Multi-criteria evaluation of a novel micro-trigeneration cycle based on α-type Stirling engine, organic Rankine cycle, and adsorption chiller

Abstract

In the present paper, the multi-criteria evaluation of a novel trigeneration cycle consisting of a Stirling engine, organic Rankine cycle, and an adsorption chiller has been investigated for domestic usage. The proposed cycle is evaluated from thermodynamic, environmental, and economic perspectives. Thermodynamic criteria include fuel energy saving ratio (FESR), exergy efficiency, the thermal efficiency of the Stirling engine, and the overall efficiency of the trigeneration system. Economic criteria consist of net present value (NPV), payback period (PB), present value percentage (PVP). Furthermore, CO2, CO, and NOx reduction ratios are approximated. A sensitivity analysis is conducted for determining the most critical criteria of the cycle and an optimization method is implemented to find the suitable size of the engine. The results reveal that the optimum size of the Stirling engine is 3.3 kW. Utilizing an engine with the aforementioned size will result in the overall efficiency of the system, FESR, and exergy efficiency becoming 76.5%, 42.13%, and 52.27%. Significant pollutants reduction was observed for the optimum prime mover size in which CO2, CO, and NOx were reduced by 28.87%, 64.9%, and 99.25%. Additionally, the economic analysis showed that the NVP and PB are 40,733 $ and 0.88 years.