Personalised Environmental Control Systems (PECS) usage thresholds: a dynamic simulation approach to assess energy, cost, and emissions saving

Personalised Environmental Control Systems (PECS) have emerged as a solution to customise thermal conditions at individual workstations, potentially reducing overall energy consumption. However, their energy performance under diverse building operating conditions remains underexplored. This study investigates the integration of PECS in office environments, focusing on their impact beyond thermal comfort – including energy efficiency, cost, and environmental outcomes. To achieve this, dynamic Building Energy Simulations (BES) were conducted, integrating heating and cooling PECS with traditional HVAC systems in an open-plan office across different climates, building insulation levels, PECS power capacities, and occupancy rates. The evaluation method, which can serve as a standard approach for assessing PECS-building energy efficiency, compares scenarios with and without PECS across various indices, including Primary Energy consumption, energy cost, and CO2 emissions. The results reveal that PECS can significantly cut energy consumption, costs, and emissions, particularly at occupancy rates below 75% for heating and 50% for cooling. PECS prove effective as a year-round solution across various climates, with notable energy savings in extreme conditions. For instance, heating PECS can reduce Primary Energy consumption by up to 33.8 kWh/m2⋅yr (78 MWh – 45%) in buildings located in cold climates with no insulation, while cooling PECS save up to 18.6 kWh/m2⋅yr (43 MWh – 53%) in insulated buildings situated in warm, temperate climates. Integrating PECS, particularly in retrofitting projects, can yield notable energy and cost savings. However, in some cases, energy use increased – mainly with high-power PECS (70–100 W) and full occupancy. These outcomes highlight a “switch point” beyond which PECS no longer yield net savings, underscoring the need for careful sizing. Overall, the study highlights the potential of PECS to enhance office energy efficiency, cost-effectiveness, and environmental sustainability, even alongside modern HVAC systems, and positions the evaluation method as a valuable standard for assessing PECS-building performance.