Enthalpy exchanger element and method for the production

Abstract

Enthalpy exchanger elements which allow the creation of enthalpy exchangers whereby the efficiency of sensible energy exchange and latent energy exchange can be varied and controlled and especially improved. Also, a method for the production of enthalpy exchanger elements including: a) perforating a flat plate element (1) according to a predetermined perforation pattern (2, 2, . . . ) within the plate outer dimensions, or providing a plate element (1) with an inherent pore structure; b) applying to at least one side (1a) of the plate element (1) a thin polymer film (3) with water vapor transmission characteristics; c) forming the plate element (1) into a desired shape exhibiting a corrugation pattern (4, 4, . . . ), whereby the polymer film (3) is formed into the same corrugation pattern shape as that of the plate element (1).

Claims

1. A method for the production of enthalpy exchanger elements, the method comprising: a) perforating a flat plate element (1) according to a predetermined perforation pattern (2, 2, . . . ) within the plate outer dimensions, or providing a plate element (1) with an inherent pore structure; b) applying to at least one side (1a) of the plate element (1) a thin polymer film (3) with water vapor transmission characteristics (water vapor transfer ratio, WVTR); c) forming the plate element (1) into a desired shape exhibiting a corrugation pattern (4, 4, . . . ), whereby the polymer film (3) is formed into the same corrugation pattern shape as that of the plate element (1); and whereby the plate element is a plastic plate and whereby a total open area for water vapor transfer on no less than 50% of the available plate exchange surface is provided; and wherein the polymer film is heat bonded or glued to the plate element while the plate element is being formed into the desired shape.

2. The method according to claim 1, characterized in that the plate is perforated using at least one of needles, pins, die and punch, or a laser.

3. The method according to claim 1 wherein the polymer film is made of a sulfonated copolymer, or a block copolymer.

4. The method according to claim 1 wherein the spatial frequency of the corrugations of the corrugation pattern and the density of the perforations in the perforation pattern is varied in a border area of the corrugation pattern and a border area of the perforation pattern in order to improve frost resistance.

5. The method of claim 1 whereby the plate element is a plastic plate providing a plate exchange surface and whereby a total open area for water vapor transfer of no less than 50% of the available plate exchange surface is provided.

6. The method of claim 1 wherein the plate element may comprise a porous polymer plate or a woven or non-woven fabric made from polymer fibers, inorganic fibers or metal fibers.

7. The method of claim 1 wherein the plate element is a composite made using a woven or non-woven fabric made from polymer fibers, inorganic fibers or metal fibers.

8. The method of claim 7 wherein the composite further includes a porous polymeric material as a matrix.

9. The method of claim 1 wherein the border areas of the plate element are not perforated, preferably in a range of 5 to 20 mm, more preferably in a range of 10 to 20 mm, from the outer dimensions of the plate element.

10. The method of claim 1 wherein the perforations may be openings of diverse shapes and with a surface area equivalent to hole diameters ranging from 30 m to 1.2 mm, preferably providing a total open area of no less than 50% of the available plate exchange surface area.

11. The method of claim 1 wherein thin polymer film is a multilayer film further comprising a sequence of polymer layers of different polymer types.

12. The method of claim 11 wherein the polymer type of each polymer layer is selected from the group consisting of polyether ester, polyether amide and polyether urethane.

13. The method of claim 11 wherein the total thickness of the thin polymer multilayer film is between 5 m and 200 m or between 10 m and 150 m.

14. The method of claim 11 wherein the thickness of each individual polymer layer within the thin polymer multilayer film is between 2 m and 20 m, or between 5 m and 20 m.

