Fluid properties

16 fluids, 12 of them as functions of temperature rather than a single pinned value.

A constant is one number that does not move. A fluid is not that — water at 5 °C and water at 80 °C differ in viscosity by a factor of four, and since Reynolds number scales as 1/µ, the same pipe at the same velocity can be in a different flow regime at the two ends of a building’s temperature range. These pages give every property at whatever temperature you actually have, and hand the whole state to a solver in one click so a density and a viscosity in the same calculation always describe the same fluid.

Water, air & steam 3

Water

ρ = 998.2 kg/m³ at 20 °Cµ = 1.002 mPa·sLiquid water from 0 to 100 °C at 1 atm — density, viscosity, specific heat, thermal conductivity and vapour pressure, all at the same state.

density · dynamic viscosity · specific heat · thermal conductivity · vapour pressure · latent heat of vaporisation

Dry air

ρ = 1.2041 kg/m³ at 20 °Cµ = 0.01813 mPa·sDry air at 1 atm from −50 to 300 °C — the ideal-gas density and Sutherland viscosity behind every duct, fan and drag calculation.

density · dynamic viscosity · specific heat · thermal conductivity

Saturated steam saturated

ρ = 2.548 kg/m³ at 150 °Cµ = 0.01419 mPa·sDry saturated steam from 100 to 200 °C — saturation pressure, vapour density and latent heat along the boiling line that low and medium pressure steam heating runs on.

density · dynamic viscosity · specific heat · thermal conductivity · vapour pressure · latent heat of vaporisation

Glycol heat transfer fluids 7

Freeze points by concentration

Both chemistries, 0 to 60 % by volume, °C and °F — the classic curve, and a solver that answers “the design day is −25 °C, how much glycol does the loop need?”

Propylene glycol, 20 % by volume

ρ = 1,020.2 kg/m³ at 20 °Cµ = 2.02 mPa·sA 20 % by volume propylene glycol solution, freeze protection to about −7 °C — the corrosion floor: any leaner and the inhibitors are too dilute to trust.

density · dynamic viscosity · specific heat · thermal conductivity

Propylene glycol, 30 % by volume

ρ = 1,024 kg/m³ at 20 °Cµ = 3.4 mPa·sA 30 % by volume propylene glycol solution, freeze protection to about −13 °C — the usual charge for a snowmelt or make-up air loop that only has to survive a Canadian shoulder season.

density · dynamic viscosity · specific heat · thermal conductivity

Propylene glycol, 40 % by volume

ρ = 1,037.4 kg/m³ at 20 °Cµ = 4.59 mPa·sA 40 % by volume propylene glycol solution, freeze protection to about −21 °C — the middle charge — full winter protection at a manageable pumping penalty.

density · dynamic viscosity · specific heat · thermal conductivity

Propylene glycol, 50 % by volume

ρ = 1,041 kg/m³ at 20 °Cµ = 7.6 mPa·sA 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.

density · dynamic viscosity · specific heat · thermal conductivity

Propylene glycol, 60 % by volume

ρ = 1,049.4 kg/m³ at 20 °Cµ = 10.04 mPa·sA 60 % by volume propylene glycol solution, freeze protection to about −51 °C — the deepest worthwhile charge, and viscosity is now the design constraint.

density · dynamic viscosity · specific heat · thermal conductivity

Ethylene glycol, 30 % by volume

ρ = 1,041 kg/m³ at 20 °Cµ = 2.4 mPa·sA 30 % by volume ethylene glycol solution, freeze protection to about −15 °C — lower viscosity than propylene at the same protection, and toxic.

density · dynamic viscosity · specific heat · thermal conductivity

Ethylene glycol, 50 % by volume

ρ = 1,072 kg/m³ at 20 °Cµ = 4.2 mPa·sA 50 % by volume ethylene glycol solution, freeze protection to about −37 °C — the standard chiller and automotive charge.

density · dynamic viscosity · specific heat · thermal conductivity

Reference liquids 4

Seawater single state

ρ = 1,025 kg/m³ at 15 °Cµ = 1.19 mPa·sOpen-ocean seawater at 35 g/kg salinity and 15 °C — 1025 kg/m³, the 64 lb/ft³ that separates salt-water from fresh-water load lines.

density · dynamic viscosity · specific heat · thermal conductivity

SAE 30 mineral oil single state

ρ = 876 kg/m³ at 40 °Cµ = 88 mPa·sA typical SAE 30 mineral engine oil at 40 °C — about 0.088 Pa·s, some ninety times the viscosity of water at 20 °C.

density · dynamic viscosity · specific heat · thermal conductivity

Ethanol single state

ρ = 789 kg/m³ at 20 °Cµ = 1.2 mPa·sPure ethanol at 20 °C — 789 kg/m³ and 1.20 mPa·s, the reference liquid behind specific-gravity work and most laboratory density checks.

density · dynamic viscosity · specific heat · thermal conductivity

Mercury single state

ρ = 13,534 kg/m³ at 20 °Cµ = 1.526 mPa·sMercury at 20 °C — 13 534 kg/m³, the density that makes a millimetre of it a usable unit of pressure.

density · dynamic viscosity · specific heat · thermal conductivity

Refrigerants 2

R-134a (saturated liquid) saturated

ρ = 1,236.8 kg/m³ at 20 °Cµ = 0.228 mPa·sR-134a saturated liquid from −40 to 60 °C — the single-component HFC whose saturation table underpins most automotive and medium-temperature commercial refrigeration.

density · dynamic viscosity · specific heat · thermal conductivity · vapour pressure · latent heat of vaporisation

R-410A (saturated liquid) saturated

ρ = 1,046 kg/m³ at 20 °Cµ = 0.14 mPa·sR-410A saturated liquid from −40 to 60 °C — the high-pressure blend in most modern split systems and heat pumps, running roughly 60 % above R-134a pressures.

density · dynamic viscosity · specific heat · thermal conductivity · vapour pressure · latent heat of vaporisation