Parabolic Trough

Graphene nanostructures-based dispersions, owing to their improved thermophysical and optical characteristics are being actively explored for use in thermal energy conversion and management. Here, thermophysical and photothermal characteristics of graphene oxide (GO), functionalized graphene oxide (f-GO), and reduced graphene oxide (rGO) based nanofluids (without surfactants) of various concentrations (0.05-0.23 wt.%) are evaluated. The structural, morphology and stability of the nanofluids are determined by XRD analysis, Transmission electron microscopy, UV-visible spectroscopy and zeta potential analysis. Subsequently, thermal conductivity and contact angle measurements are performed. Photothermal behaviour is investigated experimentally. Overall, it is found that among the prepared nanofluids, the f-GO nanofluids performed better compared to GO and rGO nanofluids. Maximum stability of f-GO nanofluids is obtained at 0.05 wt.% while the thermal conductivity and photothermal response is best obtained at 0.23 wt.% concentration.

Solar energy plays a very important role in achieving a self-sustaining city in the urban environment, but it has not been fully investigated. Reliable resource analysis should be performed to reflect its ability. This study deals with several obstacles through the use of a GIS to mapping the locations of solar potential, taking into account the suitable areas and the intensity of solar radiation as minimum as possible to illustrates the region-wise possibility of centralized photovoltaic solar power plants (PVS) and concentration solar power (CSP) based technology. The analysis is based on remotely sensed data that have been provided by NASA including the direct normal irradiance (DNI) and yearly means global horizontal irradiance (GHI) data. GIS program was used to deal with solar irradiation information, Digital Elevation Model (DEM), and land-use information using land use parameters and land topography to avoid insufficient places for the use of solar power. Additionally, land-cover parameters, total hours of sunshine, and the transformation efficiencies have been considered while measuring technological potential for solar power development in suitable land areas. The result indicates possible sites in Iraq for installing CSP plants and consolidated large scale PVS plants.

This work is first systematic assessment of combined thermal performance of different natural materials incorporated in geometry-optimized inverted pyramid made of aluminum. A comprehensive framework, which incorporates energy, exergy, and environmental parameters is used to assess the study. It also presents a new solar still design that utilizes such materials. Interrelations between the incorporation of the pebble stones with the coir fiber and sugarcane bagasse on heat transfer relationship, behavior of the evaporation, and efficiency of the entire system have never been studied previously, particularly in an optimized basin shape. In order to develop a viable and economical desalination system, the present idea combines both the geometrical solar intensification and material-enhanced thermal betterment. The experiment results proved the integrated arrangement to be the most effective one of all the scenarios taken into consideration: To regulate the temperature, pebble stones were used as thermal storage, coir fiber stimulated evaporation of thin-film using capillaries and sugarcane bagasse with its porous structure, facilitated even distribution of water in addition to restricting the thermal losses. The inverted pyramid structure enhanced thermal use by minimizing convection heat losses and enhancing solar energy concentration. The optimal construction produced 32.9% better than the reference still given a similar operating protocol and attained a peak yield of 3.16 kg/day of distillate per m 2. The increase in efficiency was identified as 36.3% with a rise in efficiency to 26.6 to 41.8% in terms of heat transfer in embodied energy respectively. This result offers viability to the logic that a sustainable and effective solution to distributed solar desalination is the addition of multifunctional natural materials on an ideal basin.

In this paper a new design of a novel CSP cavity receiver for parabolic trough collector is analyzed by means of an analytical Matlab model. The receiver, designed by the Swiss company Airlight Energy Manufacturing SA, is 212 m long consisting essentially of a feed pipe, a run-back pipe and 4608 helically coiled heat exchangers designed to capture the incident solar energy concentrated by a parabolic trough. The heat transfer fluid is air heated to temperatures above 600°C. The analytical Matlab model based on a pneumatic -electric circuit analogy was developed to assess the receiver performance in terms of mass flow rate distribution, pressure drop, air outlet temperature and thermal efficiency. A solution was proposed to approximately ensure the same mass flow rate for each cavity. Different skew angles for the incoming solar radiation were considered and the receiver geometry was optimized minimizing the pressure drop and the thermal losses through the runback pipe. The main requirement was to achieve, at the outlet section of the receiver, an air temperature of 650°C; therefore, the total inlet mass flow rate was tuned accordingly. The helically coiled heat exchanger and the receiver insulation sub-models were validated against accurate computational fluid dynamics simulations.

