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The compliance with international standards does not necessarily ensure a long-term reliability of photovoltaic modules. Field tests are required to make the standard tests more adjusted to the evaluation of new concepts. Numerous researches focus on long-term performance of standard modules, but only few studies are dedicated to lightweight modules. Therefore, the field operation of a PV system consisting of 28 lightweight modules of 4 different types (denoted as P1, P2, P3 and P4) has been being monitored for a year in warm temperate climate conditions. Over this period, the modules were tested by visual inspection, thermography and electroluminescence imaging and their electrical parameters were measured to compare results with the outcome of simulations in PVsyst. Visual inspections revealed yellowing and delamination of a few P2 and P4 modules because of issues with EVA foil. Thermography exposed many hot spots and failure of substrings in case of P2 modules. Also, the electroluminescence imaging showed numerous defects, mostly various micro cracks, which affected all modules' types. Nevertheless, excluding P2 modules, the others generated higher yield than estimated by the simulations. Analysing year-to-year degradation, results for P3 and P4 were in line with results predicted for standard PV modules in similar climates. [ABSTRACT FROM AUTHOR]

Despite myriads of mathematical and experimental studies using various heat exchanger-metal hydride assemblies, an adept comparison of reactors on standard performance defining parameters, i.e., reactor weight, external energy utilization, and alloy material, are not studied or reported for industrial storage containers and onboard applications. This lacuna is a critical barrier in developing efficacious hydrogen storage reactors for various applications. This article chronicles the 3-D design and optimization of three basic heat exchanger setups of solid-state hydrogen storage systems (shell and tube, spiral tube, and tubular) on critical parameters. For 5 kg LaNi 5 , a tubular design with small tube diameters has resulted in a shorter reaction time (120 s) for 90% saturation at 303 K and 15 bar inlet conditions; however, the reactor's gravimetric density was exceptionally high. In contrast, the reactor with three spiral tubes accomplished an exemplary reaction rate at a reasonable gravimetric density. This spiral arrangement became the base for developing a novel reactor that integrated heat pipes to reduce the sorption time. The proposed design achieved a specific output energy rate of 527 W/kg for 90% saturation in 366 s at a supply pressure of 15 bar, which is 23.7% higher than the reactor without heat pipes. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, four different configurations of Copenhagen solar cookers were tested experimentally at the same time under the same weather conditions. First tests were carried out using pots without water load. Secondly, tests were performed with the equal amount of water in each pot. Thirdly, tests were carried out with different amounts of water for one of the configurations. From the results of the first set of tests, it was found that the performance of one of the configurations depends more significantly on the solar altitude angle than the others. A large number of experiments for each set of tests were conducted covering a wide range of solar altitude angles. A thermal performance analysis based on the ASAE S580.1 standard was performed with the measured data of the second and third sets of tests. The obtained plots with the observation points of each configuration evidence that the linear trend of the standardised power is not universal. The observed trends are very dependent on the solar altitude angle. Thus, the procedure for evaluating standardised power recommended by the standard for cooker performance comparison should be improved. • The three known configurations of Copenhagen solar cooker were tested experimentally. • Cookers were tested side by side using empty pots and using water as load. • The impact of solar altitude angle on the temperature of air inside pot was investigated. • Configuration changing during one set of tests was performed according to the solar altitude. • Standard procedure for reporting standardised power is not applicable to all cooker designs. [ABSTRACT FROM AUTHOR]

Shallow Geothermal Energy (SGE) systems are emerging as an attractive solution to enhance building energy efficiency and contribute to a low-carbon economy. This research investigates a SGE system comprising 40 boreholes installed in a university building located in Aveiro City under Mediterranean climate conditions. Both the building and the underground soil were monitored during the SGE operation, and EnergyPlus® software was subsequently employed for the integrated dynamic simulation. The building energy model was calibrated using field data, and a good agreement between the measured and the simulated temperatures was archived, with a Coefficient of Variance of the Root Mean Square Error (CVRMSE) below 10 %. The case study model performance was analysed and compared to other alternatives. The impact of the climate on the system performance was investigated by analyzing nine Portuguese cities situated in different climate contexts. A sustainability indicator was proposed, and an initial sustainability assessment was conducted. The results emphasize that the SGE system offered advantages compared to other alternative systems, achieving a 55 % reduction in heating and cooling energy consumption, and mitigating climate change by 405.67 ton of CO 2 per 25-year lifespan. This study can guide further implementation of sustainable geothermal systems in Mediterranean climates. [ABSTRACT FROM AUTHOR]

