Parabolic Trough Collector Research Articles

Thermodynamic design and analysis of a multigeneration system to support sustainable dairy farming

Continued growth in the global human population and the high per capita food consumption renders it necessary to provide secure and sustainable food production systems. As current food production systems are vast users of energy and water resources, one of the most important goals achieved in this study is to contribute towards the development of sustainable and resilient energy systems for dairy farming. In this context, a novel multigeneration system is proposed in this study utilising renewable energy (solar and waste biomass) within the dairy farm. Accordingly, a comprehensive thermodynamic analysis of energy and exergy is conducted to assess the cycle's and component’s performances. The subsystems used in the system are; biomass gasifier, parabolic trough collectors, reheat organic Rankine cycle, Brayton cycle, water treatment unit and LiBr-Water absorption cooling system. Gasifier and solar parabolic trough collectors are integrated into a multigeneration system, which generates several outputs (electricity, hot water, hot air, milk evaporation, and a water filtering). The system's net power production and desalinated water can satisfy the farm's necessary energy and water requirements and provide for at least nine-hundred neighbouring houses. The system's overall energy and exergy efficiencies are calculated to be 81.6% and 42.75%, respectively.

Modelling and performance evaluation of a direct steam generation solar power system coupled with steam accumulator to meet electricity demands for a hospital under typical climate conditions in Libya

This study aims to build a dynamic model of a direct steam generation (DSG) solar power system coupled with a steam accumulator to meet electricity demands for a hospital under transient environmental conditions in Libya. The main components of the system are DSG parabolic trough collectors, a steam accumulator, a turbine, a condenser and a circulation pump. The system is modelled via using Simulink\\Simscape software blocks with integrated MATLAB functions to run a dynamic simulation. As the simulation tool reflects the transient operation of the components, advanced control strategies were applied to the model. Using the proportional integral controller (PI controller), safe operation of the system is secured by pump flow rate control, safe turbine operation is provided by pressure control and power output is matched with the demand by using a throttle valve control. 1584 m2 solar collector area and 160 m3 total volume of pressurized steam tank are used in the simulation considering the electricity demand of the hospital and solar radiation in the location. The produced work output was controlled to match the demand profile of the hospital, which needs 200 kW in the peak period and 50 kW at the night. The designed system shows a maximum thermal efficiency of 23.5% for the operation condition.

A new solar mid-and-low temperature receiver/reactor with linear Fresnel reflector

The hydrogen production by a mid-and-low temperature solar receiver/reactor traditionally uses a parabolic trough collector, where the circumferential non-uniformity of the concentrated solar flux poses a challenge to the safety of the catalyst bed and absorber tube. To address this challenge, this study proposes a new hydrogen production method that allows for a more uniform distribution of solar flux, temperature, and deformation in the receiver/reactor by combining a linear Fresnel reflector, a compound parabolic concentrator, a mid-and-low temperature receiver/reactor, and methanol steam reforming reaction. The solar light is concentrated on the surface of the receiver/reactor by the linear Fresnel reflector and the compound parabolic concentrator instead of the traditional parabolic trough collector, and then converted into chemical energy by the methanol steam reforming reaction in the receiver/reactor. A three-dimension model is established to study the performance of the mid-and-low temperature receiver/reactor, including solar flux distribution, fluid flow, mass diffusion, heat transfer, chemical reaction, and structural deformation. The influences of key factors are studied, including the inlet temperature, feeding rate of reactants, molar ratio of water to methanol, and porosity of the catalyst bed. A comparative study between linear Fresnel reflector and parabolic trough collector is conducted to discover the influence of the light-concentrating methods on hydrogen production. The results show that the temperature and reaction fields are highly influenced by the circumferential distribution of the solar flux. The linear Fresnel reflector can achieve a more uniform temperature distribution along the cross-section in the flow direction than the parabolic trough collector owing to the more uniform distribution of solar flux. The maximum temperature difference of the absorber tube in the center of the absorber tube is 12.5 % of that in the parabolic trough collector, which effectively alleviates the local overheating of the catalyst and decreases the thermal deformation of the steel tube. This study provides a reference for the mid-and-low temperature hydrogen production in the linear Fresnel reflector.

