Fabrication materials and techniques for plate heat and mass exchangers for indirect evaporative coolers

Abstract

Heat exchanger plates for indirect evaporative coolers, of the type having a dry side having low permeability to an evaporative liquid and formed to allow a product fluid to flow over a heat transfer area of its surface, a wet side designed to have its surface wet by an evaporative liquid, and formed to allow a working gas to flow over its surface to evaporate the evaporative liquid, are formed such that the wet side comprises a hydrophobic fiber sheet and the dry side comprises a non-permeable sealing layer on the sheet. Heat seal strips are formed at the inlet and outlet of the plates and air flow perforations are formed through the plates.

Description

BACKGROUND OF THE INVENTION[0001]U.S. Pat. No. 6,581,402, issued Jun. 24, 2003 is incorporated herein by reference. U.S. Pat. No. 6,705,096, issued Mar. 16, 2004 is incorporated herein by reference. U.S. Pat. No. 7,228,699, issued Jun. 12, 2007 is incorporated herein by reference. This application claims the benefit of U.S. Provisional Patent Application No. 61 / 135,640, filed Jul. 21, 2008.[0002]1. Field of the Invention[0003]The present invention relates to plate heat and mass exchangers for indirect evaporative coolers. In particular, the present invention relates to improved fabrication materials and techniques for such plate heat and mass exchangers for indirect evaporative coolers.[0004]2. Discussion of the Background Art[0005]Indirect evaporative cooling is a method of cooling a fluid stream; usually air, by evaporating a cooling liquid, usually water, into a second air stream while transferring heat from the first air stream to the second. The method has certain inherent adva...

AI Technical Summary

Benefits of technology

[0017]It is an object of the present invention to provide improved fabrication materials and techniques for such plate heat and mass exchangers for indirect evaporative coolers. An improved process for fabricating a Dew Point Evaporative Air Conditioner uses the thermo forming properties of a plastic polymer to create a seal edge on the inlet and outlet faces of a heat and mass exchanger plate and optionally around the air passageways between the dry side of the plate and a wet side. The plastic polymer material allows the edges to be sealed by melting the fiber material together eliminating the need for a second sealing material such as epoxy, as is used in previous manufacturing processes.

[0018]In addition, the improved material uses a hydrophobic plastic polymer such as polypropylene or a combination of plastic polymer hydrophobic material bonded to the top of a hydrophilic material such as a polypropylene spun bond intermingled or on top of a nylon naturally wicking material, with the hydrophobic material on the evaporative surface to improve wicking and evaporation, and retard mold.

Problems solved by technology

Wicking up a vertical surface will insure no excess water on the plate surface but also limits the height of the plate that can be used.

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