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NOVEL MICRO SOLAR

COLLECTOR FOR PORTABLEHYDROGEN PRODUCTION

Dr. Ral Zimmerman

SCHOOL OF MECHANICAL AND MANUFACTURING ENGINEERING

13/06/12

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Motivation

There is a constant increase in power

demand for remote areas and for portableapplications.

We propose to use cost-free solar energy toincrease the efficiency of current micro-reactors and

to combine this technology with a PEM fuel cell toform a portable and efficient power supply.

Solar thermal applications have been limited tomacro-scale systems to produce MW of power,or for water heating.

During the production of hydrogen by methanolreforming, a part of the fuel energy is wasted to

reach the reaction temperature.

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CH3OH + H

2O CO

2+ 3H

2

Methanol steam reforming

Catalyst: Cu / ZnO

220 C < T < 300 C

H0(250 C) = +59.5 kJ / mol

Solar Energy

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Water-Methanolmixture

Solar Energy

H2

Electricity

Schematic diagram of a solar powered fuelcell

Micro thermalcollector-methanol

reformer

H2 StorageBackupheater

Battery orEDLC

PEMFC

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25 cm

40 cm

15 cm

15 cmSolar poweredmicroreactor

+ PEM Fuel cell

Photovoltaicsolar panelh=20%

Power Supplies

Ultracells 25W

Reformed MethanolFuel Cell

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Schematic of flat-plate micro solarreformer

TiNOXSelective coating

Low reflectiveglass

CH3OH + H2O

Liquid (Tamb)

CO2 + 3H2Steam (T > 220 C)

150 mm

5mm

Vacuum Layers

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TiNOX Selective Coating

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TiNOX Emittance

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Glass:

Base:

Microreactor:

Analytical model

Fluid:

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Stagnation temperature

TiNOXselective coating

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Convection

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Conductive thermal resistance

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Water/Methanol mixture temperature

Current microreformers

0.07 to 0.9 [ml hr -1 cm-2]

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Thermal efficiency

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Experimental Setup

Chromel wire

Polished Cu

base & side walls

TiNOXSelectivecoating

Serpentine tube

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Vacuumchamber

HalogenIncandescent Lamp

ThermocouplePressure

gauge

Lowreflective

glass

Turbomolecularvacuum pump

Two-stage

rotary vanevacuum pump

Prototype

Syringepump

Experimental Setup

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Incandescent halogen lamp & Solar spectrum

Solar Spectral Irradiance

ASTM G173-03 1.5 Air Mass

Halogen Lamp (3200K)

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Model vs. Experimental results

Volumetric flow rate

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Temperatures with and without H2 production

Volumetric flow rate

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Micro concentrator

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Conclusions

A novel micro flat solar collector will supply theenergy needed for methanol reforming improving

the efficiency of current reformers.

This technology, combined with a fuel cell willallow to produce a compact, efficient and portablepower source system that takes advantage of the

free solar energy.