Wastewater treatment to improve energy and water nexus with hydrogen fuel production option: Techno-economic and process analysis

The use of fresh water to produce green hydrogen fuel through the water electrolysis process can exacerbate the challenges of water scarcity. Using non-potable water for this purpose can lead to the design of a process with high security, reliability and sustainability. This paper develops the conceptual design and techno-economic evaluation of an innovative hydrogen energy production process from a solid oxide electrolyzer (SOE) integrated with a water treatment and recovery process. Accordingly, purified wastewater and waste heat of flue gases of the power plants have been utilized as feedstocks for the electrolysis process. Two different scenarios were assumed to supply the required thermal energy of the electrolyzer: the first scenario is the use of a preheater based on fossil energies, while in the latter scenario the required thermal energy is supplied through parabolic trough collectors, PTCs,-based solar farm. The integrating fossil fuels-driven power plants with evolving green technologies can mitigate the greenhouse gas emission crisis in addition to reducing the limitations of fossil energies. The outcomes indicated that the Levelized cost of hydrogen (LCH) for the second scenario increases by almost 38.7% compared to the first scenario. The reason for the high value of LCH for the second scenario is the high capital cost of solar collectors. Furthermore, the overall conversion efficiency for the proposed hydrogen production process was calculated as 53.26%. The introduced system can be competitive and reliable from the point of view of saving water consumption. The net potential energy saving and carbon emissions of the process was also determined.

Development, exergoeconomic assessment and optimization of a novel municipal solid waste-incineration and solar thermal energy based integrated power plant: An effort to improve the performance of the power plant

Due to the growing population rate and increasing social activities, the content of municipal solid waste (MSW) production is increasing. Energy production from MSW is one of the promising ways to dispose of waste and reduce the limitations of fossil energies. However, this technology has a relatively low efficiency due to the high volume of moisture and inert materials in MSW and the lower heating value of waste. The integration of solar thermal collectors is one of the suggested solutions to increase the temperature of inlet steam to the power generation cycle in order to improve the power plant performance. In this regards, the present study develops a comprehensive thermodynamic-conceptual and exergoeconomic investigation of the performance of a MSW-incineration (MSWI) plant integrated with a parabolic trough collector (PTC)-based solar field. Accordingly, the temperature of the steam elevates by the solar field before entering the electric power generation cycle. Additionally, the solar unit is integrated with a phase change material (PCM)-based storage system. The use of storage tank at the delivery line of PTC can improve the power plant’s reliability. A comprehensive comparison of the developed power plant with the conventional MSWI power plant is presented. In addition, the technical and economic behaviors of the considered power plant have been optimized under two different single and multi-objective optimization scenarios. The outcomes indicated that the developed power plant can provide 15.75% and 15.68% higher energetic and exergetic efficiencies compared to MSWI power plant. In addition, the rate of electric power obtained from S-MSWI power plant is almost 16.1% more compared to MSWI power plant. However, the total cost rate of MSWI plant is almost 24.13% lower compared to the developed power plant. But, the value of LCOE in the developed power plant is approximately 8.93% lower than MSWI power plant. It was also found that, the multi-objective optimization can provide better and optimal results to energy engineers and decision makers compared the single-optimization. The conceptual design of the implementation of the solar field is also developed in a specific geographical condition. Additionally, this research comes from the key technology of the National Key Laboratory of Environmental Protection.

Exergetic evaluation of the effect of nanofluid utilization for performance enhancement of a solar driven hydrogen production plant

Recently, research and development on progressive and efficient hydrogen production methods has been paid lots of attention due to carbon-free feature of hydrogen. Application of nanoparticles to enhance an integrated solar-based hydrogen production unit is suggested and investigated in this work. The integrated plant consists of parabolic trough collectors coupled with a Kalina cycle for electricity generation to be consumed in a polymer electrolyte membrane electrolyzer for hydrogen production. The system performance is apprised for nanofluid as the heat transfer media for solar collectors and is compared with the pure basefluid case. Thermal model for parabolic trough collectors as well as thermodynamic models for Kalina cycle and electrolyzer are developed and validated. Also, thermo physical properties of nanofluid is assessed based on volume fraction of the nanoparticles. Parametric analyses are implemented for system performance assessment in which influence of design variables related to solar collectors, nanoparticels as well as the Kalina cycle are appraised. The effect on the hydrogen rate and solar-to-hydrogen exergy efficiency of design variables are comprehensively examined and discussed. According to the obtained results, the ηex,STH is found to be 9.19% for the case with basefluid (without nanoparticles), whereas it can be improved to 9.63% with employment of 5% volume fraction of CuO nanoparticles. Such an efficiency improvement is due to the increment of hydrogen production from 0.669 kg/h to 0.702 kg/h using CuO-based nanofluid.

