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 low range 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 low range fluid 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 low range heat transfer fluid 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 Name Paraffinic hydrocarbon
Appearance Water White Liquid
Odor Odorless
Maximum Recommended Film Temperature 500°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 Weight 160
Dielectric Breakdown voltage D1816-04 (kV, 0.1″ gap) 22.15
Dielectric Constant (1 KHz) D924-04 2.03
Dissipation Factor (1 KHz) D924-04 0.00001
Volume Resistivity at 100V (?-cm) D257-07 1.84X1014
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   Dens Therm.Cond. Visc Spec.Heat
50   6.4 0.088 2.1 0.47   8.9 0.206 10.7 0.80   9.1 0.215 5.5 0.74
-4   6.6 0.090 5.0 0.44   9.0 0.193 73.0 0.77   9.2 0.199 22.1 0.71
-22   6.7 0.090 7.3 0.43   9.0 0.188 172.8 0.76   9.3 0.193 44.0 0.70
    *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 LR Propylene Glycol Ethylene Glycol
  50   157 199 277
  -4   106 77 137
  -22   89 51 97
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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