Thermal Fluids for Sub-Zero Systems
Water is the best thermal fluid, but it has one major flaw – it does not remain fluid at extreme temperatures. For systems well-below freezing you need to use a specialty thermal fluid, and Dow Chemical makes the industry standard heat transfer fluids for a range of applications.
Stable Solutions for Sub-Zero Systems
Extremely cold equipment is required for a wide variety of industrial processes. However, it is incredibly difficult to maintain thermal stability and performance for long-term operation. Corrosion, thermal efficiency losses and system leaks can quickly become an ever-present headache if you don’t use the proper thermal fluid solution.
Dow Chemical has decades worth of experience engineering the peak performance thermal fluids for low temperature applications. The DOWTHERM™ J, SYLTHERM™ XLT, and SYLTHERM™ HF products deliver best in class thermal properties combined with an incredibly long operational lifetime.
| Key Physical Properties | DOWTHERM™ J | SYLTHERM™ XLT | SYLTHERM™ HF |
|---|---|---|---|
| Freeze Point (°F) | -120 | -168 | -115 |
| Boiling Point (°F) | 358 | 345 | 410 |
| Flash Point (°F) | 136 | 116 | 145 |
| Viscosity (cps at-70°F) | 4.6 | 7.6 | 10.0 |
| Viscosity (cps at -100°F) | 8.0 | 12.6 | 16.7 |
| Vapor Pressure (psia at 70°F) | 0.015 | 0.02 | 0.01 |
Sub-Zero Applications & Use
Dow Thermal fluid solutions provide reliable and long-term operation in some of the most extreme conditions. From environmental test chambers to large, industrial-scale food freezers and countless others inbetween, the Dow solutions provide best-in-class performance for equipment that demands precise temperature control.
The Dow Thermal Fluids listed on this page are intented for use in a closed, pressurized system under nitrogen blanket with an expansion tank.
The diagram below shows a simplified secondary cooling loop for processes requiring sustained sub-zero temperatures.
Dow Thermal Fluid Properties at -50°F
| Thermal Properties (-50°F) | DOWTHERM™ J | SYLTHERM™ XLT | SYLTHERM™ HF |
|---|---|---|---|
| Thermal Conductivity (Btu/hr ft² °F/ft) | 0.0822 | 0.0717 | 0.0712 |
| Density (lb/ft³) | 56.87 | 56.28 | 58.56 |
| Specific Heat (Btu/lb °F) | 0.394 | 0.354 | 0.364 |
| Viscosity (cP) | 3.3 | 5.6 | 7.3 |
| Heat Transfer Coefficient (Btu/hr ft²°F) (7 ft/sec, 1" pipe) | 195 | 134 | 123 |
| Pressure Drop (psi/100 ft) | 11.15 | 12.27 | 13.44 |
| Pump Horespower (100' & 70% pump efficiency) | 0.159 | 0.175 | 0.191 |