An Assessment of Solar Driven Combined Cooling, Heating, and Electric Power Generation System: Using Energy, Exergy, and CO2 Mitigation Approach

Abstract

Background: Concentrated solar power (CSP) technology has been gaining more and more attention due to its inherent sustainable merit. Further promotion of sustainability requires the effective utilization of concentrated solar thermal radiations which can achieve through combined cooling, heat and power. In this context, the key objective of the research carried out in the present study was to propose and develop a novel solar thermal-driven combined cooling, heating, and power system for producing power of 7MW. Objective: The objective of the study is to reduce heat loss at various places and to increase the overall energy and exergy efficienices of the system. The effect of very influencing parameters like direct normal irradiance (DNI), extraction pressure, turbine back pressure, turbine inlet pressure, and pump inlet temperature were ascertained on energy and exergy efficiencies for the trigeneration system. In addition, the model was extended to incorporate the evaluation to identify the causes and locations of thermodynamic imperfections. The energy and exergy efficiency and destruction were also evaluated. Methods: For this study, a solar-driven combined cooling, heating, and electric power generation system is called the trigeneration system was designed by coupling a solar-based heliostat and centralized solar receiver with a conventional Rankine-based cycle. The conventional Rankine cycle comprises a basic heat recovery generator, a steam turbine, a condenser, and eventually a pump. A thermodynamic model was developed which presented the analysis of various thermodynamic-based parameters of the integrated system comprising a solar-driven absorption refrigeration cycle. The analysis is formulated based on a cascaded system that grabs the energy and exergy-based methods in which the mass, energy, and exergy are balanced. Results: The system was run for the solar radiation range from 600 to 1000W/m2. It is found that the overall efficiency of the trigeneration system increases by 32 to 35% when DNI changed from 600 to 1000W/m2. The inlet temperature of the pump also increases from 90 to 110℃ and it can increase the overall efficiency by 2.73%. A considerable increment is observed of energy by 4000kW to 6800kW when the DNI increases from 600W/m2 to 1000W/m2. The energy destruction is also observed during the process followed at the Turbine, heat recovery steam generators (HRSG), and in the components of vapour absorption refrigeration. The exergy destruction is also identified at the central receiver of about 33%, and the next 25% in heliostat. The annual CO2 mitigated is estimated by 1437.16MMT/year for the year 2022 in India by the application of CSP plants. Conclusion: The result reveals tar the central receiver and heliostat of the solar field endanger the higher thermodynamics irreversibility of about 33% and 25% respectively. The trigeneration process can be utilized the low temperature for other applications, that is why the overall cycle efficiency will be increased. The trigeneration cycle with HRSG is the future technology and due to this cycle, CO2 can also being reduced.