Improving the efficiency of the concentrating solar power plants using heat transfer nanofluids with gold nanoplates: An analysis from laboratory to industrial scale

We report about the remarkable changes in the thermophysical properties of the heat transfer fluid used in concentrating solar power plants with parabolic-trough collectors (Dowtherm A, a mixture of diphenyl oxide and biphenyl) by addition of Au nanoplates in mass fractions around 10−2 wt%. The resulting nanofluids are stable for weeks, and their enhanced physical properties make them good candidates for the application. Particularly, with 4.8·10−2 wt% of Au nanoplates, specific heat increases by 12.0 ± 1.2 % at 523 K and thermal conductivity increases by 24.9 ± 6.1 % at 373 K, with no measurable changes in density or dynamic viscosity. This set of physical properties allows to make a realistic estimation of the performance of a prototypical concentrating solar power plant using these nanofluids for solar-to-thermal energy conversion. We determine, using computational cost-free numerical models available in literature, that the performance of a concentrating solar power plant could increase up to 35.1 %, compared to the predicted 24.7 % with the conventional heat transfer fluid, with neither rheological penalties nor economically prohibitive structural changes. The findings here reported may contribute to encourage the application of heat transfer nanofluids in order to improve the efficiency of concentrating solar power plants, and to consolidate a working scheme that positively promotes the transition from laboratory scale to industrial scale.

Multi-Objective Optimization of a Solar Combined Power Generation and Multi-Cooling System Using CO2 as a Refrigerant

This paper proposes a new combined multi-cooling and power generation system (CMCP) driven by solar energy. Carbon dioxide is used as a refrigerant. A parabolic trough collector (PTC) is employed to collect solar radiation and convert it into thermal energy. The system includes a supercritical CO2 power system for power production and an ejector refrigeration system with two ejectors to provide cooling at two different evaporating temperatures. The CMCP system is simulated hourly with weather conditions for Tunisia. The PTC mathematical model is used to calculate the heat transfer fluid outlet temperature and the performance of the CMCP system on a specific day of the year. A 1D model of an ejector with a constant area is adopted to evaluate the ejector performance. The system’s performance is evaluated by an energetic and exergetic analysis. The importance of the system’s components is determined by an exergoeconomic analysis. The system is modeled using MATLAB software. A genetic algorithm is used for multi-objective optimization to determine the best values and solutions for the system’s design parameters. The optimal energy and exergy efficiencies were found to be 13.7 percent and 37.55 percent, respectively, and the total product unit cost was 31.15 USD/GJ.

Development and assessment of a solar and natural gas-based integrated energy system with storage options

In this study, a solar and natural gas-based dual-energy source integrated plant system is designed to be thermodynamically investigated through energy and exergy approaches for multiple useful outputs, including electricity, heat and freshwater. The current system is considered for a hospital building to cover their needs and incorporates heat storage options to provide steady and flexible operation to better offset the mismatch between demand and supply. As a matter of fact, this system is not only appropriate for locations, such as deserts, where the weather is sunny and the air is dry all year round, but it is also suitable for other places where the sunshine duration is relatively shorter and the air is moderately humid by means of a storage system. With this system, which uses natural gas at a relatively modest rate of 20%, the system is enabled to operate primarily on solar energy. Thus, this renewable energy-based, natural gas-supported system obtains more green energy at a lower cost. It also intends to address the community's clean water requirement using the multi-effect desalination unit. Additionally, a molten salt thermal storage subsystem is employed to mitigate energy imbalances in the parabolic trough collector all day long. Furthermore, the necessary energy is supplied using a natural gas-powered boiler, especially in the evening and at peak times in terms of energy demand. The system is uniquely designed based on a real-world scenario using binary energy sources, where some parametric studies have been performed. While the system utilizes solar energy at a ratio of 80%, the remaining 20% comes from natural gas, and the amount of natural gas needed to assist the developed system for steady operation varies between 0.018 kg/s and 0.039 kg/s per day. The energy and exergy efficiencies of the system are determined to be 60.03% and 35.1%, respectively, while both electricity and heating production are 1.3 and 1.5 MW, and the freshwater production is found to be 17.52 kg/s, respectively.

