scholarly journals Optical properties of opaque and light-transmitting photovoltaic systems in architecture and their influence on architectural form

1970 ◽  
Vol 14 (1) ◽  
pp. 44-54
Author(s):  
Marcin Brzezicki ◽  
Magdalena Muszyńska-Łanowy

Energy-harvesting systems installed on facades have an immense influence on the perception of architecture. Technologies at various stages of advancement are currently used. Apparent (clearly visible) PV elements (e.g. old-generation applied solar panels) are being replaced by technologies that integrate those systems into the building’s envelope using miniaturization, lamination and surface mounting (e.g. BIPV). In the current application of PV, three distinct trends ca be observed: (i) the integration of energy-collecting elements into the shell and (ii) their deliberate display and use as, for example, shading, cladding or other forms of decoration, or (iii) the development of “invisible” PV systems. The research question is how the development of these systems affects architecture. Does the process of integration enrich the building’s architectural expression or negatively affect the perception of the building’s transparent surfaces?

Author(s):  
C. Nagode ◽  
M. Ahmadian ◽  
S. Taheri

Currently, the onboard applications of many electronic devices that could benefit rail operation are hindered by the lack of availability of electrical power in freight cars. Although the locomotives, of course, have available sources of power, the freight cars usually don’t have any. The systems presented in this paper are meant to provide a solution for distributed power in freight trains. Although ideas like Timken’s generator roller bearing or solar panels exist, the railroads have been slow in adopting them for different reasons, including cost, difficulty of implementation, or limited capabilities. The solutions presented in this paper are vibration-based electromechanical energy harvesting systems. With size and shape similar to conventional shock absorbers, these devices are designed to be placed in parallel with the suspension elements, possibility inside the coil spring, maximizing underutilized space. As the train goes down the track, the suspension will accommodate the imperfections and its relative displacement will be used as the input for the harvesting systems. The first prototype generation used a linear generator, with the advantage of no need for a mechanical transformation of the input. They have proven that they could work but present some limitations in terms of power and efficiency. The second generation of prototypes is built around a rotating generator. The linear input motion is transformed into rotation by a ball screw. The possibility of including a gearbox to increase the speed is the key to greatly improve performances. The latest built prototype has shown during lab tests that it is capable of providing up to 75WRMS with displacements and velocities that resemble the relative motion across a vehicle suspension.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.


Author(s):  
Benbouza Naima ◽  
Benfarhi Louiza ◽  
Azoui Boubekeur

Background: The improvement of the voltage in power lines and the respect of the low voltage distribution transformer substations constraints (Transformer utilization rate and Voltage drop) are possible by several means: reinforcement of conductor sections, installation of new MV / LV substations (Medium Voltage (MV), Low Voltage (LV)), etc. Methods: Connection of mini-photovoltaic systems (PV) to the network, or to consumers in underserved areas, is a well-adopted solution to solve the problem of voltage drop and lighten the substation transformer, and at the same time provide clean electrical energy. PV systems can therefore contribute to this solution since they produce energy at the deficit site. Results: This paper presents the improvement of transformer substation constraints, supplying an end of low voltage electrical line, by inserting photovoltaic systems at underserved subscribers. Conclusion: This study is applied to a typical load pattern, specified to the consumers region.


Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1464
Author(s):  
Marcin Walczak ◽  
Leszek Bychto

DC/DC converters are widely used in photovoltaic (PV) systems to maximize the power drained from solar panels. As the power generated by a PV panel depends on the temperature and irradiance level, a converter needs to constantly modify its input resistance to remain at the maximum power point (MPP). The input resistance of a converter can be described by a simple equation that includes the converter load resistance and the duty cycle of the switching signal. The equation is sufficient for an ideal converter but can lead to incorrect results for a real converter, which naturally features some parasitic resistances. The goal of this study is to evaluate how the parasitic resistances of a converter influence its input resistance and if they are relevant in terms of MPPT system operation.


Author(s):  
Virgilio J Caetano ◽  
Marcelo A Savi

Energy harvesting from ambient vibration through piezoelectric devices has received a lot of attention in recent years from both academia and industry. One of the main challenges is to develop devices capable of adapting to diverse sources of environmental excitation, being able to efficiently operate over a broadband frequency spectrum. This work proposes a novel multimodal design of a piezoelectric energy harvesting system to harness energy from a wideband ambient vibration source. Circular-shaped and pizza-shaped designs are employed as candidates for the device, comparing their performance with classical beam-shaped devices. Finite element analysis is employed to model system dynamics using ANSYS Workbench. An optimization procedure is applied to the system aiming to seek a configuration that can extract energy from a broader frequency spectrum and maximize its output power. A comparative analysis with conventional energy harvesting systems is performed. Numerical simulations are carried out to investigate the harvester performances under harmonic and random excitations. Results show that the proposed multimodal harvester has potential to harness energy from broadband ambient vibration sources presenting performance advantages in comparison to conventional single-mode energy harvesters.


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