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XCELTHERM® MK1 – Typical Properties

(Chemically equivalent to DOWTHERM™ A, recommended for Concentrated Solar Power Systems, PET production, Synthetic Fiber plants and many other applications that require a high temperature heat transfer fluid)

Typical Properties

Key Operating Temperatures
Maximum Bulk Fluid Operating Temperature
Liquid Phase 750°F 400°C
Vapor Phase 750°F 400°C
Maximum Film Temperature 800ºF 427ºC
Crystallizing Point 53.6°F 12°C
Flash Point (PMCC)(ASTM D93)(min) 230°F 110°C
Flash Point (COC)(ASTM D92)(min) 255°F 124°C
Fire Point (ASTM D92)(min) 260°F 127°C
Autoignition Temperature (min) 1,150°F 621°C
Pumpability, at 300 mm2/s (cSt) 55.4°F > 13°C
Normal Boiling Point at 760 mm Hg 495°F 257°C
Physical Properties
Appearance Water-white to straw yellow liquid
Odor Aromatic
Composition Stable eutectic mixture of 73% Diphenyl Oxide and 27% Biphenyl
Average Molecular Weight 166 g/mol
Density, at 77°F/25°C 1,058 kg/m3 8.83 lbs/gal
Specific Gravity, at 25°C (77°F) 1.06
Moisture Content (max) 300 ppm
Critical Temperature 930.3°F 499°C
Critical Pressure 480.3 psia 3.31 MPa
Critical Density 20.4 lb/ft3 327 kg/m3
Critical Volume 0.0508 ft3/lb 3.17 L/kg
Kinematic Viscosity, at 104°F/40°C 2.48 cSt
Kinematic Viscosity, at 212°F/100°C 0.99 cSt
Coefficient of Thermal Expansion, at 392°F/200°C 7.317 x 10-4/°F 9.341 x 10-4/°C
Heat of Vaporization, at Maximum Use Temperature 123.3 BTU/lb 286.7 kJ/kg
Volume Contraction Upon Freezing 6.30%
Volume Expansion Upon Melting 6.66%
Heat of Fusion 41.9 BTU/lb 97.5 kJ/kg
Electrical Properties
Specific Resistivity, at 68°F/20°C 6.4 x 10 ohm-cm
Surface Tension in Air, at 77°F/ 25°C 36.6 dynes/cm
* Data represents typical laboratory samples and are not guaranteed for all samples

DOWTHERM is a trademark of the Dow Chemical Company