In a cyclical process, such as a heat engine, the net work done by the system equals the net heat transfer into the system, or W=Q_{\mathrm{h}}-Q_{\mathrm{c}}, where Q_{\mathrm{h}} is the heat...In a cyclical process, such as a heat engine, the net work done by the system equals the net heat transfer into the system, or W=Q_{\mathrm{h}}-Q_{\mathrm{c}}, where Q_{\mathrm{h}} is the heat transfer from the hot object (hot reservoir), and Q_{c} is the heat transfer into the cold object (cold reservoir).
