Smart dehumidifier

1. A water extracting device comprising:

a primary channel for passage of a water transporting medium;

a quantity of a stimulus responsive polymer (SRP) supported on a carrier within the primary channel, the SRP being light responsive and capable of absorbing a quantity of water from the medium in a first state and releasing the water in a second state; and

an illumination arrangement allowing selective exposure of the SRP within the primary channel to electromagnetic radiation to switch the SRP between the first state and the second state whereby water absorbed by the SRP is released, wherein the illumination arrangement comprises light guides that conduct light from outside the primary channel to a location adjacent to the SRP, or the carrier is at least partially light emitting and is integrated with the illumination arrangement.

2. The device as claimed in claim 1 , wherein the carrier comprises a fibrous material and the SRP is present as a coating on the individual fibres.

3. The device as claimed in claim 1 , wherein the carrier comprises a shape-retaining supporting structure; and

wherein the supporting structure comprises a plurality of fins over which the water transporting medium can flow and the SRP is provided on the fins.

4. The device according to claim 1 , further comprising means to conduct heat from an interior of the primary channel to an exterior of the channel.

5. The device according to claim 1 , wherein the SRP is applied to the carrier by grafting the SRP onto individual fibres of the fibrous material.

6. The device according to claim 1 , wherein the SRP is also temperature responsive, whereby transition to the second state takes place either by exposure of the SRP to electromagnetic radiation or by increasing the temperature to above a lower critical solution temperature (LCST); and

wherein the SRP is a co-polymer of spiropyran-derivatives, N-isopropylacrylamide (NIPAAm) and acrylic acid.

7. A system comprising a housing having an inlet and an outlet and a device according to claim 1 located within the housing, whereby a medium to be dehumidified can flow from the inlet to the outlet through the primary channel.

8. The system according to claim 7 , wherein the housing further comprises a drain and a gravity flow structure leading to the drain.

9. The system according to claim 7 , further comprising a heat exchanger communicating with the outlet, whereby air leaving the outlet can flow through the heat exchanger and be cooled.

10. The system according to claim 7 , comprising a plurality of primary channels and further comprising a plurality of secondary channels extending between a secondary inlet and a secondary outlet and in heat conducting relation with the primary channels, whereby heat produced in the primary channels may be conducted to the secondary channels.

11. The system according to claim 7 , in combination with an evaporative cooling device, whereby water extracted from the medium in the water extracting device is supplied to the evaporative cooling device for evaporation into an air flow.

12. A method of extracting water from a water transporting medium comprising:

providing a device according to claim 1 ;

passing a flow of water transporting medium over the device while the SRP is in the first state, whereby the medium is in contact with the SRP and the SRP absorbs a quantity of water; and

subsequently switching the SRP from the first state to the second state whereby water absorbed by the SRP is released.

13. The method as claimed in claim 12 , further comprising:

cooling the flow and/or the device to remove the heat of absorption of the vapour;

collecting the released water by gravity flow to a drain; and

using the collected water in an evaporative cooling device.

14. A water extracting device comprising:

a plurality of primary and secondary channels in heat conducting relation with respect to each other and through which respective first and second media can flow;

a quantity of a stimulus responsive polymer (SRP) within the primary channels, the SRP being capable of absorbing a quantity of water from the first medium in a first state and releasing the water in a second state;

a source of stimulus for selectively causing the SRP to transition between the first and second states, and

a plurality of spaced, parallel conducting foils stacked together; wherein the SRP is provided on a fibrous material layer laminated to the conducting foils in the primary channels;

and wherein the conducting foils are cut and formed into a plurality of fins.

15. The device according to claim 14 , comprising spaced, parallel conducting foils wherein a space between the foils is divided by spacers into adjacent, parallel, primary and secondary channels; and

wherein the spacers comprises a light source.

16. A method of extracting water from a water transporting medium, the method comprising:

passing the water transporting medium through a primary channel containing a quantity of a stimulus responsive polymer (SRP) in a first state whereby it absorbs water vapour from the medium;

conducting heat from the primary channel to a secondary channel, adjacent to and in heat conducting relation with the primary channel;

passing a second medium through the secondary channel to remove heat therefrom; and

periodically regenerating the SRP to remove absorbed water by applying a stimulus to the SRP to cause it to transition from the first state to a second state.