Heating System Efficiency ($\xi_{hs}$):

$$\xi_{hs} = \left( \frac{Qsd}{Qaf} \right) \times 100$$

Where:

• $\xi_{hs}$ is the heating system efficiency, in percentage (%).
• $Qsd$ is the heat supplied to the dryer, in kilojoules per hour (KJ/hr).
• $Qaf$ is the heat available in the fuel, in kilojoules per hour (KJ/hr).