Strategy and criteria to optically design a solar concentration plant

AbstractThe objective of this work is to individuate the best strategy to determine the layout of a thermodynamic plant based on the concentration of solar flux by means of a large number of mirrors. Many software tools exist, both dedicated software and more general optical software. This analysis shows the advantages derived from the use of a general non-sequential optical software, proposing criteria and procedures in order to establish dedicated optical merit figures, which are suggested and evaluated from the point of view of their effectiveness to achieve a favorable layout design. Particular attention is devoted to merit figures that estimate the optical efficiency, a key quantity for all the CSP plants that can be defined in different ways. The description includes examples of application, discussion of results and various proposed alternatives for the merit figure

Mirror Surface Check on Solar Troughs by Optical Profilometry

Abstract Linear parabolic collectors usually need profilometric control since the reflector surface can be imperfectly manufactured. Optical profile assessment is generally addressed to detect small localised defects. The paper proposes two optical devices that were developed simulating profile measurements on linear parabolic mirrors. Solar troughs are employed in thermal plants and concentrating photovoltaic systems. The profilometer examines the reflector surface operating on a plane transversal to the linear axis of the trough collector. Then the detection is repeated displacing the optical device along the linear collector axis. The first profilometer includes a shifted laser source and a target placed at the collector focal distance. The second profilometer has a fixed target and a linear laser source, which is approximately located in the focal position of the solar mirror. Ray-tracing simulations and practical tests are illustrated for both optical devices

Colour preference of the deer ked Lipoptena fortisetosa (Diptera: Hippoboscidae)

SIMPLE SUMMARY: Insects use visual stimuli to find habitats, food, or a mate while moving around. This trait might be exploited to intercept flying insects to monitor their populations and reduce their presence. Among the various visual stimuli, colours are commonly used to attract insects. Lipoptena fortisetosa is a hematophagous deer ectoparasite native to Japan that has spread to several central European countries and was recently recorded in Italy. Measures to monitor and control L. fortisetosa would be helpful given its potential threat as a pathogen vector for animals and humans. The objective of this research was to assess the potential use of colour to attract and trap L. fortisetosa. The response of the winged adults was evaluated through an experimental trial carried out in a wooded area of Tuscany using differently coloured sticky panels as traps. Blue panels attracted the highest number while yellow panels showed the lowest performance. This preference for blue could be useful in the design of traps to reduce the population of this parasitic fly which, at certain times, can reach a very high density, causing annoyance to wildlife and humans visiting natural areas. ABSTRACT: Lipoptena fortisetosa, a deer ked native to Japan, has established itself in several European countries and was recently recorded in Italy. This hippoboscid ectoparasite can develop high density populations, causing annoyance to animals and concern regarding the potential risk of transmitting pathogens to humans. No monitoring or control methods for L. fortisetosa have been applied or tested up to now. This research evaluated the possible response of L. fortisetosa winged adults to different colours as the basis for a monitoring and control strategy. In the summer of 2020, a series of six differently coloured sticky panels were randomly set as traps in a wooded area used by deer for resting. The results indicated a clear preference of the deer ked for the blue panels that caught the highest number of flies during the experimental period. Lower numbers of flies were trapped on the red, green, black, and white panels, with the yellow panels recording the fewest captures. The response clearly demonstrates that this species displays a colour preference, and that coloured traps might be useful for monitoring and limiting this biting ectoparasite in natural areas harbouring wildlife and visited by people

Ultra-High Temperature Ceramics for solar receivers: spectral and high-temperature emittance characterization

We report on the preparation, room temperature spectral reflectance and high-temperature thermal emittance characterization of different boride and carbide Ultra-High Temperature Ceramics (UHTCs). The investigated samples are compared with a reference material for solar absorber applications, i.e. silicon carbide. We show that spectral and thermal emittance properties of UHTCs are promising for novel solar receivers

Optical Tests on a Curve Fresnel Lens as Secondary Optics for Solar Troughs

A curve Fresnel lens is developed as secondary concentrator for solar parabolic troughs to reduce the number of photovoltaic cells. Specific measurements and optical tests are used to evaluate the optical features of manufactured samples. The cylindrical Fresnel lens transforms the focal line, produced by the primary mirror, into a series of focal points. The execution of special laboratory tests on some secondary concentrator samples is discussed in detail, illustrating the methodologies tailored to the specific case. Focusing tests are performed, illuminating different areas of the lens with solar divergence light and acquiring images on the plane of the photocell using a CMOS camera. Concentration measurements are carried out to select the best performing samples of curve Fresnel lens. The insertion of the secondary optics within the concentrating photovoltaic (CPV) trough doubles the solar concentration of the system. The mean concentration ratio is 1.73, 2.13, and 2.09 for the three tested lenses. The concentration ratio of the solar trough is 140 and approaches 300 after the introduction of the secondary lens