Solar Collector

In Iraqi climatic conditions, the solar collector systems are characterized by high degradation in thermal performance that is a result of poor selection of tilt-angle, high dust deposition, high ambient temperatures, aerosol loading, and strong seasonal variations in solar irradiance. These drive down solar radiation absorption, behavior in heat transfer, and overall energy efficiency, and conventional fixed-angle optimization cannot guarantee longterm stable performance in hot-arid environments. In this paper, the researcher suggests an integrated heattransfer and optimization model to be used to determine optimum annual and monthly tilt angles to solar collectors at Baghdad. The model is a combination of solar geometry relations, including the beam radiation ratio (Rb) and total tilted irradiance (HT), and equations of thermal energy balance that include the convective and radiative heat transfer. Particle Swarm Optimization (PSO) and Gay Wolf Optimizer (GWO) are two metaheuristic algorithms that are used to optimize tilt-angle scheduling under different environmental conditions. The results of simulation indicate that the optimal annual tilt angle is around 29 • C with the best monthly tilt being close to 0 • C in June-July and 59 • C in December. The monthly optimized approach enhances performance in terms of thermal performance by approximately 12-15% and sensitivity to short-term fluctuations in irradiance and ambient temperature as compared to fixed-tilt systems. The proposed framework offers a convenient balance between simplicity and adaptability, providing better performance without the complex tracking systems and enabling application scale ability to solar thermal systems, PV/T systems, and hybrid systems.

This article examines the theoretical aspects of choosing a tilt angle for the solar flat-plate collectors used at ten different stations in the world and makes recommendations on how the collected energy can be increased by varying the tilt angle. In this paper, the collector surface is assumed to be facing toward equator. For Indian stations, the calculations are based upon the measured values of monthly mean daily global and diffuse solar radiation on a horizontal surface. For other stations, the calculations are based upon the data of monthly mean daily global solar radiation and monthly average clearness index on a horizontal surface. It is shown that nearly optimal energy can be collected if the angle of tilt is varied seasonally, four times a year. Annual optimum tilt angle is found to be approximately equal to latitude of the location. It is found that the loss in the amount of collected energy is around 1 % if the angle of tilt is adjusted seasonally instead of using opt for each month of the year. The loss of energy when using the yearly average fixed angle is around 15 % compared with the monthly optimum tilt.

This article examines the theoretical aspects of choosing a tilt angle for the solar flat-plate collectors used at ten different stations in the world and makes recommendations on how the collected energy can be increased by varying the tilt angle. In this paper, the collector surface is assumed to be facing toward equator. For Indian stations, the calculations are based upon the measured values of monthly mean daily global and diffuse solar radiation on a horizontal surface. For other stations, the calculations are based upon the data of monthly mean daily global solar radiation and monthly average clearness index on a horizontal surface. It is shown that nearly optimal energy can be collected if the angle of tilt is varied seasonally, four times a year. Annual optimum tilt angle is found to be approximately equal to latitude of the location. It is found that the loss in the amount of collected energy is around 1 % if the angle of tilt is adjusted seasonally instead of using opt for each month of the year. The loss of energy when using the yearly average fixed angle is around 15 % compared with the monthly optimum tilt.

Abstract- The urgent challenge of climate change calls for innovative energy solutions that reduce greenhouse gas emissions and strengthen system resilience. Solar thermal technology, when enhanced by advanced fluid dynamics, offers a promising pathway towards sustainable clean energy. This study simulates the performance of hybrid nanofluids, specifically copper and titanium dioxide nanoparticles dispersed in water, to improve heat transfer efficiency in parabolic solar thermal collectors. The governing nonlinear partial differential equations describing mass, momentum, energy, concentration, and magnetic induction are reduced to ordinary differential equations using similarity transformations and solved using MATLAB’s collocation based bvp4c solver. The model assumes two-dimensional laminar flow, thermal equilibrium between fluid phases, and temperature dependent hybrid nanofluid properties. Parametric analysis shows that Brownian diffusion and thermophoresis significantly influence velocity, temperature, and nanoparticle concentration, while Prandtl and thermal Grashof numbers strongly govern convective transport and MHD coupling. The findings provide deeper physical insight into hybrid nanofluid dynamics under electromagnetic influences and support the optimization of solar thermal collectors for enhanced thermal performance. The study contributes to Sustainable Development Goals 13 by advancing efficient and climate resilient clean energy technologies

