Constant Boiling Refrigerants

Overview

Engineering reference data for Constant Boiling Refrigerants 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

Common Refrigerants

The following table lists the refrigerants referenced in this content.

Pressure-Temperature Relationship

The fundamental relationship governing a refrigerant's boiling point is described by its vapor pressure curve. A simplified form derived from the Clausius-Clapeyron equation is often used:

$$\ln\left(\frac{P}{P_0}\right) = -\frac{\Delta H_{vap}}{R} \left(\frac{1}{T} - \frac{1}{T_0}\right)$$

Where:

• $P$ is the pressure at temperature $T$.
• $P_0$ is a reference pressure at reference temperature $T_0$ (e.g., 101.325 kPa at $T_0 = 273.15$ K).
• $\Delta H_{vap}$ is the enthalpy of vaporization.
• $R$ is the universal gas constant (8.314 J/mol·K).

This equation shows that for a given refrigerant, the boiling temperature $T$ is a direct function of the applied pressure $P$.

References

• Original Source