Exergoeconomic evaluation of small scale CHP systems

Abstract

Exergy and exergoeconomic analysis of small scale CHP systems: micro gas turbine (GT) and micro Organic Rankine Cycle (ORC) CHP system has been conducted. Thermodynamic cycles have been simulated using a modelling tool Cycle-Tempo. Specific Exergy Costing (SPECO) exergoeconomic method has been applied and exergy costs of the products: electricity and heat have been calculated. Performance of micro GT CHP system is better than micro ORC CHP system as electricity exergy cost is lower. Large exergy costs of heat and electricity generated in the ORC CHP system have been found due to the large exergy destruction rate in the boiler. Using another energy source, such as waste low grade heat from industrial processes, for the ORC system may reduce exergy cost of generated electricity and heat and improve exergy efficiency of the system.