Air Conditioning System Using a Responsive Hygroscopic Material

Abstract

An exemplary embodiment of the present disclosure provides an air conditioning process. The air conditioning process can include a latent cooling stage including absorbing, via a responsive hygroscopic material, moisture from ambient air, heating, via a heat source, the responsive hygroscopic material above a transition temperature wherein the responsive hygroscopic material transitions from being hygroscopic to being hydrophobic, expelling, from the responsive hygroscopic material, liquid, and sensible cooling the responsive hygroscopic material below the transition temperature.

What is claimed is: 
     
         1 . An air conditioning process comprising:
 a latent cooling stage comprising:
 absorbing, via a responsive hygroscopic material, moisture from ambient air; 
 heating, via a heat source, the responsive hygroscopic material above a transition temperature wherein the responsive hygroscopic material transitions from being hygroscopic to being hydrophobic; 
 expelling, from the responsive hygroscopic material, liquid; and 
 sensible cooling the responsive hygroscopic material below the transition temperature. 
   
     
     
         2 . The process of  claim 1  further comprising:
 a sensible cooling stage comprising:
 sensible cooling, via an evaporative cooler, the ambient air, 
 wherein the evaporative cooler evaporates the liquid expelled from the responsive hygroscopic material. 
 
 
     
     
         3 . The process of  claim 2 , wherein the evaporative cooler is one of a direct evaporative cooler, indirect evaporative cooler, or a partially direct and partially indirect evaporative cooler. 
     
     
         4 . The process of  claim 2 , wherein the latent and sensile cooling of the ambient air is performed without the use of conventional refrigerants. 
     
     
         5 . The process of  claim 2  further comprising:
 moving the responsive hygroscopic material from a first position to a second position, 
 wherein at the first position, the absorbing, via a responsive hygroscopic material, moisture from ambient air step is performed, and 
 wherein at the second position, the heating, via the heat source, the responsive hygroscopic material above a transition temperature step is performed. 
 
     
     
         6 . The process of  claim 1  further comprising:
 transferring at least a portion of the heat removed from the hygroscopic material by sensible cooling the responsive hygroscopic material below the transition temperature; 
 storing the heat in a recuperator; 
 and transferring at least a portion of the stored heat back to the responsive hygroscopic material. 
 
     
     
         7 . The process of  claim 1 , wherein the responsive hygroscopic material comprises PNIPAAm (poly(N-isopropylacrylamide) and one or more hydrogels. 
     
     
         8 . The process of  claim 1 , wherein the heat source comprises one or more of solar heat, waste heat, gas heat, or electric heat. 
     
     
         9 . An air conditioning system comprising:
 a latent cooling stage comprising:
 a responsive hygroscopic material configured to absorb moisture from ambient air; 
 a heat source configured to heat the responsive hygroscopic material above a transition temperature wherein the responsive hygroscopic material transitions from being hygroscopic to being hydrophobic causing the responsive hygroscopic material to expel a liquid previously absorbed from the ambient air; and 
 a heat exchanger configured for sensible cooling the responsive hygroscopic material. 
   
     
     
         10 . The system of  claim 9  further comprising:
 a sensible cooling stage comprising:
 an evaporative cooler configured for sensible cooling the ambient by evaporating the liquid expelled from the responsive hygroscopic material. 
 
 
     
     
         11 . The system of  claim 10 , wherein the evaporative cooler is one of a direct evaporative cooler, indirect evaporative cooler, or a partially direct and partially indirect evaporative cooler. 
     
     
         12 . The system of  claim 10 , wherein the latent and sensile cooling of the ambient air is performed without the use of conventional refrigerants. 
     
     
         13 . The system of  claim 9  further comprising:
 an actuator configured to move the responsive hygroscopic material from a first position to a second position, 
 wherein at the first position, the responsive hygroscopic material absorbs moisture from the ambient air, and 
 wherein at the second position, a heat source heats the responsive hygroscopic material above the transition temperature. 
 
     
     
         14 . The system of  claim 9  further comprising:
 a first polymer bed comprising the responsive hygroscopic material; 
 a second polymer bed comprising the responsive hygroscopic material; and 
 one or more actuators configured to change the airflow, as between inside air and outside air, passing over each of the first polymer bed and second polymer bed. 
 
     
     
         15 . The system of  claim 9  further comprising:
 a recuperator configured to transfer at least a portion of the heat removed from the hygroscopic material by sensible cooling the responsive hygroscopic material below the transition temperature, storing the heat in the recuperator, and transferring at least a portion of the stored heat back to the responsive hygroscopic material. 
 
     
     
         16 . The system of  claim 9 , wherein the responsive hygroscopic material comprises PNIPAAm (poly(N-isopropylacrylamide) and one or more hydrogels. 
     
     
         17 . The system of  claim 9 , wherein the heat source comprises one or more of solar heat, waste heat, gas heat, or electric heat. 
     
     
         18 . The system of  claim 9 , wherein the heat exchanger is an ambient heat exchanger. 
     
     
         19 . An air conditioning system comprising:
 a latent cooling stage comprising:
 a responsive hygroscopic material configured to absorb moisture from ambient air; 
 a heat source configured to heat the responsive hygroscopic material above a transition temperature wherein the responsive hygroscopic material transitions from being hygroscopic to being hydrophobic causing the responsive hygroscopic material to expel a liquid previously absorbed from the ambient air; and 
 a heat exchanger configured for sensible cooling the responsive hygroscopic material; and 
   a sensible cooling stage comprising:   an evaporative cooler configured for sensible cooling the ambient by evaporating the liquid expelled from the responsive hygroscopic material.   
     
     
         20 . The system of  claim 19  further comprising:
 a recuperator configured to transfer at least a portion of the heat removed from the hygroscopic material by sensible cooling the responsive hygroscopic material below the transition temperature, storing the heat in the recuperator, and transferring at least a portion of the stored heat back to the responsive hygroscopic material.