Multi-aspect evaluation of a novel geothermal-driven trigeneration system for cooling, heat, and power generation

Abstract

This paper presents a novel trigeneration process that utilizes geothermal fluid and a gas turbine to generate electricity, heat, and cooling. The trigeneration system comprises a gas turbine cycle, dual flash geothermal-organic Rankine cycle, cooling production unit, and heat and power generation unit. A comprehensive parametric study is conducted from energy, exergy, economic, and environmental perspectives to evaluate the proposed process. Thermodynamic analysis shows that the energy and exergy efficiencies of the system are 46% and 47%, respectively. The total exergy destruction of the process is calculated to be 147,006 kW, with the gas turbine cycle and combustor contributing the highest and second-highest exergy destruction ratios at 66% and 45%, respectively. Environmental analysis reveals that the indirect emission of the proposed structure is zero, and the total carbon dioxide emission is related to the flue gas of the gas turbine unit, amounting to 44,010 kgCO2/h. Considering the production capacity of the three products, the carbon dioxide footprint is determined to be 17.44 kgCO2/MJ. Furthermore, the economic analysis indicates that the total annual cost of the proposed scheme is 56,817,774 $. The production costs for cooling, electricity, and heating are 0.3 $/kg(CW,5℃), 0.073 $/kWhe, and 0.174 $/kgST, respectively. This comprehensive evaluation demonstrates the efficiency and feasibility of the trigeneration process, making it a promising option for sustainable power generation with minimal environmental impact.