Characterizing Thermal Properties in Energy Research ECN TECHNOLOGY DAY THERMAL ANALYSIS FEBRUARY 5TH, 2015 ADAM HARRIS MANAGING DIRECTOR
AGENDA Who we are? What we do? Understanding MTPS Method: Modified Transient Plane Source Application Examples: Metal Hydrides Thermoelectrics Q&A
WHO WE ARE C-THERM TECHNOLOGIES LTD.
Non-destructive, thermal sensor technology solutions for R&D, QC and production applications - delivering fast, accurate measurement of thermal conductivity and effusivity in seconds. WINNER
WHAT WE DO?
PRODUCT LINES THERMAL CHARACTERIZATION C-Therm TCi Thermal Conductivity Analyzer Clients include: NRC Philip Morris Henkel Tech. Huntsman Kodak US Air Force PHARMACEUTICAL APPLICATIONS C-Therm ESP Effusivity Sensor System Clients include: Patheon Astra Zeneca Wyeth Biovail BMS USP
NEW DILATOMETER TEMPERATURE RANGE Room Temperature to 1600 C TEMPERATURE RESOLUTION 0.1 C MAX DISPLACEMENT 4mm ΔI RESOLUTION 1.25 nm/digit ATMOSPHERE Air, Vacuum, Inert Gas SAMPLE DIMENSIONS 10 to 50mm long x max φ 12mm SAMPLE HOLDER Fused Silica, Alumina CONFIGURATIONS Single or Dual LVDT System 1200 C or 1600 C HEATING ELEMENT Kanthal Wire, SiC Rate of Increase ( C) > 50 C/min
TCi PROPERTY ANALYZER Thermal Conductivity Range Non-Destructive 0 to 500 W/mK Leaves sample intact Thermal Effusivity Range Versatile 5 to 40,000 Ws½/m²K Tests solids, liquids, powders & pastes Temperature Range Highly Flexible -50 to 200 C Designed for lab, QC & at-line testing No Sample Preparation Accuracy Unlimited sample sizes Better than 5% Precision Better than 1%
What Does It Measure? The C-Therm TCi measures two thermal properties primarily: It also indirectly measures (calculated) Thermal Diffusivity and Heat Capacity and has user input capabilities to determine Density
How Does It Work? Wood feels warm Heat always flows from a hot object to a cold object. Wood is not a good conductor of heat, so it is slow to absorb the heat. Metal has higher thermal conductivity so the heat from your hand flows into the metal quickly - creating the sensation of it being cold. Metal feels cold C-Therm sensors work like your hand, by rapidly determining the rate of heat flow from one material to another. Like your hands, our sensors supply the heat source and detect the heat flow. They also have no sample size issues, and do not destroy the sample being tested.
How Does It Work? How it works: This approach is a transient technique that uses heat reflectance, similar to Hot Wire testing. The modification is that the heating element is supported on a backing, thus allowing a one-directional heat flow. This allows the testing to be non-intrusive and permits the testing of solids without the need to be melted. Therefore, the temperature of the heating element versus the time function is used to calculate the thermal conductivity and thermal effusivity.
MODIFIED TRANSIENT PLANE SOURCE (MTPS)
Voltage ( but think Temperature) How Does It Work? Time First 0.3 Seconds: Addressing Contact Resistance, Non-Linear 0.3 0.8 Seconds: Within Sample, Linear
Which Is More Conductive? Voltage ( but think Temperature) Option A Option B Time First 0.3 Seconds: Addressing Contact Resistance, Non-Linear 0.3 0.8 Seconds: Within Sample, Linear
Easy Results Thermal Conductivity Temp. Thermal Effusivity Easily exportable to EXCEL
APPLICATIONS: ENERGY MATERIALS
THERMAL CONDUCTIVITY OF MAGNESIUM HYDRIDE JACQUES HUOT 1 AND ADAM HARRIS*2, 1 INSTITUT DE RECHERCHE SUR L HYDROGÈNE, UNIVERSITÉ DU QUÉBEC À TROIS-RIVIÈRES, QUÉBEC, CANADA 2C-THERM TECHNOLOGIES, FREDERICTON, NEW BRUNSWICK, CANADA NORTH AMERICAN THERMAL ANALYSIS SOCIETY (2010)
MAGNESIUM HYDRIDES Shows potential as a reversible "storage" medium for hydrogen which has led to interest in improving the hydrogenation and dehydrogenation reaction kinetics. Challenges: - High temperature of operation - Relatively slow kinetics - Cost ($) - Resistance to cycling - Heat transfer issues
HEAT TRANSFER ISSUES In the case of heat transfer, the problem is especially significant because of the high heat of formation of magnesium hydride (75 kj/mol). Compounded by the fact that magnesium has a low melting point. If heat is not transferred rapidly to some heat exchanger the magnesium inside the tank runs the risk of melting during absorption (an exothermic process).
