Dessicant dehumidifier for drying moist environments

• US 20050204914A1
• Filed: 03/02/2005
• Published: 09/22/2005
• Est. Priority Date: 03/04/2004
• Status: Active Grant

• Current Assignee: Therma-Stor LLC
• Original Assignee: Charles A. Boutall
• Inventors: Boutall, Charles A.
• Granted Patent: US 7,338,548 B2
• Time in Patent Office: Days
• US Class Current: 95/10
• CPC Class Codes: B01D 2259/404 using four beds
• CPC Class Codes: B01D 53/06 with moving adsorbents, e.g. rotating beds B01D53/025 takes precedence
• CPC Class Codes: B01D 53/261 by adsorption
• CPC Class Codes: F24F 2203/1032 Desiccant wheel
• CPC Class Codes: F24F 2203/1064 Gas fired reheater
• CPC Class Codes: F24F 2203/1068 comprising one rotor
• CPC Class Codes: F24F 2203/1088 comprising three flow rotor segments
• CPC Class Codes: F24F 3/1423 with a moving bed of solid desiccants, e.g. a rotary wheel supporting solid desiccants

Abstract

An apparatus and method of conditioning humidity and temperature in the process airstream of a desiccant dehumidifier used to dry moisture-laden spaces and structures by replacing moisture-laden air with dehumidified air to increase the rate of water evaporation within the affected areas. A heat-modulating dehumidifier comprises a dehumidification assembly having a desiccant rotor assembly, a post-process pre-reactivation heat exchanger assembly, a reactivation air bypass damper, a reactivation heater, and a control system. The apparatus regulates the temperature level of the dehumidified air exiting the apparatus by extracting heat from the dehumidified air prior to its ejection into an affected area, using a bypass damper that controls the amount of heat transfer from the dehumidified air to a second airstream entering the apparatus.

Claims

1. A heat-modulating dehumidifier for dehumidifying and controlling the temperature of air to be delivered to a moisture-laden area, said heat-modulating dehumidifier without the use of mechanical cooling devices, comprising:

(a) a desiccant rotor comprising at least two process chambers and a single reactivation chamber, through which chambers air can flow;

wherein said process chambers are adapted to heat and dehumidify a process air stream to produce first and second post-process air streams; and

wherein said process chambers are adapted to transfer heat to a second air stream and to transfer a selected fraction of the heat to said second air stream or said reactivation chamber;

wherein the selected fraction is between 0 percent and 100 percent;

(b) a first heat exchanger adapted to transfer heat from the first post-process air stream to the second air stream before the first and second post-process air streams are joined to form a combined post-process air stream; and

to eject the combined post-process air stream into the moisture-laden area;

(c) a first bypass damper capable of adjustably diverting at least a portion of the second air stream from said heat exchanger, and of delivering the remaining portion of the second air stream to said heat exchanger;

(d) a heater for heating the second air stream, after the second air stream has passed either through or around said heat exchanger, to a temperature sufficient to remove moisture from said reactivation chamber; and

(e) a control system comprising a temperature sensor and a damper actuator;

wherein said damper actuator is adapted to adjust the temperature of the first post-process air by actuating said bypass damper to control the amount of the second air stream that is diverted from said heat exchanger;

wherein;

(f) when said temperature sensor detects that the temperature in the moisture-laden area is greater than a pre-selected level, said damper actuator adjusts the position of said bypass damper to decrease the amount of the second air stream diverted from said heat exchanger, thereby increasing heat transfer from the first post-process air stream to the second air stream and decreasing the temperature of the first post-process air stream; and

when said temperature sensor detects that the temperature in the moisture-laden area is less than a pre-selected temperature, said damper actuator adjusts the position of said damper to increase the amount of the second air stream being diverted from said heat exchanger, thereby decreasing heat transfer from the first post-process air stream to the second air stream and increasing the temperature of the first post-process air stream.

2. A device as recited in claim 1, wherein said device is adapted to draw the process air stream from inside the moisture-laden area.

3. A device as recited in claim 1, wherein said device is adapted to draw the process air stream from outside the moisture-laden area.

4. A device as recited in claim 1, wherein said device is adapted to draw the second air stream from outside the moisture-laden area.

5. A device as recited in claim 1, wherein said device is adapted to draw the second air stream from inside the moisture-laden area having a higher humidity than the combined post-process air stream after it has been ejected into the moisture-laden area.

6. A device as recited in claim 1, wherein said heat-modulating dehumidifier further comprises a second heat exchanger adapted to receive and transfer heat from the second air stream to the process air stream after the second air stream has passed through said reactivation chamber.

7. A device as recited in claim 1, wherein said heat-modulating dehumidifier further comprises a second heat exchanger adapted to receive and transfer heat from the second air stream to the combined post-process air stream after the second air stream has passed through said reactivation chamber.