Characterization of cadmium sulfide light dependent resistors sensors for optical solar trackers

<span lang="EN-US">The aim of this paper is to study the effect of dissimilarity of the intrinsic characteristics of the light dependent resistor (LDRs) on optical sun tracking systems, designed for solar power concentration applications such as parabolic trough collectors, Fresnel mirrors concentrators, and concentrated photovoltaic, a comparative study was done between a sun tracker based on LDRs chosen randomly with and without an initial calibration of the offsets, and a sun tracker based on LDRs selected meticulously thanks to a black box test bench, developed especially for this purpose. By choosing two light dependent resistors randomly, the dissimilarity between them can reach 23.2%, which cause a bad sun tracking even with initial offset calibration, in the other hand, and by the use of selected LDRs using the test bench, the dissimilarity drops to 0.06%, which meets requirements of solar power concentration systems.</span>

Environmental impacts of solar thermal power plants used in industrial supply chains

A systematic literature review was conducted to investigate the environmental impact of solar thermal power plants in the industrial supply chains. A number of different solar thermal power collectors like parabolic trough (PT), linear Fresnel (LFR), solar dish (SD) and solar towers (ST) were considered and analysed. The first observation was that PT collectors generate the lowest level of Green House Gas (GHG) emissions, followed by LFR, DT and SD plants. There was a lack of studies dealing with the GHG emissions of LFR and SD plants, which demonstrated a need of conducting more studies to gain better understanding of their environmental performances. The second observation was that different environmental assessment software tools used for analysing the environmental impact showed conflicting results because of the different approaches used in the characterization factors management in each software. Those software tools include: SimaPro, Gabi, System Advisor Model (SAM), Umberto and Thermoflex + PEACE. The standardization of environmental software tools and life cycle impact assessment methods is required to prevent discrepancies in life cycle assessment results. The third observation was the need for integrated environmental and economic assessments to provide a comprehensive evaluation of the solar thermal plants as it will enable investors, policy-makers and researchers to make informed decisions about the environmental and economic impacts of those plants.

Green steam for sustainable extraction of essential oils using solar steam generator: A techno-economic approach

Essential oils are natural volatiles extracted using steam. Steam generation is an energy-intensive process and is invariably based on fossil fuels, briquettes or biomass. Based on the volumes of essential oil extracted, it can be considered as significant contributor to greenhouse gases. Though a lot of work is reported on essential oil extraction and characterisation, method for quantification of exact steam requirement and means for achieving it through sustainable source is not much reported.Through this study, steam requirement of 750 g/ml of Betel leaf volatile oil extracted and quantification of energy requirements for the extraction process is determined. For adoption of sustainable and clean energy source, opto-geometric optimisation and concentrating solar collectors (CSC) area calculation are carried out. The design of three CSC, namely, Linear Fresnel Reflector (LFR), parabolic dish collector (PDC) and parabolic trough collector (PTC), resulted in 78 m2, 122 m2 and 138.87 m2 of area to meet the steam requirement of the process.Adoption of CSC technologies for steam generation and replacing the prevalent technology needs detailed analysis and techno-economic comparison. This paper also focuses on cost-benefit analysis, taking into account CAPEX, OPEX, life-span, return on investment, levelized energy (steam) cost and the profitability index of net present value, payback period and internal rate of returns to check the economic feasibility of renewable energy. Analysis indicates that the cost associated with unit steam generation through CSC over the specified period is lower than a briquette-based steam generation. On adopting this sustainable technology for betel leaf oil extraction, even if the initial cost seems to be high, the payback period of LFR and PTC are 1.10 and 2.45 years, respectively. Based on this study, CSCs can provide a sustainable green solution for the extraction of essential oils.