An adverse effect of changing titanium dioxide nanoparticle shapes and concentrations on the amount of friction and Nusselt number ratio of improvement for thermal solar collectors (TSCs) has been examined. Several nanoparticle shapes (PD = 20-50 nm) and varying concentrations of TiO2 nanoparticles (NC = 1-4%) have been used for preparation of nanofluid via stirrer mechanism. Both pure water and water/TiO2 flow under diverse Reynolds numbers, spanning from 5,000 to 30,000. The permitted amount Nusselt number is found in the water/TiO2 mixture with nanoparticle concentration (NC = 4%) and nanoparticle diameter (PD = 20 nm). With water/TiO2 nanofluid flow at Re = 5,000 and 15% flow at Re = 30,000, the average Nusselt numbers climb by 23% and 13%, respectively. It has been observed that for both fluids, the skin friction factor diminishes as the Reynolds number rises. The skin friction factor of a water/TiO2 nanofluid is higher than that of pure water. Employing water/TiO2 nanofluid as the working fluid and adjusting the concentration of TiO2 nanoparticles from (NC = 1%) to (NC = 4%), the average Nusselt numbers improved by 29% at the lowest Reynolds number and by 39% at the highest Reynolds number of 30,000. Across all Reynolds principles, the Nusselt number increased as the nanoparticle diameter shrank. The maximum Nusselt number is synthesized by TiO2 nanoparticles with the smallest dimension (PD = 20 nm). The most important ratio of improvement for the Nusselt number in TSC is offered by the smallest size TiO2 nanoparticles (PD = 20 nm). This investigation showed that infusing 5% nanoparticles to water/TiO2 (diameter of 20 nm) leads to significant heat transfer development, which raises TSC's thermal performance.

In this study, combine operation of air source heat pump and vacuum tube solar collector system was experimentally observed. Contribution of heat pump system on solar collector system performance was determined. Solar collector experimentation setup was constructed with 30 lt water storage tank and 4 items vacuum tube. Heat pump condenser which is in the form of pipe coil was placed into the water storage tank. System evaporatör is fan assisted aluminium fin and 2400 W capacities. Heat pump compressor is 745 W power. Temperature was controlled by 303-363 K range thermostat. During the experimentations solar radiation intensity, heating time and temperature of water was recorded. Experimentations were repeated
for three different operation conditions. In the first day, solar collector and heat pump system, the second day, only solar collector and on the third day, only heat pump system was operated and experimentation was completed. It is determined that, the system efficiency was enhanced about 5% according to the evaluations.

The subject of this study is the seawater distillation process enhancement through integration of the solar vacuum tube into the system. Positive effects on the rate of distillated freshwater achieved by means of the enhanced system have been investigated experimentally. Experiments were done in the Turkish city of Samsun in the Black Sea region. A distillation pond setup having the volume of 0.015m 3 and a water surface area of 0.24m 2 was constructed. The distillation pond is covered with a condensation glass and also equipped with a 0.15m solar vacuum tube that is inclined at an angle of 30 o to the ground, a feed water tank connected with a ball cock, and distillated fresh water tank. Experimental results have shown that the rate of distilled fresh water was enhanced for about 62.5% by integrating the solar vacuum tube and the natural distillation pond. Isolation of the condensation glass not only prevents the light transmission to the pond but also heat loss from the pond; hence the rate of the distillated fresh water is increased for about 137.5% due to the natural distillation.

This test studies were conducted to examine the energy, exergy, and environmental-economic performance improvement of photovoltaic thermal collectors using a graphene nanoplatelet/water nanofluid, which has excellent heat transfer properties, low viscosity increases at low concentrations, nontoxicity, and long-term stability and compatibility. The study aims to contribute to the field by building a brick in the road of linking basic research in nanofluids and photovoltaics. Moreover, although studies of circulatory cooling systems draw on the grid, this research addresses this demand by using renewable energy sources, thereby reducing the grid dependency and increasing energy efficiency. Tests were carried out on photovoltaic thermal collectors (PV/T A and PV/T B) at concentrations of 0.05 mass% and 0.1 mass% nanofluids, respectively, at a flow rate of 0.4 L min-1. By circulating nanofluids, PV/T A and PV/T B collectors cooled 9% and 14% under 146 W mean solar power, respectively, while electrical outputs increased 38.31% and 48.74%. PV/T A and PV/T B yielded 37.20 W and 57.91 W of thermal power through removing heat from cells, respectively. The PV-R module, PV/T A and PV/T B had first and second law efficiency values of 7.67%, 35.86%, 50.89%, and 8.24%, 11.9%, 13.6%, respectively. The additional gain from cooling in the form of heat load and increased electricity output of the PV/T A and PV/T B increased the rate of solar energy utilization by 28.5% and 43.5%, respectively. This improvement can be considered as an environmental benefit, considering the equivalent reduction in CO 2 emissions from the grid emission factor of 84.88 kg year-1 for PV/T A and 139.64 kg year-1 for PV/T B .

