A heat engine for use in conjunction with a power generating plant, including a turbine section having a number of turbines, a heat exchanger section having a number of modules through which the expanded working fluid of the power generating plant and other sources of heat are circulated, a laminar flow inducing section, and a tower section for providing a pressure differential across the turbines of the turbine section. In use, the heat engine provides the dual function of: heating air to generate an updraft such that air forces its way into the turbine sections to drive the turbines and generate additional electricity; and using incoming colder air to condense the expanded working fluid and cool other sources of heat.