Thermodynamic performance assessment of a small size CCHP (combined cooling heating and power) system with numerical models

The aim of the this work has been to evaluate the performance of a small-size CCHP (Combined Cooling Heating and Power) system based on the integration of 20 kW Lombardini diesel engine and a double effect water-LiBr absorption chiller. This integrated system has been designed to produce both hot water, by recovering heat from the engine cooling system, and chilled water, by recovering heat from the engine exhaust gasses (the exhaust gasses are sent to the fired-combustor of the absorption chiller). The analysis has been conducted by using numerical simulations: the engine and the absorption chiller have been modeled by means of 0-1D dimensional and thermochemical models, respectively, and the validation procedure has been performed by using the available operating data. The system performance has been calculated by introducing some performance parameters that have allowed: i) to estimate the efficiency of the primary energy conversion into useful energy EUF (energy utilization factor), ii) to consider the quality difference between cool/heat and work and among heats at different temperatures ExUF (exergy utilization factor); iii) to evaluate the primary energy saving with respect to the separate production of the same energy fluxes TPES (trigeneration primary energy saving). (C) 2013 Elsevier Ltd. All rights reserved.