Moisture exchange module containing a bundle of moisture-permeable hollow fiber membranes

1 . A moisture exchange module, which comprises:

a. a moisture-permeable hollow fiber membrane shell space;

b. a bundle of moisture-permeable hollow fiber membranes arranged in the shell space for receiving a first gas stream;

c. a conduit member coupled to the shell space for supplying a second gas stream for flow around the hollow fibers; and

d. a mechanism arranged and configured in the conduit member to produce a swirling motion in the second gas stream.

2 . The moisture exchange module of claim 1 wherein the mechanism comprises an element shaped in a spiral along a flow direction of the second gas stream.

3 . The moisture exchange module of claim 1 wherein the mechanism comprises an element helically shaped along a flow direction of the second gas stream.

4 . The moisture exchange module of claim 1 wherein the mechanism comprises an element that has an end onto which a flow of the second gas stream impinges first, the end is twisted by 70° to 270°, with respect to an other end of the element.

5 . The moisture exchange module of claim 1 wherein an annular space surrounds the shell space in an area of one end of the bundle of hollow fiber membranes.

6 . The moisture exchange module of claim 5 wherein the annular space is arranged in an area of an end of the bundle of hollow fiber membranes where the first gas stream flowing through the hollow fiber membranes exits the bundle.

7 . The moisture exchange module of claim 5 wherein the conduit member communicates with the annular space centrally with respect to a cross-section of the bundle of hollow fiber membranes.

8 . The moisture exchange module of claim 5 wherein the conduit member communicates with the annular space tangentially with respect to a cross-section of the bundle of hollow fiber membranes.

9 . The moisture exchange module of claim 5 wherein a deflector element is arranged in the annular space between the conduit member and the shell space, the deflector element being arranged for deflecting the flow of the second gas stream so as to prevent the gas stream from flowing directly into the shell space.

10 . The moisture exchange module of claim 9 wherein the deflector element is arranged and configured such that the second gas stream is deflected by the deflector element such that the second gas stream flows in a flow direction parallel to the hollow fiber membranes of the bundle, at least over part of its path.

11 . The moisture exchange module of claim wherein a perforated plate is arranged in the annular space between the conduit member and the shell space, such that the second gas stream flows from the annular space into the shell space through a plurality of openings formed on the perforated plate.

12 . A fuel cell system comprising:

a. at least one fuel cell;

b. a moisture exchange module coupled to the at least one fuel cell;

c. the moisture exchange module including:

i. a moisture-permeable hollow fiber membrane shell space;

ii. a bundle of moisture-permeable hollow fiber membranes arranged in the shell space for receiving a first gas stream;

iii. a conduit member coupled to the shell space for supplying a second gas stream for flow around the hollow fibers; and

iv. a mechanism arranged and configured in the conduit member to produce a swirling motion in the second gas stream.

13 . The fuel cell system of claim 12 wherein the moisture exchange module is arranged to humidify supply air to the fuel cell system using a moist exhaust gas from at least one fuel cell of the fuel cell system.

14 . The fuel cell system of claim 13 further comprising a compression device arranged to deliver the supply gas along an outer surface of the hollow fiber membranes to the fuel cell system, the moist exhaust gas being arranged to flow through the hollow fiber membranes.