Method and plate apparatus for dew point evaporative cooler

Abstract

An improved method and apparatus for indirect evaporative cooling of a fluid stream to substantially its dew point temperature. Plate heat exchanger has perforationsand channelsandfor gas or a low temperature for liquids on a dry side and wet side. Fluid streamsflow across the dry side, transferring heat to the plate. Gas streamflows across the dry side and through perforations to channelson wet side, 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 wicksand 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.