External combustion engines

Isomeric dichlorotetra uoroben2enes have been studied for Rankine-cycle external combustion engines (225). 

An external combustion engine that has been widely supported as a low-emission power source is the Rankine cycle steam engine. Many different types of expanders can be used to convert the energy in the working fluid... 

The driver is a prime mover capable of developing the required torque at a constant speed or over a range of speeds. The driver s energy source can be either electrical or mechanical. Electrical energy is used by motors, either of the induction or synchronous type, while the mechanical covers a multitude of sources. It may be a fuel, as in internal or external combustion engines, or it may be a gas, such as steam or process gas used in a turbine or expander. 

The Stirling cycle engine is an external combustion engine. Figure 3.26 shows the Stirling cycle on p-v and T-s diagrams. 

The first widely used industrial steam engine, the Watt Steam Engine, invented in 1765, used evaporation and condensation to efficiently create energy. Fire was used to boil water in an enclosed space to produce steam. The Watt Steam Engine was an external combustion engine because of the external source of fuel. In this case, the fire burned outside of the engine itself. 

A gas turbine is an external combustion engine, which means that mechanical power is generated in two steps, with heat as an intermediate. Heat is produced from the chemical energy in the fuel in the combustion chamber. The conversion of heat into mechanical energy is then achieved in the turbine. A schematic view of a simple open-cycle gas turbine unit is given in Fig. 2 [e.g., 25,26]. 

External Combustion Engine - An engine in which fuel is burned (or heat is applied) to the outside of a cylinder a Stirling engine. 

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