Development and testing of a multi-fuel micro-CHP conversion kit

This paper describes the development of a kit for converting a spark-ignition engine installed on small-size generators in order to allow their functioning with multiple fuels, with particular reference to low-boiling-point fuels. The kit can be easily added to technological systems which have been on the market for a long time. In addition, depending on the local conditions of use, operation in cogeneration is also possible, which increases the total efficiency of such generators. The solution developed is technically simple, robust, reliable and versatile, since it can be fed with different fuels, and it can be used both for grid-connected and off-grid applications, with particular reference to the developing Countries. The results of the first phase of technical development of the system and the experimental tests carried out with LPG and bioethanol are hereby presented. They attest the feasibility of using the conversion kit in a commercial power unit and they demonstrate that the actual performances are broadly consistent with the calculated results. The overall efficiency (electric and thermal) of the prototype system reaches a value close to 40% in conditions of rated load, almost doubling the generation efficiency of the system before its conversion. Any further developments of the research will be dedicated to better investigate also the environmental and economic aspects of the kit in different operating contexts, as well as to test other suitable fuels.