Fluids / Propylene glycol, 50 % by volume
Thermal conductivity of propylene glycol, 50 % by volume vs temperature
A 50 % by volume propylene glycol solution, freeze protection to about −33 °C — full winter protection, and the concentration where the pumping penalty stops being ignorable.
Thermal conductivity in W/(m·K), from -30 to 100 °C. The chart and the table below are the same numbers; the table is the one you can copy.
| Density | 1,041 kg/m³ |
| Specific heat | 3.54 kJ/(kg·K) |
| Dynamic viscosity | 7.6 mPa·s |
| Temperature (°C) | Thermal conductivity (W/(m·K)) | Row |
|---|---|---|
| -30 | 0.368 | published |
| -20 | 0.372 | published |
| -10 | 0.376 | published |
| 0 | 0.379 | published |
| 10 | 0.38337 | interpolated |
| 20 | 0.388 | published |
| 30 | 0.39219 | interpolated |
| 40 | 0.396 | published |
| 50 | 0.39919 | interpolated |
| 60 | 0.402 | published |
| 70 | 0.40469 | interpolated |
| 80 | 0.407 | published |
| 90 | 0.40862 | interpolated |
| 100 | 0.41 | published |
Rows marked published land exactly on a source anchor and are the tabulated figure. The rest are this library’s interpolation between the two anchors either side — good enough to design with, and said out loud so you can decide that for yourself.
ASHRAE Handbook—Fundamentals, Ch. 31 (Secondary Coolants), interpolated from published tables · validated -30 to 100 °C · interpolated between 9 published anchors (values held, not extrapolated, past the ends)