Desirability Function Methodology Research Articles

Impact of Corn Fiber on the Physicochemical/Technological Properties, Emotions, Purchase Intent and Sensory Characteristics of Gluten Free Bread with Novel Flours

Gluten-free products present huge advantages for individuals with gluten intolerance or celiac disease. The most influential strategy to develop a product comparable to wheat-containing gluten products is to promote its nutritional and sensorial attributes. Recently, rice flour and teosinte flour were used to develop gluten-free bread. As a result, this work aimed to compare the physical/technological attributes of bread made with rice flour and teosinte flour with corn fiber fortification and examine consumer acceptance and purchase intent. An extreme vertices mixture design decided that a teosinte flour (43.4%), high protein white rice flour (55%), and high protein brown rice flour (1.6%) ratio of gluten-free flour mixture for bread was best based on the sensory attributes utilized for the desirability function methodology. After optimizing the gluten-free flour mixture, the bread was fortified with corn fiber under 1.7 g and 3.8 g per serving, and it was evaluated to examine its physical/technological attributes, consumer perception, liking, emotions, and purchase intent. Incorporating fiber into gluten-free bread impacted the color and texture, giving lighter and yellower colors with a firmer texture. Likewise, concerning health benefit claims, gluten-free bread with fiber claims only improves the purchase intent and overall liking of bread containing 1.7 g per serving of fiber. The flavor attribute was the main driver for consumers’ purchase decisions. This product could be beneficial for consumers who are seeking fiber in their diet.

Reduced-sodium roasted chicken: Physical/technological characteristics, optimized KCl-seasoning mixture, consumer perception, liking, emotions, and purchase intent.

For thousands of years, sodium chloride (NaCl) has been used as a preservative and flavor enhancer. In the organism, NaCl plays a role in nerve functions, osmotic pressure, and nutrient absorption. However, high consumption of NaCl could lead to health issues, such as hypertension and heart-related problems. For these reasons, potassium chloride (KCl) has been considered a salt substitute in foods, but KCl could be limited to food matrixes because of its unwanted bitterness and metallic aftertaste. As a result, the objective of this study was to analyze KCl-reduced-sodium roasted chicken in physical/technological characteristics, KCl-seasoning mixture, consumer perception, liking, emotions, and purchase intent (PI). An extreme vertice mixture design decided granulated garlic (74.09%), black pepper (9.95%), smoked paprika (14.47%), and KCl (1.39%) ratio of good seasoning-KCl mixture for roasted chicken based on sensory attributes used on the desirability function methodology. After optimizing the KCl-seasoning blend, NaCl/KCl replacement levels (0%, 25%, 50%, 75%, and 100%) were established and evaluated consumer perception, liking, emotions, and PI. Adding 25% and 50% of KCl showed no significant (p>0.05) impact on the sensory attributes. Likewise, PI significantly (p<0.05) increased when utilizing 25% and 50% of KCl after panelists received information about sodium health risks (SHR). Regarding emotional responses, unsafe and worried significantly (p<0.05) decreased among the highest KCl replacement levels (75% and 100%) after panelists obtained the SHR. Overall liking, gender, age, salt user, and positive emotional responses (satisfied and pleased) were decisive predictors concerning PI among panelists.

Multi-Response Optimization of Thermochemical Pretreatment of Soybean Hulls for 2G-Bioethanol Production

Soybean is a major crop used in the production of human food. The soybean hull (SH) is also known as the seed coat and it constitutes about 5–8% of the total seed on a dry weight basis, depending on the variety and the seed size. Dilute sulfuric acid was employed for the thermochemical pretreatment of SH prior to enzymatic saccharification and alcoholic fermentation. Empirical modeling of response surface, severity factor and multi-response desirability function methodology, were used to perform the process optimization. Temperature, acid concentration and reaction time were defined as operational variables, while furfural, 5-hydroxymethylfurfural and solubilized hemicellulose and cellulose were defined as response variables. Mathematical models satisfactorily described the process and optimal conditions were found at 121 °C; 2.5% w/v H2SO4 and 60 min. More than 80% and 90% of hemicelluloses and celluloses, respectively, were able to solubilize at this point. The fermentation performance of an industrial Saccharomyces cerevisiae strain was also evaluated. The glucose available in the hydrolysates was completely consumed in less than 12 h, with an average ethanol yield of 0.45 gethanol/gglucose. Thus, the thermochemical conditioning of SH with dilute sulfuric acid is a suitable operation for 2G-bioethanol production.