One of the crucial post-harvest processes that contribute to the unique color, flavor, and taste of a coffee drink is drying technique. Solar drying refers to a technique that utilizes incident solar radiation to convert it into thermal energy required for drying purposes. A polyhouse solar dryer is a unique and cost-efficient method of drying agricultural products on a small as well as commercial scale. The fabricated dryer has three major units: a solar collector unit, a drying unit, and chimney unit components. The aim of this study was to manufacture and evaluate a 5-meter length and 2-meter width half-circled tunnel polyhouse type solar dryer using parchment coffee and hot pepper. The experimental results showed that the developed dryer has the capacity to dry averagely about 150 kg of hot pepper and 50 kg of wet coffee per batch. The obtained data were analyzed using software such as simple descriptive statistics and Origin Pro 2019 according to their suitability. Hot pepper was dried from an initial moisture content of about 82.95% to 10.42% in a polyhouse-type solar dryer within 6 days, while conventional sun drying took around 9 days. Using hot pepper, the average temperature inside the dryer was 53.90 °C to 62.57 °C in the full load condition, which was greater than the ambient temperature in all six days of the experiment. While the ambient relative humidity varies between 34.5% and 43.5%, the dryer's relative humidity using hot pepper was altered between 21.07% and 24.69%. In all six days of the experimental period, the relative humidity of the dryer was found to be less than that of ambient relative humidity due to the polyhouse effect. The wet coffee bean was dried from an initial moisture content of about 51.89% to 11.10% in a polyhouse-type solar dryer within 3 days, while by open-sun drying it took around 6 days. Using wet coffee, the temperature inside the dryer chamber were 50.08 °C to 54.08 °C at full load condition, which was greater than the ambient temperature in all three days of a tests. Whereas the ambient humidity in the air ranges from 39.77% to 42.22%, the dryer's relative humidity using wet coffee ranged between 22.22% and 23.46%. The average dryer thermal efficiencies of a polyhouse dryer use wet coffee beans and hot pepper were 64.48% and 86.87%, respectively.

Post-harvest losses of agricultural products remain a significant challenge in semi-arid regions such as Chad, where high ambient temperatures and limited preservation technologies considerably reduce food availability and quality. Solar drying has emerged as a sustainable and energy-efficient method for preserving fruits and vegetables by reducing moisture content and inhibiting microbial growth. This study investigates the thermal performance and drying behavior of an indirect natural-convection solar dryer under the climatic conditions of N'Djamena. The experimental setup consists of a flat-plate solar air collector coupled with a drying chamber equipped with multiple trays. Key parameters-including solar radiation, ambient temperature, air velocity, relative humidity, and product mass-were continuously monitored throughout the drying process. The thermal efficiency of the solar dryer, the evolution of moisture content, and the drying kinetics of okra were evaluated. Thin-layer drying behavior was analyzed using the Page model to describe the variation of moisture ratio with drying time. Experimental results indicate that the solar dryer achieved temperatures ranging from 50˚C to 65˚C, significantly exceeding the ambient temperature (34˚C-42˚C). Under these conditions, the moisture content of fresh okra decreased from 80% to approximately 6% within 8-10 hours, whereas traditional open-sun drying required 2-3 days to reach comparable moisture levels. The thermal efficiency of the system varied between 25% and 40%, depending on solar radiation intensity and airflow conditions. These results demonstrate that natural-convection solar dryers can substantially reduce drying time, enhance product quality, and minimize con

Solar drying is one of the important techniques which are drawing more attention in the recent years. The use of solar dryer helps to preserve the product for a longer time. The present paper focuses on the development of such a technique. In this study, a mixed mode solar dryer with heat storage materials (Pebbles) is developed. 4 kg chillies were used as drying product and experiments were conducted for the metrological conditions of Ujire, Karnataka, India. Design and fabrication of the developed drying system is explained in this paper. The analysis is carried out for its performance is also focused. The obtained results are discussed in detail. Air flow rate maintained was 4 m/s, maximum drying rate obtained was 5.5 grams/min and 4.78 grams /min for upper and lower tray. The results indicate that the upper tray showed better performance than lower tray. Maximum value of overall thermal efficiency of developed drying system was 36.69 %. Use of heat storage materials increases the temperature of incoming atmospheric air so that relative humidity decreases and this increases moisture extraction ability of air. Use heat storage materials also helps to sustain the sudden variation in air temperature at inlet of the dryer cabin.

Solar drying is an effective way to remove moisture from the products and helps to store for longer duration. In this present work, a solar drying system is fabricated by using locally available low cost materials. Mild steel pieces are used for heat storage materials. Experiments are conducted for free convection and forced convection arrangements. Obtained results show that, forced convective arrangement shows superior performance over free convective arrangement.

Solar Chimney Power Plant is a straightforward control design which utilises cosmic radiation to give skyward momentum to the inflowing air, thereby transforming the thermic energy into dynamic energy. It uses an aggregate of three established technologies:-1.Wind Turbine, 2.Greenhouse, and 3. Chimney.

In the course of the actual work, the efficiencies of this collector design have been experimentally investigated using an existing setup for an indoor and an outdoor testing of collectors. Indoor experimental results of the performance of the collector will be presented. Graphs of efficiency as a function of the collector's reduced temperature were established for variable collector operating conditions. Solar irradiation intensity, airflow rate, wind velocity and temperature and air inlet temperature were variable and adjusted to get the collector efficiency at every possible location in a new solar desalination process .The response of the collector outlet temperature and the endurance-test on the collector has also been done.

