A coupled optical-thermal-electrical model to predict the performance of hybrid PV/T-CCPC roof-top systems

A crossed compound parabolic concentrator (CCPC) is applied into a photovoltaic/thermal (PV/T) hybrid solar collector, i.e. concentrating PV/T (CPV/T) collector, to develop new hybrid roof-top CPV/T systems. However, to optimise the system configuration and operational parameters as well as to predict their performances, a coupled optical, thermal and electrical model is essential. We establish this model by integrating a number of submodels sourced from literature as well as from our recent work on incidence-dependent optical efficiency, six-parameter electrical model and scaling law for outdoor conditions. With the model, electrical performance and cell temperature are predicted on specific days for the roof-top systems installed in Glasgow, Penryn and Jaen. Results obtained by the proposed model reasonably agree with monitored data and it is also clarified that the systems operate under off-optimal operating condition. Long-term electric performance of the CPV/T systems is estimated as well. In addition, effects of transient terms in heat transfer and diffuse solar irradiance on electric energy are identified and discussed

Influence of applied pressure on the probability of electronic energy transfer across a molecular dyad

A pair of covalently linked molecular dyads is described in which two disparate boron dipyrromethene dyes are separated by a tolane-like spacer. Efficient electronic energy transfer (EET) occurs across the dyad; the mechanism involves important contributions from both Förster-type coulombic interactions and Dexter-type electron exchange processes. The energy acceptor is equipped with long paraffinic chains that favor aggregation at high concentration or at low temperature. The aggregate displays red-shifted absorption and emission spectral profiles, relative to the monomer, such that EET is less efficient because of a weaker overlap integral. The donor unit is insensitive to applied pressure but this is not so for the acceptor, which has extended π-conjugation associated with appended styryl groups. Here, pressure reduces the effective π-conjugation length, leading to a new absorption band at higher energy. With increasing pressure, the overall EET probability falls but this effect is nonlinear and at modest pressure there is only a small recovery of donor fluorescence. This situation likely arises from compensatory phenomena such as restricted rotation and decreased dipole screening by the solvent. However, the probability of EET falls dramatically over the regime where the π-conjugation length is reduced owing to the presumed conformational exchange. It appears that the pressure-induced conformer is a poor energy acceptor

Thermodynamic Modeling of a Seawater-Cooled Foldable PV Panel System

Solar-powered systems can supply clean and sustainable energy for both service requirements and also for the propulsion of marine vessels. However, the restricted available area for photovoltaic panels and high setup costs inhibits the sufficient energy production for satisfying the whole needs of vessels. Due to the limited panel area that can be installed on the vessel, it is necessary to improve the system efficiency in order to obtain more power from the existing solar panel system. In this study, cooling solar panels from the back surface with seawater in an open loop cooling water circuit for a 527-W solar-powered system are investigated. In order to observe the effects of cooling the panels, thermodynamic modeling and analysis of a foldable photovoltaic panel set have been carried out. The result illustrates the potential of these systems as the power output difference of the panel set is more than the consumed power for cooling on above-specific irradiation conditions. The remaining power output, which would be up to 37% of the uncooled system, is high enough to be utilized to speed up the marine vessels or to increase their range

Probe–Integrated Electrochemical Sensing Platform for Measuring Trace levels of parathion pesticides residues in water using Au- nanoparticles anchored Nafion nano composite modified glassy carbon electrode

Nanomaterial represents a principal driver to the adoption of electrochemical sensors for pesticides residues in water. Thus, the current strategy reports facile and highly sensitive electrochemical probe for monitoring parathion residues in water. The probe was based upon the use of Au nanoparticles (AuNPs) functionalized Nafion nanocomposites modified glassy carbon electrode (Au NPs/Nafion/GCE). The surface morphology, effective surface area and electrocatalytic performance of the Au NPs/Nafion/GCE were recorded and assigned using a scanning electron microscopy (SEM), cyclic voltammetry (CV) and electronic spectra. A straightforward protocol based upon combination of Au NPs/Nafion/GCE and square wave- adsorptive cathodic stripping voltammetry at pH 7.0 was established for parathion detection. The probe displayed two linear responses between the catholic peak current (ip,c) at 0.8 V versus parathion concentrations over the ranges from 1.07 × 10 6 - 1.07 × 10 5 and 1.99 × 10 9 - 9.0 × 10 7 M with limits of detection (LOD) and quantification (LOQ) of 6.06 × 10 10 M and 2.0 × 10 9 M, respectively. The probe exhibited excellent reproducibility, repeatability with RSD of ± 0.5% (n = 5) at 8.0 × 10 7 M parathion. The probe was applied for parathion detection in water and validated by HPLC. The experimental Student texp and Fexp values were less than the tabulated ttab (2.78) and Ftab (6.39) at 95% probability

Energy in Indonesia: the main factors

This chapter will introduce the energy situation in Indonesia as well as the main factors that influence it. Being one of the world’s largest archipelagos, Indonesia has a unique and highly distributed power supply system. The population size is the main factor which causes a significant demand for energy. The growing economy of Indonesia brings optimism, including on the subject of renewable energy development

CARDIOGENIC PULMONARY EDEMA IN CRITICAL CARE

The pathobiology and classification of pulmonary edoema are more complex than the previous dichotomy of hydrostatic vs. permeability. The mechanisms of alveolar fluid clearance and the factors that influence the clearance rate are being studied thoroughly in order to develop therapeutic strategies. Patients require early oxygenation and ventilation stabilization, preferably with high-flow nasal cannula oxygen or noninvasive ventilation, while the diagnostic cause is quickly sought with echocardiography and other testing. Treatments must begin as soon as possible while evaluation continues and requires multimodal intervention. Diuretics, possibly morphine, and frequently nitrates, are used to treat cardiogenic pulmonary edema. This review summarizes current knowledge of the pathophysiology, causes, and treatment of cardiogenic pulmonary edema