Distributed cogeneration systems can be used to serve onsite energy demands in industrial and commercial
buildings. In market segments with highly variable heat-demand patterns, the thermal plant is often composed
of a boiler that is operated at part load in case of low thermal demands. To improve the plant flexibility and its
overall energy efficiency, the biomass boiler can be coupled to a combined heat and power (CHP) generation
system, as an alternative to a heat-only plant. In this work, three thermodynamic configurations are compared:
(A) a biomass furnace that acts as a heat-source for a steam Rankine cycle (ST) plant coupled to an organic
Rankine cycle (ORC) engine; (B) the same as Case A but without the bottoming ORC; and (C): the same as
Case A but without the steam cycle. All configurations assume the cogeneration of heat and power to match
onsite energy demands. The plant adopts a molten salt (MS) circuit to transfer heat from the biomass furnace
to the power generation system. The energy analysis assumes a ternary MS mixture operating up to 450 °C
and with minimum temperature of 200 °C. Two organic fluids (Pentafluoropropane R245fa and Toluene) are
considered, based on the temperature of heat available to the ORC engine. In the combined cycle of Case A,
R245fa is selected and the maximum cycle temperature is 130 °C, with a global electrical efficiency of 16.6%.
In Case C, when only the ORC system is used with Toluene as the working fluid, the electrical efficiency is
18.8% at the higher turbine inlet temperature of 330 °C. Production of hot water for cogeneration at different
temperature levels is also considered. Based on the results of the thermodynamic simulations, upfront and
operational costs assessments, and feed-in tariffs for renewable electricity, energy efficiency and investment
profitability are estimated.