• Energy Research
• 7. Clean energy close

El proyecto REVen “Rehabilitación energética de viviendas sociales, aplicando productos innovadores de ventana con marcado CE” (BIA2014-56650-JIN), tiene como objetivo realizar un análisis integral del impacto de la ventana en los aspectos relativos a eficiencia energética y calidad ambiental. Para caracterizar los flujos de energía y las condiciones ambientales internas se ha construido el Laboratorio REVen. Este artículo describe la construcción y la monitorización de este laboratorio analizando los datos de su primer año de funcionamiento. Los resultados permiten afirmar que se logra una mejora significativa del confort térmico obteniendo un ahorro de energía anual del 25 %.

In this paper, we propose and investigate an original approach to energy conversion based on polyzwitterionic hydrogels, which exhibit an antipolyelectrolyte effect that enables them to swell in salt water and shrink in water of a different (i.e., desalinated water) salinity. The swelling and shrinking processes run cyclically and can move a piston up or down reversibly, thus transforming the antipolyelectrolyte effect into a mechanical force based on the salinity gradient. This phenomenon makes polyzwitterionic hydrogels suitable for use in a smart, polymeric engine. We apply this approach to investigate energy recovery from a polysulfobetaine-based hydrogel. The cross-linking density, external load, particle size, and repeatability of energy recoverability of hydrogels are examined. The maximum energy recovery from 0.4 g of hydrogel in feed (calculated based on dry form) of 102 mJ/kg was obtained by a hydrogel with a 3% cross-linking density, a 200-300 μm particle size, and 100 g external load. Excellent reproducibility of engine cycles was achieved over 10 cycles. This concept is complementary to the osmotic engine concept based on a polyelectrolyte hydrogel. In addition, polyzwitterionic materials have become a benchmark material for preventing biofouling, and the swelling properties of such materials can be further modulated and tuned.

Beside their technological importance in soldering, the low melting eutectic alloys based on bismuth and indium have potential for commercial application in the field of phase- change materials (PCMs). In this respect, the knowledge of their microstructure and thermal properties such as melting temperature, latent heat of melting, supercooling tendency, thermal conductivity, etc. is of large importance. In this study, two ternary eutectic Bi-In-Sn alloys were investigated by means of scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS) and differential scanning calorimetry (DSC). Microstructure of the prepared eutectic alloys was analyzed using SEM- EDS and identification of co-existing phases was done. Melting temperatures and latent heats of eutectic melting were measured using DSC technique. Experimentally obtained results were compared with the results of thermodynamic calculation according to CALPHAD (calculation of phase diagram) approach and good mutual agreement was obtained.

Abstract Using an econometric energy demand model, this paper separates price from non-price conservation effects in the period 1974–1977 and examines what might have happened to Canadian energy demands if Canada had priced its energy at OPEC equivalent levels instead of pursuing a gradual ‘phase-in’ policy. Prices accounted for the major proportion of energy savings over the period 1974–1977, particularly in the industrial and transport sectors, and for oil and gas. Non-price effects seem to have had a larger impact in the earlier years and for oil and electricity. Movement to international prices during the period studied could have reduced Canadian secondary energy demands by the oil equivalent output of 1.3 Syncrude-sized (125 000 bbl/day) oilsands plants.

Technical solutions for optimizing the flame aerodynamics and the design of tangentially arranged burners in a TGMP-314 boiler are proposed. The implementation of these solutions will make it possible to achieve more reliable operation of the boiler during fuel oil combustion, smaller amount of NOx emissions during the combustion of gas and fuel oil, and a somewhat lower air excess factor in the furnace.

The paper presents a preliminary technical-economic comparison between a 3 kV DC railway and the use of trains with on-board storage systems. Numerical simulations have been carried out on a real railway line, which presents an electrified section at 3 kV DC and a non-electrified section, currently covered by diesel-powered trains. Different types of ESS have been analyzed, implementing the models in Matlab/Simulink environment. A preparatory economic investigation has been carried out.

Abstract This paper investigates the performance of a variable ratio gearbox (VRG) used in a small fixed-speed wind turbine with active blades. The major components of the VRG-enabled drivetrain are an automatic-manual gearbox and squirrel cage induction generator that connects directly to the grid. The simplicity of this system may be appealing for applications when cost and reliability are of concern. It is an alternative to variable speed systems, which necessitate a modified generator and power conditioning equipment. During partial load operation the VRG provides a discrete set of rotor speeds. This allows the controller to track the wind speed and to achieve a greater efficiency. This study suggests three VRG ratios are sufficient to improve performance when used with active blades. A case study is presented where the performance is simulated using three different wind data sets. The study suggests that the VRG can improve production between 7 and 8.5% in low wind areas. The design procedure also illustrates a technique for finding the lowest and highest gear ratios needed for VRG design. These ratios allow the system to achieve the lowest cut-in and rated speeds. The approach also has useful implications for the design of a continuously variable transmission.