Solar energy is a clean, abundant, and renewable resource with enormous potential that extends beyond just providing energy access. It plays a significant role in minimizing greenhouse gas emissions. With approximately 4 × 10 15 MW of solar energy reaching the Earth, its potential far surpasses estimated global utility demands by a factor of 200. This study presents a comprehensive numerical investigation of unsteady magnetohydrodynamic (MHD) flow of a Cu-TiO 2 /water hybrid nanofluid in a parabolic thermal solar collector. The fluid properties such as thermal conductivity and dynamic viscosity, are considered to vary linearly with fluid temperature. A variable magnetic field is applied. The governing partial differential equations were transformed to ordinary differential equations using similarity transformation. The resulting first-order system of ODEs was then solved numerically using the collocation method which was implemented in MATLAB's bvp4c solver. The profiles of various flow variables were determined, and the impact of different flow parameters on wall shear stress, heat and mass fluxes were investigated by computing the skin friction coefficient, Nusselt number, and Sherwood number, respectively. Key findings include: increasing Reynolds number by 28.6% led to a 12% increase in temperature profiles; increasing mass Grashof number by 60% led to a 10% decrease in temperature profiles; Schmidt number and Soret number positively influenced temperature profiles; the Joule heating parameter had a negative effect on temperature profiles; skin friction coefficient decreased by 15% with a 15% increase in Reynolds number; Nusselt number increased by 6% with a 20% increase in magnetic Reynolds number and by 10% with a 15% increase in Schmidt number; and Sherwood number increased by 10% with a 15% increase in Schmidt number. These findings provide valuable insights into the behavior of hybrid nanofluids in solar energy applications and can be used to optimize the design and operation of solar collectors for enhanced efficiency and sustainability.

Solar energy is a clean, abundant, and renewable resource with enormous potential that extends beyond just providing energy access. It plays a significant role in minimizing greenhouse gas emissions. With approximately 4 × 10 15 MW of solar energy reaching the Earth, its potential far surpasses estimated global utility demands by a factor of 200. This study presents a comprehensive numerical investigation of unsteady magnetohydrodynamic (MHD) flow of a Cu-TiO 2 /water hybrid nanofluid in a parabolic thermal solar collector. The fluid properties such as thermal conductivity and dynamic viscosity, are considered to vary linearly with fluid temperature. A variable magnetic field is applied. The governing partial differential equations were transformed to ordinary differential equations using similarity transformation. The resulting first-order system of ODEs was then solved numerically using the collocation method which was implemented in MATLAB's bvp4c solver. The profiles of various flow variables were determined, and the impact of different flow parameters on wall shear stress, heat and mass fluxes were investigated by computing the skin friction coefficient, Nusselt number, and Sherwood number, respectively. Key findings include: increasing Reynolds number by 28.6% led to a 12% increase in temperature profiles; increasing mass Grashof number by 60% led to a 10% decrease in temperature profiles; Schmidt number and Soret number positively influenced temperature profiles; the Joule heating parameter had a negative effect on temperature profiles; skin friction coefficient decreased by 15% with a 15% increase in Reynolds number; Nusselt number increased by 6% with a 20% increase in magnetic Reynolds number and by 10% with a 15% increase in Schmidt number; and Sherwood number increased by 10% with a 15% increase in Schmidt number. These findings provide valuable insights into the behavior of hybrid nanofluids in solar energy applications and can be used to optimize the design and operation of solar collectors for enhanced efficiency and sustainability. Hybrid nanofluid • Parabolic solar collector • Magnetohydrodynamic (MHD) flow • Heat transfer • Mass transfer • Solar energy • Numerical simulation List of symbols Roman symbols a Radius of the receiver tube, [m] B Total magnetic field, [N/Am] s] d p Diameter of nanoparticle, [m] H Induced magnetic field, [N/Am] H Applied magnetic field, [N/Am] J wall Wall mass flux, [kg/m 2 s] k Thermal conductivity, [W/m ⋅ K] 0 Mean absorption coefficient, [1/m] p Pressure, [Pa] q wall Wall heat flux, [W/m 2 ] r Radial distance, [m]