Photovoltaic (PV) modules experience a reduction in electrical performance when their surface temperature rises
beyond the recommended operating range. Most of the incident solar energy is converted into heat rather than electricity,
leading to efficiency loss and reduced panel life. This project investigates a photovoltaic-thermal (PVT) system using nanocoolant-based cooling to regulate PV surface temperature and enhance overall performance.

Parabolic trough collectors often face efficiency losses due to limited heat transfer and high pressure drops. This study numerically investigates the combined impact of ternary hybrid nanofluids and twisted tape inserts on thermal performance under turbulent flow (Reynolds number from 10,000 to 20,000). Using ANSYS Fluent, 15 models were developed with varying twisted tape configurations (0-4 inserts) and ternary hybrid nanofluid concentrations (0-24 wt%), assuming single-phase nanofluid flow under a 600 kW/m² non-uniform heat flux. Results show that the maximum Nusselt number improvement (44.3%) and friction factor enhancement (62.3%) occur in the model using 4 twisted tapes and 24 wt% ternary hybrid nanofluid. Also, the performance evaluation criterion reaches 1.219 using the optimal model with 2 twisted tapes and 24 wt% ternary hybrid nanofluids. These findings suggest that combining nanofluids and passive inserts can substantially enhance the thermal performance of parabolic trough collectors, guiding the design of next-generation solar receivers.

МЕТОДИЧНІ ВКАЗІВКИ ДО ВИКОНАННЯ ЛАБОРАТОРНИХ РОБІТ З ДИСЦИПЛІНИ «ВСТУП ДО ТЕХНІКИ ВИМІРЮВАНЬ» для бакалаврів з галузі знань 15 «Автоматизація та приладобудування» за спеціальністю 153 Мікро-та наносистемна техніка, та 17 «Електроніка та телекомунікації» за спеціальністю 171 Електроніка Рекомендовано Вченою радою факультету електроніки НТУУ «КПІ ім. Ігоря Сікорського» Київ -2017 МІНІСТЕРСТВО ОСВІТИ І НАУКИ УКРАЇНИ НАЦІОНАЛЬНИЙ ТЕХНІЧНИЙ УНІВЕРСИТЕТ УКРАЇНИ "КИЇВСЬКИЙ ПОЛІТЕХНІЧНИЙ ІНСТИТУТ імені ІГОРЯ СІКОРСЬКОГО" І.Д. Шовкун, Т.А. Саурова, О.В. Семеновська МЕТОДИЧНІ ВКАЗІВКИ ДО ВИКОНАННЯ ЛАБОРАТОРНИХ РОБІТ З ДИСЦИПЛІНИ «ВСТУП ДО ТЕХНІКИ ВИМІРЮВАНЬ» для бакалаврів з галузі знань 15 «Автоматизація та приладобудування» за спеціальністю 153 Мікро-та наносистемна техніка, та 17 «Електроніка та телекомунікації» за спеціальністю 171 Електроніка Київ -2017

Recibido el 28 de septiembre de 2004, aceptado el 21 de abril de 2005 RESUMEN Se diseñó y construyó un sistema de calentamiento de agua residencial, mediante dos colectores solares y un estanque. En el sistema se utilizaron tubos de cobre perforados por taladrado por fluencia térmica (TFT), unidos con soldadura de plata. El sistema funciona por termosifón y se emplea como fluido de calentamiento una mezcla de etilenglicol-agua. El fluido de calentamiento pasa a través de un serpentín de cobre a un estanque de 200 litros. Diariamente se calientan 80 litros de agua a una temperatura máxima de 45º C.

Owing to fossil fuels’ consumption and environmental pollution, it is necessary to make efficient use of energy based on the different renewable energy sources such as solar energy. The present research has focused on the design, construction, and assembly of a train of solar energy collectors consisting of five concentrators, which individually have significant differences in the arrangements focus tube reflective surface and the greenhouse effect. The collectors are operated under the same environmental conditions. In the analysis presented on the train of solar energy collectors, a theoretical–experimental study was performed on the different reflecting surfaces of each collector, such as the mirrors’ reflecting surface, reflecting surface of the 316 L stainless-steel mirror polished, reflecting surface of the aluminum foil’s reflective surface with an aluminum paint, surface reflective type 304 stainless steel-mirror polish. The present study was developed to analyze and discuss...

This article presents a feedback linearization control of a distributed solar collector field, which main purpose is to heat a fluid using the energy provided by the solar irradiation. The control objective is to track an outlet temperature reference manipulating the fluid flow trying to attenuate the effect of disturbances (mainly radiation and inlet temperature). A feedback linearization technique has been developed and implemented to control this nonlinear plant by merging both feedforward and feedback control. The design of the feedback controller is performed based on a linear simplified version of the system. Experiments in the real plant are shown.

