Comparative sensitivity analysis of micro-scale gas turbine and supercritical CO2 systems with bottoming organic Rankine cycles fed by the biomass gasification for decentralized trigeneration

In this article, the performance of a micro gas turbine (mGT) and a supercritical CO2 (sCO2) system fuelled by a biomass gasifier and with similar nominal net power output is compared. Both plants include a bottoming organic Rankine cycle system to maximise the electrical power output. Using a component-oriented, off-design modelling approach a sensitivity analysis is performed by varying the main operating parameters. In addition, the integrated systems are also evaluated in combination with a network of residential apartments to assess their adaptability to variable users' thermal and electrical demands.

Results have shown that at full load and ambient temperature of 15 °C, the average net electric power of the whole integrated sCO2 system is around 126 kWe which is approximately 25% higher than the one of the mGT system, but with a lower net electric efficiency resulting in 75% higher biomass consumption. Nonetheless, the net thermal power production of the integrated sCO2 system is almost 355 kWt which is 4.35 times higher than the mGT system resulting in higher overall efficiency. When combined with residential apartments, the sCO2 system proves to be suitable for 140 apartments operating with higher overall efficiency compared to the mGT system coupled with 30 apartments.