Energy, exergy, economic and environmental evaluations of a finned absorber tube parabolic trough collector utilizing hybrid and mono nanofluids and comparison

Parabolic trough collectors (PTCs) are an important part of solar thermal power plants. Past studies have shown that the dispersion of MWCNT or Fe3O4 nanoparticles in the working fluid of PTCs improves the performance, but there has not been any study on utilization of MWCNT–Fe3O4/Therminol VP-1 hybrid nanofluid in PTCs yet. In this study, thermal, exergy, economic and environmental evaluations of a PTC with smooth and finned absorber tubes have been performed using this hybrid nanofluid and its associated mono nanofluids. The length of PTC is 7.8 (m) and its width is 5 (m). In order to model the solar heat flux a new concentration ratio has been defined. For the high volume flow rate of 150 (L/min) and irrespective of absorber type, increasing inlet temperature reduced thermal efficiency, but change of the working fluid or change of the absorber type had minor effect on thermal and exergetic efficiencies, although the hybrid nanofluid performed slightly better. However, inlet temperature increase enhanced the exergetic efficiency significantly. The levelized cost of energy (LCOE) of the PTC with internally finned absorber was higher than that of smooth absorber for all working fluids and inlet temperatures. However, for every absorber type and at any inlet temperature, utilization of mono or hybrid nanofluids did not have a significant effect on LCOE. For CO2 emission evaluation, two methods of embodied energy and life cycle have been used. Based on the method of embodied energy, the CO2 emission of the PTC with finned absorber tube was approximately 18% more than that of smooth tube for all of working fluids and inlet temperatures, while the method of life cycle predicted almost the same amount. The results showed that the method of life cycle is more accurate, since it considers all stages of PTC life time.

Experimental study on the solar drying of Rhubarb (Rheum ribes L.) with parabolic trough collector assisted with air recycling system, nanofluid and energy storage system

In the present work the thermo-economical calculation of dried Rhubarb slices in a dryer integrated parabolic trough solar collector assisted with air recycling mechanism and Al2O3 3.75 % as working fluid was investigated. Using air recycling system at the inlet section of the dryer and phase change material increases the thermal performance of the dryer and reduces the drying time of Rhubarb slices. Two adjustable valves at inlet and outlet part of the dryer and the amount of return flow was considered to control the airflow. In this study, the effect of air recycling flow at the inlet part of indirect chamber at four levels of 0–25–50–70 % was considered and the amount of specific energy consumption, total drying efficiency and solar collector efficiency was analyzed. To determine the performance of the system, Rhubarb slices in 5 mm as thin layer were used. In addition, CFD modeling was applied to predict temperature changes inside the dryer. The drying time decreased with increasing the recirculation of air, considerably. The overall drying efficiency increased about 2.32–8.21 %, and specific energy consumption decreased at least 1.91 % by applying air recycling mechanism, nanofluid and PCM in dryer related to the system without them. The exergy efficiency for drying of Rhubarb slices varies between 35.4 and 61.3 %. The optimization of the system was carried out based on the conditions and the result revealed this leads to decrease the payback time.

Sustainability and exergoeconomic assessments of a new MSW-to-energy incineration multi-generation process integrated with the concentrating solar collector, alkaline electrolyzer, and a reverse osmosis unit

The current article develops a conceptual study and simulation of a multigeneration process based on the solid waste-incineration power plant coupled with a field of solar thermal system. The considered multi-generation layout is comprised of a municipal solid waste incineration unit, a steam cycle, the concentrating solar thermal collectors (based on the parabolic trough collectors), an organic steam cycle, a desalination unit (based on a reverse osmosis unit), and a hydrogen fuel production unit (based on the alkaline electrolyzer). The planned multi-generation process can produce electricity, thermal energy, hydrogen energy, and freshwater. The paper addresses a multi-generation process with a new structure, configuration and relationships between the units of the process. A comprehensive thermodynamic-conceptual, exergoeconomic and sustainability evaluations of the multi-generation process is developed. The findings indicated that the process can achieve energetic and exergetic efficiencies of 21.72% and 16.94%, respectively. Moreover, approximately 42.2 MW of the exergy is destroyed by the process. In such a context, the total cost and sustainability index of the proposed process were 653.03 USD/h and 1.72, respectively. It was also found that the Levelized Cost of Energy of the system was almost 0.072 USD/kWh. A parametric analysis is also provided to identify influencing factors.

