Energy, exergy and exergoeconomic optimization of a cogeneration system integrated with parabolic trough collector-wind turbine with desalination

Hybrid solar desalination systems driven by parabolic trough and parabolic dish CSP technologies: Technology categorization, thermodynamic performance and economical assessment

When it comes to seawater desalination in the small- to medium-electricity ranges, the organic Rankine cycle (ORC) powered by solar energy stands out as the most energy-efficient technology currently available. Various solar techniques have been developed to capture and absorb solar energy. Among them, the parabolic trough collector (PTC) has gained recognition as a low-cost solar thermal collector with a long operating life. This study investigates the thermodynamic performance and economic parameters of a PTC-powered ORC using Dowtherm A and toluene as working fluids for the solar cycle and ORC cycle, respectively. Thermo-economic multi-objective optimization and decision-making techniques are applied to assess the system’s performance. Four key parameters are analyzed for their impact on exergy efficiency and total hourly cost. Using TOPSIS decision-making, the best solution from the Pareto frontier is identified, featuring an ORC exergy efficiency of 30.39% and a total hourly cost of 39.38 US$/h. The system parameters include a mass flow rate of fresh water at 137.7 m3/h, a total output net power of 577.9 kJ/kg, and a district heating supply of 1074 kJ/kg. The cost analysis reveals that the solar collector represents approximately 68% of the total hourly cost at 26.77 US$/h, followed by the turbine, thermoelectric generator, and reverse osmosis (RO) unit.

Combined solar organic Rankine cycle with reverse osmosis desalination process: Energy, exergy, and cost evaluations

In this study, thermodynamic and environmental assessments of waste heat driven cogeneration systems are carried out. The cogeneration systems include basic and modified configurations of Organic Rankine cycle (ORC), Reverse osmosis (RO) unit and Proton exchange membrane (PEM) electrolyser. The ORCs are aimed at transforming waste heat into power for the operation of a reverse osmosis (RO) unit and a proton exchange membrane (PEM) electrolyser, for generation of fresh water and hydrogen, respectively. The systems were simulated in engineering equation solver (EES). Among the studied configurations and working fluids, the findings demonstrate that the ORC configuration that combines both an internal heat exchanger and a mixing chamber (HMORC) and employing Isopentane as working fluid showed optimal performance, and showcasing energy and exergy efficiencies, and sustainability index values of 19.31%, 24.63%, and 2.033, respectively. Furthermore, this setup achieves maximum flow rates of 5.211 m 3 /h for fresh water and 2.737 kg/h for hydrogen. Moreover, The parametric study indicates that performance of the cogeneration systems improves with rise in evaporator pressure and drop in condenser pressure. The results highlight the promise of optimised system configuration for effective waste heat recovery and sustainable resource use.

Energy and exergy analyses of a hybrid system integrating solar-driven organic Rankine cycle, multi-effect distillation, and reverse osmosis desalination systems

Comparison of Medium-size Concentrating Solar Power Plants based on Parabolic Trough and Linear Fresnel Collectors

Energy, exergy, economic and environmental (4E) evaluation of a solar-integrated energy system at medium–high temperature using CO2 as the parabolic trough collector (PTC) working medium

Concentrating solar power (CSP) plants with parabolic trough collector (PTC) using thermal oil as heat transfer fluid (HTF) and conventional steam Rankine cycle (SRC) as power generating cycle is the most commercially developed technology. Direct steam generating linear Fresnel reflector (LFR) systems are developed as a cheaper alternative to PTC systems. The major drawbacks of LFR systems are low optical efficiency and production of saturated steam. These result in higher solar field area requirement compared to PTC based plants of same capacity. Organic Rankine cycle (ORC) based power block, with dry working fluids, offers higher cycle efficiency as well as improved part-load turbine efficiency compared to SRC in modular scale plants with heat sources up to 400 °C. ORC is more suitable to LFR based CSP plants. In this paper, thermo-economic analysis of PTC and LFR based CSP plants with ORC has been presented. An approximate selection methodology, for LFR and PTC based CSP plants, is proposed and the selection diagram generated using the proposed methodology can be used for LFR and PTC based CSP plants with any working fluid of Rankine cycle. The applicability of the selection diagram is demonstrated using case studies of n-Pentane, Octamethyltrisiloxane (OMTS) and water working fluids based plants. Selection diagram captures the variations of power generating cycle efficiency, and costs of collector fields.