Optimized mechanical properties of magnesium matrix composites using RSM and ANN

This study investigated the effect of stirring speed, stirring time, and particle weight fraction on the mechanical properties of magnesium matrix composites (Mg-MMCs) synthesized by the stir casting process. In addition, response surface methodology (RSM) and artificial neural network (ANN) models were used to optimize process parameters and create predictive models for evaluating the mechanical properties of Mg-MMCs. According to the results, the optimal parameter conditions for maximum mechanical properties based on the desirability function methodology were achieved at a stirring speed of 312.8 rpm, a stirring time of 11.9 min, and a weight fraction of particles of 9.9 wt%. In conjunction with the ANN and RSM models, the expected findings in this study will present beneficial recommendations in selecting main process parameters, contributing to the development of a good database for magnesium composites in manufacturing and mechanical performance evaluation.

Goldenberry powder processing: analysis by a response surface methodology

Goldenberry (Physalis peruviana) is a fruit of great interest for its nutritional properties and bioactive compounds, such as carotenoids. This study aimed to determine the ideal conditions for the development of a goldenberry powder. A Central Composite Design (CCD) was adopted to obtain response surfaces. For processing, different temperatures (50 - 70ºC) and times (27.18 - 32.82 hours) were used for dehydration of the fruits, evaluating the content of total carotenoids as a response and the moisture content around 15%. Data obtained were tested by analysis of variance (ANOVA) and fitted to a second-order polynomial equation using multiple regression analysis. An optimization study was carried out and the desirability function methodology was applied to find the ideal process condition. The optimization was determined at 52ºC and in a time of 27.18 hours, in which the experimental value obtained for total carotenoids was 12656.5 ± 527.22 mg 100 g-1 and moisture content of 15.00 ± 0.26%. In this condition, the global desirability value was 1.000 and the experimental values agreed with the predicted ones. Second-order polynomials were able to predict the carotenoids content in goldenberry powder, as well as the moisture content of the powder. The CCD and response surface tools were effective in optimizing the process. The production of goldenberry powder under these experimental conditions represents a viable alternative for adding value to the fruits, enabling the production of a potential food ingredient with carotenoid retention.

Analysis of interactions between polymeric gel and esophageal mucosae by a multivariate experimental approach

Gels with mucoadhesive properties have been proposed to deliver drugs by several routes of administration. The aim of this work was to study the in vitro mucoadhesion of a polymeric gel on pig esophageal mucosa by the tensile strength analysis using a texturometer and to evaluate the influence of instrumental variables on mucoadhesive properties. The influence of contact force, contact time, probe withdrawal speed and volume of hydration liquid on measured maximum detachment force and detachment work was studied using a multivariate approach. The results showed that the detachment force was clearly influenced by the contact force, contact time, probe withdrawal speed and their interactions. The values of maximum detachment force and work varied from 0.090 to 1.710 N and 0.089–0.788 N.mm, respectively. The values of standard deviations for both force and work were proposed to indicate the best experimental conditions and ranged from 0.004 to 1.129 and 0.001 to 0.305, respectively. The optimal conditions for detachment force and work measurement were determined by the desirability function methodology, resulting in experimental values of 0.5008 ± 0.0840 N and 0.2967 ± 0.0484 N.mm, respectively. The approach of using standard deviations to optimize experimental conditions proved to be effective for reproducible assays.

Experimental and computational study of fluidized-microwave drying process of shrinking parchment coffee and determination of quality attributes

Abstract This work presents the fluidized bed drying process combined with microwaves applied to Parchment coffee. In order to study different parameters that affect the quality of the grains, a mathematical model that describes energy and mass transfer during the drying process is presented and solved using Finite Elements Method (FEM) through COMSOL Multiphysics software. The model also considered the shrinkage of the grains due to water removal. Experiments were carried out in experimental prototype equipment obtaining the drying curves, which were utilized to validate the mathematical model. To study the impact of the operating conditions on the quality of the processed coffee, total polyphenolic content and antioxidant capacity were determined by Folin-Ciocalteau and free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods, respectively. Finally, nutritional parameters were related to operating conditions by the polynomial regression and desirability function methodology. Optimal operating conditions (1.4 m/s and 500 W) were found, which provides a product of excellent final quality.

