Distributed heat and power generation: thermoeconomic analysis of Biomass-fired Rankine cycle systems with molten salts as heat transfer fluid

Title: Distributed heat and power generation: thermoeconomic analysis of Biomass-fired Rankine cycle systems with molten salts as heat transfer fluid
Authors: Pantaleo, AM
Camporeale, S
Sorrentino, A
Braccio, G
Markides, C
Item Type: Conference Paper
Abstract: 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.
Issue Date: 17-Jun-2018
Date of Acceptance: 12-Jun-2018
URI: http://hdl.handle.net/10044/1/62192
Publisher: ECOS
Journal / Book Title: Proceedings of ECOS 2018
Copyright Statement: © 2018 The Author(s)
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Funder's Grant Number: EP/P004709/1
Conference Name: The 31st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems
Publication Status: Published
Start Date: 2018-06-17
Finish Date: 2018-06-22
Conference Place: Guimarães, Portugal
Appears in Collections:Faculty of Engineering
Chemical Engineering

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