Analysis and Assessment of A Biomass Energy-Based Multigeneration System with Thermoelectric Generators

This study demonstrates comparative energy and exergy analyses of an advanced biomass energy-based integrated multigeneration system with two innovative embodiments of thermoelectric generators. These two systems uniquely integrate the configurations of thermoelectric generators for better performance. System 1 incorporates an integration of the thermoelectric generators at the exhaust of the gas turbine. In system 2, thermoelectric generators are considered at the inlet of organic Rankine cycle 1. The heat rejected at the low temperature interface of the thermoelectric devices generates the electricity through organic Rankine turbine 2. Some of the electricity produced by thermoelectric generators is used to operate an electrolyzer to produce hydrogen. The utilization of thermoelectric device developed in system 2 increases the energetic and exergetic efficiencies of the overall multigeneration system and organic Rankine cycle 1. Also, the net amount of work output by organic Rankine cycle 1 of system 2 is improved greatly. Furthermore, the design configurations of the thermal system and the influence of operating conditions on the energy and exergy efficiencies of the multigeneration system and organic Rankine cycle are investigated for comparative assessments. The present results show that an increase in combustion temperature improves the work rate by turbines and thermoelectric generators appreciably. In addition to this, the overall energetic and exergetic efficiencies of system 1 are found to be 73.4% and 33.3%, respectively, whereas for system 2 these efficiencies are enhanced in the order 74.5% and 34.02%, respectively. The net amount of work output by organic Rankine cycle 1 in embodiment 2 is improved from 8023 kW to 8908 kW. The highest amount of exergy destruction (accounting for 91.5%) occurs in the gas turbine of system 1 followed by organic Rankine cycle 1 (accounting for 6.64%) of system 2. The proposed system has superior and unique features as compared to conventional systems with thermoelectric generation.