Solid-state passive evaporative cooling system and method

Patent metadata

Field	Value
Publication number	US-12013156-B2
Application number	US-202318353122-A
Country	US
Kind code	B2
Filing date	Jul 17, 2023
Priority date	Jul 20, 2022
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A solid-state passive evaporative cooling system includes a hydrogel body, a water supply channel, a hydrogel root, and a water supply device. One end of the water supply channel is embedded into the hydrogel body, and a plurality of water outlets are formed in an outer wall of the water supply channel embedded into the hydrogel body. A water inlet at the other end of the water supply channel is connected to the water supply device which is configured to pump an aqueous solution into the water supply channel. The hydrogel root is disposed within the water supply channel. The aqueous solution is solidified by the hydrogel body to achieve the water-saving effect. During evaporative cooling, an osmotic pressure may be spontaneously created or enhanced within the system. The water supply channel is capable of adjusting the water content of the hydrogel body and providing a water supply driving force.

First claim

What is claimed is:

1. A solid-state passive evaporative cooling system, comprising a hydrogel body ( 2 ), a water supply channel ( 1 ), a hydrogel root ( 3 ), and a water supply device ( 4 ), wherein the water supply channel ( 1 ) is connected to the water supply device ( 4 ); the water supply device ( 4 ) is configured to pump an aqueous solution into the water supply channel ( 1 ); a plurality of water outlets ( 7 ) are formed in a wall of the water supply channel ( 1 ) and are embedded into the hydrogel body ( 2 ); and the hydrogel root ( 3 ) is disposed within the water supply channel ( 1 ); one end of the hydrogel root ( 3 ) is connected to the hydrogel body ( 2 ) and fills up the water outlets ( 7 ) of the water supply channel ( 1 ), and another end of the hydrogel root ( 3 ) is immersed into the aqueous solution within the water supply channel ( 1 ); and a shape of the another end of the hydrogel root ( 3 ) is one of a plane, a sawtooth shape, and a triangle, or a combination thereof; a charged ionic network is formed within the hydrogel body ( 2 ) and the hydrogel root ( 3 ).

2. The solid-state passive evaporative cooling system according to claim 1 , wherein the hydrogel body ( 2 ) has one side for direct contact with an object to be cooled and another side for evaporative heat dissipation, and a microstructure is formed on a surface of the another side.

3. The solid-state passive evaporative cooling system according to claim 1 , wherein a supercharging device is disposed within the water supply device ( 4 ).

4. A method for preparing the solid-state passive evaporative cooling system according to claim 1 , comprising the following steps:
S1, preparing a hydrogel solution;
S2, immersing the water supply channel ( 1 ) into an interfacial coupling agent solution, taking out and air-drying the water supply channel ( 1 ), and placing a plurality of water supply channels ( 1 ) in a mold in parallel or crosswise;
S3, pouring the hydrogel solution into the mold, pumping air out of the water supply channel such that the hydrogel solution fills up the water supply channel ( 1 ), and allowing the mold to stand such that a hydrogel is polymerized and molded by photo-initiation or thermal initiation;
alternatively, pouring the hydrogel solution into the water supply channel, sealing the water supply channel at two ends after being full of the hydrogel solution, allowing the water supply channel to stand such that the hydrogel solution is molded and placing the water supply channel into the mold; and pouring the hydrogel solution into the mold, and subjecting the hydrogel to be polymerized and molded by photo-initiation or thermal initiation; and
S4, drilling a through hole from a port of the water supply channel ( 1 ) located outside the hydrogel body ( 2 ) along an axis of the water supply channel using a drilling device such that the drilled through hole penetrates through the water supply channel ( 1 ), wherein the through hole has a cross section, of which a shape is one of a plane, a sawtooth shape, and a triangle, or a combination thereof, and forms the hydrogel root ( 3 ); and the hydrogel root ( 3 ) located within the water supply channel ( 1 ) is integrally connected to the hydrogel body ( 2 ).

5. The method according to claim 4 , wherein a bottom of the mold is rough for forming the microstructure on the surface of the hydrogel body ( 2 ).

6. A cooling method using the solid-state passive evaporative cooling system according to claim 1 , comprising:
contacting one side of the hydrogel body ( 2 ) with an object to be cooled, pumping the aqueous solution having an ionic concentration lower than an ionic concentration of the hydrogel body into the water supply channel ( 1 ) by the water supply device ( 4 ), and keeping a water pressure within the water supply channel ( 1 );
when water evaporates from a surface of the hydrogel body, creating a transpirational pressure within the hydrogel body to drive the hydrogel root ( 3 ) to absorb water and to drive water molecules to be transported within the hydrogel body, wherein dynamic evaporation at an evaporation interface of the hydrogel body results in an increased ionic concentration at the evaporation interface of the hydrogel body, which forms an ionic concentration gradient with an interior of the hydrogel body, and an osmotic pressure is created or increased due to an ionic concentration gradient difference; and
driving water molecules to be transported from the water supply channel ( 1 ) to an evaporation surface of the hydrogel body ( 2 ) by the aqueous solution in the water supply channel ( 1 ) under a combined action of the osmotic pressure, the transpirational pressure and the water pressure, thus improving an efficiency of cooling.

7. The cooling method according to claim 6 , wherein the osmotic pressure of the hydrogel root and the aqueous solution is changed by adjusting a concentration and a type of the aqueous solution pumped by the water supply device ( 4 ) into the water supply channel ( 1 ).

Assignees

• Univ Zhejiang Normal

Inventors

• Xu Zisheng
• Zhang Zhiyuan
• E Shiju

Classifications

• F25D7/00 Primary

  Devices using evaporation effects without recovery of the vapour (butter or cheese dishes with cooling devices A47G19/26) · CPC title

• F28D15/025

  having non-capillary condensate return means · CPC title

• F28D15/0233

  the conduits having a particular shape, e.g. non-circular cross-section, annular (F28D15/0241, F28D15/0266 take precedence) · CPC title

• F28D2021/0029

  Heat sinks · CPC title

• B01J13/0052

  Preparation of gels · CPC title