Experimental research and application possibilities of microcogeneration system with Stirling engine

摘要

In the first part of this paper there has been the thermodynamic analysis presented, for the microcogeneration system with the Stirling engine, for the working gases most frequently used, among other gases: helium, nitrogen, and air. The methods of performance regulation for the Stirling engine were depicted, among which the increase of the gas pressure in the working chamber and rising of the temperature of the upper heat source can be rated. The results of the experimental tests have been shown: the influence of the growth of pressure and temperature for the working gases, in this experiment they were: helium, nitrogen, and air. In this paper the focus was also placed on the maximum power flow. The tests were performed at the laboratory test stand with the single–action Stirling engine, alpha type, that is located at the Faculty of Automotive and Construction Machinery Engineering, Warsaw University of Technology, at the Integrated Laboratory of the Mechatronic Systems of Vehicles and Construction Machinery. In the second part of this paper the authors presented the power flow in the hybrid system (Senkey diagram) on the internal combustion engine with the Stirling engine, which is employed as a microcogeneration device of the distributed generation. It enables transforming a high-temperature waste heat into mechanical work and transition of mechanical work into electric energy with the help of an electrical appliance, which in consequence makes it possible selling the generated electrical energy to the mains. While analysing the power flow in the hybrid cogeneration system the attention was paid to low-temperature heat which can be utilised through electrical thermogenerators, among other things. The suggested microgeneration assembly (the Stirling engine and electrical thermogenerators) could be applied to regain the energy from the waste heat produced by the combustion engine during combustion of scrap heap biogas. The influence of used microcogeneration systems on the increase in general efficiency of the combustion engine was also taken into consideration in this work. Moreover, there were the test results presented of combustion gases temperatures in the exhaust system of the combustion engine fuelled by scrap heap biogas, with the full-load condition of the combustion engine. The chosen limitations of the Stirling engine build were also discussed, in the situation where it would cooperate with the combustion engine, with waste gases used as a high-temperature heat source.