Thermodynamic, Environmental and Economic Simulation of an Organic Rankine Cycle (ORC) for Waste Heat Recovery: Terceira Island Case Study

The aim of this study is to analyse from the thermodynamic, environmental and economic point of view an ORC for heat recovery from urban waste, using R245fa as a working fluid on the example of Terceira Island (Azores). The proposed ORC system includes two evaporators, two turbines, a condenser, a pump and a generator. The thermodynamic model is created using the Visual Basic programming language. In order to analyse the influence of pressure, temperature and mass flow on net output, efficiency, and mass flow rate of the power plant, the sensibility analysis is carried out. The results show that from the energetic point of view, urban waste recovery (using an ORC) could be a viable solution on Terceira Island, since the maximum net output produced from this system for a mass rate of 19 727 tonnes is 485 kW. The efficiency of the ORC is 25 %. Environmentally, the incineration of the urban waste produced on the island is a positive solution for these residues since it will reduce the amount of waste deposited in the landfill. However, this project is not economically viable. The losses estimated in this study exceed 500 000 EUR (per year).