Dual desirability function and RSM approaches for modeling the ideal nonwoven cover bunch for protecting date fruit

According to literature survey, many works have dealt with studying the effect of some bags on biological, chemical and physical quality of date fruit. In this study, RSM (response surface methodology) modeling and desirability function methods were applied and compared to predict the overall quality of cover date bunch samples. Five nonwoven bagging product are selected to be examined that are used for the first time on date palm sector. The results proved that a high quality of bagging product could be obtained in optimal conditions. Using the influential parameters and optimized conditions as fabric weight, thickness, air permeability, resistance to water penetration, tear strength and tensile strength, the results indicate that the cover date bunch remains influenced especially by the air permeability properties and tensile strength as well. Desirability function has been proven to be effective to achieve ideal design performance. The results show that the highest desirability reached is 0.6.However, the efficient approaches to identify the relevant parameters and the relation between different quality features and parameters have not been completely studied. To overcome the gap, a combined method including desirability function and response surface methodology (RSM) was proposed. Referring to previous works, desirability function allows a high level of flexibility over classical mathematical methods in evaluating and defining global quality. According to the analytical results obtained, the desirability function method gives a more accurate prediction than the RSM one.

Protein recovery from sweet potato starch wastewater using modified chitosan

This study reports an effective method to explore the significant role of modified chitosan in recovering a protein from starch wastewater of sweet potato. Fourier transform infrared (FT-IR) spectroscopy, energy dispersive X-ray analysis (EDX), polarizing optical microscopy (POM), and scanning electron microscope analysis (SEM) are used to characterize modified chitosan. Parameters, such as agitation time, chitosan dose, initial pH, and settling time, are monitored over the protein recovery process. Also, the second-order polynomial model was developed with Box Behnken design (BBD). 3-D response surface contour graphs are plotted to learn about the interactive effects of process parameters on protein recovery. The optimum operating conditions are determined by using the desired function methodology. Under these optimal conditions, 95% of the protein was recovered. An artificial neural network (ANN)-based model was developed for simulating protein recovery. Electrophoresis analysis has shown that recovered protein can be used as livestock feed ingredients.

Optimization of Anthocyanin Extraction from Cockspur Coral (Erythrina Crista-Galli L.) Petals with Microwave-Assisted Extraction (MAE) using Response Surface Methodology

Cockspur coral (Erythrina crista-galli L) petals are flowers that contain anthocyanins and active compounds of flavonoids and tannins. This study aims to determine the optimum conditions for the anthocyanin extraction process of cockspur coral petals using Microwave-Assisted Extraction (MAE), analyzed through the Response Surface Method (RSM). This process uses ethanol-hydrochloric acid solvents and a Box-Behnken experimental design involving three factors, namely the solvent ratios (w/v) (1:5, 1:15, and 1:25), microwave powers (300, 450, and 600 watts), and extraction times (3, 9, and 15 minutes). As a result, the second-order polynomial model was enhanced and sufficient to explain the variation of the data that denoted the significant correlation with the independent variables and the response. Derringer's desired function methodology was used for optimizing studies and generated ideal conditions for each or combined an independent variable. The optimum anthocyanin extract of 5.82 mg/L was obtained at a power condition of 325,5 Watts, an extraction time of 3.05 minutes, and a solvent ratio of 20.5. Meanwhile, the operating conditions at a power of 310.8 Watts, a time of 14.94 minutes, and a solvent ratio of 24.96 resulted in the optimum color intensity (IC) of 1040.26. In the meantime, the optimum antioxidant activity was obtained at a power of 585.97 Watts, a time of 4.93 minutes, and a solvent ratio of 5.43 with IC50 of 0.115.

Optimisation of the ultrasound-assisted extraction of betalains and polyphenols from Amaranthus hypochondriacus var. Nutrisol

The present study optimised the ultrasound-assisted extraction (UAE) of bioactive compounds from Amaranthus hypochondriacus var. Nutrisol. Influence of temperature (25.86–54.14 °C) and ultrasonic power densities (UPD) (76.01–273.99 mW/mL) on total betalains (BT), betacyanins (BC), betaxanthins (BX), total polyphenols (TP), antioxidant activity (AA), colour parameters (L*, a*, and b*), amaranthine (A), and isoamaranthine (IA) were evaluated using response surface methodology. Moreover, betalain extraction kinetics and mass transfer coefficients (KLa) were determined for each experimental condition. BT, BC, BX, TP, AA, b*, KLa, and A were significantly affected (p < 0.05) by temperature extraction and UPD, whereas L*, a*, and IA were only affected (p < 0.05) by temperature. All response models were significantly validated with regression coefficients (R2) ranging from 87.46 to 99.29%. BT, A, IA, and KLa in UAE were 1.38, 1.65, 1.50, and 29.93 times higher than determined using conventional extraction, respectively. Optimal UAE conditions were obtained at 41.80 °C and 188.84 mW/mL using the desired function methodology. Under these conditions, the experimental values for BC, BX, BT, TP, AA, L*, a*, b*, KLa, A, and IA were closely related to the predicted values, indicating the suitability of the developed quadratic models. This study proposes a simple and efficient UAE method to obtain betalains and polyphenols with high antioxidant activity, which can be used in several applications within the food industry.

