Desiccant dehumidification system with chiller boost
A hybrid dehumidification system for controlling the humidity and/or both humidity and temperature in a space includes a cooling coil for first cooling, or cooling and reducing the humidity of, an airstream to be supplied to the space with an aqueous cooling medium, passing the thus cooled airstream through a desiccant adsorption means to further reduce the humidity of the airstream before supplying the airstream to the space, and regenerating the desiccant adsorption means by heating the desiccant with waste heat from a heat pump used to further cool the first aqueous cooling medium.
1. A dehumidification system for use with an aqueous/liquid chiller cooling system used to cool a heating load and including a circulating supply of chilled aqueous/liquid coolant in a recirculating line, said dehumidification system including a desiccant material for removing moisture from a supply/process air stream; a separate direct expansion refrigeration means for cooling the chilled aqueous/liquid coolant in the aqueous/liquid cooling system, said separate direct expansion refrigeration means including at least one condenser for supplying heat through the condenser to a regeneration air stream before the regeneration air stream enters the desiccant material and an evaporator heat exchanger for cooling the aqueous liquid coolant in the aqueous/liquid cooling system; and another, separate heat exchanger directly fluidly connected to said evaporator heat exchanger of the direct expansion refrigeration means, said separate heat exchanger being located in the supply/process air stream, receiving chilled aqueous/liquid from the aqueous/liquid chiller cooling system, and cooling the supply process air stream, the regeneration air stream flowing directly through the condenser to supply heat to the regeneration air stream before the regeneration air stream enters the desiccant material.
2. The dehumidification system as defined in claim 1 wherein said separate heat exchanger connected to said evaporator heat exchanger of the direct expansion refrigeration means is located in the supply/process airstream in a position before that supply/process airstream enters the desiccant material.
3. The dehumidifier system as defined in claim 1 wherein said separate heat exchanger connected to said evaporator heat exchanger of the direct expansion refrigeration means is located in the supply/process airstream in a position after the supply/process air stream leaves the desiccant material.
4. The dehumidification system as defined in claim 2 or claim 3 wherein said desiccant material comprises a rotatable desiccant wheel.
5. The dehumidification system as defined in claim 2 or claim 3 including means for supplying chilled aqueous/liquid coolant from the aqueous/liquid cooling system to the evaporator heat exchanger of the direct expansion refrigeration means wherein the chilled aqueous/liquid coolant is further cooled, then for supplying the chilled aqueous/liquid coolant from the evaporator heat exchanger to the separate heat exchanger in the supply/process air stream to cool the supply/process air stream and then to the recirculating line.
6. The dehumidification system as defined in claim 2 or claim 3 wherein said at least one condenser includes a first condenser connected to the evaporator heat exchanger of the direct expansion refrigeration system and a second condenser located in the regeneration air stream, and means for supplying aqueous/liquid coolant from the chilled aqueous/liquid cooling system to said first condenser communicating in heat exchange relation with the evaporator heat exchanger of the direct expansion refrigeration means and then to the second condenser in the regeneration air stream to first raise the temperature of the aqueous/liquid coolant in the first condenser, and for supplying the thus warmed aqueous/liquid from the first condenser to the second condenser, whereby heat from both the direct expansion refrigeration means and the warm aqueous/liquid coolant is supplied to the regeneration air stream.
7. A dehumidification system for use with an aqueous/liquid chiller cooling system used to cool a heating load and including a circulating supply of chilled aqueous/liquid coolant in a recirculating line, said dehumidification system including a desiccant material for removing moisture from a supply/process air stream; a separate direct expansion refrigeration means for cooling the chilled aqueous/liquid coolant in the aqueous/liquid cooling system, including a condenser for supplying heat through the condenser to a regeneration air stream before it enters the desiccant material for regeneration of the desiccant material and an evaporator heat exchanger for cooling the chilled aqueous/liquid coolant in the aqueous liquid cooling system; a separate heat exchanger directly fluidly connected to said evaporator heat exchanger of the direct expansion refrigeration means and located in the supply/process air stream; and means for supplying chilled aqueous/liquid coolant from the aqueous/liquid cooling system to the separate heat exchanger to cool the supply/process air stream, then supplying the aqueous/liquid coolant from the separate heat exchanger to the evaporator heat exchanger of the direct expansion refrigeration means, and then supplying the aqueous/liquid coolant from the evaporator heat exchanger to the recirculation line in the aqueous/liquid chiller cooling system whereby the direct expansion refrigeration means will generate higher temperatures in the condenser of the direct expansion refrigeration means, the regeneration air stream flowing directly through the condenser to supply heat to the regeneration air stream before the regeneration air stream enters the desiccant material.
8. The dehumidification system as defined in claim 7 wherein said separate heat exchanger connected to said evaporator heat exchanger of the direct expansion refrigeration means is located in the supply/process airstream in a position before that supply/process airstream enters the desiccant material.
9. The dehumidifier system as defined in claim 7 wherein said separate heat exchanger connected to said evaporator heat exchanger of the direct expansion refrigeration means is located in the supply/process airstream in a position after the supply/process air stream leaves the desiccant material.
10. The dehumidification system as defined in claim 8 or claim 9 wherein said desiccant material comprises a rotatable desiccant wheel.
