How to calculate COP?

In reference to the standard heat engine, Coefficient of Performance is given by

\begin{array}{l} K = \frac{Q_{c}}{W_{i n}} \end{array}

Where,

k = Coefficient of Performance

Q_c = Heat dispelled from the system

W_in = Work input to the system

If no work was input to the system (W_in= 0) the Coefficient of Performance would equal infinity.

Hence,

\begin{array}{l} K < \infty \end{array}