Personalized evaporative cooler to reduce energy consumption and improve thermal comfort in free-running spaces

Abstract

The need to reduce energy consumption in buildings is imperative, but we must maintain individual thermal comfort of the occupants to ensure their well-being and productivity. Personal conditioning systems (PCS) have been suggested as a strategy to achieve both energy efficiency and thermal comfort, as they are considered to be low-energy consumers, allow increasing set-point temperatures, and give occupants the chance to control their own personal environment. While most warm-environment PCS are based on air-movement devices, the potential of using desk direct evaporative coolers (dDEC) has been scarcely explored. This work presents the results of the characterization of a dDEC and its potential for improving the indoor temperature and thermal comfort in a free-running office space. The study proposes adapted corrective power (CPa) and cooling fan efficiency for evaporative systems (CFEe) indexes. Results show that the dDEC achieves thermal comfort with a local effect, and it is recommended to be positioned directly on the desk surface, orientated to the occupant, and at a certain distance. Under these conditions, the CPa reaches −2.8 °C, involving better CFEe than the desk fans studied in the literature. Speed has little effect on the local air conditions, though it does improve the perception of thermal comfort. The relative humidity of the air does not exceed the recommendable limits, but renovation of the indoor air enables better conditions.