50-50 Ethylene glycol-water & air properties



This sheet will be of interest to those who work with coolant-coolant or coolant-air heat exhchangers. It will calculate certain properties of 50/50 Ethylene glycol and water between -30C and +120C. Also the properties of air between -40C and +200C Properties calulated are:- Density, heat capacity, dynamic & kinematic viscosities, thermal conductivity and Prandtl number. No macros are used. The formulae can be easily pasted and integrated into other spreadsheets.

Calculation Reference
Fluid Properties
Fluid Mechanics
Heat Transfer

A 50-50 ethylene glycol-water mixture is a common coolant used in various applications, such as automotive engines and HVAC systems. The properties of this mixture and air are important for understanding their behavior under different conditions.

  1. Properties of a 50-50 ethylene glycol-water mixture:
  • Freezing point: Approximately -37°C (-34.6°F). This mixture offers excellent low-temperature protection, helping to prevent freezing in the cooling system.

  • Boiling point: Around 106°C (222.8°F) at atmospheric pressure. The boiling point can be further increased with a pressurized cooling system.

  • Specific heat capacity: Approximately 3.5 kJ/kg·K (0.83 Btu/lb·°F). This value is lower than that of pure water, meaning the mixture can absorb less heat per unit mass, but it still provides sufficient heat transfer capabilities for most cooling applications.

  • Density: Approximately 1060 kg/m³ (66.2 lb/ft³) at 20°C (68°F). The density is higher than that of pure water, which can slightly affect the flow characteristics and pumping requirements in a cooling system.

  • Viscosity: Around 4.2 cP (0.0042 Pa·s) at 20°C (68°F). The viscosity of the mixture is higher than that of pure water, potentially affecting flow rates and pressure drops in the cooling system.

  • Thermal conductivity: Approximately 0.41 W/m·K (0.237 Btu/hr·ft·°F). This value is lower than that of pure water, leading to a slightly reduced rate of heat transfer in the cooling system.

  1. Properties of air:
  • Density: Approximately 1.225 kg/m³ (0.0765 lb/ft³) at sea level and 20°C (68°F).

  • Specific heat capacity: Approximately 1.006 kJ/kg·K (0.240 Btu/lb·°F) at constant pressure for dry air.

  • Viscosity: Approximately 1.81 x 10?? Pa·s (1.81 x 10?? N·s/m²) at 20°C (68°F) for dry air.

  • Thermal conductivity: Approximately 0.0257 W/m·K (0.0149 Btu/hr·ft·°F) at 20°C (68°F) for dry air.

These properties of the 50-50 ethylene glycol-water mixture and air are important for designing and analyzing various thermal and fluid systems, such as cooling systems, heat exchangers, and HVAC equipment. Note that the properties may vary depending on the temperature, pressure, and other factors, so always refer to manufacturer data or reliable sources for accurate information.

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12 Sep 2010
Last Modified
25 Apr 2023
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File Author:
Ivan Stewart

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fdf 3 years ago