scholarly journals A New Thermal-Solar Field Configuration: The Rotatory Fresnel Collector or Sundial

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4139
Author(s):  
Javier Cano-Nogueras ◽  
Javier Muñoz-Antón ◽  
José M. Martinez-Val
Keyword(s):  
Solar Radiation ◽  
Vertical Plane ◽  
Vertical Axis ◽  
Central Line ◽  
Field Configuration ◽  
Radius Of Curvature ◽  
Angle Of Incidence ◽  
The Sun ◽  
Azimuthal Component ◽  
Solar Field

A new type of Fresnel array has been devised and constructed as an answer to the need to reduce the investment costs of solar thermal collectors, without jeopardizing their efficiency in capturing solar radiation at high temperatures. The array of mirror bands is fixed onto a horizontal platform, which rotates around a virtual vertical axis, so that the sun is in the extrapolated vertical plane of symmetry of the array. The receptor central line is also placed in said plane, and it is physically made of at least one tube at each side of the plane. The geometrical relation between the mirrors and the receptor is therefore fixed. The platform rotates with the same speed as that of the sunlight’s azimuthal component. On the contrary, the angle of incidence of the sunlight on the mirrors changes as the sun rises and declines in its daily apparent motion, but this effect does not disturb the radiation concentration kinematics, although it induces a shift along the receptor. This is a new configuration based on the use of simple and cheap flat mirrors to obtain circular cylindrical mirrors. These mirrors are made of originally flat mirrors that are bent by applying an inexpensive and simple bending technique patented by our research group. The radius of curvature of each mirror is tuned to the distance from the mirror to the receiver central line. The integration of different scientific domains (such as structural analysis) and elementary technologies (such as 3D printing) in this innovative solar radiation concentrator and receiver can lead to a large reduction in costs. Nevertheless, the first experimental campaign has shown additional problems in the receiver configuration, which should be addressed in a next stage of research. This paper explains the methodology used and procedures in the development of the first prototype of the Sundial.

Numerical Modeling of Solar Radiation Heat Transfer for a Truck Cabin

2015 ◽  
Vol 813-814 ◽  
pp. 742-747
Author(s):  
S. Senthilkumar ◽  
K. Ramkumar ◽  
M. Velshankar ◽  
S. Karthikeyan ◽  
D. Parthipan
Keyword(s):  
Solar Radiation ◽  
Radiation Heat Transfer ◽  
Angle Of Incidence ◽  
The Sun ◽  
Radiation Heat ◽  
Abrupt Increase ◽  
Vehicle Cabin ◽  
Environment Temperature ◽  
Different Seasons ◽  
Materials Used

The temperature inside the vehicle cabin will be higher than the outside environment temperature in parked conditions due to radiative effects. This increased temperature is not uniformly spread within the driver cabin due to absorption capacities of the various materials used for construction and the angle of incidence of the incoming radiation. The objective of the work is to predict the accumulation of heat inside the cabin numerically and find hotspots throughout the cabin. The path of the sun in different seasons and timings on a particular location was calculated and is implemented for the angle of incidence of radiation on the cabin. The investigation provides the variations of temperature, transmitted solar radiation and amount of absorption by various components that are subjected to assessment. Thus the major contributing factor for the abrupt increase in temperature was found.

scholarly journals Factors of photovoltaic system cost affect in Ecuador

2019 ◽  
Vol 5 (6) ◽  
pp. 1-11
Author(s):  
Janner Leonel Santos Mantuano ◽  
Mario Javier Carreño Vera ◽  
Ever Nevárez Cedeño
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Electrical Energy ◽  
Photovoltaic System ◽  
Photovoltaic Systems ◽  
Angle Of Incidence ◽  
The Sun ◽  
The Hours ◽  
The Impact

A photovoltaic system is a set of devices that take advantage of the energy produced by the sun and convert it into electrical energy. The impact produced by the possibility of using solar energy in a controlled manner for different uses and purposes has allowed the development of complete systems of transformation, storage and distribution of the energy produced with photovoltaic systems as appropriate. The production of electricity from solar radiation using solar cells and photovoltaic panels is an application that has yet fully disseminated in Third World countries, such as Ecuador. The generation of electric power will depend on the hours that the sun shines and affects the solar panel, the type and quantity of modules installed, orientation, inclination, solar radiation that reaches them, quality of the installation and the power that can be delivered to the user. Ecuador is in a privileged location in terms of solar radiation, because the equatorial line that divides the planet into two hemispheres passes through it, being almost perpendicular to the radiation it receives. In addition, this does not change during the year and there a constant angle of incidence, characteristics that give photovoltaic solar energy a great potential for use. In the investigation, an analysis of how the prices of photovoltaic systems affect the Province of Manabí, the methodology used has been the bibliographic review to know as much as possible about what replenishes the costs of photovoltaic systems.

Sun Load Analysis and Testing on Automotive Front Lighting Products

2020 ◽  
pp. 116-122
Author(s):  
Emre Öztürk ◽  
Mehmet Aktaş ◽  
Tunç Şenyüz
Keyword(s):  
Prolonged Exposure ◽  
Hot Spot ◽  
Load Test ◽  
Angle Of Incidence ◽  
The Sun ◽  
Solar Simulator ◽  
Automotive Lighting ◽  
Inclination Angles ◽  
Plastic Parts ◽  
Load Simulation

The purpose of this research is to reach good correlation between sun load simulation and solar focusing test for exterior automotive lighting products. Light coming from sun is highly collimated (parallel rays) and focusable from lenses with concave structure. Focusing incidence leads to a hot spot on lens surrounding plastic parts which may cause melting failures at high temperature zones. Sun load simulation is performing to eliminate risk of discoloration, deformation, out gassing, coating failures and fire with prolonged exposure from field. Irradiance values in W/m2 defined in simulation as heat source depending of an angle of incidence of the sun radiation. At first step, simulation is performing with 5 degree intervals to define the critical zones then intervals decreased to 2 degree to detect the critical azimuth and inclination angles. Critical azimuth and inclination angles is checking with ray trace analysis to check the bouncing of sun rays and possible solution to eliminate focuses with design solutions. After numerical analysis to release and validate the automotive lighting products regarding the sun load test, measurement with first parts is necessary. Measurement is performing for all critical angles which have been detected at simulation with thermal camera under ultra high-collimation solar simulator. Measured temperatures are settled according to environment conditions and correlation is checking with simulations.

