Microturbine for Micro-Cogeneration Application

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Murray, Paul
Cogeneration , Microturbine
A micro-cogeneration system based on an ArtesJet KJ-66 hobby microturbine may be able to provide a single family dwelling with required heat and power, increasing total efficiency due to utilization of waste heat. The feasibility of such a system was investigated. An engine model based on the similar JG-100 engine was developed, written in Microsoft Excel™ and Visual Basic™. The predicted running characteristics of the KJ-66 were simulated, and a prediction of how these characteristics would be shifted if a diffuser was attached to the engine was made. An experimental test program was carried out on the KJ-66 engine to determine if this prediction was correct, and to more accurately characterize the performance of the engine. Two diffusers were constructed to use with the testing, along with the nozzle that was supplied with the engine. Having the diffusers on the engine reduced the fuel air ratio by approximately 20% as predicted. A hypothetical micro-cogeneration system was simulated building on the earlier engine model, with modified turbomachinery maps and combustor performance based on the experimental data. An 85% effective recuperator was included in the model, as well as a recovery heat exchanger. The simulation showed an electrical output of 8.9 kW, a heat output of 30.9 kW, an electrical efficiency of 15.5%, and a total efficiency of 69.0%. While these efficiencies are low, improvements could be made by modifying the turbomachinery and by using a condensing recovery heat exchanger to give a better overall efficiency for the micro-cogeneration system.
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