Paratherm™ LR Low Range Heat Transfer Fluid

Paratherm™ LR Low Range Heat Transfer Fluid

Single Fluid Heating and Cooling – Non Aromatic – Non Aqueous

Paratherm LR heat transfer fluid is an aliphatic-hydrocarbon based heat transfer fluid designed for use in closed-loop, liquid phase heating and cooling systems up to 450°F in electric and steam heaters and down to a -58°F surface temperature in direct-expansion exchangers. Registered HT-1 for incidental food contact by NSF

Applications include:

    • Specialty chemical batch heating and cooling
    • Pharmaceutical Production Equipment
    • Secondary Coolant (“Brine”) Systems
    • Replacing Silicone Oil? Simply drain and refill
    • Food Processing

Reduce Process Hazards when Processing Water-Sensitive Product

Many products undergo a violent exothermic reaction when exposed to water. Paratherm LR can be used safely for temperature control in these reactions because, unlike water/glycols, it’s not mixed with water. And because it contains no double bonds or bonded oxygen molecules, it’s extremely stable.

Wider Temperature Range than Glycols

Paratherm LR has higher heat-transfer coefficients than 50% ethylene-glycol and 50% propylene-glycol solutions below -22°F and -4°F respectively. And while glycol solutions have a maximum operating temperature of 320°F, Paratherm LR is completely stable up to it’s 450°F maximum operating temperature. Stability tests showed less than 3% degradation after 500 hours at 550°F.

Typical Properties*

Chemical NameParaffinic hydrocarbon
AppearanceWater White Liquid
Maximum Recommended Film Temperature500°F/260°C
Maximum Recommended Operating Temperature 450°F/232°C
Minimum Operating Temperature 20 cPs (20 mP-s)-58°F/-50°C
Minimum Start-up Temperature 300 cPs (300 mP-s)-112°F/-80°C
Viscosity at 60°F cSt (mm2 /sec)2.4
Density at 60°F/15.5°C lb/gal (kg/m3 )6.4 (766)
Flash Point Closed Cup (D56)>130°F/54°C
Autoignition Temperature (maximum 10 sec ignition delay>500°F/260°C
Boiling Point (14.7 psia/101 kPa)397°F/202°C
Vapor Pressure @ maximum operating temperature psia (kPa)21 (145)
% Volume expansion over recommended operating temperature per 100°F (°C) 6.8 (12.2)
Average Molecular Weight160
Dielectric Breakdown voltage D1816-04 (kV, 0.1″ gap)22.15
Dielectric Constant (1 KHz) D924-042.03
Dissipation Factor (1 KHz) D924-040.00001
Volume Resistivity at 100V (?-cm) D257-071.84X1014
Heat of combustion (approximate) BTU/lb (kJ/kg)20,000 (46,300)
Heat of vaporization (approximate) BTu/lb (kJ/kg)113 (262)

 * These are typical laboratory values, and are not guaranteed for all samples.  ** Note: Normal practice is to size expansion tanks so that they are 1/4 to 1/3 full when the system is cold, and 2/3 to 3/4 full when the system is at the maximum normal operating temperature.

Paratherm LR™ vs. Ethylene Glycol and Propylene- Glycol Solutions — Comparison of Heat Transfer Coefficients

Physical Properties

Paratherm LR
 Propylene Glycol** Ethylene Glycol**
Temp* Density*ThermalConduct.*Viscosity*Spec.Heat Dens.Therm.Cond.Visc.Spec.Heat DensTherm.Cond.ViscSpec.Heat
50 6.40.0882.10.47 8.90.20610.70.80 9.10.2155.50.74
-4 6.60.0905.00.44 9.00.19373.00.77 9.20.19922.10.71
-22 6.70.0907.30.43 9.00.188172.80.76 9.30.19344.00.70
  *Density, lb/gal*Thermal Conductivity,        BTU/(hr- ft²-°F/ft)*Viscosity, cP*Specific Heat, Btu/(lb-°F)


*Temperature, ºF

 **All data pertaining to Propylene and Ethylene glycol was obtained from Dow literature for the Dowfrost HD and Dowtherm 4000 @ 50% by Volume respectively  

Fluid Film Coefficient – hi***

 Temp Paratherm LRPropylene GlycolEthylene Glycol
 50 157199277
 -4 10677137
 -22 895197
Based on 3/4″ Sch. 40 pipe @ 4’/sec.***hi, BTU/(hr-ft²-°F)


  • At 50°F, glycol solutions have higher coefficients
  • At -4°F, LR has a higher coefficient than Propylene Glycol solution
  • At -22°F, LR has almost the same coefficient as Ethylene Glycol solution

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