Extraction of flavonoids in pomelos’ peels using Box-Behnken response surface design and their biological activities

The objectives of this study were to optimize the extraction conditions of flavonoids from the pomelo peel using the Box-Behnken response surface methodology and to investigate the chemical composition and biological activities of the extracts from three different pomelo species under optimized extraction conditions. Three extraction condition factors of were varied, including the solid-solvent ratio (1/15-1/45 g/ml), temperature (30-60oC), and time (20-60 min), which affected the efficiency of the total flavonoid content (TFC). The high R2 coefficient of 0.93 indicated that the experimental data obtained in this study fit well to a second-order polynomial using multiple regression analysis. The maximum TFC extracted from the pomelo peel was 6.0 mg/g (dried basis, db), which was obtained using Derringer’s desired function methodology under the following optimum conditions: a solid-solvent ratio of 1/44 g/ml, temperature of 30.7oC, and time of 34.6 min. The results also indicated that the Tan Trieu pomelo peel had the highest TFC and naringin concentration followed by the Nam Roi and Duong Hong pomelo peels, whereas the Nam Roi pomelo peel had a higher hesperidin concentration than the others. The extracts of the pomelo peels exhibited strong antioxidant activities with low IC50 values. However, these extracts showed only a slight effect on cancer cells, including lung cancer and breast cancer, when tested at 100 μg/ml.

Thermohydraulic performance optimization of cooling system of an electric arc furnace operated with nanofluid: A CFD study

This article optimizes the thermohydraulic performance of a cooling system of an electric arc furnace working with the alumina–water nanofluid under turbulent flow regime. The impacts of Reynolds number (Re), mass flow rate, and nanoparticle concentration on the temperature distribution through the panel and pumping power are assessed. The cooling performance of the panel improves with the elevation of the concentration and Re, and it is found that this increment is more intense at smaller Re values. Thereby, at ϕ = 0%, the internal wall temperature of slag decreases around 10.0% with the increment of the Re from 25,000 to 100,000 but it decreases only about 2.5% with the increment of the Re from 100,000 to 200,000. The pumping power heightens when either concentration or Re increases. The concentration has greater influence on the pumping power at larger Re values. The desirability function methodology is utilized to determine the optimum value of the Reynolds number, while the assumed objective function is employed to minimize the temperature together with pumping power. The optimum values for the temperature of the cooling panel wall and pumping power are about 533 K and 206 W, respectively, at the optimal Reynolds number of 123,485. The composite desirability with the value of 0.92 verifies that the optimization process is done with favorable results.

Effects of high volume dolomite sludge on the properties of eco-efficient lightweight concrete: Microstructure, statistical modeling, multi-attribute optimization through Derringer's desirability function, and life cycle assessment

Micro fines stone sludge (μSS) as dolomite, is a hazardous waste and creates many health problems along with air, water and land pollution. The research paper presents the statistical models with the help of response surface methodology, aiming to develop μSS incorporated structural grade lightweight cellular concrete (SG- LCC) using novel mix design (with 15 design steps). The three level-three factorial (33) Box Behnken Design was employed to investigate the effects of three input parameters i.e. temperature of water to be diluted with surfactant (Tw), flowability value (FV) and percentage replacement of μSS (%RμSS) on all the dependent responses i.e. oven dry density (ρOD), uniaxial compressive strength (fc.28d), performance factor for uniaxial compressive strength (PFc.28d) and thermal conductivity (λ-value). The regression analysis and Derringer's desired function methodology was applied to find out an optimum condition for developing SG-LCC (as replacement of masonry brick) containing maximum volume of wet μSS. It was finally concluded that by optimizing above sensitive input parameters, eco-efficient SG-LCC can be produced at Tw of 31°C, %RμSS of 51.50% and FV of 135.50%.The developed SG-LCC have ρOD of 1243 kg/m3, fc.28d of 8.23 MPa, PFc.28 of 6621 Pa/(kg/m3) and λ-value of 0.456 W/mK. Microstructure studies indicated that μSS filers does not participate chemically in cement hydration reactions. However, these filers imparted physical effect by acting as nucleation sites for the cement hydration products. The economic index was 18.42% higher for the final optimized mix, than that of the control mix. Use of wet μSS (up to 51%) to produce optimized SG-LCC mix, will not only reduce the production cost up to 17.54%, but also it will conserve natural RS and tap water by 26.28% and 100%, respectively. Life cycle assessment also showed that production of SG-LCC containing higher amount of μSS; consumes lower energy, and emits lesser amount of greenhouse gases that are the key parameters requirements for sustainable development goals.

