Energetic and exergetic study of a 10RT absorption chiller integrated into a microgeneration system

This paper shows a thermodynamic cogeneration model (single-effect LiBr/H2O absorption chiller coupled to a 30 kW microturbine, a cooling tower and a heat exchanger) and analyzes energetic and exergetic behavior of the system. A computational algorithm was developed on the EES-32 platform to evaluate the influence of the main operating parameters of the cogeneration system. The effect of parameters such as hot water temperature, the microturbine load, the ambient temperature, etc. on the cooling capacity and the COP (Coefficient of Performance) of the chiller are analyzed. The balance equations are based on the principles of conservation of energy, mass and species. The total exergy of the working fluids was calculated taking into account the physical and chemical characteristics. In the cogeneration system, the greatest irreversibility was found in the microturbine with 52.88 kW and the least in the absorption chiller with 1.78 kW. The analysis was performed by varying the load of microturbine and its influence on the COP and the cooling capacity. The COP values are based on the first and second law of thermodynamics. Due to the load variation of the microturbine, and its influence on inlet and outlet temperatures of the water, the COP values were obtained 0.74 and 0.24, respectively. Finally the overall energy and exergy efficiencies of cogeneration was determined, these values were about 50% and 26%, respectively.