Method and plate apparatus for dew point evaporative cooler using a trough wetting system

An indirect evaporative cooler comprising:

• a) a plate having dry and wet sides, the wet side being at least partially wet by an evaporative liquid, and further having two or more first channels across the dry side of the plate and one or more second channels across the wet side of the plate;
• and
• b) a product flow stream and a working gas stream separately flowing across the dry side and thereby transferring heat to the plate;
• c) a passageway through the plate in the area of the working stream on the dry side, the working stream flowing through the perforation from the dry side to the wet side and further flowing across the wet side;
• d) the plate transfers heat to the working gas stream on the wet side by direct evaporative cooling and thereby cooling the plate and the product flow and working gas streams flowing on the dry side;
• and
• e) a trough formed in a portion of the plate to hold and transfer the evaporative liquid to the wet side of the plate.

A method of indirect evaporative cooling comprised of the following steps:

• a) having a heat transfer surface;
• b) wetting one portion of the heat transfer surface with an evaporative liquid that is held temporarily in a trough formed in the heat transfer surface;
• c) having gas pass through the heat transfer surface from the dry portion to the wet portion;
• d) passing a product fluid stream across the dry portion of the heat transfer surface to be cooled and used;
• e) passing a working stream across the dry portion of the heat transfer surface where there are passages;
• f) the working stream flowing through the passages in the heat transfer surface to the wet portion of the heat transfer surface;
• g) cooling of the heat transfer surface by evaporation of the evaporative liquid into the working stream on the wet portion of the heat transfer surface;
• and
• h) cooling the product stream and working stream by contact with the cooled heat transfer surface in the dry portion.

An improved method to cool a fluid where it is comprised of the following steps:

• a) having a plate for the heat transfer surface;
• b) using two or more plates;
• c) having adjacent plates with their opposed surfaces being of the same type, such as both wet surfaces, thereby forming a spacing between the adjacent plates;
• d) having guides between adjacent plates to guide the fluid of the product stream and working stream in desired directions;
• e) having the passages in all of the plates being in the same area;
• f) having the guides in the dry space between adjacent plates guide the product stream separate from the working stream;
• g) having the guides in the wet space between adjacent plates guide the working stream after it has entered the wet space in a direction other than parallel to the direction of the product stream yielding cool fluid of the product stream without any addition of humidity;
• and
• h) having the trough areas nested with each other and holding the evaporative liquid temporarily to wet the wet sides of the plates.