The present work assesses the real-world performance of novel improved mud-based cookstoves (MBC) - Pavak 1 (P1) and Pavak 2 (P2) in a remote community in Khandwa, Madhya Pradesh, India. These MBC's were designed using multi-parameter optimization based on extensive laboratory testing. These MBCs are affordable and durable, and can be locally manufactured without compromising cooking quality, taste, or convenience while still meeting the Indian cookstove performance standards (BIS IS 13152 (Part 1): 2013) for emissions and efficiency. MBC's performance was compared to traditional stoves (TS) in accordance with the ISO 19869:2019 cookstove field testing protocol. 45 cooking sessions were captured (22 P1; 13 P2; 10 TS). Fuel-based emission factors (EF) for PM 2.5 and CO were estimated using the carbon balance method. Results indicate reductions in PM 2.5 (56% for P1 and 46% for P2) and CO emissions (15% for P1 and 0.85% for P2) compared to TS. Analysis of real-time modified combustion efficiencies showed that MBCs exhibited prolonged periods in pure flaming conditions compared to TS. A user perception survey was conducted in the intervention households to understand community acceptability. Our results demonstrate the potential for increased adoption rates, emphasizing the importance of information, education, and communication (IEC) programs to maximize health and climate benefits. [ABSTRACT FROM AUTHOR]

The measurement of power performance is an important procedure in the design verification and ongoing health monitoring of a tidal turbine. Standardised methods state that the performance should be measured relative to two independently located flow sensors, the arrangement of which is often non-trivial and necessitates additional cost. Recent interest in the usage of flow sensors mounted on the turbine has demonstrated their capabilities in profiling the rotor approach flow, but this instrument configuration is not recognised in the performance assessment standard. This study evaluates the merits of the turbine mounted configuration by measuring the performance of a tidal turbine relative to this reference and to a conventional seabed placed instrument. The turbine mounted sensor is found to provide a better reference of the free-stream conditions, evident from an improved agreement with theoretical predictions of device performance and a reduced amount of variation in the results. This new method could reduce both the costs and uncertainty associated with existing performance assessment best practices. • The power curve from a full-scale tidal turbine is measured. • Measurements from conventional seabed instrument inadequately capture turbine flows. • A new method is proposed using measurements obtained from a turbine mounted sensor. • Turbine sensor results show less variation and are in better agreement with theory. • New method reduces costs and uncertainties associated with performance assessment. [ABSTRACT FROM AUTHOR]

The measurement of power performance is an important procedure in the design verification and ongoing health monitoring of a tidal turbine. Standardised methods state that the performance should be measured relative to two independently located flow sensors, the arrangement of which is often non-trivial and necessitates additional cost. Recent interest in the usage of flow sensors mounted on the turbine has demonstrated their capabilities in profiling the rotor approach flow, but this instrument configuration is not recognised in the performance assessment standard. This study evaluates the merits of the turbine mounted configuration by measuring the performance of a tidal turbine relative to this reference and to a conventional seabed placed instrument. The turbine mounted sensor is found to provide a better reference of the free-stream conditions, evident from an improved agreement with theoretical predictions of device performance and a reduced amount of variation in the results. This new method could reduce both the costs and uncertainty associated with existing performance assessment best practices. • The power curve from a full-scale tidal turbine is measured. • Measurements from conventional seabed instrument inadequately capture turbine flows. • A new method is proposed using measurements obtained from a turbine mounted sensor. • Turbine sensor results show less variation and are in better agreement with theory. • New method reduces costs and uncertainties associated with performance assessment. [ABSTRACT FROM AUTHOR]

Organic Rankine cycles are one of the available solutions for converting low grade heat source into electrical power. However the development of plants tends to be very expansive due to the specific design of the expander. Usually, the input parameters for designing an ORC plant are the temperature and power of the heat and cold sources. They lead to the selection of a working fluid, pressures and temperatures. The expander is then designed based on the required operating parameters. Using standard turbine easily available on the market and with well known performances would allow to reduce the development and manufacturing cost. However, the ORC would have to be adapted to make the expander work in its best conditions. For a solar concentrated heat source, the temperature and power can be adapted by adjusting the concentration factor and the total area of the collector. In this paper, a given gas turbine is considered to be used as the expander of the ORC. Knowing the turbine's performances with air, the optimal operating parameters (pressure, temperature, flow rate and rotational speed) of the ORC with different fluids are sought based on similitude rules. The adaptation aims to maintain the same density evolution, inlet speed triangle and inlet Mach number with the working fluid as with air. The performance maps of the turbine are then computed with CFD simulations and showed a maximum isentropic efficiency close to the one with air, about 78%. • The potential of a given gas turbine to be used as turbo expander of an adapted solar-ORC is studied. • Simple similitude rules allow finding the best operating point for a given fluid. • The ORC parameters are adapted to use the turbine at its best operating point. • CFD simulations for SES36 and R245fa confirmed the ability of the proposed methodology. • Detailed parameters and sizing of the adapted solar ORC with parabolic through collectors are computed for SES36 and R245fa. [ABSTRACT FROM AUTHOR]

