Desiccant air conditioning methods and systems using evaporative chiller
An air conditioning method includes the steps of: dehumidifying an air stream to be provided to a building space by exposing the air stream to a liquid desiccant in a conditioner; diverting a portion of the air stream dehumidified in the conditioner to an air treatment unit acting as an evaporative chiller to that causes the portion of the dehumidified air stream to absorb water from a water source and thereby cool a heat transfer fluid, and providing the heat transfer fluid cooled in the air treatment unit to the conditioner to cool the air stream to be provided to the building space; and regenerating the liquid desiccant used in the conditioner.
1. An air conditioning method, comprising the steps of:
dehumidifying an air stream to be provided to a building space by exposing the air stream to a liquid desiccant in a conditioner;
diverting a portion of the air stream dehumidified in the conditioner to an air treatment unit acting as an evaporative chiller that causes the portion of the dehumidified air stream to absorb water from a water source and thereby cool a heat transfer fluid, and providing the heat transfer fluid cooled in the air treatment unit to the conditioner to cool the air stream to be provided to the building space; and
regenerating the liquid desiccant used in the conditioner.
2. The method of claim 1 , further comprising utilizing return air from the building space to absorb water from the liquid desiccant when regenerating the liquid desiccant.
3. The method of claim 1 , further comprising varying the amount of the dehumidified air stream diverted from the conditioner to regulate the temperature of the air stream entering the building space.
4. The method of claim 1 , wherein the conditioner includes a plurality of structures arranged in a substantially parallel orientation, each structure including an outer surface across which the liquid desiccant is flowed, each structure further including a desiccant collector at an end of the structure for collecting the liquid desiccant, wherein the air stream flows between the structures.
5. The method of claim 4 , further comprising causing turbulence in the air stream entering the structures.
6. The method of claim 4 , wherein each structure includes an internal passage, and the method further comprising flowing the heat transfer fluid through the internal passage in each structure.
7. The method of claim 1 , further comprising transferring chilled heat transfer fluid from the evaporative chiller to one or more liquid-to-air heat exchangers in the building space to provide sensible space cooling.
8. The method of claim 1 , wherein in a cold weather operation mode, the method further comprises utilizing the liquid desiccant for humidifying the air stream and utilizing the heat transfer fluid for heating the liquid desiccant in the conditioner and in the air treatment unit.
9. The method of claim 8 , further comprising heating the heat transfer fluid in the conditioner in the cold weather operation mode.
10. The method of claim 8 , further comprising pre-heating the air streams entering the conditioner or the air treatment unit in the cold weather operation mode.
11. The method of claim 1 , further comprising
depositing the liquid desiccant in a tank;
allowing the liquid desiccant to settle such that the liquid desiccant varies in concentration along the height of the tank; and
drawing liquid desiccant from the tank at a given selected height of the tank in order to obtain liquid desiccant having a desired given concentration.
12. A method for treating an air stream entering a building space, comprising the steps of:
providing a conditioner including a plurality of structures arranged in a substantially parallel orientation, each structure including an outer surface, each structure further including a desiccant collector at an end of the structure;
flowing a liquid desiccant across the outer surface of each structure and collecting liquid desiccant in the desiccant collector for that structure;
flowing the air stream between adjacent structures such that the liquid desiccant dehumidifies the air stream in a warm weather operation mode;
diverting a portion of the air stream dehumidified in the conditioner for use in an air treatment unit acting as an evaporative chiller that causes the portion of the dehumidified air stream to absorb water from a water source in the warm weather operation mode for cooling a heat transfer fluid used in the conditioner;
receiving liquid desiccant from the desiccant collectors in the conditioner and absorbing water from the liquid desiccant in a regenerator; and
circulating the liquid desiccant between the conditioner and the regenerator.
13. The method of claim 12 , wherein each structure includes an internal passage, and the method further comprising flowing the heat transfer fluid through the internal passage in each structure.
14. The method of claim 12 , further comprising utilizing return air from the building space to absorb water from the liquid desiccant.
15. The method of claim 12 , further comprising varying the amount of the dehumidified air stream diverted from the conditioner to regulate the temperature of the air stream entering the building space.
16. The method of claim 12 , further comprising
depositing the liquid desiccant in a tank;
allowing the liquid desiccant to settle such that the liquid desiccant varies in concentration along the height of the tank; and
drawing liquid desiccant from the tank at a given selected height of the tank in order to obtain liquid desiccant having a given desired concentration.
17. The method of claim 12 , wherein in a cold weather operation mode, the method further comprises utilizing the liquid desiccant for humidifying the air stream and a heat transfer fluid for heating the liquid desiccant in the conditioner.
18. The method of claim 17 , further comprising heating the heat transfer fluid in the conditioner in a cold weather operation mode.
19. The method of claim 17 , further comprising pre-heating the air streams entering the conditioner or the air treatment unit in a cold weather operation mode.
20. The method of claim 12 , further comprising causing turbulence in the air stream entering the structures.
21. The method of claim 12 , further comprising transferring chilled heat transfer fluid from the evaporative chiller to one or more liquid-to-air heat exchangers in the building space to provide sensible space cooling.