Editing Stirling engine (section)

=== Heat sink ===
The larger the temperature difference between the hot and cold sections of a Stirling engine, the greater the engine's efficiency. The heat sink is typically the environment the engine operates in, at ambient temperature. In the case of medium- to high-power engines, a [[radiator]] is required to transfer the heat from the engine to the ambient air. Marine engines have the advantage of using cool ambient sea, lake, or river water, which is typically cooler than ambient air. In the case of combined heat and power systems, the engine's cooling water is used directly or indirectly for heating purposes, raising efficiency.{{citation needed|date=July 2020}}

Alternatively, heat may be supplied at ambient temperature and the heat sink maintained at a lower temperature by such means as [[cryogen|cryogenic fluid]] (see [[Liquid nitrogen economy]]) or iced water.{{citation needed|date=July 2020}}