Barwnikowe ogniwa słoneczne [Dye-sensitized solar cells]

This paper studies color photovoltaic cells - their construction, manufacture, characteristics and application. Color photovoltaic cells are third generation cells, using a non-silicon technology based on new functional materials, such as nanoparticles of metals, metal oxides and conductive polymers. In comparison to typical silicon cells, color photovoltaic cells don't require a very clean atmosphere and the ability to control the color or transparency of a photovoltaic cell allows for a wide range of applications: as shadowing surfaces, building fronts or decorative parts.</p

Fundamentals of solar energy

The spectrum of solar light which approaches earth's surface changes due to interactions of light with earth's atmosphere. It is clearly seen that the interaction of radiation with the ozone sheath significantly reduces the amount of potentially hazardous UV radiation. In order to enable better photovoltaic (PV) design and planning the global horizontal irradiance (GHI) has been defined which corresponds to the total amount of shortwave radiation received from the sun by a surface horizontal to the ground. This value includes two fluxes: direct normal irradiance (DNI) and diffuse horizontal irradiance (DIF). DNI represents the solar radiation that comes in a straight line from the sun at its current position in the sky. Solar energy is converted into direct current (DC) by photovoltaic modules. The produced direct current passes through a voltage regulator and is then stored in accumulators

Tests and theoretical analysis of a PVT hybrid collector operating under various insolation conditions

The main goal of the study was to investigate the relationship between the orientation of the PVT (PhotoVoltaic Thermal) collector and the thermal and electric power generated. Extensive research was performed to find optimal tilt angles for hybrid solar thermal collectors, which combine photovoltaic as well as thermal collection in a single unit, known as PVT (PhotoVoltaic Thermal) modules for an office building with working hours between 7.00 and 16.00. The comprehensive study included field measurements of the modules in central Poland and tests under AM (air mass) 1.5 conditions in a certified laboratory KEZO (Centre for Energy Conversion and Renewable Resources) Polish Academy of Sciences in Jablonna. Furthermore, a PVT system was investigated using the simulation method based on the dedicated Polysun software. The PV characteristics and efficiency of the PV module and the relation between power or efficiency of the PVT module and incidence angle of solar-irradiance were studied. Optimal work conditions for commercial PVT modules were ascertained. In addition, it was found that the maximum efficiencies of PV module (ηPV), solar thermal-collector (ηc) and PVT hybrid collector (ηPVT) registered under field conditions were higher than the ones measured under laboratory conditions.</p

Spray-deposited carbon-nanotube counter-electrodes for dye-sensitized solar cells

Carbon nanotubes due to their catalytic properties are a promising alternative to platinum counter electrodes (CE) for dye-sensitized solar cells (DSSC). In this study, counter electrodes were made from double-walled carbon nanotube (DWCNT) ink using the spray printing technique and afterwards they were thermally treated at temperatures ranging from 120 to 300 °C. Morphology and structure was studied using scanning electron microscopy and Raman spectroscopy. DSSCs were constructed from titanium-dioxide photoanodes and DWCNT counter electrodes cured at various temperatures. The current-voltage characteristics of DSSCs and their impedance spectra recorded under illumination have been studied and compared. The photoconversion efficiency (PCE) of the solar cell reached a maximum value of 4.59% when the carbon layer was thermally treated at 300 °C and is 16% higher than that registered for devices with a standard platinum counter electrode.</p

Tests and theoretical analysis of a PVT hybrid collector operating under various insolation conditions

The main goal of the study was to investigate the relationship between the orientation of the PVT (PhotoVoltaic Thermal) collector and the thermal and electric power generated. Extensive research was performed to find optimal tilt angles for hybrid solar thermal collectors, which combine photovoltaic as well as thermal collection in a single unit, known as PVT (PhotoVoltaic Thermal) modules for an office building with working hours between 7.00 and 16.00. The comprehensive study included field measurements of the modules in central Poland and tests under AM (air mass) 1.5 conditions in a certified laboratory KEZO (Centre for Energy Conversion and Renewable Resources) Polish Academy of Sciences in Jablonna. Furthermore, a PVT system was investigated using the simulation method based on the dedicated Polysun software. The PV characteristics and efficiency of the PV module and the relation between power or efficiency of the PVT module and incidence angle of solar-irradiance were studied. Optimal work conditions for commercial PVT modules were ascertained. In addition, it was found that the maximum efficiencies of PV module (ηPV), solar thermal-collector (ηc) and PVT hybrid collector (ηPVT) registered under field conditions were higher than the ones measured under laboratory conditions

Application of Leather Waste Fractions and Their Biochars as Organic Fertilisers for Ryegrass Growth: Agri-Environmental Aspects and Plants Response Modelling

The automotive upholstery industry, which processes bovine leathers, has struggled with vast amounts of solid waste, of which the majority are fractions, such as shavings and splits and offcuts, both containing chromium (Cr) and free of Cr. In this work, a novel leather waste-to-fertiliser approach has been tested: four lightly processed (incubation with effective microorganisms) and three aggressively processed (using pyrolysis or hydrolysis processes) tanned leather waste fractions were used. They were applied as organic nitrogen-based fertilisers in two separate glasshouse experiments, consisting of four subsequent harvests, under spring–autumn conditions in northern Poland. The Cr stressing effect caused by bovine shavings containing Cr and splits and offcuts containing Cr stimulated an increase in ryegrass growth after 30 days, providing twice the dry matter yield than bovine shavings free of Cr and splits and offcuts free of Cr, then (after 90 and 120 days) it inhibited growth. The Monod kinetics model was developed using the best fitting procedure (R2 > 0.94) for the efficiency of internal N use in ryegrass for the lightly processed fractions of tanned leather-waste fractions and each harvest. In the case of the processed leather waste-fractions, the relation was quasi linear, evidencing less growth inhibition and no over-fertilisation effects. The acid hydrolysate of bovine shavings containing Cr showed the best performance, reaching a relative agronomic effectiveness (RAE, N utilization-based) equal to 89%, 95%, 19%, and 38% for 30, 60, 90, and 120 days, respectively, and 71% in total. For the lightly processed fractions, it was lower than 12%. The future perspective should focus on steps including scaling up the tests to field conditions; transportation, storage, and application methods; effectiveness for other crops; usage in crop rotation systems; environmental impact assessment; production carbon footprint; commercial potential; and optimizing the production processes