Functional properties of extracts and residual dietary fibre from pomegranate (Punica granatum L.) peel obtained with different supercritical fluid conditions

The objective of this study was the optimization of supercritical fluid extraction (SFE) using CO2 for extraction of bioactive compounds from pomegranate peel, evaluating the functional properties of different extracts (SFE extracts and alcohol-insoluble residues (AIR)). A Box–Behnken design combined with response surface methodology (RSM) was used to optimize extraction pressure (250–300 bar), temperature (45–55 °C) and time (2–4 h). The results showed that these SFE conditions have a significant effect on the responses studied. Antioxidant activities of the extracts, residual dietary fibre and pectin were the parameters that best fitted the quadratic model developed in this study. RSM optimization of these parameters was performed using Derringer's desired function methodology, estimating optimal conditions for extraction pressure (291 bar), temperature (46.5 °C) and time (2.5 h). The results reveal that supercritical technology is an interesting option for fractionating and recovering high-value compounds from pomegranate by-products.

Ipomoea carnea: a novel biosorbent for the removal of methylene blue (MB) from aqueous dye solution: kinetic, equilibrium and statistical approach

The biosorption potential of cost-effective and agricultural residue, Ipomoea carnea wood (ICW) was examined by the removal of cationic dye, methylene blue (MB) from aqueous solution. The surface morphology, structural and thermal properties of untreated ICW were analyzed using Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Thermo-gravimetric Analysis (TGA), respectively. The effects of different parameters namely concentration of biosorbent, initial pH, initial MB composition and temperature on biosorption capacity and biosorption (%) were studied. The kinetic and equilibrium models were developed to fit the experimental data on MB biosorption. The maximum biosorption capacity of 39.38 mg g−1 was obtained at 40 °C using Langmuir model. The removal of MB was found to be significantly varying with temperature. Box–Behnken design was applied to optimize the biosorption parameters. The optimized condition for MB biosorption was evaluated as dosage of 3.1 g L−1, pH of 7.04, Temperature of 49.1 °C, MB concentration of 30.48 mg L−1 and maximum biosorption (%) of 83.87. The regeneration of ICW was investigated by five cycles using a suitable eluting agent. Hence, ICW without any pretreatment and chemical modification is a potential candidate for the removal of MB in terms of availability and economy of the process. Novelty statement Ipomoea carnea wood (ICW) without any pretreatment explored a potential biosorbent for the removal of methylene blue (MB) in terms of availability and economy of the process. The physico-chemical properties of ICW characterized using Scanning Electron Microscopy, Fourier transform infrared spectroscopy and Thermo-gravimetric Analysis showed ICW as a promising biosorbent for MB removal. Presence of heterogeneous with rugged morphological structure, cavities, irregular shape and size of large pores provide the better biosorption capability for MB molecules using ICW without any pretreatment or chemical modification. Analysis of kinetic and isotherm models was performed to examine the better fitness of experimental data with model. Thermodynamic parameters indicating feasible and endothermic MB biosorption. Statistical design of experiments is used to optimize the condition and corresponding maximum MB removal using Derringer’s desired function methodology. Untreated ICW is a potential reusable biosorbents, effectively employed in successive biosorption and desorption process for the removal of MB from aqueous solutions.

