Heat exchangers

Abstract

Provided herein are air-to-air heat exchangers. In some embodiments, the air-to-air heat exchanger comprises at least one first air passageway extending between a first air inlet and a first air outlet; at least one second air passageway extending between a second air inlet and a second air outlet; at least one heat-conductive wall separating the at least one first air passageway from the at least one second air passageway; and at least one electrohydrodynamic device disposed in at least one of the first and second air passageways for enhancing airflow therein. Also provided herein is a method of using electrohydrodynamic devices to enhance airflow and efficiency of air-to-air heat exchangers.

1 . An air-to-air heat exchanger, comprising:
 at least one first air passageway extending between a first air inlet and a first air outlet;   at least one second air passageway extending between a second air inlet and a second air outlet;   at least one heat-conductive wall separating the at least one first air passageway from the at least one second air passageway; and
 at least one electrohydrodynamic device disposed in at least one of the first and second air passageways for enhancing airflow therein, wherein each electrohydrodynamic device comprises one or more emitter electrodes, one or more enhancer electrodes positioned downstream of the one or more emitter electrodes, and one or more collector electrodes positioned downstream of the one or more enhancer electrodes. 
   
     
     
         2 . The heat exchanger of  claim 1 , wherein the at least one heat conductive wall comprises at least one essentially planar wall. 
     
     
         3 . The heat exchanger of  claim 1 , wherein the at least one heat conductive wall comprises a plurality of essentially planar walls that are essentially parallel to one another. 
     
     
         4 . The heat exchanger of  claim 3 , wherein the plurality of heat conductive walls are essentially equidistantly arranged. 
     
     
         5 . The heat exchanger of  claim 3 , wherein airflow in the first air passageway and airflow in the second air passageway are essentially in opposite direction. 
     
     
         6 . (canceled) 
     
     
         7 . The heat exchanger of  claim 1 , wherein the one or more emitter electrodes, the one or more enhancer electrodes, and the one or more collector electrodes extend essentially parallel to heat conductive walls and essentially orthogonal to the airflow. 
     
     
         8 . The heat exchanger of  claim 7 , wherein the one or more emitter electrodes have a higher electric potential than the one or more enhancer electrodes, and wherein the one or more enhancer electrodes have a higher electric potential that the one or more collector electrode. 
     
     
         9 . The heat exchanger of  claim 8 , wherein the one or more enhancer electrodes are grounded. 
     
     
         10 . The heat exchanger of  claim 9 , wherein the one or more enhancer electrodes are positioned closer to the one or more emitter electrode than to the one or more collector electrodes. 
     
     
         11 . The heat exchanger of  claim 10 , wherein the one or more emitter electrodes are separated from the closest heat conductive wall by an emitter-wall distance. 
     
     
         12 . The heat exchanger of  claim 11 , wherein the one or more enhancer electrodes and the one or more collector electrodes are attached to the heat conductive wall, and wherein the heat conductive wall is dielectric. 
     
     
         13 . The heat exchanger of  claim 12 , wherein the one or more enhancer electrodes and the one or more collector electrodes are made of heat conductive material. 
     
     
         14 . The heat exchanger of  claim 11 , wherein the heat conductive wall is electrically conductive and grounded, wherein the one or more enhancer electrodes are separated from the closest heat conductive wall by an enhancer-wall distance, and wherein the one or more collector electrodes are separated from the closest heat conductive wall by a collector-wall distance. 
     
     
         15 . The heat exchanger of  claim 14 , wherein the collector-wall distance is smaller than the enhancer-wall distance. 
     
     
         16 . The heat exchanger of  claim 15 , wherein the collector-wall distance and the enhancer-wall distance are both smaller than the emitter-wall distance. 
     
     
         17 . The heat exchanger of  claim 14 , wherein each electrohydrodynamic device further comprises one or more arrays of convection promoter electrodes positioned downstream of the one or more collector electrodes. 
     
     
         18 . The heat exchanger of  claim 17 , wherein one or more arrays of convection promoter electrodes extend essentially parallel to the heat conductive walls and essentially orthogonal to the airflow. 
     
     
         19 . The heat exchanger of  claim 18 , wherein the convection promoter electrodes are separated from the closest heat conductive wall by a promoter-wall distance of (h) that is smaller than any of the emitter-wall distance, enhancer-wall distance, and collector-wall distance. 
     
     
         20 . The heat exchanger of  claim 19 , wherein the convection promoter electrodes within each array are separated from one another by a promoter-promoter distance (s) that is greater than the promoter-wall distance (h). 
     
     
         21 . The heat exchanger of  claim 20 , wherein each electrohydrodynamic device comprises two array of the convection promoter electrodes positioned between two adjacent heat conductive walls, wherein both arrays and have same electrical potential. 
     
     
         22 . The heat exchanger of  claim 21 , wherein one array of convection promoter electrodes of a first electrohydrodynamic device and one array of convection promoter electrodes of a second electrohydrodynamic device are disposed on opposite side of a heat conductive wall with an offset distance (u), and have opposite electric potentials. 
     
     
         23 . The heat exchanger of  claim 22 , wherein the promoter-promoter distance (s) is no less than 2h+u, and wherein the promoter-promoter distance (s) is no greater than X(2h+u), wherein X ranges between 1.5 and 2.0. 
     
     
         24 . The heat exchanger of  claim 1 , wherein the at least one first air passageway, the at least one second air passageway, the at least one heat-conductive wall, and the at least one electrohydrodynamic device are enclosed in a housing. 
     
     
         25 . The heat exchanger of  claim 24 , wherein the housing comprises the first air inlet, the first air outlet, the second air inlet, and the second air outlet. 
     
     
         26 . A ventilation system comprising a desiccator and the heat exchanger of  claim 25 , wherein the first air inlet of the heat exchanger is configured to receive air from atmosphere, the first air outlet of the heat exchanger is connected to the desiccator. 
     
     
         27 . The ventilation system of  claim 26 , wherein the second air inlet of the heat exchanger is configured to receive exhaust air from the ventilation system, and wherein the second air outlet of the heat exchanger is configured to release air into atmosphere. 
     
     
         28 . The ventilation system of  claim 26 , wherein a temperature of air entering into the first air inlet of the heat exchanger is higher than a temperature of air exiting the second air outlet of the heat exchanger. 
     
     
         29 . A method of enhancing air flow in an air-to-air heat exchanger, the method comprising:
 activating at least one electrohydrodynamic device disposed in air passageways of the air-to-air heat exchanger, wherein each electrohydrodynamic device comprises one or more emitter electrodes, one or more enhancer electrodes positioned downstream of the one or more emitter electrodes, and one or more collector electrodes positioned downstream of the one or more enhancer electrodes,   wherein the activation comprises creating gradient electric potential differential from the emitter electrodes to the enhancer electrodes and to the collector electrodes.   
     
     
         30 . The method of  claim 1 , wherein the activation comprises coupling the emitter electrodes with a source of positive electric potential, coupling the collector electrode with a source of negative electric potential, and grounding the enhancer electrodes.