A novel cooling and power cycle based on the absorption power cycle and booster-assisted ejector refrigeration cycle driven by a low-grade heat source: Energy, exergy and exergoeconomic analysis

Abstract

Nowadays, different renewable sources and energy systems are attracting world attention due to the significant concerns about excessive emissions and the global energy crisis. To achieve both power and cooling supply for users, a new combined cooling and power system is proposed to utilizing low-grade heat sources, such as industrial waste heat, solar energy, and geothermal energy. In this paper, to enhance the efficiency of the traditional power and cooling combined system, a novel system based on the absorption power cycle (APC) and booster-assisted ejector refrigeration system is designed. In the proposed combined power and ejector refrigeration (CPER) cycle, a booster compressor is devised between the ejector and evaporator to enhance the output cooling. The system operates using the low-grade heat source (LGHS). The thermodynamic and thermoeconomics models are developed to analyze the proposed combined power and cooling system, after which, considering the mathematical analysis, the parametric investigation is employed to evaluate the impact of the design parameters on the main performance criteria. The results showed that the proposed system assisted with booster compressor has higher energy efficiency than the traditional APC cycle. The modeling results revealed that the proposed system could provide a cooling capacity of 23.89kW and the net output power of 18.52kW by receiving 195.5kW energy from the low-grade heat source. Also, the first-law efficiency, second-law efficiency, and the total SUCP (Sum unit cost of the product) of the proposed plant are obtained by 21.7%, 52.22%, and 93.52$/GJ, respectively. From the exergy analysis, it can be inferred that the maximum rate of exergy destruction among all the constitutes of the system belongs to the ejector which constitutes around 27.05% of the overall exergy destruction of system. Besides, the vapor generator 2 is responsible for the 24.31% of total exergy destruction rate. And, the highest cost of exergy destruction corresponds to the condenser followed by ejector. The parametric analysis revealed some valuable results such as a drop in the total SUCP by decreasing vapor generator 1 hot PPTD (Pinch point temperature difference), final absorption temperature, turbine inlet pressure, and LiBr mass fraction. The cooling output capacity is increasing by the increment of vapor generator 1 hot PPTD, turbine inlet pressure, and LiBr mass fraction.