Transformation of Heat Energy into Mechanical Work at Low Environmental Pollution
The most frequently used heat engines for transformation of heat into useful mechanical work are internal and external combustion engines. These engines work with high combustion temperatures and large temperature differences are necessary to achieve high efficiency. Harmful byproducts result from the combustion processes. In order to solve the environmental problem during the transformation of heat into mechanical work, new alternative fuels, alternative drives and new technologies are being investigated. This paper hypothesizes that it is possible to transform heat into work at low temperatures and at low temperature differences with less environmental pollution. First, the Stirling and internal combustion engines are compared in view of efficiency, mechanical and heat load, engine start and its adaptability to various working regimes, used fuel, material of engine components, and economy and ecology characteristics. To verify the advantages of the Stirling engine, a small unique model of a working Stirling engine was developed and a thermodynamic analysis of this model performed. The thermal efficiency of this engine, running at maximal temperature of the working fluid of and maximal temperature difference of , is 7.4 %. Such an engine can be driven by the heat of the sun, exhaust gasses, and similar sources. In this manner a Stirling engine can use the energy, which would otherwise be lost.