thermal comfort

Climate change is a growing global concern and building stock, in particular, is responsible for the emission of greenhouse gases, largely due to its poor energy efficiency. This problem is especially serious in educational buildings, where it is necessary to encourage energy efficient retrofitting under the parameters of nearly Zero Energy Building (nZEB), an objective which in Europe has been set for 2050. This is expected to produce economic, energy saving, hygrothermal comfort and health-safety benefits.

A Personalized Environmental Control System (PECS) aims to condition the immediate surrounding of occupants. This approach is fundamentally different from typical HVAC systems, which aim to create uniform indoor environments, regardless of the occupant preferences. PECS has several advantages including allowing occupants to adjust their immediate surroundings according to their preferences, which could improve their satisfaction with the indoor environment, and may lead to higher productivity.

Personalized Environmental Control Systems (PECS) condition the immediate surroundings of occupants, and they are expected to provide increased comfort, health, and productivity. Studies have reported on their benefits and limitations in addressing individual Indoor Environmental Quality (IEQ) factors, especially in terms of thermal comfort and indoor air quality. The COVID-19 pandemic and risks associated to climate change, such as heat waves, highlight the necessity for PECS that can address multiple IEQ factors.

Personalized Environmental Control Systems (PECS) with the functions of heating, cooling, ventilation, lighting, and acoustics have the advantage of controlling the localized environment at occupant’s workstation by their preference instead of conditioning an entire space. This improves personal comfort, health of the occupants, and energy efficiency of the entire heating, ventilation and air-conditioning (HVAC) system substantially. Some of the major advantages and limitations of PECS are summarized. 

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. 

Occupant exposure to airborne pathogens in buildings can be reduced by a variety of means, including adequate provision of outdoor air by ventilation. This is particularly important in buildings, such as hospitals, which may house a higher number of infected individuals relative to the wider population. In tropical Africa, however, there is evidence that new hospitals built with air-conditioning to cope with the extreme heat are poorly ventilated compared to existing hospitals that were designed to be naturally ventilated.

Thermal environment affects occupants’ work performance and well-being. Office workers’ complaints regarding thermal environment are often related to either too warm room temperature or draught. Efficiency demands have increased the heat loads in offices, and increased cooling is needed to control the room air temperature. Draught problems occurs typically in these situations when the workstation is located in the downfall area of the inlet jet. 

Mitigating the risk of overheating and associated thermal discomfort inside school classrooms is a global concern due to its significant impacts on students’ academic performance, health and wellbeing. Thus, rising ambient temperatures resulting from climate change can be challenging, especially in low energy schools designed to optimise their heating season performance. According to recent studies, many low energy school buildings fail to meet comfort standards and experience overheating, resulting in low student productivity and the need for using air conditioning systems.

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.

In the frame of the project Flux50 smart ventilation, researchers and industrials aim at qualifying ventilation in mid-sized buildings through multidisciplinary consideration of sleep quality, user satisfaction, acoustic comfort, installation, maintenance, resilience and indoor air quality. As those factors may impact at different levels it is important to select a common metric for evaluation. Assessment of financial costs induced by the various categories will be used in that purpose.