| Sumario: | This research is centered on thermoeconomic assessment of the joint production of electricity, fresh-water, cooling and process heat for solar polygeneration plants, to create scientific knowledge basis for the development of concentrated solar power (CSP) technologies in zones with high direct irradiation conditions, and the rational and optimal use of polygeneration schemes to increase the overall system energy conversion efficiency and minimize the costs of the final products. The main objective of this dissertation is to model, evaluate, and optimize solar polygeneration plants in thermoeconomic terms, configured by a CSP parabolic trough collector field, thermal energy storage and backup system, a multi-effect distillation (MED) module, a single-effect absorption refrigeration (REF) module, and a process heat (PH) module, whose prime mover is the CSP plant, and considering that the polygeneration plants are located in an area with high solar irradiation conditions, and large demands of energy and water. The solar polygeneration plants are simulated in a transient regime, in a representative location with high irradiation conditions, such as in northern Chile. In the development of this dissertation IPSEpro, Microsoft Excel, MATLAB, EES (Engineering Equation Solver), and the ExIO module as a complement of the Microsoft Excel software were used. In order to expand thermoeconomic analysis in the assessment of solar polygeneration schemes, the methodology includes the use of two thermoeconomic methods. The first method, based on the exergy costing method, was used to assess the actual cost of each product; to conduct a sensitivity analysis of investment, fuel cost and demand, and to evaluate the effects of solar field size and the sizing of thermal energy storage. Three configurations are investigated: two polygeneration schemes and one considering stand-alone systems. Furthermore, this method was compared with the levelized cost method in terms of the costs allocation and the unit specific cost of each product. Whereas the second method, based on the symbolic exergoeconomic method, was used to analyze in depth the process of exergy cost formation, compare with stand-alone systems, and establish the best configuration in cogeneration, trigeneration and polygeneration schemes, in which twenty-one configurations are investigated: eight of cogeneration, eight of trigeneration, four polygeneration schemes, and one considering stand-alone systems. This dissertation was developed through three journal papers. This study reveals that a solar polygeneration plant is more efficient and cost-effective than stand-alone systems for a zone with high irradiation conditions and proximity to consumption centers, such as mining industries, which require continuous operation and energy supply with fundamentally constant demand. Furthermore, according to northern Chilean market, solar polygeneration configurations are competitive regarding electricity, fresh-water, cooling and heat productions. Additionally, solar polygeneration plants might increase the economic profit by selling carbon credits and credits of renewable-energy quotas based on the Kyoto Protocol and Chilean legislation, respectively. Also reveals that the thermoeconomic method is an equitable and rational cost allocation method which is suitable for applying in a solar polygeneration plant. Another result is that this method is recommended when a more precise analysis it is necessary to assess the proper costs of different products, and for assessing the benefits of a polygeneration plant, when compared to stand-alone systems. On the other hand, the levelized cost method is a simple and fast method, and a deep knowledge of thermodynamics is not required, being recommended when it is necessary to perform a first approached of the costs of each product. Another important result is that the key equipment, in which the design should be improved in solar multi-generation plants, are: solar collector, productive subsystems (MED, REF, and PH plants), evaporator, and reheater. Also, the recommended configurations for the integrated solar multi-generation plants (cogeneration, trigeneration, and polygeneration) are those, in which the MED plant replaces the condenser of the power cycle, and the refrigeration plant, as well as the process heat module are coupled to turbine extractions. Those plants were the most cost-effective configuration. The results delivered provide useful information that could serve to decision-makers to point out the actual potential offered by solar polygeneration systems, and could constitute a guide to understand these methods.
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