Over the years, traditional wisdom has supported the idea of a water body such as pond, lake or a fountain to provide cooling effect to the surrounding environment. This effect lowers the indoor air temperature – a widely known concept of evaporative cooling. This phenomenon is largely witnessed in systems such as desert coolers in most Indian households.
Evaporative cooling lowers the indoor air temperature thus lowers the energy cost for air-conditioning in buildings. Reduced energy load contributes towards meeting the NZEB design goals. However, evaporative cooling is mostly effective in hot and dry climate where the humidity is low.
Evaporative coolers can replace mechanical cooling in hot-dry climates. In composite climates evaporative cooling systems can be used to reduce HVAC system use during early summer months when the temperatures are high and humidity is low.
It has been calculated that temperature of 1 M3 of air will be reduced by 1° centigrade by the evaporation of 0-5 gm of water.