Evaporative Cooling Across Building Types and World Climate Zones

Cooling demand in buildings is rising, met mostly by electric air conditioners. Evaporative cooling uses water instead of a synthetic refrigerant, but its benefit depends on the climate and on how much humidity a building can accept. We reviewed 27 case studies in eight building types (homes, offices, schools, hospitals, industrial halls, data centers, greenhouses and animal houses), twelve of which used simulation, and placed each site in a Köppen–Geiger climate zone. Most studies came from the dry B zones; the other zones contributed only two to four studies each. In dry zones, direct systems were usually enough for greenhouses and animal houses, office workers accepted evaporatively cooled rooms, and an indirect unit cooled a data center without a compressor for 97% of the year. In humid zones (Cfa and Aw), people needed air drying or a compressor as well, but animals and plants still benefited. In the Cfb zone, a hybrid indirect unit cut office electricity use by 45% on the design day. Water use, hygiene and maintenance set the practical limits. We propose a building-type and climate matrix with a confidence rating for each cell and an early-design decision path; most cells rest on one to three studies.