Air conditioning system using thermally responsive liquid desiccants

Abstract

An exemplary embodiment of the present disclosure provides an air conditioning system including a lower critical solution temperature (LCST) liquid desiccant, a heater, a separator, an absorber, and a desorber. The lower critical solution temperature (LCST) liquid desiccant can be configured to have a moderate phase liquid configured to separate into a weak phase liquid and strong phase liquid upon heating. The heater can be configured to transfer heat to the moderate phase liquid to separate the moderate phase liquid into the weak phase liquid and the strong phase liquid. The separator can be configured to physically separate the weak phase liquid and strong phase liquid. The absorber can be configured to receive the strong phase liquid which absorbs moisture from air thereby dehumidifying the air. The desorber can be configured to receive the weak phase liquid which desorbs moisture to air thereby cooling the desorber through evaporative cooling.

1 . An air conditioning system comprising:
 a lower critical solution temperature (LCST) liquid desiccant configured to have a moderate phase liquid configured to separate into a weak phase liquid and strong phase liquid upon heating;   a heater configured to transfer heat to the moderate phase liquid to separate the moderate phase liquid into the weak phase liquid and the strong phase liquid;   a separator configured to physically separate the weak phase liquid and strong phase liquid;   an absorber configured to receive the strong phase liquid, wherein the strong phase liquid is configured to absorb moisture from air thereby dehumidifying the air; and   a primary desorber configured to receive the weak phase liquid, wherein the weak phase liquid is configured to desorb moisture to air thereby cooling the primary desorber through evaporative cooling.   
     
     
         2 . The system of  claim 1  further comprising:
 a recuperator configured to transfer heat to the moderate phase liquid from the weak phase liquid and the strong phase liquid. 
 
     
     
         3 . The system of  claim 1  further comprising:
 an air-to-air heat exchanger; 
 wherein the air to air heat exchanger is configured to receive the dehumidified air from the absorber and the humidified air from the primary desorber and transfer heat from the dehumidified air to the humidified air. 
 
     
     
         4 . The system of  claim 1  further comprising:
 one or more liquid-to-air heat exchangers configured to transfer heat from at least one of the weak phase liquid or strong phase liquid to ambient. 
 
     
     
         5 . The system of  claim 1  further comprising at least one of:
 a first fan configured to blow air over the absorber to reduce its temperature; or 
 a second fan configured to blow air over the primary desorber, thereby cooling the air passing over the primary desorber. 
 
     
     
         6 . (canceled) 
     
     
         7 . The system of  claim 1  further comprising:
 a secondary desorber configured to receive the weak phase liquid leaving the primary desorber; 
 wherein the weak phase liquid desorbs moisture to air. 
 
     
     
         8 . The system of  claim 1 , wherein the absorber comprises:
 absorber channels configured to have downward flowing strong phase liquid and upward flowing air; and   heat exchanger fins extending from an exterior of the absorber channels.   
     
     
         9 . The system of  claim 1 , wherein the primary desorber comprises:
 absorber channels configured to have downward flowing strong phase liquid and upward flowing air; and   heat exchanger fins extending from an exterior of the absorber channels.   
     
     
         10 . The system of  claim 1 , wherein the heater comprises:
 a section of pipe configured to have LCST liquid desiccant flowing in it;   wherein the section of pipe comprises a color exterior configured to absorb energy from the sun.   
     
     
         11 . The system of  claim 1 , wherein the heater is selected from the group consisting of a solar heat heater, a waste heat heater, a gas heat heater, an electric heat heater, and a combination thereof. 
     
     
         12 . The system of  claim 2 , wherein the recuperator comprises:
 a first recuperator heat exchanger configured to transfer heat from the weak phase liquid to the moderate phase liquid; and   a second recuperator heat exchanger configured to transfer heat from the strong phase liquid to the moderate phase liquid.   
     
     
         13 . The system of  claim 2 , wherein the recuperator comprises;
 a single recuperator heat exchanger configured to have the moderate phase liquid flowing in a first direction and the weak and strong phase liquids flowing in a second direction;   wherein the moderate, weak, and strong phase liquids are all physically separated.   
     
     
         14 . The system of  claim 1  further comprising:
 a desiccant storage tank configured to store excess LCST liquid desiccant; 
 wherein the separator comprises:
 a separation tank configured to separate, via gravity, the weak phase liquid and the strong phase liquid. 
 
 
     
     
         15 . (canceled) 
     
     
         16 . The system of  claim 1  further comprising:
 a combined desiccant storage tank configured to store excess LCST liquid desiccant and separation tank configured to separate, via gravity, the weak phase liquid and the strong phase liquid. 
 
     
     
         17 . A method of air conditioning with the air conditioning system of  claim 1  comprising:
 heating the lower critical solution temperature (LCST) liquid desiccant with the heater to a temperature higher than ambient temperature so that the LCST separates from the moderate phase liquid to the strong phase liquid and the weak phase liquid; 
 separating the strong phase liquid from the weak phase liquid with the separator; 
 cooling the strong phase liquid and the weak phase liquid; 
 absorbing moisture from air to the strong phase liquid with the absorber, thereby dehumidifying the air; 
 desorbing moisture from the weak phase liquid to air with the primary desorber, thereby humidifying the air and cooling, via evaporative cooling, ambient; and 
 recombining the strong phase liquid with the weak phase liquid. 
 
     
     
         18 . The method of  claim 17  further comprising:
 exchanging heat from the dehumidified air to the humidified air. 
 
     
     
         19 . The method of  claim 17  further comprising:
 transferring heat from the weak phase and strong phase liquids to the moderate phase liquid with a recuperator. 
 
     
     
         20 . The method of  claim 17 , wherein the heater comprises a section of pipe;
 wherein heating is achieved at least partially by heating by the section of pipe with LCST flowing in it; and   wherein the section of pipe is a color configured to absorb energy from the sun.   
     
     
         21 . The method of  claim 17 , wherein heating is achieved at least partially by at least one of solar heat, waste heat, gas heat, or electric heat. 
     
     
         22 . An air conditioning system comprising:
 a lower critical solution temperature (LCST) liquid desiccant configured to have a moderate phase liquid configured to separate into a weak phase liquid and strong phase liquid upon heating;   an outside portion comprising:
 a recuperator configured to transfer heat to the moderate phase liquid from the weak phase liquid and the strong phase liquid; 
 a heater configured to transfer heat to the moderate phase liquid to separate the moderate phase liquid into the weak phase liquid and the strong phase liquid; 
 a separator configured to physically separate the weak phase liquid and strong phase liquid; 
 an absorber configured to receive the strong phase liquid, wherein the strong phase liquid is configured to absorb moisture from outside air thereby dehumidifying the outside air; and 
 an air-to-air heat exchanger; and 
   an inside unit comprising:
 a desorber configured to receive the weak phase liquid, wherein the weak phase liquid is configured to desorb moisture to inside air thereby cooling the desorber through evaporative cooling; and 
 a liquid-to-liquid heater configured to transfer heat from the weak phase liquid entering the desorber to the weak phase liquid leaving the desorber; 
   wherein the air-to-air heat exchanger is configured to receive the dehumidified outside air from the absorber and the humidified inside air from the desorber and transfer heat from the dehumidified outside air to the humidified inside air.