# US 2014/0196498 A1 · Evaporative Heat Transfer System

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- Number: US 2014/0196498 A1
- Document ID: US20140196498A1
- Status: Published application
- Kind: A1
- Application number: 14/152,120
- Filed: 2014-01-10
- Published: 2014-07-17
- Earliest claimed: 2013-01-14
- Assignees: Massachusetts Institute of Technology
- Applicants: Massachusetts Institute of Technology
- Inventors: Rong Xiao; Rishi Raj; Shankar Narayanan; Evelyn N. Wang; Ryan Enright; Shalabh Chandra Maroo
- Web page: https://patentgrep.com/patent/US20140196498A1

## CPC

- F25B 39/02: Evaporators
- H10W 40/47: by flowing liquids, e.g. forced water cooling
- H10W 40/73: for cooling by change of state
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Evaporative heat transfer system. The system includes a substrate and a plurality of substantially parallel, spaced-apart ridges extending from the substrate forming vertical liquid manifolds therebetween. A nanoporous membrane is supported on the ridges and a pump delivers a dielectric fluid across the ridges. The fluid is drawn through the liquid manifolds via capillarity provided by the nanoporous membrane and evaporates to dissipate heat flux through the substrate. A preferred dielectric fluid is pentane. It is preferred that membrane porosity vary across the membrane to tailor thermal resistances to limit temperature rises.

## Claims

### Claim 1

Evaporative heat transfer system comprising:
a substrate;
a plurality of substantially parallel, spaced-apart ridges extending from the substrate forming vertical liquid manifolds therebetween;
a nanoporous membrane supported on the ridges; and
a pump for delivering a dielectric fluid across the ridges, whereby the fluid is drawn through the liquid manifolds via capillarity provided by the nanoporous membrane and evaporates to dissipate heat flux through the substrate.

### Claim 2 (depends on 1)

The system of claim 1 wherein the dielectric fluid is pentane.

### Claim 3 (depends on 1)

The system of claim 1 wherein pore size in the nanoporous membrane is selected to provide high capillary pressures.

### Claim 4 (depends on 3)

The system of claim 3 wherein the pore size is approximately 40 nm and capillary pressure is approximately 1.1 MPa.

### Claim 5 (depends on 1)

The system of claim 1 wherein membrane porosity varies across the membrane to tailor thermal resistances to limit temperature rises.

### Claim 6 (depends on 1)

The system of claim 1 wherein the system is configured to dissipate greater than 1 kW/cm2 on a 1 cm2 area having a 200 by 200 μm hotspot dissipating greater than 5 kW/cm2.

### Claim 7 (depends on 1)

The system of claim 1 further including a condenser to capture vapor and recirculate liquid to the pump.

### Claim 8 (depends on 1)

The system of claim 1 wherein the substrate is SiC.