thermal comfort

Building energy behaviour and indoor environmental conditions have been changing due to different external events that have been taking place at global level from 2020, from the COVID pandemic (2020-2022) to the energy crisis (mainly from the war in Ukraine from February 2022). During these events, existing naturally ventilated (NV) buildings have had to balance minimum thermal comfort, high levels of ventilation (to reduce CO2 concentration and risk of infection) and the lowest energy costs.

Accounting for inter- and intra-personal differences requires individual and cohort comfort models. For their development, emulators for thermal sensation of occupants are needed. Physiological signals can be acquired using both wearable and contactless devices. However, due to the widespread availability of sensing methods it is difficult to select the proper measuring method for the application.

Personalized Environmental Control Systems (PECS) have advantages of controlling the localized environment at occupants’ workstation by their preference instead of conditioning an entire room. A new IEA EBC Annex (Annex 87 - Energy and Indoor Environmental Quality Performance of Personalised Environmental Control Systems) has recently started to establish design criteria and operation guidelines for PECS and to quantify their benefits. This topical session will provide an introduction to the objective/scope, activities, and intended outputs of the annex.

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.

In recent years, naturally ventilated glass façades have become a common feature in the design and retrofit of large-scale non-residential buildings, integrating architectural aesthetics and energy efficiency. These façade systems are complex and multifaceted. Thus, introducing them in buildings poses many challenges from economic, engineering, health and behavioural perspectives that can reduce optimal building performance. Building occupant behaviour and preferences are important contributors to the gap between the predicted and actual building energy performance.

With rising insulation standards and air tightness in buildings, the use of mechanical ventilation becomes more relevant. In this context, energy recovery offers a significant contribution to the decarbonisation of building operations. Heat recovery systems are widely spread in residential ventilation. Moreover, enthalpy exchangers recovering sensible and latent heat have an increasing share of use in residential ventilation, especially in cold climates, as they not only reduce the energy demand but also increase the indoor air humidity in winter seasons.

Nowadays, due to climate change, heatwaves become stronger in terms of frequency and intensity. This phenomenon can have serious impact on the indoor environments, indoor thermal comfort and on public health. These situations of high indoor thermal conditions can expose the occupants to health risks such as hyperthermia, dehydration, and heat strokes. Then, the estimation of these risks is crucial. The currently used indices to estimate health risks such as WBGT, HSI and PHS are generally dedicated to outdoor environments and for subjects exerting heavy activities.

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.