This chapter addresses the description and thermodynamic analysis for the integration of desalination plants into the power cycle described in Chap. 4. The systems chosen for this study combine a Concentrating Solar Power plant using parabolic-trough collector technology for electricity generation with various desalination plants, giving rise to what is known as a parabolic-trough concentrating solar power and desalination (PT-CSP + D) plant. The description of the PT-CSP plant, based on the Andasol-1 (Blanco-Marigorta et al., 2011) commercial plant, is detailed in Chap. 4, showing all the model equations. The desalination technologies selected to combine with the PT-CSP plant were multi-effect distillation (MED) and reverse osmosis (RO), as discussed in Chap. 1. On one hand, the simultaneous production of water and electricity using an RO plant connected to a CSP plant seems the simpler option. On the other hand, the integration of a low-temperature MED (LT-MED) plant is an interesting alternative because it allows replacement of the conventional power-cycle condenser by using exhaust steam as the thermal energy source for the desalination plant. However, to satisfy demand, while providing a certain performance, the LT-MED plant inlet temperature should be around 70 °C (corresponding to 0.031 bar absolute), meaning that the steam does not completely expand through the turbine and therefore the power-cycle efficiency is low compared with a stand-alone electricity-generating plant. This is the reason why another alternative to the MED plant, MED with thermal vapour compression (TVC), is considered. In this case, the steam expands completely in the turbine until it reaches the permitted value for the condenser conditions. However, part of the steam circulating through the turbine is extracted and used as high-pressure steam; this, together with the low-pressure steam coming from one of the MED effects, generates the inlet steam required in the first stage of the desalination plant. Moreover, in this study, a new concept of CSP + MED plants is evaluated (which, until now, has not been studied in published works), a thermally fed LT-MED plant with steam coming from a thermocompressor (LT-MED + TVC). In this case, the low-pressure steam (the entrained vapour) used by the thermocompressor comes from the exhaust steam of a PT-CSP plant instead of one of the MED effects. In each of the systems studied, desalinated water production is evaluated as well as the power and efficiency of the dual thermal solar power and desalinated water cycle.

The paper presents a study of a thermal assessment of an Organic Rankine Cycle (ORC) energized by heat absorbed from a parabolic trough collector (PTC) located in Derna, Libya. Both the ORC and PTC are modeled using the IPSEpro software. The simulation results are used to evaluate the system performance using energy and exergy analysis. The study showed the PTC collector was the main contributor of the energy and exergy losses within the PTC system and the evaporator within in the ORC. At this specific weather conditions, the ORC was able to produce about 3 MW electrical powers from the powered PTC heat. Moreover, exergy efficiency of the PTC was 47.7 %, the heat engine was 23.3 % and for the overall system (PTC and ORC) was 11.1 %.

Thermo-economic comparisons between solar steam Rankine and organic Rankine cycles

A novel solar-geothermal trigeneration system integrating water desalination: Design, dynamic simulation and economic assessment

Several countries are already facing water shortages as a result of increased consumption and climate change over the years. Countries, mainly in the Persian Gulf region, turned to desalination, an energy-intensive process that extracts salt from water. Fortunately, most arid regions that suffer from water scarcity are located in places with high solar irradiance, in other words, they have solar energy potential. Integrating Concentrated Solar Power (CSP) and desalination technologies is a way to simultaneously produce desalinated water and energy. Thus, the objective of this work was to develop a model for thermodynamic analysis, and verification of the feasibility of desalinated water and energy cogeneration systems. A model describing the Multi-Effect Distillation (MED) process together with a Thermal Vapor Compressor (TVC) system was implemented and validated against data from commercial plants available in the literature. The MED desalination model worked in conjunction with a computer program to simulate the performance of CSP parabolic trough systems. In addition, the compatibility between Reverse Osmosis (RO) process and CSP technology was also analyzed. The city of Fortaleza-CE was used as a case study for the feasibility analysis of installing concentrated solar power and desalination technologies. The results of the studies showed that the MED, MED-TVC and RO desalination systems combined with the CSP technology present good performances under the simulated weather conditions, and the CSP+RO option presents a production advantage over the other configurations.

Energy, exergy, and exergoeconomics (3E) analysis and multi-objective optimization of a multi-generation energy system for day and night time power generation - Case study: Dezful city

Exergy and exergoeconomic evaluation of hydrogen and distilled water production via combination of PEM electrolyzer, RO desalination unit and geothermal driven dual fluid ORC