Design and experimental testing of a low-cost high-efficiency micro cogeneration unit for distributed energy conversion

The paper discusses the design and global performance of a cogeneration unit suitable for distributed energy conversion based on an automotive internal combustion engine, which is a spark ignition methane fuelled unit, previously converted from a Diesel engine and chosen on the market as an efficient, low cost energy powerplant, to be adopted for different applications (such as domestic and commercial). It is explained the philosophy that led to the adoption of such a type of engine in order to produce the electric power, together with all the most important characteristics of this spark ignited gas fuelled stoichiometric unit. Significant elements and solutions are discussed, in order to give the system a long endurance (i.e. a life of 30.000 hours), high efficiency, low gaseous emissions and reduce running cost deriving from maintenance. The unit has been coupled with a specifically designed liquid cooled induction generator and then tested as an electricity and heat production system; the test results of its running behavior are reported in the paper.