New System for the Acceleration of the Airflow in Wind Turbines

Background: This patent is based on the wind industry technology called Diffuser Augmented Wind Turbines (DAWTs). This technology consists of a horizontal axis wind turbine, which is housed inside a duct with diverging section in the direction of the free air stream. In this paper, a review of preceding patents related to this technology is carried out. Objective: This paper presents an innovative patent to improve the performance of horizontal axis wind turbines. In particular, this system is aimed at improving the performance of those turbines that otherwise might not be installed due to the low wind resource existing at certain locations. Methods: The most innovative elements of this patent are: (1) the semi-spherical grooves, which are mechanized on the surface of the two diffusers in order to guarantee a more energetic boundary layer; (2) the coaxial diffuser, which is located downwind following the first diffuser in order to increase the suction effect on the air mass close to the inlet; (3) the coaxial rings located around the first diffuser outlet, which are used to deflect the external airflow toward the turbine wake; and (4), the selforientating system to orientate the system by the prevailing wind direction. Results: An application of the patent for increasing the power generated by a horizontal axis wind turbine with three blades is presented. The patent is designed and its performance is evaluated by using a Computational Fluid Dynamics code. The numerical results show that this system rises the airflow going through the rotor of the turbine. Conclusion: The patented device is an original contribution aimed at enabling a more profitable installation of wind turbines in places where the wind resource is insufficient because of the wind shear caused both by the proximity of the earth and the obstacles on the earth surface.This work was supported by the OASIS Research Project that was cofinanced by CDTI (Spanish Science and Innovation Ministry) and developed with the Spanish companies: Iridium, OHL Concesiones, Abertis, Sice, Indra, Dragados, OHL, Geocisa, GMV, Asfaltos Augusta, Hidrofersa, Eipsa, PyG, CPS, AEC and Torre de Comares Arquitectos S.L and 16 research centres. The authors also acknowledge the partial funding with FEDER funds under the Research Project FC-15-GRUPIN14-004. Finally, we also thank Swanson Analysis Inc. for the use of ANSYS University Research programs as well as the Workbench simulation environment

Direct confirmation of the radial-velocity planet β Pictoris c

Context. Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive to planets with a small orbital period, whereas direct detection is more sensitive to planets orbiting at a large distance from their host star. This dichotomy makes it difficult to combine the two techniques on a single target at once. Aims: Simultaneous measurements made by direct and indirect techniques offer the possibility of determining the mass and luminosity of planets and a method of testing formation models. Here, we aim to show how long-baseline interferometric observations guided by radial-velocity can be used in such a way. Methods: We observed the recently-discovered giant planet β Pictoris c with GRAVITY, mounted on the Very Large Telescope Interferometer. Results: This study constitutes the first direct confirmation of a planet discovered through radial velocity. We find that the planet has a temperature of T = 1250 ± 50 K and a dynamical mass of M = 8.2 ± 0.8 M[SUB]Jup[/SUB]. At 18.5 ± 2.5 Myr, this puts β Pic c close to a `hot start' track, which is usually associated with formation via disk instability. Conversely, the planet orbits at a distance of 2.7 au, which is too close for disk instability to occur. The low apparent magnitude (M[SUB]K[/SUB] = 14.3 ± 0.1) favours a core accretion scenario. Conclusions: We suggest that this apparent contradiction is a sign of hot core accretion, for example, due to the mass of the planetary core or the existence of a high-temperature accretion shock during formation

Constraining the nature of the PDS 70 protoplanets with VLTI/GRAVITY

We present K-band interferometric observations of the PDS 70 protoplanets along with their host star using VLTI/GRAVITY. We obtained K-band spectra and 100 $\mu$as precision astrometry of both PDS 70 b and c in two epochs, as well as spatially resolving the hot inner disk around the star. Rejecting unstable orbits, we found a nonzero eccentricity for PDS 70 b of $0.17 \pm 0.06$, a near-circular orbit for PDS 70 c, and an orbital configuration that is consistent with the planets migrating into a 2:1 mean motion resonance. Enforcing dynamical stability, we obtained a 95% upper limit on the mass of PDS 70 b of 10 $M_\textrm{Jup}$, while the mass of PDS 70 c was unconstrained. The GRAVITY K-band spectra rules out pure blackbody models for the photospheres of both planets. Instead, the models with the most support from the data are planetary atmospheres that are dusty, but the nature of the dust is unclear. Any circumplanetary dust around these planets is not well constrained by the planets' 1-5 $\mu$m spectral energy distributions (SEDs) and requires longer wavelength data to probe with SED analysis. However with VLTI/GRAVITY, we made the first observations of a circumplanetary environment with sub-au spatial resolution, placing an upper limit of 0.3~au on the size of a bright disk around PDS 70 b

Sustainable microgrids with energy storage as a means to increase power resilience in critical facilities: An application to a hospital

