COOLING PHOTOVOLTAIC SYSTEMS: A SURVEY OF AVAILABLE TECHNOLOGIES

ArticleCooling is a key operation factor to take into consideration to achieve higher efficiency when operating solar photovoltaic systems. Proper cooling can improve the electrical efficiency, and the heat removed by the cooling system can be used in other domestic, commercial or industrial applications. This paper is a survey of various methods that can be used to minimize the negative impacts of the increased temperature while making an attempt to enhance the efficiency of photovoltaic solar panels operating beyond the recommended temperature from the Standard Test Conditions (STC). These technologies are discussed based on their operation principles, technical advantages, and disadvantages. The results of this study highlight that any technology selected to cool a photovoltaic panel should be used to keep the operating surface temperature low and steady, be simple and reliable and, if possible, enable the use of extracted thermal heat to enhance efficiency of the overall conversion system

A survey of airborne radar systems for deployment on a High Altitude Powered Platform (HAPP)

A survey was conducted to find out the system characteristics of commercially available and unclassified military radars suitable for deployment on a stationary platform. A total of ten domestic and eight foreign manufacturers of the radar systems were identified. Questionnaires were sent to manufacturers requesting information concerning the system characteristics: frequency, power used, weight, volume, power radiated, antenna pattern, resolution, display capabilities, pulse repetition frequency, and sensitivity. A literature search was also made to gather the system characteristics information. Results of the survey are documented and comparisons are made among available radar systems

Classification of land use data

For the data collected under the 2007 global survey, the classification system developed for the 2006 survey was used, but slightly modified. When the 2006 survey began, FiBL did not yet have a classification system, as it was not known what kind of data would be available, if any (Baraibar 2006). As the data were collected, a classification system was developed according to the kind of data received. FiBL and SOEL are planning to improve the classification system and to ultimately bring it in line with classification systems that are currently being developed for organic farming

The 2XMMi/SDSS Galaxy Cluster Survey. III. Clusters associated with spectroscopically targeted luminous red galaxies in SDSS-DR10

We present a sample of 383 X-ray selected galaxy groups and clusters with spectroscopic redshift measurements (up to z ~ 0.79) from the 2XMMi/SDSS Galaxy Cluster Survey. The X-ray cluster candidates were selected as serendipitously detected sources from the 2XMMi-DR3 catalogue that were located in the footprint of the Sloan Digital Sky Survey (SDSS-DR7). The cluster galaxies with available spectroscopic redshifts were selected from the SDSS-DR10. We developed an algorithm for identifying the cluster candidates that are associated with spectroscopically targeted luminous red galaxies and for constraining the cluster spectroscopic redshift. A cross-correlation of the constructed cluster sample with published optically selected cluster catalogues yielded 264 systems with available redshifts. The present redshift measurements are consistent with the published values. The current cluster sample extends the optically confirmed cluster sample from our cluster survey by 67 objects. Moreover, it provides spectroscopic confirmation for 78 clusters among our published cluster sample, which previously had only photometric redshifts. Of the new cluster sample that comprises 67 systems, 55 objects are newly X-ray discovered clusters and 52 systems are sources newly discovered as galaxy clusters in optical and X-ray wavelengths. Based on the measured redshifts and the fluxes given in the 2XMMi-DR3 catalogue, we estimated the X-ray luminosities and masses of the cluster sample.Comment: A&A in press, 12 pages, 15 figures, 1 table, http://www.aanda.org/index.php?option=com_article&access=doi&doi=10.1051/0004-6361/20132297