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A new concept of a system for Combined Heat and Power generation is presented. The concept is based on hybrid use of two renewable energy sources, direct solar (thermodynamic solar) and biomass (indirect solar energy). Biomass combustion is conducted using a fluidized bed combustor. A second source of energy, given by the direct irradiation of the bed with a concentrated solar radiation, is integrated in the same system, using the fluidized bed as solar receiver. A Stirling engine converts heat into mechanical power. A Scheffler type mirror is adopted to allow irradiation of the system in a fixed focal point. Advantages of the proposed solution are illustrated and some preliminary results on the performance of the system, obtained with a simple model, are presented. The principal improvements with respect to existing systems of similar size and primary energy source are illustrated. The most important are the enhanced heat transfer processes that are realized with the help of the fluidized bed, and the possibility of continuous cogeneration during the day. Different working conditions are considered to estimate the contribution given by the burning of fuel, in presence as well as in absence of sun irradiation (as during the night). The distribution of energy shares among the different flux contributes is reported versus the amount of biomass burned per unit time. The results clearly demonstrate the advantage of coupling, in the same system, two sources for heat generation, thus maintaining the option of producing electricity without the supply of biomass fuel.

In this paper we argue for the need to apply a cognitive approach to understand deep dynamics and determinants of technological evolutions. After examining main contributions from innovation studies to the conceptualization of innovation and change in complex socio-technical environments, we highlight the contribution coming from the application of the cognitive approach to evolutionary studies on technologies and we introduce the concept of technological memory as an interpretative tool to understand those changes. We discuss our hypothesis with reference to several observations carried out in different local contexts – Mexico, India and Italy – in relation to technological change in the water sector. In those cases deliberate attempts to substitute traditional technologies with modern ones led to interesting trajectories of change ranging from the collapse of old technologies to the development of multifaceted hybridization patterns. Tema. Journal of Land Use, Mobility and Environment, 2014: INPUT 2014 - Smart City: planning for energy, transportation and sustainability of the urban system

Laser Grooved Buried Contact (LGBC) solar cell technology is an attractive way for the production of solar cells designed to operate at one sun. Although LGBC cells can have higher efficiency when compared to standard screen-printed solar cells, a more complex manufacturing process is required, increasing their relative costs. In the FP6 EU funded project “Lab2Line,” screen print and LGBC solar cell processing techniques are hybridized in order to produce lower cost high efficiency solar cells processed on large area mono-crystalline wafers, using techniques scalable to industry. Two hybrid approaches have been considered: in the first, screen-print (SP) is applied for both rear and front contacts; in the second process SP is applied only to the rear and then electroless plating is used to form the front contacts. Both Lab2Line hybrid approaches offer high average efficiencies with a small performance distribution, while simultaneously presenting a more compact, cost effective option to production. The combination of SP techniques with LGBC processes and electroless plating has led to a maximum efficiency of 17.34% for the first process and 18% (17.44% average on 171 wafers) for the latter. Modules having such cells result in FF of 79.0% and efficiency of 17.0%. 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 1660-1664

The thin film (TF) solar market is challenged to produce solar modules with higher energy conversion efficiency while at the same time reducing the manufacturing cost. One way to improve the energy efficiency is to move to higher performance systems like Cadmiumtellurid (CdTe) or Cu(In,Ga)(S,Se)2 (CIGS) in comparison to TF Silicon (Si) based technologies. As today’s a-Si and CdTe structuring technology for module development is based on laser scribing, the technology for CIGS modules is mostly dominated by mechanical scribing. As inexpensive as the mechanical scribing technology seems, it has its drawbacks when it comes to high precision scribing of TF materials and, subsequently, the reliability in the manufacturing process. Bringing together a high speed, high accuracy motion system with ultra short pulse laser sources opens up new ways CIGS solar cell production can be perceived. We present with this work an in depth evaluation of the influences of the laser pulse width and wavelength to the CIGS scribing process on glass substrate. A variation of the pulse width in the range of 10 ps to 100 ps and 1 ns up to 30 ns is studied and monitored to determine the influences on the scribing quality. At the end, a functional mini-module is presented featuring a dead zone of less than 200 μm. Incorporating the results into a scribing tool an innovative industrial concept is developed for future integration. An outlook is given on the possible impact on cell efficiency, manufacturing costs, and cost of ownership implementing such a concept into production. 26th European Photovoltaic Solar Energy Conference and Exhibition; 2986-2991

Upconversion (UC) of sub-band-gap photons is a promising approach to increase solar cell efficiencies, because it makes these sub-band-gap photons useful as well. We investigate the application of -NaYF4:20% Er3+ to silicon solar cells. We determine the external quantum efficiency of an UC silicon solar cell, both under monochromatic excitation and under white light illumination. We demonstrate that an UC silicon solar cell responds under white light with an average UC efficiency of 1.07 ± 0.13% in the spectral range from 1460 to 1600 nm. Concepts are discussed how the narrow absorption range of the UC material can be overcome. 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 229-233

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