Thermodynamic and economic analysis of a supermarket transcritical CO2 refrigeration system coupled with solar-fed supercritical CO2 Brayton and organic Rankine cycles

Aiming to reduce the use of conventional energy sources, alternative methods should be applied in order to cover society’s needs. In this context, in the present study, the operation of a transcritical CO2 commercial refrigeration unit is investigated, coupled with two power production cycles. The first cycle is a supercritical CO2 Brayton system that is supplied with heat by a solar field including parabolic trough collectors, while the second one is an organic Rankine cycle, utilizing as a heat source the low enthalpy CO2 exiting the first cycle. The novelty of this system is attributed to the combination an advanced transcritical CO2 refrigeration system with power production cycles that operate under the optimal conditions, as well as to the reason that the operation of the refrigeration unit is independent from the solar energy, since it can provide refrigeration output regardless of the solar heat input. The results prove that the increased number of solar collectors leads to more advantageous power production results, although with higher capital costs. Furthermore, greater energy production is noted when the ambient temperature is lower and abundant solar power is available. For the case of installing five solar collectors and an organic Rankine cycle, it is found that the annual energy production of the total system is 173.72 MWh, while the annual energy consumption of the refrigeration unit is 466.66 MWh, meaning that 37.23 % of energy savings are achieved annually. For the same configuration, according to the life cycle cost analysis, the capital cost is found equal to 243.72 k€, leading to a payback period of 7.6 years. By the end of the project’s lifetime, the operation of the installed system returns 298.42 k€ to the investor.

Wind Load Effect Study on Large-Aperture Parabolic Trough Collector Mirror Fields

Abstract Large-aperture parabolic trough collectors (LPTCs) are recognized as one of the most promising next-generation linear-focus concentrating solar power (CSP) technologies. However, large apertures inevitably introduce higher wind loads and stronger inter-row interactions. In the present study, a multi-physics-coupled model is established to study the wind load effect on multiple rows of LPTCs. First, it is found that wind load fluctuates significantly in the first four rows and then decreases gradually. The first and second rows suffer the most and least damage, respectively. Because wind load effect is highly dependent on the row number, it is recommended to build wind fences and reinforce the strength of collectors according to their positions in the solar field. Second, the wind load reduction effectiveness of the varied focal length design, incorporated in the LPTC, is numerically validated so that the stress and optical efficiency loss can be reduced by 29.1% and 58.9%, respectively. Finally, the optical efficiency loss is first introduced to evaluate the wind load reduction performance of different mirror gap sizes. The optimal mirror gap size is found to be dependent on the weight coefficient between the wind load reduction and the optical efficiency, which should be determined by the actual scenario. For weight coefficients of 1:1, 1:2, and 2:1, optimal mirror gap sizes of 90 mm, 30 mm, and 120 mm, respectively, are recommended for reference.

Numerical study of perforated obstacles effects on the performance of solar parabolic trough collector.

The current work presents and discusses a numerical analysis of improving heat transmission in the receiver of a parabolic trough solar collector by introducing perforated barriers. While the proposed approach to enhance the collector's performance is promising, the use of obstacles results in increased pressure loss. The Computational Fluid Dynamics (CFD) model analysis is conducted based on the renormalization-group (RNG) k-ɛ turbulent model associated with standard wall function using thermal oil D12 as working fluid The thermo-hydraulic analysis of the receiver tube with perforated obstacles is taken for various configurations and Reynolds number ranging from 18,860 to 81,728. The results are compared with that of the receiver without perforated obstacles. The receiver tube with three holes (PO3) showed better heat transfer characteristics. In addition, the Nusselt number (Nu) increases about 115% with the increase of friction factor 5-6.5 times and the performance evaluation criteria (PEC) changes from 1.22 to 1.24. The temperature of thermal oil fluid attains its maximum value at the exit, and higher temperatures (462.1K) are found in the absorber tube with perforated obstacles with three holes (PO3). Accordingly, using perforated obstacles receiver for parabolic trough concentrator is highly recommended where significant enhancement of system's performance is achieved.