8. A device as recited in claim 1, wherein said desiccant rotor comprises three process chambers.

9. A device as recited in claim 1, wherein said heat-modulating dehumidifier further comprises a second bypass damper capable of adjustably diverting at least a portion of the first post-process air around said heat exchanger, and allowing any remaining portion of the first post-process air stream to flow through said heat exchanger.

10. A device as recited in claim 9, wherein said second bypass damper is actuated by said damper actuator to adjust the temperature of the first post-process air by controlling the amount of first post-process air available for heat transfer through said heat exchanger to the second air stream.

11. A device as recited in claim 1, wherein said temperature sensor comprises a thermostat.

12. A device as recited in claim 1, wherein said temperature sensor comprises a thermometer.

13. A device as recited in claim 1, wherein said damper actuator comprises an electronically-actuated proportional controller.

14. A device as recited in claim 1, wherein said damper actuator comprises an actuating handle.

15. A method for drying a moisture-laden area, comprising the steps of:

(a) introducing a process air stream and a second air stream into a heat-modulating dehumidifier comprising a desiccant rotor comprising at least two process chambers and a single reactivation chamber, through which chambers air can flow;

a first heat exchanger;

a heater;

a bypass damper; and

a control system comprising a temperature sensor and a damper actuator;

wherein the process air stream is drawn into the desiccant rotor through the process chambers; and

a selected fraction of the second air stream is drawn into the first heat exchanger, while the remaining portion of the second air stream is diverted around the first heat exchanger to the heater;

wherein the selected fraction is between 0 percent and 100 percent;

(b) heating and dehumidifying the process air stream by flowing the process air stream through the process chambers and carrying over heat from the reactivation chamber to the process air stream; and

wherein the heat produced by the reaction chambers allows for dehumidification of the process air stream by absorbing water vapor from the reactivation chamber;

(c) separating the process air stream into a first and second post-process air stream;

(d) transferring heat from the first post-process air stream to the second air stream;

(e) monitoring the temperature level in the moisture-laden area;

(f) adjusting the temperature in the moisture-laden area by adjusting the heat transfer from the first post-process air stream to the second air stream;

wherein if the temperature sensor detects a temperature in the moisture-laden area greater than a pre-selected level, then the damper actuator adjusts the position of the first bypass damper to decrease the amount of the second air stream being diverted from the first heat exchanger, thereby increasing heat transfer from the first post-process air stream to the second air stream and decreasing the temperature of the first post-process air stream; and

if the temperature sensor detects a temperature in the moisture-laden area less than a pre-selected level, then the damper actuator adjusts the position of the first damper to increase the amount of the second air stream being diverted from the first heat exchanger, thereby decreasing heat transfer from the first post-process air stream to the second air stream and increasing the temperature level of the first post-process air stream;

(g) combining the first and second post-process air streams; and

(h) ejecting the combined first and second post-process air streams into the moisture laden area.

16. A method as recited in claim 15, wherein the device is adapted to draw the process air stream from inside the moisture-laden area.

17. A method as recited in claim 15, wherein the device is adapted to draw the process air stream from outside the moisture-laden area.

18. A method as recited in claim 15, wherein the device is adapted to draw the second air stream from outside the moisture-laden area.

19. A method as recited in claim 15, wherein the device is adapted to draw the second air stream from inside the moisture-laden area having a higher humidity than the combined post-process air stream after it has been ejected into the moisture-laden area.

20. A method as recited in claim 15, wherein the heat-modulating dehumidifier further comprises a second heat exchanger adapted to receive and transfer heat from the second air stream to the process air stream after the second air stream has passed through the reactivation chamber.

21. A method as recited in claim 15, wherein the heat-modulating dehumidifier further comprises a second heat exchanger adapted to receive and transfer heat from the second air stream to the combined post-process air stream after the second air stream has passed through the reactivation chamber.

22. A method as recited in claim 15, wherein the desiccant rotor comprises three process chambers.

23. A method as recited in claim 15, wherein the heat-modulating dehumidifier further comprises a second bypass damper capable of adjustably diverting a selected fraction of the first post-process air around the heat exchanger, and allowing any remaining portion of the first post-process air stream to flow through the heat exchanger;

wherein the selected fraction is between 0 percent and 100 percent.

24. A method as recited in claim 23, wherein the second bypass damper is actuated by the damper actuator to adjust the temperature of the first post-process air by controlling the amount of first post-process air available for heat transfer through the heat exchanger to the second air stream.

25. A method as recited in claim 15, wherein the temperature sensor comprises a thermostat.

26. A method as recited in claim 15, wherein the temperature sensor comprises a thermometer.

27. A method as recited in claim 15, wherein the damper actuator comprises an electronically-actuated proportional controller.

28. A method as recited in claim 15, wherein the damper actuator comprises an actuating handle.