The exergy analysis method was applied in order to evaluate the new combined cycle proposed by Goswami [Solar thermal technology: present status and ideas for the future. Energy Sources 1998;20:137–45], using Hasan–Goswami–Vijayaraghavan parameters. This new combined cycle was proposed to produce both power and cooling simultaneously with only one heat source and using ammonia–water mixture as the working fluid. The simulation of the cycle was carried out in the process simulator ASPEN Plus. The Redlich–Kwong–Soave equation of state was used to calculate the thermodynamic properties. The cycle was simulated as a reversible as well as an irreversible process to clearly show the effect of the irreversibilities in each component of the cycle. At the irreversible process two cases were considered, changing the environmental temperature. However, in order to know the performance of the new cycle at different conditions of operation, the second irreversible case was analyzed varying the r...

Solar collector's configuration plays important role on solar-powered refrigeration systems to work as heat source for generator. Three types of solar collector consisting of flat plate, evacuated tube, and compound parabolic solar collectors are compared to investigate their performances. The performances consist of the behavior of heat which can be absorbed by the collectors, heat loss from the collectors and outlet temperature of working fluid at several slopes of the solar collectors. The new accurate analysis method of heat transfer is conducted to predict the performance of the solar collectors. The analysis is based on several assumptions, i.e. sky condition at Bandung is clear and not raining from 08.00 until 17.00 and thermal resistance at cover and absorber plate is negligible. The numerical calculation results confirm that performance of the evacuated tubes solar collector at the same operating conditions is higher than the others. For the case of an evacuated-tubes s...

This research presents the comparative thermal analysis of chimney assisted greenhouse solar dryer and open sun drying. Recognizing the critical role of solar drying in minimizing post-harvest losses within sustainable agriculture, prototype was developed in my PhD thesis work at AKS University, Satna (MP), India. The structures was engineered using MS steel angle frames and glazed with 200-micron polyethylene sheets to maximize the greenhouse effect, integrated with an attached chimney to induce a natural draft for enhanced ventilation. The investigation monitored key performance indicators at one-hour intervals, including solar irradiance, air velocity, relative humidity, dryer temperature, and crop moisture content. Experimental results demonstrated that the greenhouse effect significantly elevates the internal chamber temperature, confirming the dryer’s superior thermal capability. The findings suggest that this chimney assisted design provides an efficient, low-cost solution for improving drying rates and maintaining crop quality in agricultural processing. Thermal analysis revealed that the greenhouse solar dryer achieved a peak internal temperature of 38°C, significantly higher than the ambient temperature of 25°C. Drying trials conducted on paddy showed a reduction in moisture content from an initial 18.2% (wb) to a final 13% (wb) within the chimney assisted system. In comparison, traditional open sun drying only reduced the moisture content to 16.3% (wb) over the same period, highlighting the superior drying efficiency of the chimney-assisted greenhouse design. Design geometry and chimney height accounted for a 13°C temperature increase above ambient levels during trials conducted in Satna (MP) in December 2022.

A thermal analysis of the performance of a solar flat-plate collector operating in nonboiling. boiling, and superheated regimes is presented. The performance of the collector under these single and multiphase conditions is governed by the axial fractional channel lengths of the subcooled (nonboiling) and the superheated regions. The overall thermal loss coefficient, the dimensionless capacitance rate, and collector efficiency factors for various collector operating regions are defined. A new "Generalized Heat Removal Factor," ~,, and a new overall thermal loss coefficient, UL, for fiat-plate collectors under any operation mode are developed. The thermal efficiency a flat-plate collector, whether under nonboiling. boiling, or superheated conditions, is evaluated using ~, and UL. It is shown that the value of ~, de- creases and the value of UL increases as the degree of superheat increases. Current applications of fiat- plate collectors having multiphase flows are represente...

Flat plate solar collector (FPSC) and parabolic trough solar collector (PTSC) are widely used for residential solar water heating (SWH) applications. This work studied two different solar collector systems. Nanofluid and its influence on the residential solar water heating (SWH) systems were investigated. The two SWH systems were designed, installed, tested, and compared at varying mass flow rates (m f) of 0.47, 1.05, and 1.75 kg min-1 in ambient environmental conditions. The comparative study was conducted according to thermal efficiency (η th), useful energy gain (Q U), stored energy (Q S), outlet hot water temperature (T o), and difference temperature (ΔT) between the cold inlet and hot outlet water from the collectors. The analysis of outcomes showed that the PTSC was more efficient than FPSC. The FPSC and PTSC systems performance were investigated using two different types of nanofluids. Carbon nanotubes in water and ethylene glycol were utilized. A remarkable improvement in the average thermal efficiency 64.1 % and 80.6 % of FPSC and PTSC systems using ethylene glycol nanofluid were obtained respectively. The total reduction in CO 2 emissions was 31.26 kg/day and 39.28 kg/day for the FPSCs and PTSCs, respectively in the presence of ethylene glycol nanofluid. A significant saving in CO 2 release is owing to the renewable clean energy of solar collectors.

