Long Term Outdoor Testing of Low Concentration Solar Modules

A 1‐axis carousel tracker equipped with four 3‐sun low‐concentration mirror modules has now been under test outdoors at the University of Nevada in Las Vegas (UNLV) for three years. There are three unique features associated with this unit. First, simple linear mirrors are used to reduce the amount of expensive single crystal silicon in order to potentially lower the module cost while potentially maintaining cell efficiencies over 20% and high module efficiency. Simple linear mirrors also allow the use of a single axis tracker. Second, the azimuth carousel tracker is also unique allowing trackers to be used on commercial building rooftops. Third, an experiment is underway comparing aluminum based mirrors with novel 3M Company multilayer polymeric mirrors which are potentially very low cost. Comparing the data from March of 2008 through March of 2011 shows that the aluminum mirror degradation to date is negligible and that the carousel tracker has been operating continuously and reliable. Also, no degradation has been observed for the 3M brand cool mirrors after one year in use

Burner, Emitter, and Recuperator Development for Lightweight Thermophotovoltaic Power Supply

Like batteries, thermophotovoltaic generators produce DC electricity quietly. TPV uses infrared photovoltaic cells to convert infrared radiation from a combustion heated ceramic IR emitter. However, because the specific energy in a hydrocarbon fuel like propane or butane is 12,900 Wh/kg, much larger than the specific energy of 145 Wh/kg for a Li-ion battery, TPV is very promising as a lightweight DC power supply. A portable cylindrical thermophotovoltaic (TPV) battery replacement concept has been previously described. It consists of a cylindrical TPV receiver assembly using simple diffused junction GaSb IR cells along with a novel omega recuperator and a novel doped ceramic matched IR emitter. For high energy conversion efficiency, it is very important to match the IR spectrum emitted with the IR PV receiver cells. While the GaSb IR cells have been previously demonstrated, development and demonstrations of the omega recuperator and the IR matched emitter are described for the first time here. The matched IR emitter consists of NiO doped MgO ceramic rods arrayed in a 26 mm diameter picket fence configuration. A burner, emitter, and recuperator test station is described consisting of this picket fence emitter heated at up to 1300 C by propane combustion along with an omega recuperator to preheat the combustion air. The emitted IR intensity is measured with a single GaSb test cell. Given a TPV conversion efficiency of 10%, this lightweight TPV cylinder along with 1.8 kg of fuel promises a very high specific energy of approximately 700 Wh/kg. This specific energy is 5 times higher than the specific energy for a Li-ion battery with a similar power rating making this TPV unit very lightweight. The key is the goal of 10% system efficiency. Progress towards achieving this goal is described here

Vitalit\ue0 della cultura classica nel dialogo con il contemporaneo (a proposito della mostra di F. Vezzoli \u201cMuseo Museion\u201d)

Il contributo \ue8 incentrato sul tema dell'attualizzazione dell'arte e della cultura classica realizzata nella mostra di Francesco Vezzoli intitolata "Museo Museion", esposta presso il Museo d'arte moderna e contemporanea di Bolzano. Essa offre l'esempio di una originale rilettura e di un vitale dialogo tra passato e presente, particolarmente adatto ad incuriosire e coinvolgere le nuove generazioni, nel confronto - talvolta bonariamente ironico - fra armonia classica ed emotivit\ue0 moderna