An
improved method and apparatus for indirect evaporative cooling of a fluid
stream to substantially its
dew point temperature.
Plate heat exchanger has perforations 11 and channels 3, 4 and 5 for gas or a low temperature for liquids on a dry side and wet side. Fluid streams 1 flow across the dry side 9, transferring heat to the plate. Gas
stream 2 flows across the dry side and through perforations to channels 5 on wet side 10, which it then cools by evaporative cooling as well as conductive and
radiative transfer of heat from plate. A wicking material provides
wetting of wet side. In other embodiments, a
desiccant wheel may be used to dehumidify the gas, air streams may be recirculated, feeder wicks 13 and a pump may be used to bring water from a
water reservoir, and fans may be used to either force or induce a draft. The wicking material may be
cellulose, organic fibers, organic based fibers,
polyester,
polypropylene, carbon-based fibers,
silicon based fibers, fiberglass, or combinations of them. The device may be operated in winter months to scavenge heat from exhaust gases of a space and thus pre-heat
fresh air, while simultaneously humidifying the
fresh air.