Cascade desiccant air-conditioning/air drying process and apparatus with cold thermal energy storage

• US 4,527,398 A
• Filed: 01/16/1984
• Issued: 07/09/1985
• Est. Priority Date: 01/16/1984
• Status: Expired due to Fees

• Current Assignee: Walter J. Schaetzle
• Original Assignee: Walter J. Schaetzle
• Inventors: Schaetzle, Walter J.
• Primary Examiner(s): Capossela, Ronald C.
• Application Number:
  US06/571,071
• Time in Patent Office: 540 Days
• Field of Search: 62/93, 62/94, 62/271, 55/61, 55/179, 55/208
• US Class Current: 62/94
• CPC Class Codes: F24F 12/00 Use of energy recovery systems in air conditioning, ventilation or screening with both heat and humidity transfer between supplied and exhausted air F24F3/147
• CPC Class Codes: F24F 2003/144 by dehumidification only
• CPC Class Codes: F24F 3/1417 with liquid hygroscopic desiccants
• CPC Class Codes: F24F 5/0046 using natural energy, e.g. solar energy, energy from the ground

Abstract

A process using a cascade desiccant air-conditioning/air drying apparatus having cold thermal energy storage means is used to produce a major increase in the system'"'"'s thermal coefficient of performance. The latent heat of vaporization from the water separation occurring in desiccant regeneration is recovered in the heating process for desiccant regeneration in the next stage. This energy recovery results in a major improvement in thermal coefficient of performance in air-conditioning or air drying processes. Values greater than 1.0 are expected to be common and values greater than 2.0 are possible. Presently most thermal driven air-conditioning systems have a thermal coefficient of performance less than 1.0 with an average value less than 0.7.

Claims

1. A cascade desiccant air-conditioning process for conditioning an air flow utilizing a plurality of desiccating means, comprising:

desiccating said air flow by removing moisture therefrom to produce a desiccated air flow, wherein said step of desiccating said air flow further comprises passing said air flow through said plurality of desiccating means such that said moisture of said air flow is absorbed by said plurality of desiccating means;

cooling said desiccated air flow to produce a cooled, desiccated air flow by passing said desiccated air flow through heat exchanging means;

chilling said cooled, desiccated air flow to produce a conditioned air flow, wherein said step of chilling said cooled, desiccated air flow further comprises injecting water into said cooled, desiccated air flow such that said water is adiabatically evaporated by said cooled, desiccated air flow to lower a temperature of said cooled, desiccated air flow;

exhausting said conditioned air flow; and

desorbing said moisture absorbed by said plurality of desiccating means as steam in a cascade manner wherein a first steam produced by desorbing serves as an energy source for subsequent desorbing to produce a second steam such that a major increase in a thermal coefficient of performance of said cascade desiccant air-conditioning process is effected by recovering a latent heat of vaporization of said moisture through desorption of said moisture from said plurality of desiccating means as said first and second steam.

2. A cascade desiccant air-conditioning process as claimed in claim 1 wherein said step of desorbing said moisture further comprises:

passing a high temperature fluid through first heat exchanging means cooperating with first desiccating means of said plurality of desiccating means to desorb moisture absorbed by said first desiccating means as a first steam having a first temperature; and

passing said first steam through second heat exchanging means cooperating with second desiccating means of said plurality of desiccating means, said first steam condensing in said second heat exchanging means to desorb moisture absorbed by said second desiccating means as a second steam having a second temperature and wherein said second temperature is less than said first temperature.

3. A cascade desiccant air-conditioning process as claimed in claim 1 wherein said step of desorbing said moisture absorbed by said plurality of desiccating means further comprises regenerating said plurality of desiccating means to generate a plurality of zero loss cold thermal energy storage means such that air flowing through said plurality of zero loss cold thermal energy storage means is chilled without an additional energy input.

4. A cascade desiccant air drying process for conditioning an air flow utilizing a plurality of desiccating means, comprising:

desiccating said air flow by removing moisture therefrom to produce a desiccated air flow, wherein said step of desiccating said air flow further comprises passing said air flow through said plurality of desiccating means such that said moisture of said air flow is absorbed by said plurality of desiccating means;

cooling said desiccated air flow to produce a cooled, desiccated air flow by passing said desiccated air flow through heat exchanging means;

exhausting said cooled, desiccated air flow; and

desorbing said moisture absorbed by said plurality of desiccating means as steam in a cascade manner wherein a first steam produced by desorbing serves as an energy source for subsequent desorbing to produce a second steam such that a major increase in a thermal coefficient of performance of said cascade desiccant air drying process is effected by recovering a latent heat of vaporization of said moisture through desorption of said moisture from said plurality of desiccating means as said first and second steam.

5. A cascade desiccant air drying process as claimed in claim 4 wherein said step of desorbing said moisture further comprises:

passing a high temperature fluid through first heat exchanging means cooperating with first desiccating means of said plurality of desiccating means to desorb moisture absorbed by said first desiccating means as a first steam having a first temperature; and

passing said first steam through second heat exchanging means cooperating with second desiccating means of said plurality of desiccating means, said first steam condensing in said second heat exchanging means to desorb moisture absorbed by said second desiccating means as a second steam having a second temperature and wherein said second temperature is less than said first temperature.

6. A cascade desiccant air drying process as claimed in claim 4 wherein said step of desorbing said moisture absorbed by said plurality of desiccating means further comprises regenerating said plurality of desiccating means to generate a plurality of zero loss cold thermal energy storage means such that air flowing through said plurality of zero loss cold thermal energy storage means is chilled without an additional energy input.

