Variable air volume (VAV) systems with reheat, commonly used in North America and beyond, have a widespread summer overcooling problem, causing discomfort and using excessive energy. This study evaluated a new controls approach that both reduced energy consumption and reduced warm season discomfort by half. ASHRAE Journal

The predicted mean vote (PMV) and predicted percentage of dissatisfied (PPD) are the most widely used thermal comfort indices. However, their performance remains a contested topic. We used the ASHRAE Global Thermal Comfort Database II, the largest of its kind, to evaluate the prediction accuracy of the PMV/PPD model.  Findings demonstrate the low prediction accuracy of the PMV–PPD model, indicating the need to develop high prediction accuracy thermal comfort models. For demonstration we developed a simple prediction model based only on air temperature, and its accuracy for this data set was higher than PMV. Building and Environment

High CO2 concentrations have been shown to negatively impact work performance and increase acute health symptoms. This study explored the impacts of office activities, desk settings and personal differences on the CO2 concentration in the ‘inhalation zone’ and at a wearable sensor. A key finding is that a small portable desk fan significantly reduced the CO2 concentration: on average a 177 ppm reduction when using a fan, which is 25 ppm higher than the background CO2 measurement.  Journal of Building Engineering

This study includes practical insights into the use of ceiling fans in commercial spaces, based on practitioner interviews to compile common themes of experience. We also report on in-situ airspeed measurements at five sites. This work serves as a resource for designers and others to offer a path forward for appropriate inclusion of ceiling fans in commercial buildings, which are infrequently used even though they offer potential benefits of increased occupant comfort and energy efficiency. Building and Environment

Observed global warming trends undermine the conventional practice of using historic weather files. The authors of this paper used future weather files to conduct whole-building energy simulations to assess the sensitivity and feasibility of natural ventilation for three different climate types. The results demonstrate how building performance, as measured by thermal comfort metrics, will change over time depending on the future climate conditions. Proceedings 34th International Conference on Passive and Low Energy Architecture

This paper proposes and evaluates an integrated workflow that simultaneously uses ventilation, thermal, and luminous autonomy for the assessment of passive design strategies, introducing a potential way to integrate these three metrics in the design process. We developed a new metric, ventilation autonomy, and a novel visualization to display the hourly and yearly environmental autonomy values. The three metrics together offer designers a means to assessing contradicting design directions. Building and Environment

A field study demonstrated how overcooling and energy use were reduced by expanding the indoor temperature range to reduce the HVAC energy intensity, while providing personal comfort systems for 26 subjects (heated/cooled chair, footwarmer, legwarmer based on occupants’ own choices). Occupants’ satisfaction rate increased from 56% to over 80%, while HVAC zone energy use was reduced by 60% in heating and 40% in cooling. Proceedings 15th Conference of the International Society of Indoor Air Quality & Climate