A Renewable Energy Type Solar energy is, by definition, the radiant energy emitted by the sun. And, in many ways, we owe much of our different types of energy to the sun. Fossil fuel energy, discussed in Chapters 1-3, is certainly the result of solar energy, as well as millions of years of heat and pressure in the interior of the earth. Since fossil fuels are formed from the anaerobic decomposition of dead organisms, such as algae, prehistoric plants and animals, and plankton, there would be no organisms to decompose if it were not for their growth from solar energy. And, the hydroelectric power discussed in Chapter 5 also owes its energy, in part, to the sun. Rivers and streams flow downhill but the water for them comes from winter snow, glaciers, and melting; melting is caused by solar energy. As well, rivers and streams grow from rain. The rain occurs because of the sun heating the atmosphere, causing ground moisture to evaporate, rise into the atmosphere, form clouds, and eventually rain. Likewise, wind energy discussed in Chapter 6, is caused by solar energy heating the earth and causing air movement. And some energy types discussed in later chapters, ethanol (Chapter 8), biomass (Chapter 9), hydrogen (Chapter 11), and the Fischer-Tropsch synthesis (Chapter 12), use fuels that were generated by the sun. Ethanol and biomass use biofuels while hydrogen and the Fischer-Tropsch synthesis rely on fossil fuels and are therefore also the indirect result of solar energy. The only two energy types discussed in this book that do not rely on solar energy are nuclear and geothermal energy. Uranium is thought to have been formed from supernovas around 6.6 billion years ago, with a supernova being defined as a star reaching the end of its life that has an explosion ejecting most of its mass. This is certainly not something we want from our sun and, in fact, the sun is thought to not have enough mass to explode as a supernova. Geothermal energy comes from heat within the earth's core, and the source of this heat is from when the planet was formed, frictional heating from material movement, and heat from radioactive decay. This chapter focuses on the direct use of solar energy to make electricity. There are basically two methods of generating electricity from solar energy including photovoltaic (PV) solar energy and solar thermal energy. In the case of PV solar energy, sunlight is directly converted into electricity using panels made of semiconductor cells while solar thermal energy uses solar energy to heat a fluid (such a gas, oil, or molten

This article presents a comprehensive review of recent research on renewable-driven multigeneration systems using integrated 3E (Energy, Exergy, Environment) and Life Cycle Assessment (LCA) frameworks. The proposed integration provides a comprehensive understanding of a system's performance, identifying potential hotspots, optimizing resource utilization, and ultimately driving the development of more environmentally friendly energy solutions. The manuscript reviews the system's energy potentials (both inputs and outputs) with an emphasis on total energy efficiency and identifying areas of energy loss. The exergy analysis evaluates energy quality by measuring thermodynamic losses and irreversibility. A cost-benefit analysis is also performed to analyze the economic sustainability of the multigenerational system (MGS). The LCA provides environmental impact indicators. The innovative multigeneration systems are intended to generate many useful outputs (power, heat, hydrogen, and cooling) from renewable resources like solar or biomass. The study provides data for making educated decisions on system design, technology selection, and process optimization that fit with environmental goals and economic feasibility. The MGS improves energy and exergy efficiency by manufacturing many products at the same time, resulting in less waste and greater utilization of primary resources. Using renewable resources and producing diverse products significantly reduces carbon footprints and greenhouse gas emissions, encouraging environmental conservation and sustainability. Instead of proposing a new optimization strategy, this review synthesizes existing multi-objective optimization approaches applied to renewabledriven multigeneration systems and critically discusses the trade-offs among energy, exergy, economic, and environmental objectives within integrated 3E-LCA frameworks.

