This example shows how a simple steady states simulation for a steam circuit of a truck – using ethanol as working fluid – can be set up. It consists of the steam circuit itself (closed circuit), an exhaust gas circuit (as source of the heat) and an open water/glycol circuit which acts as heat sink (condenser).
The rankine circuit is – similar to the A/C circuit – a thermodynamic cycle. The principle works like this:
In a first step the feed pump provides the working fluid for the expansion device, whereby the steam valve is used for controlling this system. It can either set the exit temperature at the evaporator or a defined mass flow. In a next step the evaporator transfers the energy from the hot exhaust gas to the fluid and changes the medium’s state from liquid to gaseous. This energy is converted in the expansion device (if not bypassed) to mechanical power and cooled down in the condenser (to guarantee a liquid state for the feed pump).