Free ProSol L-HT Glycol

Heat Transfer Fluid for vacuum tube collectors. Available in 5 US Gal (18.93 L) pails and 50 US Gal (189L) drums.

Premixed reversibly vaporizable special Propylene Glycol-based Heat Transfer Fluid, for solar heating installations

default ProSol L-HT Solar Glycol - Technical Product Brief (307 KB)

default ProSol L-HT Solar Glycol - MSDS Sheet (28 KB)

Chemical Composition:

A blend of virgin (not recycled) propylene glycol, water and inhibitors.

Physical Properties:

  Clear, fluorescent yellow colored liquid
Density 22°C (72°F)
  1055.40 kg/m³ (65.88  lb/ft³)
Refractive index 22°C (72°F)
pH value
Reserve Alkalinity (min)
  16.0 ml
Viscosity 10°C (50°F)
  10.6481mPa·s (10.65 cps)
Boiling point     °C @ 101 kPa 
(°F@ 760 mmHg)
Flash point 
Water content 
  46 – 50 %
Burst protection °C /°F
  -46 / -50

Getting it right is critical in maintaining industry reputation

Modern-day Thermal Solar combo-systems for DHW and Space heating are subject of overheating and stagnation because of low heat demand in summer time. Continuing design improvements of solar collectors sig­nificantly change the requirements to the heat transfer fluids regarding its ability to take thermal stress.

However, stagnation temperatures of up to 400°F (204°C) in flat plate collectors still can be handled by traditionally inhibited solar fluids. In contrast to this, absorber temperatures of up to 550°F (287°C) as reached in vacuum tube collectors require the use of a more ad­vanced fluid containing reversibly vaporizable cor­rosion inhibitors.

Solarnetix Inc. recently introduced a new Pro Sol – L-HT propylene glycol/ water mix, with specially designed industrial package of liquid inhibitors.

The Glycol Mix has been designed especially for use as a heat transfer fluid in solar thermal systems operating under elevated thermal conditions (vacuum tube collectors).

In case of stagnation those components evaporate together with propylene glycol and water, the collector remains empty, and no damaging insoluble residues may cause any flow obstruction or blocking.

The corrosion inhibitors contained in ProSol™ L-HT reliably provide protection against acid corrosion, scale and sedimentation formation in systems with materials normally used in solar thermal installations.

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