The configuration of an external solar dish improves the performance of stepped slope solar still (SS) in an experimental setting. The use of an external solar dish raises the effects of the water basin, resulting in a higher rate of evaporation. The stepped still was designed, built, and tested in Ismailia, Egypt, using local weather conditions. The proposed SS had a 1 m 2 base area and eight steps, a solar dish with a concentration ratio of 80, a cone tank, two centrifugal pumps, four photovoltaic modules totaling 1000 W, a control unit, and solenoid valves. The impact of utilizing the storage material during the phases was investigated. A nozzle was installed at the top of the cone tank. Four mass flow rates of circulated water were examined 250, 350, 450, and 550 mL/min. The control unit receives inputs from the photovoltaic output, photodiodes, and water temperature inside the cone. The control unit outputs the signal for the two solar dish motors, centrifugal pumps, and solenoid valves. First, a standard stepped SS, second, a stepped SS using phase change material (PCM), and finally, a stepped SS using PCM combined with a solar dish were investigated. The conventional stepped SSs with PCM had an optimal mass flow rate of 250 mL/min, whereas the stepped SS integrated with the solar dish had 550 mL/min of mass flow rate (an optimum value). The highest daily freshwater productivity was 7.63, 9.18, 11.23, and 13.9 kg/d for water spraying mass flow rates of 250, 350, 450, and 550 mL/min, respectively, with 0.0161 $/L/m 2 of a maximum projected cost, according to data from an integrated stepped SS.

Different researches were performed by using thermal storage materials, solar concentrators, reflectors, and other technologies to increase the productivity of solar stills. The main objective of the present study is to enhance the basin solar still productivity by using ecomaterials from the wastes of workshops and factories. So, this study presents an experimental investigation of basin solar still performance using steel wool pads, internal reflectors, and woven wire mesh. The experimental setup was performed at Suez Canal University, Ismailia City, Egypt. Two solar stills were included: one represents the conventional design (CSS), and the second one is the modified with steel wool pads, internal reflectors, and woven wire mesh (MSS). Both solar stills were evaluated under identical climate conditions, considering water depths of 1, 2, 3, and 4 cm, and the required parameters were measured and tabulated during the working days. The results indicated that incorporating these modifications led to a notable increase in accumulative productivity and daily thermal efficiency with minimum cost per liter. The MSS enhanced the daily yield and thermal efficiency by 22.1% and 28.0%, respectively, versus CSS at a water depth of 1 cm. In addition, the energy production factor (EPF), energy payback time (EPT), and the average exergy waste were 1.2 years, 0.85, and 400.2 J, respectively, for MSS. The annual exergy output, environmental effect factor (EEF), improvement potential (IP), and sustainability index were 462.7 kWh, 10.4, 290.6 W, and 1.09, respectively, for MSS. Finally, the cost per liter and the annual CO 2 reduction over a lifetime for CSS and MSS were 0.023 $/l, 17.4 tons, and 0.11 $/l, 20.4 tons, respectively. These results align with and reinforce previous publications on desalination, highlighting the potential of these modifications for addressing the pressing challenges of affordable and efficient water using solar energy.

The present study explores enhancing the productivity of solar still through the utilization of different enhancement configurations, such as Iron Hemispherical Pieces (IHPs) and Steel Wool Pads (SWPs). Two solar stills were used in this study, one of them is a conventional solar still (CSS) as a comparison reference and the other is a modified solar still (MSS) with different enhancement configurations. Different parameters were continuously monitored to evaluate their influence on the efficiency of the solar stills. Mathematical model was performed to calculate the experimental heat transfer coefficients and the productivity for the stills under different amounts of basin water. Energy Efficiency (EE) and Exergy Efficiency (EXE) were employed to analyze their impact for the different configurations. The findings indicated that increasing the number of IHP to 120 IHPs leads to increase the productivity by 35 % compared to 30 IHPs. Using 5 L of water yielded an accumulated productivity of 3800 ml, whereas employing 15 L decreased productivity by 26 %. Moreover, the addition of Steel Wool Pads (SWPs) significantly enhanced productivity by 28 %. Additionally, the MSS + 120IHP configuration exhibited maximum EE and EXE values of 47.53 % and 3.2 %, respectively, with daily average values of 24.53 % and 1.55 % at 5 L of water. Similarly, the MSS + 120IHP + 60SWP configuration attained maximum EE and EXE values of 55.24 % and 3.5 %, respectively, with daily average values of 30.00 % and 1.90 %. Subsequently, the experimental measurements of hourly production were validated against the corresponding theoretical values, demonstrating good agreement between them. Finally the cost evaluation was performed and the MSS has the minimum cost per liter (CPL) compared with the conventional one.