Cassava, a vital staple crop in developing countries, plays a significant role in ensuring food security and income generation for smallholder farmers. However, the lack of modern drying technology in rural area necessitate the need for a more efficient and controllable drying process which reduces post-harvest losses and ensure better product quality while taking sustainability into account by utilizing biomass as the energy source. Therefore, drying cassava roots to produce highquality cassava flour was the goal of the biomass heat-generated cabinet dryer, which was designed and built for drying in rural locations. The main components of the dryer include heat exchanger, blower, and drying chamber unit which was designed based on engineering standards utilizing locally available materials. The drying chamber consists of two racks of 10 trays each for drying. The dryer was found to be capable of drying 40, 60, and 80 kg of wet cassava mash each batch, when the loading capacity was 2, 3, or 4 kg/tray. At temperatures ranging from 50 to 115 °C, with drying duration of 10 to 120 minutes, thermal efficiency, drying time, and heating energy were investigated. Moisture levels reduced to 10.6%, 11.0% and 11.2% from initial moisture content of 38.21%. At 40 kg, 60 kg, and 80 kg material capacities, drying efficiencies averaged 74.77%, 59.22%, and 88.24%, respectively, with biomass efficiencies 3.0%, 3.5%, and 4.0%. Despite a low biomass efficiency, drying efficiency shows that the dryer is relatively efficient in drying. Hence, biomass fueled dryer should be employed for drying.

n this study, the performance of a linear Fresnel reflector (LFR) is analyzed using three
types of nanofluids (Syltherm800-Cu, Therminol-Al2O3, and water-graphite ) as heat
transfer fluids with a range of volume fraction of 0.01% to 6%. A comparison between
pure-fluids and nanofluids is conducted regarding thermal efficiency, exergy efficiency,
pumping power, and heat transfer coefficient. Nanofluids have a consistently positive
impact on the thermal performance of solar collectors which as thermal efficiency
enhancement was 4% and 3.3% for a volume fraction of 6% in the case of TherminolAl2O3 and Sylthem-Cu ,respectively. Regarding the heat transfer coefficient, a constant
improvement in values was found when using nanofluids, it reached a maximum of 44%
and 35% at a volume fraction of 6% for Therminol Al2O3 and Syltherm-Cu, respectively.
With regards to the direct absorption technology, nanofluids show a marked increase in
optical and thermal performance, compared to the base-fluid.

An approach to the control of a Distributed Solar Collector field relying on a non-linear adaptive constrained model-based predictive control scheme with steady-state offset compensation is developed and implemented. This methodology is based on a non-linear state-space neural networks within a model-based predictive control framework. The neural network training is carried out online by means of a distribution approximation filter approach. In order to get rid of static offsets an offset compensator is incorporated in the control loop. Tests on the ACUREX field illustrate the feasibility of the proposed approach.

La diversite climatique de la Tunisie lui confere des possibilites d'exportation d'une gamme importante de plantes aromatiques et medicinales. Mais, le sechage de ces produits constitue un domaine particulierement vorace en energie, ce qui nous incite a reflechir sur l'utilisation plus rationnelle des ressources disponibles et surtout l'utilisation des energies renouvelables, comme l'energie solaire. L'objectif de ce travail, base sur une etude purement theorique, est de rechercher la rentabilite energetique de deux composants d'une unite de sechage solaire (capteur, stock) sans appoint et dont le but de satisfaire un dimensionnement deja realise a l'echelle macroscopique pour une demande energetique bien definie: secher une quantite de produit donne pendant une journee de la saison de recolte, soit entre les mois de mai et septembre avec un stockage de chaleur qui relaye la nuit.

Photovoltaic/Thermal (PV/T) systems are widely employed as renewable energy solutions in various engineering applications. This study aims to determine the optimal operating conditions and propose enhanced configurations to improve system performance. Numerical simulations were conducted using ANSYS Fluent software to evaluate the effects of various modifications on the PV/T system. To mitigate the adverse impact of elevated operating temperatures on system efficiency, different cooling fluids were employed, including forced air, water, multi-walled carbon nanotube (MWCNT)-water nanofluid, and graphene nanoparticle-water nanofluid. Simulation outcomes-including CFD-generated contour plots, Taguchi optimization results, and performance data derived from energy and exergy analyses-were systematically evaluated and visualized through appropriate graphs. Among the tested fluids, the MWCNT/water nanofluid demonstrated 5% higher total energy efficiency and 0.4% higher exergy efficiency on average compared to the graphene/water mixture. For the MWCNT/water nanofluid, which exhibited the highest exergy efficiency, a multiple regression model was developed as follows: ex η =

In this paper it is described an algorithm, implemented in a biaxial solar tracker, that can instantly calculate the sun position at the latitude and longitude of a set point. The algorithm can drive up to two engines which are able to change the position of a solar panel, in order to increase its efficiency, for tracking the sun in its movement from east to west (azimuth motion) and in its elevation up to solar noon (tilt motion). The whole system is adaptable to various types of structures as it involves a cycle of self-learning of the structure and consequently the adaptation of calculations to the tracker on which it is installed.

