# US 9,518,784 B2 · Indirect evaporative cooler using membrane-contained, liquid desiccant for dehumidification

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- Number: US 9,518,784 B2
- Document ID: US9518784B2
- Status: Granted
- Kind: B2
- Application number: 14/286,577
- Filed: 2014-05-23
- Published: 2014-11-06
- Granted: 2016-12-13
- Earliest claimed: 2014-05-23
- Assignees: Alliance for Sustainable Energy, LLC
- Applicants: Alliance for Sustainable Energy, LLC
- Inventors: Eric Joseph Kozubal
- Web page: https://patentgrep.com/patent/US9518784B2

## CPC

- F24F 3/1417: {with liquid hygroscopic desiccants}
- F24F 1/0007: Indoor units, e.g. fan coil units (self-contained units F24F1/02)
- F24F 1/0063: by the mounting or arrangement of the heat exchangers
- F24F 3/1411: {by absorbing or adsorbing water, e.g. using an hygroscopic desiccant}
- F24F 3/147: with both heat and humidity transfer between supplied and exhausted air
- F24F 5/0035: {using evaporation}
- F24F 13/30: Arrangement or mounting of heat-exchangers
- F28D 15/02: in which the medium condenses and evaporates, e.g. heat pipes {(heat pipes used in solar heat collectors F24S10/95; in radiators F28D1/0226; in nuclear reactors G21C15/257)}
- F28D 21/0015: {Heat and mass exchangers, e.g. with permeable walls}
- F24F 2003/1435: {comprising semi-permeable membrane}
- F24F 2003/1458: {using regenerators}
- Y02B 30/54: Free-cooling systems
- F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02)
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

An indirect evaporative cooler for cooling inlet supply air from a first temperature to a second, lower temperature using a stream of liquid coolant and a stream of exhaust or purge air. The cooler includes a first flow channel for inlet supply air and a second flow channel adjacent the first for exhaust air. The first and second flow channels are defined in part by sheets of a membrane permeable to water vapor such that mass is transferred as a vapor through the membrane from the inlet supply air to a contained liquid desiccant for dehumidification and also to the exhaust air as heat is transferred from the inlet supply air to the liquid coolant. A separation wall divides the liquid desiccant and the coolant but allows heat to be transferred from the supply air to the coolant which releases water vapor to the counter or cross flowing exhaust air.

## Claims

### Claim 1

A method of conditioning a supply air stream, comprising:
dehumidifying the supply air stream to provide a dehumidified air stream, wherein the dehumidifying includes directing the supply air stream through a channel defined by a surface of a vapor permeable membrane containing liquid desiccant; and
cooling the dehumidified air stream from a first temperature to a lower second temperature using indirect evaporative cooling.

### Claim 2 (depends on 1)

The method of claim 1, wherein the liquid desiccant comprises a weak desiccant.

### Claim 3 (depends on 1)

The method of claim 1, further comprising transferring heat from the liquid desiccant to a coolant flowing in a layer of wicking material in heat transfer contact with the liquid desiccant.

### Claim 4

A method of conditioning a supply air stream, comprising:
dehumidifying the supply air stream to provide a dehumidified air stream;
cooling the dehumidified air stream from a first temperature to a lower second temperature using indirect evaporative cooling; and
humidifying the cooled air stream by providing a flow of water adjacent to the cooled air stream, whereby a temperature of the cooled air stream is reduced to a post-humidification temperature.

### Claim 5 (depends on 4)

The method of claim 4, wherein the humidifying includes containing the flow of water with a vapor permeable membrane or within a layer of wicking material.

### Claim 6 (depends on 4)

The method of claim 4, wherein the dehumidifying includes directing the supply air stream through a channel defined by a surface of a vapor permeable membrane containing liquid desiccant.

### Claim 7 (depends on 4)

The method of claim 4, wherein the liquid desiccant comprises a weak desiccant.

### Claim 8 (depends on 4)

The method of claim 4, wherein the liquid desiccant comprises a regenerable desiccant.

### Claim 9 (depends on 4)

The method of claim 4, wherein the liquid desiccant comprises a glycol.

### Claim 10 (depends on 4)

The method of claim 4, wherein the liquid desiccant comprises a salt concentrate or ionic salt solution.

### Claim 11 (depends on 10)

The method of claim 10, wherein the liquid desiccant comprises lithium chloride.

### Claim 12 (depends on 10)

The method of claim 10, wherein the liquid desiccant comprises calcium chloride.

### Claim 13 (depends on 1)

The method of claim 1, wherein the liquid desiccant comprises a regenerable desiccant.

### Claim 14 (depends on 1)

The method of claim 1, wherein the liquid desiccant comprises a glycol.

### Claim 15 (depends on 1)

The method of claim 1, wherein the liquid desiccant comprises a salt concentrate or ionic salt solution.

### Claim 16 (depends on 15)

The method of claim 15, wherein the liquid desiccant comprises lithium chloride.

### Claim 17 (depends on 15)

The method of claim 15, wherein the liquid desiccant comprises calcium chloride.

### Claim 18 (depends on 1)

The method of claim 1, further comprising humidifying the cooled air stream by providing a flow of water adjacent to the cooled air stream, whereby a temperature of the cooled air stream is reduced to a post-humidification temperature.

### Claim 19 (depends on 18)

The method of claim 18, wherein the humidifying includes containing the flow of water with a vapor permeable membrane or within a layer of wicking material.