Optimizing the removal of COD and Phenolic compounds from olive mill wastewater by Fenton oxidation using experimental design

The production of olive oil, leads to the co-production of large quantities of olive mill wastewater (OMW). This waste has a high polluting power as well as a high antibacterial activity exerted, among others, by various phenolic compounds. In this study, the Fenton process using hydrogen peroxide (H 2 O 2 ) as oxidant and ferrous ions (Fe 2+ ) as catalyst was used to treat OMW. Box–Behnken design (BBD) based on the response surface methodology (RSM) was adopted to evaluate the effects of concentration [H 2 O 2 ], concentration [Fe 2+ ] and reaction time on the chemical oxygen demand (COD) removal, phenolic compounds (PC) removal and the residual H 2 O 2 level remaining in the solution. According to the Analysis of Variance (ANOVA), the three quadratic models that were developed using multiple regression analysis were reliable and successfully fit the experimental data with a high coefficient of determination R 2 ranging from 0,9969 to 0,9999. Optimal operating conditions based on the desirability function methodology were found to be [H 2 O 2 ] = 13,79g/l (0,4mol/l), [Fe 2+ ] = 0,55g/l (0,01mol/l) and reaction time = 5,73h. Under the values of these variables, COD removal of 88,70% and PC removal of 84,26% with no residual H 2 O 2 were predicted with a desirability value of 1.

Property enhancement of mustard stalk biomass by Torrefaction: Characterization and optimization of process parameters using response surface methodology

Present work is devoted to the study of independent operating parameters namely torrefaction temperature (TT), residence (torrefaction) time (RT), and heating rate (HR) on the slow pyrolysis or torrefaction of an important agro residue namely mustard stalk (MS). Response surface methodology along with three-factor and three-level Box-Behnken design is applied to find the effect of above mentioned three parameters on the higher heating value, energy yield, and fixed carbon of the torrefied MS. Experimentation and modeling analysis reveal that the effect of these three factors' responses follows the sequence: (TT) > (RT) > (HR). Also, the experimental data were analyzed using analysis of variance and fitted to a second-order polynomial model applying multiple regression analysis. Predictive models were obtained which were able to satisfactorily fit the experimental data, with the coefficient of determination (R2) values higher than 0.95. Derringer’s desirability function methodology was used for the optimization study which showed that the HHV, EY, and FC at optimum condition TT 300 °C, RT 20 min, HR 5 °C/min were obtained as 21.26 MJ/kg, 81.26 %, and 35.38 wt%, respectively for MS. Torrefied MS, as compared to raw MS, showed better solid fuel properties for co-combustion with coal and gasification. The experimental values closely agree with the corresponding predicted values. The functional behavior of raw and torrefied MS was studied by Fourier Transform Infra-Red Spectrometry.

Optimization for sensory and nutritional quality of a mixed berry fruit juice elaborated with coconut water

A new juice market, consisting of mixtures of fruits, is expanding in the beverage segment, in order to increase even more the nutritional and sensory characteristics. In addition, in the preparation of juices, the option exists to replace water with coconut water. The aim of this study was to develop and optimize mixed juices based on coconut water and berries (strawberry, blackberry, and red raspberry), through the mixture design, desirability function, and response surface methodology. Mixed juices were evaluated by rheological, physical, physicochemical, sensory, and nutritional characteristics. The treatments produced with strawberry (50% or 100%) were preferred among the tasters, and the juices elaborated using blackberry contributed to higher viscosity, antioxidant activity, phenolic compounds, and total anthocyanins. According to optimization, the mixed juices should contain 50-60% strawberry, 40% blackberry, and 0-10% raspberry. Thus, the mixed juices produced from these fruits have better characteristics than the juice of only one fruit type.

Energy and exergy analysis of SiO2/Ag-CuO plasmonic nanofluid on direct absorption parabolic solar collector

Experimental investigations on the application of SiO2/Ag-CuO plasmonic nanofluid on direct/volumetric absorption parabolic solar collectors is presented in this article. The process variables for the preparation of nanofluid were optimised by employing the desirability function and response surface methodology (RSM). The optimisation was performed to achieve nanofluid with maximum possible thermal conductivity and solar absorptivity. The final solar radiation absorbed fraction and relative thermal conductivity noted for the optimised nanofluid was 82.84% and 1.234, respectively. The performance of the collector was evaluated at various flow rates from 60 lph to 90 lph, using water and optimised nanofluid as the heat transfer fluid. It is noted from the results that the thermal efficiency of the collector increases with the flow rate whereas, the exergy efficiency decreases for both water and nanofluid. The highest temperature difference of 11.27 K was noted at 60lph for nanofluid which corresponds to a thermal efficiency of 57.47%. A maximum thermal efficiency of 64.05% was noted at 90 lph which corresponds to an enhancement of 48.19% in comparison with water. Exergy efficiency of the nanofluid was enhanced by 9.4% at 60 lph, in comparison with water.