Annual Energy Savings and Thermal Comfort of Autonomously Heated and Cooled Office Chairs

Energy use in offices buildings is largely driven by air conditioning demands. But the optimal temperature is not the same for all building occupants, leading to the infamous thermostat war. And many occupants have independently overcome building comfort weaknesses with their own space heaters or fans. NREL tested is a customized office chair that automatically heats and cools the occupant along the seat and chair back according to the occupants' personal preferences. This product is shown to deliver markedly better comfort at room temperatures well above typical office cooling setpoints. Experimental subjects reported satisfaction in these elevated air temperatures, partly because the chair's cooling effect was tuned to their own individual needs. Simulation of the chair in office buildings around the U.S. shows that energy can be saved everywhere, with impacts varying due to the climate. Total building HVAC energy savings exceeded 10% in hot-dry climate zones. Due to high product cost, simple payback for the chair we studied is beyond the expected chair life. We then understood the need to establish cost-performance targets for comfort delivery packages. NREL derived several hypothetical energy/cost/comfort targets for personal comfort product systems. In some climate regions around the U.S., these show the potential for office building HVAC energy savings in excess of 20%. This report documents this research, providing an overview of the research team's methods and results while also identifying areas for future research building upon the findings.