satisfaction. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) requires that at least 80% of occupants are satisfied with the indoor thermal conditions.

Current building regulations are designed to ensure that buildings, including newly built and retrofitted residential dwellings, are more energy efficient. This has raised concerns and practical challenges in relation to maintaining acceptable indoor environmental and air quality. However, there are minimal data available regarding long-term indoor air pollutant concentrations in low-energy residential buildings.

This paper reports preliminary analysis from a large field study of 100 university classrooms in Central Texas. Lecture classrooms and auditoriums were sampled for three consecutive weekdays in the 2019 – 2020 academic year. Carbon dioxide (CO2) concentrations, used as a marker for both ventilation and exposure, and temperature were measured in the general room area and when able, the supply airstream. HVAC control data that relates to ventilation was also saved for comparison.