Stirling Engine: Converting Heat into Mechanical Work

Introduction:

The Stirling engine has huge potential to be applied for converting heat into the mechanical work among a high thermal efficiency. Its thermal efficiency might be as high as the Carnot efficiency. The Stirling engine is an external combustion engine and it can be powered by various heat sources and waste heat. It is a simple type of external-combustion engine so it can be uses a compressible fluid as a working fluid. The thermal limit for the operation of a Stirling engine depends on the material used for its construction (Minassians & Sanders 2011).

The simplified schematic diagram of the engine representing the heat exchanger and the pistons configuration of the system is as shown in figure 1 (Minassians & Sanders 2011). The gas circuit of the displacer subsystem is closed by means of tubing in order to provide a closed engine chamber. Both the displacer and the power piston have equal dimensions. In single-phase operation, the power piston interacts

Two pistons, called the hot and cold pistons are used on the side of the cooler, regenerator and heater. These pistons move uniformly in the similar direction to provide constant-volume heating or cooling processes of the working fluid. When the entire working fluid has been transferred into one cylinder, one piston is fixed and the other piston moves to expand or compress the working fluid. The compression work is done by the cold piston and the expansion work is done by the hot piston. In the beta-configuration, a displacer and a power piston contained within the same cylinder. The cylinder moves working fluid between the cold space and the hot space of the displacer through the heater, regenerator, and cooler. The power piston placed at the cold space of the cylinder, expands the working fluid when the working fluid is in the hot space and compresses the working fluid when the working fluid is moved into the cold