The Swiss start-up Insolight aims to be the first company to commercialize a high-efficiency III-V based low profile micro-CPV product that uses planar micro-tracking to eliminate the need for a tilting solar tracker, allowing rooftop mounting using typical flat-plate hardware, as well diffuse light capture using low cost Si solar cells which cover the area of the back plane not taken up by III-V solar cells. The IES-UPM has made an initial performance evaluation of a 0.1m2 prototype. We show that the integrated planar tracking can reach 55° AOI, show CSTC efficiency near to 30% for III-V output, and demonstrate the diffuse capture and planar tracking capability in a multi-week test campaign at our test site in Madrid. Index Terms-integrated planar tracking, diffuse light collection, micro-concentrator photovoltaics.
A tracking-integrated hybrid micro-concentrator module is presented that can harvest direct, diffuse, and albedo irradiance components. It uses biconvex 180× lens arrays to concentrate direct light on high-efficiency III-V solar cells (29% module efficiency has been demonstrated outdoors on direct sunlight at Concentrator Standard Test Conditions) and a planar micro-tracking mechanism to allow installation in static frames. Two architectures have been developed to harvest diffuse irradiance: (1) a hybrid architecture where the backplane is covered with monofacial or bifacial Si cells; (2) a translucent architecture where diffuse light is transmitted through the module for dual-land-use applications, such as agrivoltaics. Simulations show that the hybrid architecture provides an excess of yearly energy production compared to 20% efficiency flat-plate photovoltaic (PV) module in all locations studied, including those with a low direct normal irradiance (DNI) content, and up to 38% advantage in high-DNI locations. The use of bifacial heterojunction and interdigitated back-contact Si cells has been explored for the glass-Si-glass backplane laminate to harvest albedo light. Bifacial gains modeled can boost energy yield by about 30% in the best scenario. We discuss the perspectives of the translucent modules for dual-land-use applications as well, such as integration in greenhouses for agriculture-integrated PV (agrivoltaics). This architecture can provide up to 47% excess electricity compared to a spaced reference Si array that transmits the same amount of solar
Planar micro-tracking concentrator photovoltaic modules hold great promises, as they enable the combination of efficiencies greater than 30% with the form factor of conventional rooftop panels operating at fixed tilt. Over the past three years, Insolight has been developing a fixed-tilt system, combining a biconvex silicone lens array, high efficiency multi-junction cells and integrated micro-tracking. A first prototype built in 2016 was validated with a peak conversion efficiency of 36.4 %. On the path towards industrialization of the systems, we present the evolution from the first lab prototype to fully automated panels featuring several thousands cells, installed on a rooftop pilot site. Continuous operation and data logging of the outdoor installation over a year enable us to validate a simple and robust integrated micro-tracking scheme. Recent measurements showed a module efficiency of 29% at concentrated standard test conditions. Different hybrid PV-CPV architectures are under evaluation for the capture of global irradiance.
Around one-third of patients diagnosed with COVID-19 develop a severe illness that requires admission to the Intensive Care Unit (ICU). In clinical practice, clinicians have learned that patients admitted to the ICU due to severe COVID-19 frequently develop ventilator-associated lower respiratory tract infections (VA-LRTI). This study aims to describe the clinical characteristics, the factors associated with VA-LRTI, and its impact on clinical outcomes in patients with severe COVID-19. This was a multicentre, observational cohort study conducted in ten countries in Latin America and Europe. We included patients with confirmed rtPCR for SARS-CoV-2 requiring ICU admission and endotracheal intubation. Only patients with a microbiological and clinical diagnosis of VA-LRTI were included. Multivariate Logistic regression analyses and Random Forest were conducted to determine the risk factors for VA-LRTI and its clinical impact in patients with severe COVID-19. In our study cohort of 3287 patients, VA-LRTI was diagnosed in 28.8% [948/3287]. The cumulative incidence of ventilator-associated pneumonia (VAP) was 18.6% [610/3287], followed by ventilator-associated tracheobronchitis (VAT) 10.3% [338/3287]. A total of 1252 bacteria species were isolated. The most frequently isolated pathogens were Pseudomonas aeruginosa (21.2% [266/1252]), followed by Klebsiella pneumoniae (19.1% [239/1252]) and Staphylococcus aureus (15.5% [194/1,252]). The factors independently associated with the development of VA-LRTI were prolonged stay under invasive mechanical ventilation, AKI during ICU stay, and the number of comorbidities. Regarding the clinical impact of VA-LRTI, patients with VAP had an increased risk of hospital mortality (OR [95% CI] of 1.81 [1.40–2.34]), while VAT was not associated with increased hospital mortality (OR [95% CI] of 1.34 [0.98–1.83]). VA-LRTI, often with difficult-to-treat bacteria, is frequent in patients admitted to the ICU due to severe COVID-19 and is associated with worse clinical outcomes, including higher mortality. Identifying risk factors for VA-LRTI might allow the early patient diagnosis to improve clinical outcomes.Trial registration: This is a prospective observational study; therefore, no health care interventions were applied to participants, and trial registration is not applicable.
Subsea equipment covered by the API Spec 17 subcommittee has had limited focus on assessing fatigue life because of external environmental loads using traditional analysis methods. With the current trend of high-pressure, high-temperature (HPHT) development, the industry is migrating to an era of modern analysis methods with complex material testing programs to assess potential fatigue life impacts due to such high-pressure and -temperature exposures as well. This paper presents an approach and an example of a multiaxial strain-life analysis method that meets the provided HPHT design guidelines of API Technical Report 17TR8. The paper bridges the gap between theory and practicality in strain-life-based fatigue analysis and presents a robust process developed for HPHT nickel alloy components, which are part of the subsea 20,000-psi vertical monobore subsea tree. The endeavor includes strategizing for required material tests in environment, actual material testing, followed by material data processing, which includes statistical corrections and extraction of parameters necessary for efficient fatigue analysis. The components are then analyzed in finite-element analysis (FEA) with typical loading sequences as seen in its life of field. Finally, the FEA results are postprocessed using the critical plane approach for all nodes in the model. The governing equations are presented throughout the analysis to enable readers to develop their own results. The 20,000-psi vertical monobore tree fatigue analysis depends on the operations forecasted for its life cycle. Using the expected load histogram, a series of pressure and thermal analyses were executed to produce cycles to failure. Implementing the Palmgren–Miner's rule enabled obtaining the total damage produced by factory acceptance tests total field life shut-ins, and flow-in pressure cycles. This not only serves as verification that the required safety factor is met per API Technical Report 17TR8 but also enables making engineering assessments of "what-if" operations. In this sense, a change or addition of an operation will lead to a simple recalculation of fatigue damage without requiring performing the analysis from the ground up. The method also allows for computation of cycles to failure for a pressure range when the other pressure ranges and conditions don't change. In addition to the life cycle calculation, the method evaluates the damage of all nodes, which produces full-contour plots. The contour plots, in addition to displaying the hot-spot locations, when used with structural analysis results, enable the engineer to assess areas of improvement and product optimization. The method proposed gives an effective way to communicate and recommend the design life capabilities of a product to the operator to predict life expectancy for combinations of expected load scenarios.
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