Desalination is a critical process to address water scarcity in arid regions worldwide, and solar stills provide an economical solution despite their productivity limitations. This study aimed to enhance the performance and productivity of solar stills by constructing two stills with different natural and artificial absorbing materials such as black luffa, luffa, fine steel wool, and steel wool pads. The solar stills were tested in Egypt under comparable weather conditions, and their productivity, solar intensity, wind velocity, and temperature were measured to determine their thermal efficiency and exergo-economic analysis. Results showed that the choice of absorbing material significantly impacted solar still productivity, with steel wool pads achieving the highest yield of 4.384 l/m 2 . Moreover, steel wool pads also exhibited the highest thermal efficiency at 32.74%. The cost per liter (CPL) was the lowest with steel wool pads at 0.0034 $/l/m 2 . Finally, the payback period and exergoeconomic analysis demonstrated that incorporating steel wool pads was the most promising modification for enhancing solar still performance compared to other modifications.

This study investigates the influence of activation energy on the magnetohydrodynamic (MHD) Darcy-Forchheimer flow of a Casson hybrid nanofluid over two distinct geometries: a cone and a wedge. The research is motivated by the superior thermal and rheological properties of hybrid nanofluids, which hold significant potential for improving energy efficiency in industrial heat transfer systems. Governing equations that account for variable viscosity, thermal conductivity, and diffusivity are converted into a dimensionless form and solved numerically via the Keller-Box method. The analysis examines profiles for velocity, temperature, and concentration, alongside key engineering parameters: skin friction, Nusselt number, and Sherwood number. Results indicate that wedge geometries exert a more pronounced influence on the flow and thermal fields than cones. Furthermore, the use of hybrid nanofluids is shown to markedly enhance heat transfer performance. Validation against established limiting cases confirms excellent agreement with prior published results. The insights gained from this work offer a foundation for optimizing thermal management in engineering systems utilizing complex nanofluid flows. The study concludes by discussing novel practical applications in advanced heat exchangers, electronic cooling systems, and energy-efficient industrial processes, underscoring its direct practical relevance.

Technologies that utilize natural renewable resources and rely on no fuels are more sustainable and could, in part, solve the world's current water and energy problems. The aim of this study is to fabricate and develop a single solar still that is directly connected with a solar parabolic trough and does not utilize any heat exchanger. An innovative feeding water tank was installed with the parabolic unit. Fieldworks and manufacturing, laboratory experiments, and water quality analysis were the tools used in this study. The results of the field experiments demonstrated that the overall water productivity of the modified solar still increased by 177% compared to the conventional still. The average hourly quantity of freshwater obtained from the modified and unmodified models of the solar still were 0.67 L/m 2 /hr and 0.38 L/m 2 /hr, respectively. Building on these results, this study also proposed the future investigation of a step-shaped conical unit for the same device, which appears more promising and easier to handle, install, and maintain. This study showed feasible and viable results and verifies the importance of technologies that rely on renewable resources to achieve secure and sustainable management of the world's water and energy needs.

A low-cost rigid foam-based concentrator technology development program was funded by the DOE SunShot Initiative to meet installed cost goals of $75/m2 vs. current costs of $200–250/m2. The cost reduction in this approach focuses primarily on designing a mirror module with a rigid foam center with stainless steel facesheets and reflective film. The low mechanical strength of the foam is compensated by optimizing the densities and dimensions to meet pointing accuracy requirements of 4 milliradians (mrad) in 27mph winds. Two alpha concentrators were built to validate the mirror module manufacturing process and one of them was accurate to 0.15 mrad RMS vs. the design requirement of 1 mrad RMS. To understand the lifetime reliability of the panels, fifteen 4-inch square samples were exposed to various environmental conditions including acid rain, bird droppings, thermal cycling, and the final results indicated no loss in reflectivity of 95%. UV testing will be performed in the next phase...

In this study, the coldest days of 2022 in the Djelfa region, Algeria, were determined using astronomical and climatic data. The timing of sunrise, sunset, and duration of sunlight, as well as changes in solar radiation intensity and air temperature, were analyzed. By converting solar radiation into heat and solving differential equations, the study examined water exit temperature, thermal energy, and total yield as outputs of a renewable energy converter. The effect of different glass coverings on these outputs was also investigated. The coldest day in 2022 was found to be the first day of January, with nine hours and 43 minutes of sunlight, a maximum solar radiation intensity of 670.34 MW/m², and a maximum air temperature of 16.9 °C. The outputs of the solar center followed a parabolic pattern for the first two parameters and increased over time for the remaining outputs, regardless of the glass type. However, using glass with a high emission coefficient, such as clear monochromatic glass, resulted in the highest values for the outputs: 52.57 °C, 7.5 kW, 162 MW, and 70.62%. By understanding solar energy conversion and thermal behavior, the study contributes to energy-efficient designs and renewable integration, aiding in sustainable urban development. Findings can inform decision-makers in optimizing material selection, promoting resilient infrastructure, and advancing sustainable practices for a low-carbon future.

