• Module 11
  • Module 12
  • Module 13
  • Module 14
  • Module 15
  • Module 16
  • Module 17
  • Module 18
  • Module 19
  • Module 20
  • Module 1
  • Module 2
  • Module 3
  • Module 4
  • Module 5
  • Module 6
  • Module 7
  • Module 8
  • Module 9
  • Module 10
  • Module 11
  • Module 12
  • Module 13
  • Module 14
  • Module 15
  • Module 16
  • Module 17
  • Module 18
  • Module 19
  • Module 20
  • Module 1
  • Module 2
  • Module 3
  • Module 4
  • Module 5
  • Module 6
  • Module 7
  • Module 8
  • Module 9
  • Module 10

Thermal fluids properties

The choice of a thermal fluid to transfer calories or frigories to a process depends on temperature and pressure conditions that affect this fluid.

The best thermal fluid is WATER, since it comes with many advantages: very low cost and excellent thermal performance.

However water also has two drawbacks that may prevent from using it:

  • - Water may be extremely reactive to reactors in the process, which might create an accident in case of containment rupture.
  • - The specific weight of solid water is lower than this of liquid water. This very rare property of water (only shared with bismuth) is the origin of much damage.

An interesting compromise is this of a thermal fluid based on water:

  • - BRINE, calcium chloride solution in water, whom fusion point, at a negative temperature, depends on concentration. The thermal performances of brine are higher than those of water, but corrosion from brine limits its use to low temperatures.
  • - GLYCOLED WATER, a mix of water and glycol ethylene, may be used at low or high temperatures. The addition of glycol brings the advantages of being able to lower the fusion point of water and to reduce saturated steam pressure at high temperatures.

Organic solvents may also be used, pure or with added water, but only at low temperatures to avoid any flaming hazard:

  • - Ethanoled water, mix of water and ethanol for cold supply network
  • - Methanol in pure form, for monofluid loop applications in cryogenic mode between –80 and 50°C.

For very low or very high temperatures, or for a working point oscillating between those extreme temperatures, it is necessary to use specific thermal oil. 

The use of those oils should be limited to very necessary cases, since they are very expensive but also very flammable.

In France, the use of a thermal fluid at a temperature higher than its flashpoint is ruled by classified installations rules, note #2951.

Useful physical characteristics for chemistry calculation are often hard to find. That's why we have regrouped those characteristics in several tables which you may consult:

Pures solvents
pdfWATER
pdfMETHANOL
pdfETHANOL
pdfISOPROPANOL
pdfMETHYLCYCLOHEXANE
pdfXYLENE


Aqueous solutions
pdfGLYCOLED WATER
MEG monoethylene glycol at :
25% 30% 35% 40% 45% 50%
pdfGLYCOLED WATER
MPG monopropylene glycol at:
25% 30% 35% 40% 45% 50%
pdfETHANOL
10% 20% 30% 40% 50% 60% 70% 80% 90%
pdfMETHANOL
10% 20% 30% 40% 50% 60% 70% 80% 90%


Synthetic oils
pdfDOWTHERM J
pdfDYNALENE MV
pdfJARYTHERM AX320
pdfJARYTHERM BT06
pdfJARYTHERM CF
pdfJARYTHERM DBT
pdfMARLOTHERM LH
pdfMARLOTHERM SH
pdfMARLOTHERM X
pdfPARACRYOL
pdfPARATHERM CR
pdfPARATHERM HR
pdfSANTOTHERM 59
pdfSANTOTHERM LT
pdfSYLTHERM 800
pdfSYLTHERM XLT
pdfTHERMINOL 66
pdfTHERMINOL ADX10
pdfTHERMINOL ALD
pdfTHERMINOL D12
pdfTHERMINOL XP


The values of pure solvents and aqueous solutions are issued from thermodynamical data.

The datasheets for synthetic oils are issued from technical documents of producing companies : ARKEMA, DOW CHEMICAL, DYNALENE, MONSANTO, PARATHERM, SASOL, SULZER,…