11. The dehumidification system as defined in claim 8 or claim 9 wherein said separate heat exchanger in the supply/process air stream has first and second heat exchanger sections, and said system includes means for supplying a first portion of chilled aqueous/liquid coolant from the aqueous/liquid coolant line to the first heat exchanger section to cool the supply/process air stream and then to a return line, and for supplying a second portion of the chilled aqueous/liquid coolant from the aqueous/liquid coolant line to the evaporator heat exchanger of the direct expansion refrigeration means wherein the second portion of the chilled aqueous/liquid coolant is further chilled, then to the second heat exchanger section in the supply/process air stream to further cool the supply/process air stream and then to the recirculation line.
12. A method of dehumidifying a supply/process air stream for use with an aqueous/liquid cooling system used to cool a heating load and including a circulating supply of chilled aqueous/liquid coolant in a recirculation line, said method comprising the steps of using a desiccant material to remove moisture from a supply/process air stream, using an evaporator heat exchanger of a direct expansion refrigeration system for cooling coolant in the aqueous/liquid cooling system, supplying heat through the condenser of the direct expansion refrigeration system to a regeneration air stream before it enters the desiccant material, and fluidly connecting a separate heat exchanger directly to said evaporator heat exchanger of the direct expansion refrigeration means, said separate heat exchanger being located in the supply/process air stream, receiving aqueous/liquid coolant, and cooling the supply air stream, the regeneration air stream flowing directly through the condenser to supply heat to the regeneration air stream before the regeneration air stream enters the desiccant material.
13. The method as defined in claim 12 including the step of locating said separate heat exchanger connected to the evaporator heat exchanger of the direct expansion refrigeration means in the supply/process airstream in a position before the supply process airstream enters the desiccant material.
14. The method as defined in claim 12 including the step of locating said separate heat exchanger connected to the evaporator heat exchanger of the direct expansion refrigeration means in the supply/process airstream in a position after the supply/process airstream leaves the desiccant material.
15. The method as defined in claim 13 or claim 14 wherein said step of using a desiccant material includes the step of using a rotatable desiccant wheel.
16. The method as defined in claim 13 or claim 14 including the step of supplying chilled aqueous/liquid coolant from the aqueous/liquid cooling system to the evaporator heat exchanger of the direct expansion refrigeration means whereby the chilled aqueous/liquid coolant is further cooled, then supplying the further cooled aqueous/liquid coolant to the separate heat exchanger in the supply/process air stream to cool the supply/process air stream and then supplying the coolant from the heat exchanger to a recirculation line.
17. The method as defined in claim 13 or claim 14 including the steps of supplying aqueous/liquid coolant from said chilled aqueous/liquid cooling system to the direct expansion refrigeration condenser to raise the temperature of that aqueous/liquid coolant and then supplying the thus warmed aqueous/liquid from the condenser to a second separate heat exchanger, and locating the separate second heat exchanger in the regeneration air stream whereby heat from both the direct expansion refrigeration means and the warm aqueous/liquid coolant is supplied to the regeneration air stream.
18. A method of dehumidifying a supply/process air stream for use with an aqueous/liquid chiller cooling system used to cool a heating load and including a circulating supply of chilled aqueous/liquid coolant in a recirculating line, said method comprising the steps of using a desiccant material to remove moisture from a supply/process air stream, using a direct expansion refrigeration system including an evaporator heat exchanger and a condenser, locating the condenser directly in a regeneration air stream supplied to the desiccant material for heating the regeneration air stream before it enters the desiccant material, supplying chilled aqueous/liquid coolant from the aqueous/liquid cooling system to a separate heat exchanger located in the supply/process air stream to cool the supply process air stream, then supplying the aqueous/liquid coolant from the separate heat exchanger directly to the evaporator heat exchanger of the direct expansion refrigeration system, and then supplying the aqueous/liquid coolant from the evaporator heat exchanger to the recirculation line whereby the direct expansion refrigeration system will generate higher temperatures in the condenser.
19. The method as defined in claim 18 including the step of locating said separate heat exchanger connected to the evaporator heat exchanger of the direct expansion refrigeration means in the supply/process airstream in a position before the supply process airstream enters the desiccant material.
20. The method as defined in claim 18 including the step of locating said separate heat exchanger connected to the evaporator heat exchanger of the direct expansion refrigeration means in the supply/process airstream in a position after the supply/process airstream leaves the desiccant material.
21. The method as defined in claim 19 or claim 20 wherein said step of using a desiccant material includes the step of using a rotatable desiccant wheel.
22. The method as defined in claim 19 or claim 20 including the steps of providing the separate heat exchanger in the supply/process air stream with first and second heat exchanger sections, supplying a first portion of chilled aqueous/liquid coolant from the aqueous/liquid coolant recirculation line to the first heat exchanger section to cool the supply/process air stream and then supplying that first portion of the chilled aqueous/liquid coolant to the recirculation line, and supplying a second portion of the chilled aqueous/liquid coolant from the aqueous/liquid coolant recirculation line to the evaporator heat exchanger of the direct expansion refrigeration means wherein the second portion of the chilled aqueous/liquid coolant is further chilled, then supplying that further chilled second portion to the second heat exchanger section in the supply/process air stream to further cool the supply/process air stream and then supplying that second portion to the recirculation line.