A system for measurement of monochromatic attenuation for each wavelength of the spectrum, understood as such the attenuation at a wavelength of the spectrum with the spectral width provided by the measurement equipment, of the spectral attenuation in the spectral range of measurement, understood as such the set of monochromatic attenuations at all the wavelengths throughout the spectral range of measurement, and the total attenuation, understood as such the attenuation calculated by the integration of the spectral attenuation in the spectral range of measurement weighted with the solar spectrum. A method for measurement, providing measurement of attenuation in the entire spectral range for the best energy system efficiency evaluation and for achieving a differential measurement of meteorological phenomena causing the attenuation, providing relevant information for the meteorological forecast in this specific field, which can be used for evaluating the attenuation phenomenon for solar plants site selection and for operating plants.

A passive cooler of the disclosure includes a thermal emitter having a substrate and a coating disposed on at least a portion of a first side of the substrate. The cooler has a beam guide made from a material having a high absorption to solar wavelengths and high reflectance at mid-infrared wavelengths. The beam guide is configured such that at least a portion of incident light is acted on by the beam guide before reaching the thermal emitter. In some embodiments, the beam guide has a graded optical index.

A method for controlling the orientation of a single-axis solar tracker orientable about an axis of rotation, including observing the evolution over time of the cloud coverage above the solar tracker; determining the evolution over time of an optimum inclination angle of the solar tracker substantially corresponding to a maximum of solar radiation on the solar tracker, depending on the observed cloud coverage; predicting the future evolution of the cloud coverage based on the observed prior evolution of the cloud coverage; calculating the future evolution of the optimum inclination angle according to the prediction of the future evolution of the cloud coverage; servo-controlling the orientation of the solar tracker according to the prior evolution of the optimum inclination angle and depending on the future evolution of the optimum inclination angle.

A method for controlling the orientation of a single-axis solar tracker orientable about an axis of rotation, including observing the evolution over time of the cloud coverage above the solar tracker; determining the evolution over time of an optimum inclination angle of the solar tracker substantially corresponding to a maximum of solar radiation on the solar tracker, depending on the observed cloud coverage; predicting the future evolution of the cloud coverage based on the observed prior evolution of the cloud coverage; calculating the future evolution of the optimum inclination angle according to the prediction of the future evolution of the cloud coverage; servo-controlling the orientation of the solar tracker according to the prior evolution of the optimum inclination angle and depending on the future evolution of the optimum inclination angle.

An electromagnetic radiation collecting device is presented, which is particularly useful for the collection of solar radiation, providing optimal radiation collection throughout the daytime, and throughout yearly seasonal changes. The collector entails a redundant number of static collectors arranged in such a manner as to provide maximal and chronologically evened collection outline.

An electromagnetic radiation collecting device is presented, which is particularly useful for the collection of solar radiation, providing optimal radiation collection throughout the daytime, and throughout yearly seasonal changes. The collector entails a redundant number of static collectors arranged in such a manner as to provide maximal and chronologically evened collection outline.

Methods and functional elements for enhanced thermal management of predominantly enclosed spaces to enable the construction of buildings with reduced power requirements for heating and/or air-conditioning systems. The methods may be in part based on dynamically changing functional elements with variable properties, or effective properties, in terms of their electromagnetic radiative behavior and/or their thermal energy storage properties, or the spatial distribution of the stored thermal energy, which permits the application of methods to control the overall thermal behavior of the entire structure in such a way that desired levels of inside temperature can be reached with reduced consumption of external energy (typically electricity, gas, oil, or coal). In some instances no conventional heating of cooling is required at all. In some instances the invention reduces the time to reach desired temperatures inside such buildings, habitats, or other predominantly enclosed spaces.

Methods and functional elements for enhanced thermal management of predominantly enclosed spaces to enable the construction of buildings with reduced power requirements for heating and/or air-conditioning systems. The methods may be in part based on dynamically changing functional elements with variable properties, or effective properties, in terms of their electromagnetic radiative behavior and/or their thermal energy storage properties, or the spatial distribution of the stored thermal energy, which permits the application of methods to control the overall thermal behavior of the entire structure in such a way that desired levels of inside temperature can be reached with reduced consumption of external energy (typically electricity, gas, oil, or coal). In some instances no conventional heating of cooling is required at all. In some instances the invention reduces the time to reach desired temperatures inside such buildings, habitats, or other predominantly enclosed spaces.

The invention relates to a switchable absorber element and a photovoltaic cell based thereon. A switchable absorber element according to the invention has an absorber layer. The absorber element furthermore has at least one front side reflection layer and at least one rear side reflection layer, wherein the absorber layer is arranged between front side reflection layer and rear side reflection layer, wherein the optical path length between front side reflection layer and rear side reflection layer is less than 400 nm at least for light impinging perpendicularly onto the cell. The absorber element according to the invention is characterized in that at least one of the reflection layers has a switchable reflectivity.

The invention relates to a switchable absorber element and a photovoltaic cell based thereon. A switchable absorber element according to the invention has an absorber layer. The absorber element furthermore has at least one front side reflection layer and at least one rear side reflection layer, wherein the absorber layer is arranged between front side reflection layer and rear side reflection layer, wherein the optical path length between front side reflection layer and rear side reflection layer is less than 400 nm at least for light impinging perpendicularly onto the cell. The absorber element according to the invention is characterized in that at least one of the reflection layers has a switchable reflectivity.