Specific Heat Capacity Ethanol Cp CV Isobaric Isochoric Ethyl Alcohol

Overview

Engineering reference data for Specific Heat Capacity Ethanol Cp CV Isobaric Isochoric Ethyl Alcohol in thermodynamics.

Key Formulas

First Law

$\Delta U = Q - W$

Energy is conserved — heat added minus work done.

Ideal Gas Law

$PV = nRT$

Relates pressure, volume, and temperature of an ideal gas.

Heat Transfer

$Q = mc\Delta T$

Sensible heat transfer.

Carnot Efficiency

$\eta = 1 - T_C/T_H$

Maximum efficiency between two temperatures.

Variables

Temperature-Dependent Specific Heat Data

The specific heat capacity of ethanol varies significantly with temperature and pressure. For accurate engineering calculations in heating or cooling systems, this data should be used.

Key Insights for Engineering Calculations

1. Temperature Dependence: For liquid ethanol, Cp increases from approximately 2.03 kJ/kg·K at -23°C to 3.91 kJ/kg·K at 151°C (at saturation pressure). This variation is significant and must be accounted for in precise heat transfer calculations.
2. Pressure Dependence: For practical purposes in liquid-phase processing below the critical point (241°C, 61.5 bara), specific heat is relatively constant with pressure.
3. Phase Change: The specific heat values change drastically between liquid and gaseous ethanol at the same temperature (e.g., at 25°C and ~0.08 bara).
4. Cp/Cv Ratio: The ratio increases with temperature for both liquid and gas phases, indicating changing thermodynamic behavior.

Unit Conversions for Specific Heat Capacity

The following conversions are essential for working with international engineering data:

• 1 kJ/kg·K = 0.23885 Btu/lb·°F = 0.23885 kcal/kg·°C = 2.7778×10⁻⁴ kWh/kg·K
• 1 Btu/lb·°F = 1 kcal/kg·°C = 4.1868 kJ/kg·K
• 1 kcal/lb·°F = 1.2248 Btu/lb·°F = 5.1279 kJ/kg·K
• 1 J/kg·K = 2.3885×10⁻⁴ kcal/kg·°C = 2.3885×10⁻⁴ Btu/lb·°F

Interactive Charts

References

• Original Source