15. A method for the production of enthalpy exchanger elements, the method comprising: a) perforating a flat plate element (1) according to a predetermined perforation pattern (2, 2, . . . ) within the plate outer dimensions, or providing a plate element (1) with an inherent pore structure; b) applying to at least one side (1a) of the plate element (1) a thin polymer film (3) with water vapor transmission characteristics (water vapor transfer ratio, WVTR); c) forming the plate element (1) into a desired shape exhibiting a corrugation pattern (4, 4, . . . ), whereby the polymer film (3) is formed into the same corrugation pattern shape as that of the plate element (1); and wherein the applying to at least one side (1a) of the plate element (1) a thin polymer film (3) with water vapor transmission characteristics is accomplished by co-forming the plate element (1) and the thin polymer film (3) into a desired shape exhibiting a corrugation pattern (4, 4, . . . ), whereby the polymer film (3) is formed into the same corrugation pattern shape as that of the plate element (1) and is permanently bonded to the plate element during the forming of the corrugation pattern shape; whereby the plate element is a plastic plate and whereby a total open area for water vapor transfer on no less than 50% of the available plate exchange surface is provided.

Description

(1) Further features, advantages and aspects of the invention become obvious from the following description of the drawings. The drawings show:

(2) FIG. 1 a flow chart illustrating a sequence of steps of the production method according to the invention; and

(3) FIG. 2 a sequence of states of the production of an enthalpy exchanger element in cross sectional view during the production method according to the invention.

(4) In FIG. 1, a sequence of steps of the production method according to the invention are shown. Each step shown in FIG. 1 corresponds to a resulting state schematically shown in FIG. 2. It should be noted that the illustrated geometric parameters such a thicknesses, hole diameters, curvatures etc. in FIG. 2 are for exemplary purposes, only. Therefore, they do not necessarily represent the proper or preferred ratios of such parameters.

(5) In providing step S1, a flat yet unformed plastic plate element 1 with defined outer dimensions is provided. In perforating step S2, a portion of the flat plastic plate element 1 is transferred to a perforation device (not shown) where the flat plastic plate element 1 is perforated by a needle-roller or a punching die (not shown) depending on the desired size of the holes. In the present case, the entire plate element 1 is perforated with a symmetric hole pattern, except for the border areas (not shown) to allow welding of the plate elements 1 in order to form the plate exchanger (not shown). The perforation pattern is made up of a plurality of holes 2 extending across the entire plate thickness from a first surface 1a to a second surface 1b of the plate element 1.

(6) Subsequently to the perforating step, in covering step S3, one side, i.e. surface 1a, of the now perforated plate element 1 is completely covered by a thin polymer film 3. The polymer film is made of a proprietary sulfonated block copolymer or any type of such sulfonated block copolymers.

(7) Subsequently to the covering step, in forming step S4, the now perforated and covered flat plate element 1 is transferred to a forming device, which is embodied by a vacuum forming device, where the flat plate element 1 and the thin polymer film 3 are formed into a desired shape. In this forming step S4, the border areas, fluid inlets and outlets and corrugations 4 are formed into the plate element 1. The corrugation pattern is made up of a plurality of corrugations 4 extending across the plate area.

(8) In the present embodiment of the invention, the border areas are being formed in non-perforated areas, while the corrugations are being formed in perforated areas of the plate element 1.

(9) Thereby, during the forming step S4 which is a co-forming step of the flat plate element 1 and the thin polymer film 3, the thin polymer film 3 is formed into the exact same shape as the plate element 1 and is permanently bonded thereto, due to the heat, which is applied by the vacuum forming device.

(10) These thin-polymer-film-covered and co-formed plates 1 constitute the enthalpy exchanger plates according to the invention. They will be stacked to build an enthalpy exchanger (also referred to as a total energy exchanger) core e.g. for ventilation systems to exchange heat from outgoing to incoming air (or vice versa for free cooling in summer) as well as humidity from outgoing to incoming air in winter (or vice versa for moisture reduction in summer or all year round in hot and humid climatic zones).

(11) The cross sectional shape of the corrugations 4 may be rectangular, square or triangular. It may also be trapezoidal such half hexagonal.

(12) The drawing and the description do in no way restrict the invention and are meant for illustrating the invention by an example, only.

REFERENCE NUMERALS

(13) 1 flat plate element 1a first surface 1b second surface 2 hole 3 thin polymer film 4 corrugation S1 providing step S2 perforating step S3 covering step S4 forming step (co-forming)