This manuscript proposes to study different cases that require the use of renewable energies in addition to diesel generators and energy storage systems with the aim of increasing the resilience of a microgrid feeding critical facilities. The aim of the work here presented is to quantify the benefits provided by an improvement of the energy resilience that could be achieved by installing a microgrid in a hospital fed by renewable energy sources. The microgrid will use a scheme based on solar PV in addition to diesel generators and an energy storage system based on electrochemical batteries. First, it has been evaluated how the implant of the microgrid increases the resilience of the power supply when a power failure occurs, considering that the main application in a hospital, even in the event of breakdowns, is to ensure the continuity of the surgical procedures and safely store drug stocks. Thus, these have been defined as the critical loads of the system. The components sizes have been optimized by considering both economic profitability but also the resilience capacity, observing that, by installing solar photovoltaic modules, Li-ion batteries and diesel generators, according to simulations performed in REopt\uae software, the microgrid could save approximately $ 440,191 on average over a 20-year life cycle of the facility (both considering the mitigation of energy provide by the power grid and the avoided losses during probable power services interruptions), while increasing the minimum resilience of the installation more than 34 h

Electricity Spot Prices Forecasting for MIBEL by using Deep Learning: A comparison between NAR, NARX and LSTM networks

In the latest times, power markets in Europe, including the Spanish one called MIBEL (Mercado Ib\ue9rico de Electricidad), are being deregulated and coupled. As a result, electricity can be easily purchased and sold across further areas and countries. On the other hand, trying to guarantee renewable projects profitability, Power Purchase Agreements and Options contracts are arising as a feasible solution. The problem arises when the power plant owners have to negotiate the purchase electricity price in order to optimize risks and profits, as well as make future plans. Thus, several methods for Electricity Price Forecasting (EPF) have been developed and presented, showing different results, as market spot prices suffer from strong seasonality, spikes and high volatility. In this paper, three methods, based on Deep Learning Dynamic Neural Networks (NAR, NARX and LSTM) applied to forecast MIBEL electricity spot prices are discussed in order to evaluate their adequacy, accuracy and reliable horizon

Hydrogen as an energy vector to optimize the energy exploitation of a self-consumption solar photovoltaic facility in a dwelling house

Solar photovoltaic (PV) plants coupled with storage for domestic self-consumption purposes seem to be a promising technology in the next years, as PV costs have decreased significantly, and national regulations in many countries promote their installation in order to relax the energy requirements of power distribution grids. However, electrochemical storage systems are still unaffordable for many domestic users and, thus, the advantages of self-consumption PV systems are reduced. Thus, in this work the adoption of hydrogen systems as energy vectors between a PV plant and the energy user is proposed. As a preliminary study, in this work the design of a PV and hydrogen-production self-consumption plant for a single dwelling is described. Then, a technical and economic feasibility study conducted by modeling the facility within the Homer Energy Pro energy systems analysis tool is reported. The proposed system will be able to provide back not only electrical energy but also thermal energy through a fuel cell or refined water, covering the fundamental needs of the householders (electricity, heat or cooling and water). Results show that, although the proposed system effectively increases the energy local use of the PV production and reduces significantly the energy injections or demands into/from the power grid, avoiding power grid congestions and increasing the nano-grid resilience, operation and maintenance costs may reduce its economic attractiveness for a single dwelling

The ExoGRAVITY project: using single mode interferometry to characterize exoplanets

Stars and planetary system

Constraining the Nature of the PDS 70 Protoplanets with VLTI/GRAVITY ∗ ∗ Based on observations collected at the European Southern Observatory under ESO programmes 0101.C-0281(B), 1103.B-0626(A), 2103.C-5018(A), and 1104.C-0651(A).

Abstract: We present K-band interferometric observations of the PDS 70 protoplanets along with their host star using VLTI/GRAVITY. We obtained K-band spectra and 100 μas precision astrometry of both PDS 70 b and c in two epochs, as well as spatially resolving the hot inner disk around the star. Rejecting unstable orbits, we found a nonzero eccentricity for PDS 70 b of 0.17 ± 0.06, a near-circular orbit for PDS 70 c, and an orbital configuration that is consistent with the planets migrating into a 2:1 mean motion resonance. Enforcing dynamical stability, we obtained a 95% upper limit on the mass of PDS 70 b of 10 M Jup, while the mass of PDS 70 c was unconstrained. The GRAVITY K-band spectra rules out pure blackbody models for the photospheres of both planets. Instead, the models with the most support from the data are planetary atmospheres that are dusty, but the nature of the dust is unclear. Any circumplanetary dust around these planets is not well constrained by the planets’ 1–5 μm spectral energy distributions (SEDs) and requires longer wavelength data to probe with SED analysis. However with VLTI/GRAVITY, we made the first observations of a circumplanetary environment with sub-astronomical-unit spatial resolution, placing an upper limit of 0.3 au on the size of a bright disk around PDS 70 b