A geospatial comparative analysis of solar thermal concentrating power systems in Greece

Solar concentrating power is an important weapon for facing the energy crisis and environmental issues. Greece is a country with great solar potential and thus it is an ideal candidate for the development of important solar concentrating power plants. These plants present the advantage of easy energy storage with thermal storage tanks, something beneficial for the production of a relatively stable electricity production profile, something critical for the further development of renewable energy systems. The objective of the present work is the detailed investigation of the solar concentrating technologies in different Greek locations in order to define in which locations solar concentrating power is a promising solution. Moreover, three typical solar concentrating technologies are studied and more specifically the parabolic trough collector (PTC), the linear Fresnel reflector (LFR) and the solar DISH. Thirteen different Greek regions are investigated by using hourly weather data from the typical meteorological year (TMY). The solar potential, the available irradiation, the useful heat production, the electricity production and the exergy production, as well as the respective efficiency indexes and the levelized cost of electricity (LCOE), are calculated. It is important to highlight that this study is focused on the systems of small capacity which are ideal for distributed renewable power production. It was concluded that the most efficient and economically feasible technology is the solar DISH, with the PTC to follow and LFR to be the last choice. Moreover, southern Greece is found to be a better choice for the installation of solar-concentrating power plants compared to northern Greece. More specifically, in the Southern Aegean Sea, it was calculated that the specific electricity production is 253.0 kWh/m2 with PTC, 160.7 kWh/m2 with LFR and 296.8 kWh/m2 with DISH, while the LCOE at 0.0882 €/kWh with PTC, 0.1046 €/kWh with LFR and 0.0843 €/kWh with DISH.

Techno-economic and environmental assessment of a novel polygeneration system based on integration of biomass air-steam gasification and solar parabolic trough collector

Renewable energy-based polygeneration energy systems, in addition to providing a variety of products, can effectively improve this planet's environmental conditions and reduce emissions. Therefore, in the present work, a novel polygeneration system has been proposed to produce power, heat, freshwater, and hydrogen-based on biomass and solar energy. In the present system, the Kalina cycle, Gas turbine cycle, double-pressure steam cycle, and organic Rankine cycle are used to produce power, Multi-effect desalination and reverse osmosis are used to produce freshwater, and the PEM electrolyzer is used to produce hydrogen. Also, the exhaust syngas from the gasification process has been used to supply steam to the gasifier reactor. Considering the determination of environmental laws and the need to transform Kish Island into a green island for residents and tourists, a proposed system has been defined for Kish Island in Iran. In the proposed system, the feasibility of three biomass fuels, Municipal Solid Waste (MSW), Mixed Paper Waste (MPW), and Date Palm Waste (DPW), was studied from a technical, economic, and environmental point of view. Air and steam agents have been used for the gasification of mentioned fuels. To evaluate the performance of the system in terms of thermodynamics, economics, and environment during the year, the analysis of the average monthly solar for the studied system has been used. MED has been analyzed using artificial intelligence techniques. Finally, a sensitivity analysis is performed for the main operational parameters. The results of the proposed system modeling show that MSW is the most economical fuel and the use of DPW has the least environmental impact on the system, but in terms of operating conditions, MPW with overall energy and exergy efficiency of 41.68% and 34.19% compared to other fuels perform better. The overall results of the 4E analysis for MSW fuel show that the overall energy and exergy efficiency of the polygeneration system is 39% and 32.01%, respectively. Power generation costs and environmental impacts for MSW biomass are 0.014 $/kWh and 0.002 Pts/kWh, respectively. The monthly analysis of the studied system for all three fuels shows that the net power generation decreases in the summer months. The results of the sensitivity analysis of the studied system show that the optimal design of gasification temperature, air compressor pressure ratio, condenser pressure, and the number of MED effects play a key role in the objective functions of the studied system.