Enhancing individual thermal preference satisfaction and energy efficiency in multi-occupant spaces through stratified micro-environments

This investigation assesses the capability of stratified micro-environments (SMEs) to cater to individual thermal preferences while enhancing energy efficiency within a shared space. The test environment is a ventilated chamber featuring a series of adjustable supply air terminals, strategically positioned to serve eight occupied positions. Employing a computational fluid dynamics (CFD) model, which is experimentally validated, the research utilizes metrics such as the predicted mean vote (PMV) and draft rate (DR) to reflect individual preferences and ascertain comfort levels. The study leverages jet theory and regression analysis to devise predictive models of thermal comfort that cater to various supply air conditions and occupant positions, conducting an exhaustive search for viable solutions. Practical limitations are taken into account to delineate the operational feasibility of SMEs. Results indicate that SMEs can produce a PMV variation of up to 1.8 and a DR variation of up to 24.0% across different positions, disparities that total volume ventilation (TVV) systems cannot accommodate. The energy-saving merits of SMEs are accentuated, which become particularly significant when occupants favor a lower PMV. Through case studies involving diverse PMV preference distributions, it is demonstrated that SMEs more effectively fulfill individual preference combinations than TVV in 98.9% of cases, with minimal PMV discrepancies (0.2). In decision-making that weighs both thermal comfort and energy efficiency, SMEs consistently exhibit a significant advantage — ranging from 96.6% to 100% — across various weights and population distributions. These insights advocate for the integration of SMEs in the design and management of multi-occupant environments. © 2024 Elsevier Ltd