SAMPLE PREPARATION: BALL MILLING A ball mill, a type of grinder, is a cylindrical device used in grinding (or mixing) materials like ores, chemicals, ceramic raw materials and paintsball mills rotate around a horizontal axis, partially filled with the material to be ground plus the grinding medium. Intensively used for doping magnesium hydride with catalysts
RESULTS 21
SEM Scanning Electron Microscope (SEM) micrographs of powder MgH2 in the as-received state (A), after 10 hours milling (B), after 10 hours mill with 2% add of vanadium(c), and after 10 hours mill with 2% add of V2O5(D)
RESULTS 23
RESULTS Thermal conductivities as a function of relative density of MgH2 in the as-received state, after 10 hours milling, after 10 hours mill with 2% add of vanadium, and after 10 hours mill with 2at.% of V2O5.
CONCLUSIONS The effect of ball milling and catalyst addition on thermal conductivity of magnesium hydride in powder and compacted pellets was investigated. Particle size has a big impact on thermal conductivity, smaller particles having thermal conductivity 33% lower than big particles. Compaction does not change this situation even if densification is higher for powder with small particle size. A compound with big particles (20 μm and bigger) is preferable to small particle sizes.
NEXT STEPS? HIGH PRESSURE CELL (HPC) 2013 C-Therm Technologies Ltd.
HIGH PRESSURE CELL (HPC) 1. Intermediate Flange 2. Cover 3. Eye Bolt 4. Modified TCi Sensor 5. Power Lead Gland 6. Vessel 7. Socket Head Cap Screw (Long) 8. Socket Head Cap Screw 9. Lock Pin 10. Pressure In/Out Adaptor, with purge 11. Thermocouple Adaptor 12. Adaptor for TCi (cable feedthrough) 11 12 2013 C-Therm Technologies Ltd.
HPC CLOSED 2013 C-Therm Technologies Ltd.
HPC OPEN 2013 C-Therm Technologies Ltd.
THERMOELECTRICS
PERFORMANCE Figure of Merit: ZT (dimensionless) λ Power Factor Thermal Conductivity Where S = = T = λ = Seebeck Coefficient, electrical conductivity absolute temperature thermal conductivity
Magnesium Silicide
THERMAL CONDUCTIVITY VS TEMPERATURE Thermal Conductivity (W/mk) MgSi 8.0 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 R² = 0.9637 25 50 75 100 125 Temperature ( C) 150 175 200
OPTIMIZATION OF THE THERMOELECTRIC PROPERTIES OF POLY[CUX(CU-ETHYLENETETRATHIOLATE)] PENG SHENGA,B, YIMENG SUNA,B, FEI JIAOA,B, CAIMING LIUA, WEI XUA,, DAOBEN ZHUA, ABEIJING NATIONAL LABORATORY FOR MOLECULAR SCIENCES, KEY LABORATORY OF ORGANIC SOLIDS, INSTITUTE OF CHEMISTRY, CHINESE ACADEMY OF SCIENCES, BEIJING 100190, CHINA BUNIVERSITY OF CHINESE ACADEMY OF SCIENCES, BEIJING 100049, CHINA
CURRENT STUDY poly(cu-ethylenetetrathiolate) Chosen because; exhibit high room-temperature electrical conductivities Easy to synthesize Researchers previous experience
EQUIPMENT SB-100 Seebeck Measurement System (MMR Tech.) KEITHLEY 2002 Multimeter (Keithley Inst. Inc.) C-Therm TCi Thermal Conductivity Analyzer
THERMAL CONDUCTIVITIES Reduction Oxidation Both oxidation and reduction decrease the thermal conductivity. However, the oxidation causes a greater decrease overall in the thermal conductivity measured with the TCi
HIGH PERFORMANCE DISPENSER PRINTED MA P-TYPE BI0.5SB1.5TE3 FLEXIBLE THERMOELECTRIC GENERATORS FOR POWERING WIRELESS SENSOR NETWORKS DEEPA MADAN1,*, ZUOQIAN WANG1, ALIC CHEN1, PAUL K. WRIGHT1, JAMES W.EVANS2 1DEPARTMENT OF MECHANICAL ENGINEERING, UNIVERSITY OF CALIFORNIA, BERKELEY, CA 94720 2DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING, UNIVERSITY OF CALIFORNIA, BERKELEY, CA 94720
PROTOTYPE DEVICE
THERMAL CONDUCTIVITY The thermal conductivity of conductivity of MA Bi0.5Sb1.5Te3 with 8 wt% extra Te dispensed printed film was 0.24 W/m-K. Lower thermal conductivity as compared to the bulk (1.1 W/m-K) is due to the insulating nature of epoxy. Fine grain (5µm) active filler particles also increase the potential barrier scattering that contributes to lower thermal conductivity. Thermal Conductivity (W/mK) 1.2 1 0.8 0.6 0.4 0.2 0 Bulk with 8 wt% extra Te
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CONTACT C-THERM Adam Harris Managing Director C-Therm Technologies Ltd. Email: aharris@ctherm.com Phone: +1 (506) 457 1515