Thermoelectrically powered indirect evaporative cooling system with desiccant dehumidification

Abstract

Disclosed is a system for cooling using indirect evaporative cooling, dehumidification using desiccant, and a thermoelectrically powered heat exchanger. The thermoelectric heat exchanger pulls heat from the working air exiting the indirect evaporative cooler and injects that heat energy into ambient air that is then forced through a portion of the rotating desiccant wheel to regenerate the desiccant by removing water molecules from the desiccant material. Liquid water that is condensed by cooling the working air with the thermoelectric heat exchanger is saved and provided to the indirect evaporative cooler for use to cool via evaporation.

1 . A method of indirect evaporative cooling a space, the method comprising:
 cooling a flow of hot and humid working air via a cold side of a thermoelectrically powered heat exchanger, to provide a flow of cooled working air;   mixing the cooled working air with a first incoming flow of ambient air, to provide a combined flow of air;   dehumidifying the combined flow of air via a dry portion of a rotating desiccant wheel, to provide a flow of cooled and dehumidified working air;   transferring thermal energy from a first portion of the cooled and dehumidified working air to a second portion of the flow of cooled and dehumidified working air via an indirect evaporative cooler, so that the second portion becomes the flow of hot and humid air, and so that the first portion becomes a flow of conditioned air;   distributing the flow of conditioned air from the indirect evaporative cooler to the space to be cooled;   heating a second incoming flow of ambient air via a hot side of the thermoelectrically powered heat exchanger, to provide a flow of heated ambient air;   regenerating the rotating desiccant wheel using the flow of heated ambient air to drive moisture from a water laden portion of the rotating desiccant wheel;   recovering, at the cold side of the thermoelectrically powered heat exchanger, water condensed via cooling of the flow of hot and humid working air; and   supplying the recovered water to the indirect evaporative cooler for use in evaporating into the second portion of cooled and dehumidified working air.   
   
   
       2 . An air conditioning system for conditioning air in an interior space, the system comprising:
 a thermoelectric heat exchanger module connected to receive a flow of hot and humid working air into a cold side fluid passage so that a flow of cooled humid working air emerges from the cold side fluid passage;   a rotating desiccant wheel connected to dry the flow of cooled humid working air receive from the thermoelectric heat exchanger module so that a flow of cooled dried working air emerges from the rotating desiccant wheel;   an indirect evaporative cooler having a wet channel and a dry channel, the wet channel being connected to receive a first portion of the flow of cooled dried working air from the rotating desiccant wheel, the dry channel being connected to receive a second portion of the flow of cooled dried working air and to supply conditioned air for the interior space, and the wet channel producing the hot and humid working air;   a return conduit connected to route the hot and humid working air emerging from the wet channel of the indirect evaporative cooler to the cold side fluid passage of the thermoelectric heat exchanger module; and   a regeneration conduit connected to provide heated ambient air emerging from a hot side fluid passage of the thermoelectric heat exchanger module to a moisture laden portion of the rotating desiccant wheel to remove moisture from the desiccant wheel; and   a moisture recovery assembly connected to gather liquid water condensed in the cold side fluid passage of the thermoelectric heat exchanger and supply the gathered liquid water to the indirect evaporative cooler to be evaporated in the wet channel.   
   
   
       3 . A thermoelectric heat exchanger module comprising:
 plural thermoelectric devices, each of the devices having a hot plate, a cold plate, a positive electrode, and a negative electrode;   a cold side fluid passage having plural cold side lumens, each of the cold side lumens being in thermal contact with the cold plate of at least one of the thermoelectric devices;   a hot side fluid passage having plural hot side lumens, each of the hot side lumens being in thermal contact with the hot plate of at least one of the thermoelectric devices;   wherein the plural thermoelectric devices are connected electrically in a parallel circuit with one another and are physically disposed so that adjacent pairs of the thermoelectric devices either sandwich one of the cold side lumens between their respective cold plates, or sandwich one of the hot side lumens between their respective hot plates.   
   
   
       4 . The thermoelectric heat exchanger module of  claim 3 , wherein each thermoelectric device comprises a solid-state active heat pump which transfers heat from the cold plate to the hot plate. 
   
   
       5 . The thermoelectric heat exchanger module of  claim 3 , wherein each thermoelectric device comprises a Peltier effect cell.