Low-drag, high-efficiency microchannel polymer heat exchangers

Patent metadata

Field	Value
Publication number	US-2022010981-A1
Application number	US-202117148359-A
Country	US
Kind code	A1
Filing date	Jan 13, 2021
Priority date	Jan 13, 2020
Publication date	Jan 13, 2022
Grant date	—

Abstract

The disclosed embodiments relate to a system that provides a polymer heat exchanger with internal microscale flow passages. The system includes a set of plates comprised of a polymer that includes internal microscale flow passages, which are configured to carry a liquid. The set of plates is organized into a stack, wherein consecutive plates in the stack are separated by fins to form intervening air passages. The system includes a liquid flow pathway, which flows from a liquid inlet, through the internal microscale flow passages in the stack of plates, to a liquid outlet. It also includes an airflow pathway, which flows from an airflow inlet, through the intervening air passages between the consecutive plates in the stack of plates, to an airflow outlet. The liquid flow pathway flows in a direction opposite to a direction of the airflow pathway to provide a counterflow design that optimizes heat transfer between the liquid flow pathway and the airflow pathway.

First claim

What is claimed is:

1 . A system that provides a polymer heat exchanger, comprising:
a set of plates comprised of a polymer that includes internal microscale flow passages, which are configured to carry a liquid; wherein the set of plates is organized into a stack, wherein consecutive plates in the stack are separated by fins to form intervening air passages; wherein the polymer heat exchanger includes a liquid flow pathway, which flows from a liquid inlet, through the internal microscale flow passages in the stack of plates, to a liquid outlet; wherein the polymer heat exchanger includes an airflow pathway, which flows from an airflow inlet, through the intervening air passages between the consecutive plates in the stack of plates, to an airflow outlet; and wherein the liquid flow pathway flows in a direction opposite to a direction of the airflow pathway to provide a counterflow design that optimizes heat transfer between the liquid flow pathway and the airflow pathway.

2 . The system of claim 1 , wherein the fins that separate consecutive plates in the stack of plates are formed by protrusions, which are manufactured onto outer surfaces of the set of plates.

3 . The system of claim 2 , wherein the fins that separate consecutive plates are configured to be one or more of straight, interrupted and contoured.

4 . The system of claim 1 , wherein the internal microscale flow passages within the set of plates include arrays of microscale pin fins to facilitate heat transfer and liquid flow distribution.

5 . The system of claim 4 , wherein pins that comprise the array of microscale pins are configured to be one or more of circular, airfoil-shaped and twisted.

6 . The system of claim 1 , wherein the polymer heat exchanger is part of a heating and/or cooling system for a building, which comprises:
an external heat pump located outside of the building, which uses a low global warming potential (GWP) refrigerant; a refrigerant-to-liquid heat exchanger located outside of the building, which exchanges heat between the low GWP refrigerant from the external heat pump and a heat-transfer liquid; and the polymer heat exchanger located inside the building, which exchanges heat between the heat-transfer liquid from the refrigerant-to-liquid heat exchanger and air, which flows through a heating and/or cooling system in the building.

7 . The system of claim 1 , wherein each plate in the set of plates is designed to be fabricated through an injection molding process, wherein a top surface and/or a bottom surface of the plate are formed through injection molding, and the top surface and the bottom surface are bonded together to form the plate, which includes the internal microscale flow passages.

8 . The system of claim 1 , wherein each plate in the set of plates is designed to be manufactured through an additive manufacturing process.

9 . The system of claim 1 , wherein each plate in the set of plates includes features that form a plenum, wherein when plates in the set of plates are stacked together, the plena in the individual plates form a continuous plenum, which is configured to carry liquid from the liquid inlet to the internal microscale flow passages, and from the internal microscale flow passages to the liquid outlet.

10 . The system of claim 1 , wherein the stacked set of plates forms a heat exchanger module that provides a duct for airflow for the airflow pathway, wherein the system includes multiple heat exchanger modules, which are stacked in one or more dimensions orthogonal to a direction of the airflow to form a larger duct assembly.

11 . The system of claim 1 , wherein the liquid in the polymer heat exchanger comprises one of water and glycol.

12 . The system of claim 1 , wherein the internal microscale flow passages in the set of plates are 0.25 mm to 1.0 mm or less in width.

13 . The system of claim 1 , wherein the system is configured to be used in industrial processes to efficiently extract low grade waste heat from gaseous heat sources.

14 . The system of claim 1 ,
wherein the system is configured to measure a flow rate of air by measuring a pressure drop across the polymer heat exchanger; and wherein the system is configured to use the pressure drop to continuously monitor the state of the polymer heat exchanger to determine whether the polymer heat exchanger needs to be serviced.

15 . A method for fabricating a polymer heat exchanger with microscale flow passages, comprising:
fabricating a set of plates using a polymer, wherein the set of plates includes internal microscale flow passages, which are configured to carry a liquid; organizing the set of plates into a stack, wherein consecutive plates in the stack are separated by fins to form intervening air passages; forming a liquid flow pathway, which flows from a liquid inlet, through the internal microscale flow passages in the stack of plates, to a liquid outlet; and forming an airflow pathway, which flows from an airflow inlet, through the intervening air passages between the consecutive plates in the stack of plates, to an airflow outlet; wherein the liquid flow pathway flows in a direction opposite to a direction of the airflow pathway to provide a counterflow design that optimizes heat transfer between the liquid flow pathway and the airflow pathway.

16 . The method of claim 15 , wherein fabricating the set of plates comprises fabricating protrusions in outer surfaces of the set of plates, wherein when the set of plates is organized into the stack, the protrusions form the fins that separate the consecutive plates in the stack of plates.

17 . The method of claim 15 , wherein fabricating the set of plates comprises forming arrays of microscale pin fins in the internal microscale flow passages within the set of plates to facilitate heat transfer and liquid flow distribution.

18 . The method of claim 15 , wherein each plate in the set of plates includes features that form a plenum, wherein when plates in the set of plates are stacked together, the plena in the individual plates form a continuous plenum, which is configured to carry liquid from the liquid inlet to the internal microscale flow passages, and from the internal microscale flow passages to the liquid outlet.

19 . The method of claim 15 , wherein fabricating each plate in the set of plates comprises:
forming a top surface and/or a bottom surface of the plate through an injection molding process; and bonding the top surface and the bottom surface together to form the plate, which includes internal microscale flow passages.

20 . The method of claim 15 , wherein fabricating each plate in the set of plates comprises using an additive manufacturing process to form the plate.

21 . The method of claim 15 ,
wherein the stacked set of plates forms a heat exchanger module that provides a duct for airflow for the airflow pathway; and wherein the method further comprises stacking multiple heat exchanger modules in one or more dimensions orthogonal to a direction of the airflow to form a larger duct assembly.

22 . A method for operating a polymer heat exchanger with microscale flow passages, comprising:
directing a liquid through a liquid flow pathway in the polymer heat exchanger, wherein the liquid flow pathway flows from a liquid inlet, through internal microscale flow passages in a set of plates, which is comprised of a polymer and is organized into a stack, to a liquid outlet, and wherein consecutive plates

Assignees

• Univ California

Inventors

• Narayanan Vinod
• Rasouli Erfan

Classifications

• F28F3/10

  Arrangements for sealing the margins · CPC title

• F28F2260/02

  having microchannels · CPC title

• F24F1/0067 Primary

  by the shape of the heat exchangers or of parts thereof, e.g. of their fins · CPC title

• F28F2255/143

  injection molded · CPC title

• F28F2250/10

  Particular pattern of flow of the heat exchange media · CPC title