ALTERNATIVE LOW TEMPERATURE STIRLING ENGINE BASED SOURCE OF ENERGY FOR AUTONOMOUS CONSUMERS
Introduction. The relevance lies in the use of a motor with an external heat supply to convert solar radiation into electrical energy, while the source of thermal energy is a solar collector. Aim. To develop an alternative energy source for remote consumers based on a low-temperature Stirling engine capable of converting low-grade heat of heated water into mechanical energy with subsequent generation of electric current of industrial frequency. In contrast to the classical design of the well-known Stirling engine, the presented DVPT has a significant displacer volume, which exceeds the volume of the working piston by more than 20 times; this allows it to operate at a lower temperature difference between the heater and the cooler. The operating temperature of the heater is 90-100 °C, which is 7-9 times less than the known Stirling engine. Materials and methods. To work out the results of full-scale experiments, computer modeling was used; the dependence graphs for the change in the pressure of the working fluid and its volume when compressed by the working piston are presented. Results. A brief description of the design features of a low-temperature engine with an external heat supply operating according to the Stirling cycle is given, as well as some results of research and computer modeling. Conclusion. The use of air as a working fluid is not justified, since when using it, the mass and size dimensions of the DVPT per unit of power produced are larger than that of internal combustion engines. For a low-temperature DVPT, a prerequisite is the difference in the volumes of the displacer and the working piston; for a heater temperature within 90 °C, the displacer must be 20 to 40 times larger in volume. The efficiency is influenced by the temperature difference between the heater and the cooler and the pressure of the working fluid.