A high performance solar collector was developed to modify agricultural building environment such as dairy, poultry farm buildings and greenhouses. Moreover it should be efficiently utilized as a solar dryer for drying various agricultural products and by products. The materials used include steel sheet with high performance of reflecting light, absorber tube, and angle iron and fully insulated drying chamber. A CPTSC was a tilted at 340south (Equivalent to the latitude of Peshawar) Pakistan. A CPTSC a total reflecting surface area was 2.9 m2 respectively. The absorber tube having a surface of 0.376 m2 was fixed in front of the reflector at the distance equal to the focal length. The total volume of drying chamber was 0.3135 m3. An experiment was conducted to enhance the efficiency of the CPTSC and two air mass flow rate treatments were tested with normal and convective mass air flow rate, 0.6 kg. Min-1 and 1.72 kg. Min-1 under the average temperature of the month (January, February and March, 2012). Moreover, the process was replicated three times under the completely randomized design. The result showed that both air mass flow rate and average temperature of the month significantly effected the efficiency of a concentrating parabolic trough solar collector. The new model of a CPTSC increased the efficiency from 8 to 25 % with increase in both air mass flow rates and average temperature of the months. Therefore it is concluded that the solar collector efficiency increased with increasing air mass flow rate.

Photovoltaic thermal is the device produced heat and electricity simultaneously. Consisted of photovoltaic module, collector, insulator in a single unit made the efficiency based on varied factors. For the thermal efficiency, the collector of the PVT is the crucial factor in determined a good results. In this study, the polymer and aluminum collector have been investigated to see the effect of the fin efficiency and collector efficiency factor. Knowing the fin efficiency and collector efficiency factor will be increase with the high thermal conductivity, this study observed the varied dimensions and gaps of tubes. The selected diameters were 6 mm, 12 mm and 18 mm and the gaps from 1 to 10 mm. It clearly showed the higher collector efficiency factor obtained for very small gaps for polymer. The increment width of tubes reduced the collector efficiency factor for both materials. The polymer collector reduce tremendously compared the aluminum collector. The efficiency collector factor ...

Solar drying is one of the methods that have been used since ancient times. This system has been constantly developed in the last few years to acquire better effective results and drying performance. The efficiency of the solar dryer is essentially depends on the thermal distribution and uniformity of flow inside the dryer body. In this paper, a conceptual design of a mixed mode solar dryer which includes direct and forced indirect solar drying integrated with desiccant materials is developed and proposed. Some concepts of this design are new and others are inspired from recent works. Based on these, this mixed mode solar dryer is prospective to be superior in the rate of drying as well as air flow uniformity. Moreover, this improved drier which can be utilized for drying the diverse agricultural products is a simple system and might be manufactured locally. In addition, a simulation of the system using CFD (Computational Fluid Dynamic) software was performed for the optimization of...

The photovoltaic thermal (PVT) is a device that can produce electric and thermal energies simultaneously. The main components of PVT consist of the photovoltaic module, absorber collector, insulator, and mounting frame. The design of the absorber collector is crucial in the good performance of thermal energy. The heat removal factor FR, which is the ratio of the actual energy gain to the useful energy gain of a collecter when the entire collector surfaces are at the fluid inlet temperature, is one of the key parameters in determining the thermal efficiency of PVTs. A high FR means large thermal efficiency and losses and vice versa. In this study, the heat removal factor of four serpentine tubes with varying dimensions and profiles is analyzed. The rectangle tube shows the highest FR (0.93). This high FR value could be caused by the small diameter of the rectangle tube. In addition, a high number of tubes enhance the heat transfer between photovoltaic and serpentine collector absorber.

The installation of solar drying systems have been constantly developed in the last few years to acquire better effective results and drying performance. Baes on the previous designs, It might be concluded that the efficiency of the solar dryers is essentially depends on the thermal distribution and uniformity of flow inside the dryer chamber. There are various types of solar dryers that have been developed and they are classified based on the mode of air circulation (natural circulation and forced circulation), or based on the type of drying such as, direct solar drying, indirect solar drying and mixed mode solar drying etc. Several solar dryers have been utilized recently, however, they do not perform well in terms of high temperature and air distribution throughout the dryer which negatively affects the efficiency of the dryer. Moreover, relying on a single mode of these drying system might not provide the optimum results. Therefore, in this study a conceptual devise of a mixed m...

The solar assisted solid desiccant dryer was designed and developed to dry agricultural product. The experiment was carried out to study the performance of the component in the dryer system and drying air condition without load. The system can produce drying air at average temperature 52 o C under average solar radiation of 797 W/m 2 which is suitable for heat sensitive product to maintain the fresh color, taste and nutrient content. The collector efficiency, heat exchanger effectiveness 1 and 2 was 70%, 77% and 67%, respectively. The thermal, regeneration and dehumidification effectiveness was 48%, 29% and 6%, respectively. The poor performance of desiccant wheel may be improved by increasing the regeneration temperature above 65 o C. Some improvements are still required to improve the overall performance of the system such as decrease the regeneration air flow rate, increase electrical heater power and using direct connection from the solar collector to the dryer system.

