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The issue logic of a dynamically-scheduled superscalar processor is a complex mechanism devoted to start the execution of multiple instructions every cycle. Due to its complexity, it is responsible for a significant percentage of the energy consumed by a microprocessor. The energy consumption of the issue logic depends on several architectural parameters, the instruction issue queue size being one of the most important. In this paper we present a technique to reduce the energy consumption of the issue logic of a high-performance superscalar processor. The proposed technique is based on the observation that the conventional issue logic wastes a significant amount of energy for useless activity. In particular, the wake-up of empty entries and operands that are ready represents an important source of energy waste. Besides, we propose a mechanism to dynamically reduce the effective size of the instruction queue. We show that on average the effective instruction queue size can be reduced by a factor of 26% with minimal impact on performance. This reduction together with the energy saved for empty and ready entries result in about 90.7% reduction in the energy consumed by the wake-up logic, which represents 14.9% of the total energy of the assumed processor.

Nowadays, it is increasingly common to hear about environmental issues. This fact keep us to continually try to improve energy optimization, either through new storage devices that pollute less or improvements in the environmental energy generation systems. Recent new types of devices under study are those called supercapacitors. Supercapacitors are electronic devices able to store charge in form of electrical energy. This energy is stored as an electric field, so supercapacitors are less polluting than standard batteries, which obtained its energy by chemical reactions. Their name is determinate by the high capacity that can achieve (up to 1000 F). The aim of this project is to find a model to characterize the behaviour of supercapacitors from their charge and discharge, analyze the efficiency of these devices and try to find if the energy losses could be represented only by a series resistance or not. The steps that have been followed to achieve the main aim were to design a charge-discharge circuit based on two methods (constant current source and pulse current source); collect and process the measurements obtained and analyze the supercapacitors behaviour during the process of charge-discharge. Finally, a model of an equivalent circuit for supercapacitors have been found and characterize whit the values obtained from the results of charge-discharge process. In order to validate the model searched, it has been simulated with a simulation program.

Wastes from tanneries present a good opportunity to produce biogas and use it in high temperature fuel cells for combined heat and power systems. Biogas is considered a renewable fuel, domestically produced and free of carbon emissions, while molten carbonate fuel cells are ultra-clean and highly efficient power generators. In this paper, we study the economic viability of a fuel cell (considerating capacities from 300kW to 1200kW) operating on biogas. The results are based on Spanish legislation, which establishes a special feed-in tariff for biogas and cogeneration. Paybacks range from 5.7 to 8.5 years depending on the fuel cell capacity. Due to the high investment and operating and maintenance cost, the Spanish feed-in tariff for cogeneration using biogas is not enough to make the project economically viable in a short-term. Further fuel cell price reducation and longer lifetime as well as new government subsidies are required

El presente proyecto tiene como objeto dar una respuesta integral a las exigencias de producción de ACS, y climatización para un edificio de apartamentos situado en la ciudad de Guatemala, Guatemala. Se analizara para tal objeto la situación del país en cuanto a iniciativas y políticas de apoyo o promoción para la aplicación de energías renovables. Partiendo de un diagnostico de los requerimientos y demandas del proyecto se definirá un criterio de diseño y dimensionado, analizando los resultados de las demandas se intentara llegar a la solución que mejor cubra estas exigencias. Un sistema con tecnología capaz de obtener el mayor provecho de una instalación solar térmica de captadores solares, procesa la energía obtenida a través del sol y la transforma en frio para cubrir las demandas de refrigeración en épocas de altas temperaturas, en épocas de temperaturas bajas utilizaremos esta misma energía para calefactar los ambientes, mientras que se produce durante todo el año ACS para las demandas del proyecto. Los resultados del cálculo de las cargas térmicas de calefacción y refrigeración nos servirán para poder dimensionar el área de captadores solares que mejor se adapte a las demandas y exigencias del sistema integral y a la vez dimensionar el equipo seleccionado para dicho fin. Al final del proyecto podremos verificar si este tipo de proyectos son viables y si además son aplicables a una latitud tan diferente a la europea. Los resultados de los ahorros energéticos se traducirán a ahorro en emisiones de CO2 y ahorro en la facturación de energía mensual del proyecto.

Due to the ever increasing data traffic demands, which are directly connected to increased energy consumption, it becomes challenging for operators to achieve capacity enhancement while limiting their electric bill. To that end, exploiting the context awareness of future cognitive networks is expected to play a key role. Next generation cellular networks are about to include a plethora of small cells, with users being able to communicate via multiple bands. Given that small cells are expected to be eventually as close as 50 m apart, not all of them will have a direct connection to the core network; thus, multihop communication through neighboring small cells may be required. In such architectures, the user association problem becomes challenging, with backhaul energy consumption being a definitive parameter. Thus, in this article, we study the user association problem in cognitive heterogeneous networks. We evaluate the existing approaches in terms of energy efficiency and show the potential of exploiting the available context-aware information (i.e., users' measurements and requirements, knowledge of the network architecture, and the available spectrum resources of each base station) to associate the users in an energy-efficient way, while maintaining high spectrum efficiency. Our study considers both the access network and backhaul energy consumption, while the performance of the association algorithms is evaluated under two different case study scenarios. Grant number : This work has been funded by the Research Projects GREEN-T (CP8-006), COST-TERRA (IC0905). © 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

Around the world, the growing concern about sustainability, self-reliance, healthy diets, and the increasing interest and use of solar energy make our project and our goals as interesting as important. We are developing a product for a very specific and relatively new market niche, which is however rapidly expanding. Our target group – private consumers, such as small farmers, families with a garden or a terrace, or simply any person who is concerned about maintaining a healthy diet and a healthy planet – is one that will keep growing in the years to come. The project consists in developing and building a solar food dehydrator. It is a food processing device which is used to extract moisture from different kinds of foods or herbs. The product is specifically designed for the dehydration of fruit and vegetables. The goal is to develop an optimized and ideal fruit and vegetable dehydrator, encouraging the use of food dehydration as a healthy and efficient method for food preservation Treball desenvolupat dins el marc del programa 'European Project Semester'.

This report paper offers the reader an outline of the development of a MLR model to predict fuel consumption for double-stack intermodal trains in Canada. Results suggested the necessity to classify the data in a non-finished project and design categories for various factors. Furthermore, the conclusion extracted is the requirement to compose small-scale models for specific conditions of track and train in order to obtain the results for an entire railroad section. Whereas the lack of success on the original goal of this research, which was to predict fuel consumption for intermodal trains in any random configuration under any condition of railroad track, the scope of the project was shortened to a very specific piece of section of the Canadian railway network for trains that travel full power. This was as a result of complications disclosed during the development of the project and troubles discerning the vast data