Factors Influencing the Thermodynamic Efficiency of Stirling Engines

Abstract

This meta-study examines the factors which contribute to Stirling engine efficiency. Working fluids should have high specific heat capacity, low viscosity and low density making noble gases the most suitable. Each different working fluid has its own optimum power output at varying pressures and temperatures. The best being Helium at 4.14 MPa and 922K. Dead volume also affects the power output of Stirling engines. Theoretical engines with zero dead volume are ideal but dead volume can occupy over 50% of the engine. Engine configuration also impacts on the efficiency of a Stirling engine. The layout of pistons and cylinders about each other can also have drastic effects on these efficiencies. Currently the most effective engine layout is the ‘gamma’ configuration, which measures 30%-32% efficient. Future research is required to produce a more efficient Stirling engines, based on the factors considered above to determine the viability of these engines as a replacement for coal and fossil fuel powered combustion engines.

A Simplified Analytical Model of Stirling Engine Efficiency Calculation. A Theoretical Analysis of Working Gas

“…The energetic and efficiency of Stirling engines characterization of the ideal Stirling engine cycle is based on the first and second principle of thermodynamics that establishes the connection between the mechanical work performed, the amount of heat and the variation of the internal energy of the working gas [Allan J. Organ, 2010;G. Giannakakis et al, 2017;G.…”

“…It is worth mentioning that the cycle of isothermal or adiabatic models have a quasi-elliptical shape and are closed in the ideal cycle of the Stirling engine [Allan J. Organ, 2010;G. Giannakakis et al, 2017].…”

“…The Stirling engine is a mechanical assembly consisting of seven distinct compartments, as follows: swept and clearance in compression and expansion, regenerator, cooler and heater, respectively [Allan J. Organ, 2010;G. Giannakakis et al, 2017].…”

Numerical investigation of alpha Stirling engine performance based on ideal and actual adiabatic analysis

“…Any appropriate driving mechanism moves the gas inside the enclosed space that separates the chamber's heated and cooled sections. [2]. The Stirling engine may be built in one of three distinct designs are alpha, beta, and gamma (figure 1), each type has the similar components and principal work with different mechanical arrangement design.…”