7. A cascade desiccant air-conditioning/air drying apparatus for conditioning an air flow, comprising:

first flow ducting means for conducting said air flow therein;

first and second desiccating means operatively associared with said first flow ducting means for removing moisture from said air flow wherein said moisture in said air flow is desorbed therefrom by circulating said air flow through said first and second desiccating means to produce a desiccated air flow;

second flow ducting means operatively associated with said first and second desiccating means for receiving said desiccated air flow;

cooling means associated with said second flow ducting means for cooling said desiccated air flow to produce a cooled, desiccated air flow and wherein said cooled, desiccated air flow is subsequently exhausted from said second flow ducting means;

first heat exchanging means adapted to cooperate with said first desiccating means for desorbing moisture therefrom;

second heat exchanging means adapted to cooperate with said second desiccating means for desorbing moisture therefrom;

steam piping means interconnecting said first desiccating means to said second heat exchanging means for conducting a first steam produced in said first desiccating means to said second heat exchanging means;

exhausting means operatively associated with said second desiccating means for removing a second steam produced in said second desiccating means; and

isolating means operatively associated with said first and second desiccating means and first and second flow ducting means for alternately isolating said first and second desiccating means from said first and second flow ducting means and wherein

when said isolating means isolates said first and second desiccating means from said first and second flow ducting means a high temperature fluid flowing through said first heat exchanging means desorbs moisture absorbed by said first desiccating means as said first steam having a first temperature, and said first steam is conducted through said steam piping means to said second heat exchanging means and condenses therein to desorb moisture absorbed by said second desiccating means as said second steam having a second temperature less than said first temperature, and said second steam is removed from said second desiccating means by passing through said exhausting means and wherein a major increase in a thermal coefficient of performance of said cascade desiccant air-conditioning/air drying apparatus is effected by recovering a latent heat of vaporization of said moisture through desorption of said moisture from said first and second desiccating means as said first and second steam.

8. A cascade desiccant air-conditioning/air drying apparatus as claimed in claim 7 further comprising:

moisture injecting means associated with said second flow ducting means for chilling said cooled, desiccated air flow prior to subsequent exhaustion from said second flow ducting means.

9. A cascade desiccant air-conditioning/air drying apparatus as claimed in claim 8 wherein said first and second desiccating means further comprise:

first and second containers operatively associated with said first and second flow ducting means;

first and second desiccants disposed in said first and second containers, respectively.

10. A cascade desiccant air-conditioning/air drying apparatus as claimed in claim 7 wherein said first and second desiccating means further comprise:

first and second containers operatively associated with said first and second flow ducting means;

first and second desiccants disposed in said first and second containers, respectively.

11. A cascade desiccant air-conditioning/air drying apparatus for conditioning an air flow, comprising:

first and second flow ducting means for conducting said air flow therein;

first and second desiccant spraying means operatively associated with said first and second flow ducting means, respectively, for removing moisture from said air flow wherein said moisture in said air flow is desorbed therefrom by injecting said air flow with first and second liquid desiccant sprays from said first and second desiccant spraying means, respectively, to produce a desiccated air flow;

first and second cooling means associated with said first and second flow ducting means, respectively, for cooling said desiccated air flow to produce a cooled, desiccated air flow and wherein said cooled, desiccated air flow is subsequently exhausted from said first and second flow ducting means;

first and second collecting basins operatively associated with said first and second flow ducting means, respectively, for collecting first and second moisture-laden liquid desiccants, respectively, after said first and second liquid desiccant sprays have passed through said air flow and absorbed said moisture therefrom;

first and second high pressure pumping means operatively associated with said first and second collecting basins, respectively, for pumping said first and second moisture-laden liquid desiccants from said first and second collecting basins, respectively, and wherein said first and second high pressure pumping means are adapted to operate such that said first moisture-laden liquid desiccant is pumped from said first collecting basin by said first high pressure pumping means at a first predetermined pressure and said second moisture-laden liquid desiccant is pumped from said second collecting basin by said second high pressure pumping means at a second predetermined pressure and wherein said first predetermined pressure is greater than said second predetermined pressure;

first and second containers operatively associated with said first and second high pressure pumping means, respectively, for receiving said first and second moisture-laden liquid desiccants, respectively;

first heating means operatively associated with said first container for desorbing said first moisture-laden liquid desiccant by heating thereof such that a first liquid desiccant and a first steam having a first predetermined temperature are produced in said first container;

second heating means operatively associated with said first and second containers for desorbing said second moisture-laden liquid desiccant by condensing said first steam in said second heating means such that a second liquid desiccant and a second steam having a second predetermined temperature are produced in said second container thereby recovering a latent heat of formation of said first steam by generating said second steam;

water separator means operatively associated with said second container for removing said second steam therefrom; and

first and second cycling means operatively associated with said first and second containers, respectively, and said first and second desiccant spraying means, respectively for transferring said first and second liquid desiccants to said first and second desiccant spraying means, respectively, such than an operating cycle for said cascade desiccant air-conditioning/air drying apparatus is maintained continuously.

12. A cascade desiccant air-conditioning/air drying apparatus as claimed in claim 11 further comprising first and second water injecting means operatively associated with said first and second flow ducting means, respectively, for chilling said cooled, desiccated air flow prior to subsequent exhaustion from said first and second flow ducting means.