Application of tray dryer is widely used in agricultural drying because of its simple design and capability to dry products at high volume. However, the greatest drawback of the tray dryer is uneven drying because of poor airflow distribution in the drying chamber. Implementing the proper design of a tray dryer system may eliminate or reduce non-uniformity of drying and increases dryer efficiency. This paper discussed several design of tray dryer system for drying agricultural products and its performance. Most of the dryer systems have been developed are using solar energy because the systems run at low operating cost. Computational fluid dynamics simulation is a very useful tool in the optimization of the drying chamber configuration by predicting the airflow distribution and the temperature profile throughout the drying chamber.

This study developed a thermal model of a photovoltaic thermal collector (PVT) to predict the performance and outlet temperature of the system. The PVT consisted of a polycrystalline photovoltaic module, a polymer collector–type sheet in a tube, and an insulator. The motivation of the present work is that the polymer materials are flexible, low cost and lightweight which are for the PVT applications. The outlet temperature of the PVT increased with the decreasing rate of mass flow into the riser because the water had sufficient time for thermal heating. One unit of polymer collector can achieve an outlet temperature of 69 °C at 500 W/m2 at a mass flow rate of 0.0063 kg/s.

This work is based on the design of a special purpose dish washing machine. Its special purpose lies in the fact that it handles only dishes made of ceramics. The machine is designed to use electrical energy for heating water and to produce rotation of the spray arm which project hot water unto the dishes. The principle on which the dish washing machine is designed is based on the fact that the pressure and water temperature of water jets required to produce scouring and softening effect on dirt and easily remove them is about 300kPa and 45 o C respectively. The force of the water jet impacting unto the dishes is taken into account in the design and the pressure due to the force exerted by the water jet produced, is negligible compared to both the tensile strength (1138 MPa) and compressive strength (2400 MPa) of the ceramic (Alumina Porcelain) or any other ceramic, and hence cannot break any of the ceramic dishes. The machine is designed to be fitted with a water heater, electric motor and a water pump of power rating 2.2KW, 0.25KW and 0.5KW respectively. The fabricated design of this special purpose dish washing machine will handle 20 dishes in a batch process and complete a wash cycle in a minimum of seven (7) minutes.

African Leafy Vegetables hold a high potential as an income source for resource poor rural dwellers in Cameroon but this potential has not been realized because of lack of appropriate post harvest packages resulting in high losses. A solar tunnel dryer was designed and constructed using local materials and evaluated for drying leafy vegetables and other agricultural products. Four drying trays made of wood and plastic mesh with a total surface area of 3.25 m 2 were used for drying. The dryer was south facing with an inclination of 6º, and the solar radiation falling on the dryer surface was estimated at 12.13 kJ/m 2 per day. At sunset during the wet harvesting period, the temperature inside the dryer was 5ºC above the ambient because of additional heating due to heat storage. The complete dryer could dry 17 kg of sliced cabbage from 95% moisture content wet basis down to 9% in five days in a period characterized by intermittent downpours and permanent cloud cover. The overall dryer efficiency was 17.68%, with a moisture extraction efficiency of 79.15% and airflow of 9.68 m 3 /hr. The relative humidity of the air inside the dryer varied from 75% in the morning down to about 35% at noon. Tests on other high moisture products showed that the dryer could reduce the drying time by 30 to 50% depending on the product and the final product was acceptable in taste and colour.

This study investigates the influence of photovoltaic (PV) panel sizes on wind-induced loads on residential gable roofs. The motivation arises from increasing industry demand to install larger PV panels on residential buildings, an area where current standards, such as ASCE 7, provide limited guidance-particularly for panels exceeding 6.7 ft (2.04 m) in chord length. With larger PV panel sizes gaining popularity, understanding the implications of these dimensions on wind pressures and structural integrity is essential for enhancing safety and refining design standards.

In traditional solar desalination stills, operating by phase change, a profitability problem exists, because the quantity of produced fresh water is rather small (3-4 liters per day per square meter of collecting surface). This article gives an account, via numerical simulation, of the time evolution of the various parameters and variables characterizing a triple effect system functioning on solar energy. It also gives an idea of the evolution of produced fresh water, brine discharge, and feed flowrate, and thus highlights the improvement of the daily water production per square meter. This simulation also shows the infl uence of the presence of salt on the thermodynamic characteristics of salt water solutions. Finally, a system of regulation of feed flowrates makes it possible to control salinity and thus to avoid the filling of salt into components of the installation like heat exchangers. The modelling of the system presented in this study, is based on the conservation equations of mass and energy for the various components.