High levels of solar radiation are available in Cyprus and any attempt to devise or implement a solar AC system with feasible costs could be worthwhile. In this paper, the energy performance of a variable refrigerant flow (VRF) heat pump system in a 2-story office building in Paralimni, a city in Cyprus, is investigated and the AC system is integrated with a solar-driven Organic Rankin Cycle (ORC). An organic Rankine cycle with an internal heat exchanger is designed with a constant output rate of 3.920 kW, which delivers a total of 8,154 kWh yearly. The solar system consumes a 454 kWh auxiliary heating rate per year to deliver the desired mass flow rate and outlet temperature for the ORC. As a result, the designed solar-driven organic Rankin cycle delivers a net of (8,154 – 454) kWh = 7,700 kWh output energy each year, meaning 7,700 kWh energy saving per year, equal to 97% of VRF annual energy demand. This amount of yearly energy saving yields 2,010 USD yearly capital saving as the reward of investment in this system, and defining a 20-year project, the implementation of this solar-driven power generation system at the end of the project’s lifetime would save 40,200 USD. This scheme, suggests a technically practical approach for low cost or free air conditioning for all year for this country, with its high demands for thermal comfort at low costs.

The primary heat source from the sunlight is solar energy (SE), which is used in photovoltaic (PV) panels, solar power plates, PV, streetlights, and solar-based hybrid nanocomposites. Currently, research is focused on analyzing and improving the efficiency of SE, particularly for powering aircraft, by combining solar power with nanotechnology advancements. As such, this study focuses on examining concentrated solar power and proposes a method to improve the performance of solar airplanes by employing nanotechnology. Furthermore, the work is based on the investigation of the flow rate, thermal distribution, and entropy generation of the magnetized tangent hyperbolic hybrid nanofluid (HNF) along the interior parabolic solar trough collector of an aircraft wing. This work utilizes similarity variables to simplify the partial derivative model into ordinary differential equations. These equations are then solved using the Galerkin weighted residual approach with the help of MATHEMATICA 11.3 software. From the obtained outcomes, it is reflected that the HNFs have high thermal conductivity than the NF. Intensification of Weissenberg number improves the performance of airplane wings subjected to heat transmission. Therefore, this research contributes to improved thermal management in advanced nanotechnology and solar aircraft.

The main aim of this experimental work is enhancing the thermal performance of a modified PTSC system by using a corrugated absorber tube with a Fuzzy model system to predict the thermal efficiency (ηth) and Nusselt number (Nu). The experimental work is carried out at mass flow rates (m˚) of 0.02 Kg/s, 0.025 Kg/s, 0.03 Kg/s, 0.035 Kg/s, and 0.04 Kg/s. The Reynolds number (Re) were determined in the ranges of 2000 to 4000. According to the data are obtained in the experimental work, the fuzzy model of the PTSC system has been created considering five inputs and two outputs data. The input parameters include the inlet water temperature (Tin), the outlet water temperature (Tout), receiver temperature (Tr), mass flow rate (m˚), and solar intensity (I). While the output parameters include the thermal efficiency (ηth) and Nusselt number (Nu) of the PTSC system. The triangular MFs and the Mamdani-style of model systems are used in this modeling. The final results show that the inner geometry modified technique enhanced the heat transfer coefficient and the thermal efficiency of the PTSC system to generated vortex in the flow. More specifically, the use of a using a corrugated absorber tube enhanced the collector efficiency by 5.1% to 5.5% compared with a smooth absorber tube. Also, the predict value are founding to been in near settlement with the investigational counterparts with accuracy of ~92 %. Therefore, the proposed Fuzzy model system has high validity and accuracy for predicting a PTSC system's performance relative to that of the conventional model. The benefits of this approach are speed, flexibility, and the using of specialist information for predict as compared to that of the conventional model.