In this study, the performance of a forced convection mixed-mode solar dryer with thermal energy storage is experimentally analyzed. The main goal was to develop an efficient and cost effective dryer that maintains drying process after sunset. The dryer mainly consists of a solar collector/absorber, drying chamber and a fan. A photovoltaic panel and battery storage are also integrated with the dryer to supply the required electrical energy. The experiments are carried out to dry fresh apricot slices at different working conditions. The effect of using phase change material to store thermal energy during daytime is analyzed. It is concluded that the performance of the solar collector is improved and the drying process is effectively extended when solar energy was not available. It is also observed that the rate of drying is almost constant along the drying chamber. The moisture pick-up efficiency and the overall thermal efficiency of the dryer are about 10% and 11%, respectively. [ABSTRACT FROM AUTHOR]

Porous media play an important role in the process of storage energy. In this paper, the influence of porous media on the performance of a double pass hybrid PV/thermal air collector was achieved by building an experimental set-up for this purpose. The study showed that using porous media expanded the area of heat transfer and thus increased the thermal efficiency and temperature of the exit air from the hybrid solar collector. The compound efficiency was increased (3%) after using the porous medium in the lower ducts of the double-pass hybrid collector. At the same time, the pressure drop was increased after using the porous media. In this analysis, it was concluded that the hybrid solar collector with porous media and glass cover is more thermally efficient than the other design form. The results showed a rise in the electrical efficiency with the increase of the fluid flow rate. This increase in the value of the electrical efficiency was due to the higher volumetric air flow which enhanced the PV panel cooling. Also, the results displayed that fixing a glass layer on the hybrid collector caused the rise in thermal efficiency and reduction in the electrical efficiency of the hybrid collector. The highest value for the daily thermal efficiency was 80.23% in the collector that used porous media and glass cover, while the higher value for the thermal efficiency was 51.25% without porous media and glass cover. Also, the highest value for the daily electrical efficiency was 8.7% in the collector that used porous media and the higher value for the daily electrical efficiency was 10.91% without porous media and without glass cover. The use of porous media and glass cover in the hybrid system is a desirable option when using the hybrid system for electrical generation only. [ABSTRACT FROM AUTHOR]

The solar dish is a point-focusing concentrator with a very high concentration ratio ranging from hundreds to thousands. Practical assessment and optimization methods are necessary to assemble solar dishes with satisfying concentration ratios and flux density distributions, which is very important for the overall solar thermal systems to achieve high efficiency. A solar dish usually consists of many mirror facets installed on a supporting structure with a dual-axis tracking system. Small mirror facets are easy to manufacture, but the alignment of many mirror facets is very challenging. A model-based approach for optical performance assessment and optimization of a solar dish was proposed, and flux density measurements were carried out to validate the approach. The simulation and experimental results showed very good consistency and suggested that the concentration ratio and the intercept factor could be increased from ∼500 to ∼1500 and 0.66 to 0.9 respectively after assembly optimization. [ABSTRACT FROM AUTHOR]

Abstract: The global growth in small wind turbine (SWT) markets and in the number of SWT manufacturers has brought about an urgent need for more rigorous testing of SWTs in order to ensure safety, reliability and performance. This work presents modelling of the wind resource at the Australian National Small Wind Turbine Centre (NSWTC) test site to give insight into the scope and scheduling of power performance tests, and assess testing completion requirements for national and international SWT performance standards. Wind modelling of the long-term wind resource at the site was used to guide the NSWTC testing program and develop a tool to provide recommendations regarding suitable months for testing particular turbines. The predictions from the tool are compared to the results of testing a SOMA 1000 small wind turbine. The results indicate that current testing standards need to specify more than 10 min worth of data in each bin in order to reduce uncertainty errors in power curves, particularly at higher wind speeds and during furling and unfurling of the turbine. Furthermore, this work supports observations that there are often notable discrepancies between published SWT manufacturer power curves and test results at high wind speeds. [Copyright &y& Elsevier]