Thermodynamic analysis of a combined cooling and power system driven by waste exhaust heat from industrial boilers in the energy and climatic context of the city of Douala, Cameroon

The present work studies the recovery and conversion of waste heat from industrial boiler flue gases into cooling and electricity in the energy and climatic context of the city of Douala, Cameroon. To achieve this, a computer program was developed and implemented in Engineering Equation Solver (EES) software to model and simulate the performance of seven working fluids with low global warming potential (GWP) and ozone depletion potential (ODP). The aim was to identify the most suitable fluid(s) for a combined system based on an organic Rankine cycle (ORC) cascaded with a vapor compression cycle (VCC). The influence of three key parameters (flue gas temperature, flue gas mass flow rate, and ambient temperature) on the system's energy and exergy performance was analyzed. The results of the simulations, carried out under baseline conditions and as part of a parametric analysis, show that if requirements are mainly geared towards cold production, the R717 fluid performs best, with a maximum cooling capacity of 276.3 kW. On the other hand, if electricity production is the main requirement, R1233zd(E) is the most efficient fluid, with a maximum electrical output of 102.6 kW.