Three‐component sonde orientation in a deviated well

Geophysics ◽  
1990 ◽  
Vol 55 (10) ◽  
pp. 1386-1388 ◽  
Author(s):  
M. Becquey ◽  
M. Dubesset
Keyword(s):  
Hydraulic Fracturing ◽  
Coordinate System ◽  
Vertical Plane ◽  
Vertical Axis ◽  
Horizontal Axis ◽  
Orthogonal Coordinate System ◽  
Coordinate Rotation ◽  
Orthogonal Components ◽  
Particle Velocities

In well seismics, when operating with a three‐component tool, particle velocities are measured in the sonde coordinate system but are often needed in other systems (e.g., source‐bound or geographic). When the well is vertical, a change from the three orthogonal components of the sonde to another orthogonal coordinate system can be performed through one rotation around the vertical axis and, if necessary, another one around a horizontal axis (Hardage, 1983). If the well is deviated, the change of coordinate system remains easy in the case when the source is located at the vertical of the sonde, or in the case when the source stands in the vertical plane defined by the local well axis. In the general case (offset VSPs or walkaways) or when looking for unknown sources (such as microseismic emissions induced by hydraulic fracturing), coordinate rotation may still be performed, provided that we first get back to a situation in which one of the axes is vertical.

scholarly journals Comparative Modeling of a Parabolic Trough Collectors Solar Power Plant with MARS Models

Energies ◽  
2017 ◽  
Vol 11 (1) ◽  
pp. 37 ◽  
Author(s):  
Jose Rogada ◽  
Lourdes Barcia ◽  
Juan Martinez ◽  
Mario Menendez ◽  
Francisco de Cos Juez
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Power Plant ◽  
Solar Radiation ◽  
Thermal Energy ◽  
Power Plants ◽  
Solar Power ◽  
Rankine Cycle ◽  
Heat Transfer Fluid ◽  
Solar Field

Power plants producing energy through solar fields use a heat transfer fluid that lends itself to be influenced and changed by different variables. In solar power plants, a heat transfer fluid (HTF) is used to transfer the thermal energy of solar radiation through parabolic collectors to a water vapor Rankine cycle. In this way, a turbine is driven that produces electricity when coupled to an electric generator. These plants have a heat transfer system that converts the solar radiation into heat through a HTF, and transfers that thermal energy to the water vapor heat exchangers. The best possible performance in the Rankine cycle, and therefore in the thermal plant, is obtained when the HTF reaches its maximum temperature when leaving the solar field (SF). In addition, it is necessary that the HTF does not exceed its own maximum operating temperature, above which it degrades. The optimum temperature of the HTF is difficult to obtain, since the working conditions of the plant can change abruptly from moment to moment. Guaranteeing that this HTF operates at its optimal temperature to produce electricity through a Rankine cycle is a priority. The oil flowing through the solar field has the disadvantage of having a thermal limit. Therefore, this research focuses on trying to make sure that this fluid comes out of the solar field with the highest possible temperature. Modeling using data mining is revealed as an important tool for forecasting the performance of this kind of power plant. The purpose of this document is to provide a model that can be used to optimize the temperature control of the fluid without interfering with the normal operation of the plant. The results obtained with this model should be necessarily contrasted with those obtained in a real plant. Initially, we compare the PID (proportional–integral–derivative) models used in previous studies for the optimization of this type of plant with modeling using the multivariate adaptive regression splines (MARS) model.

Evolution of Comets into Asteroids?

1971 ◽  
Vol 12 ◽  
pp. 413-421 ◽  
Author(s):  
B.G. Marsden
Keyword(s):  
Solar Radiation ◽  
Solar Nebula ◽  
Oort Cloud ◽  
Original Version ◽  
Terrestrial Planets ◽  
Minor Planets ◽  
The Sun ◽  
Physical Difference ◽  
Short Period ◽  
The One

There has long been speculation as to whether comets evolve into asteroidal objects. On the one hand, in the original version of the Oort (1950) hypothesis, the cometary cloud was supposed to have formed initially from the same material that produced the minor planets; and an obvious corollary was that the main physical difference between comets and minor planets would be that the latter had long since lost their icy surfaces on account of persistent exposure to strong solar radiation (Öpik, 1963). However, following a suggestion by Kuiper (1951), it is now quite widely believed that, whereas the terrestrial planets and minor planets condensed in the inner regions of the primordial solar nebula, icy objects such as comets would have formed more naturally in the outer parts, perhaps even beyond the orbit of Neptune (Cameron, 1962; Whipple, 1964a). Furthermore, recent studies of the evolution of the short-period comets indicate that it is not possible to produce the observed orbital distribution from the Oort cloud, even when multiple encounters with Jupiter are considered (Havnes, 1970). We must now seriously entertain the possibility that most of the short-period orbits evolved directly from low-inclination, low-eccentricity orbits with perihelia initially in the region between, say, the orbits of Saturn and Neptune, and that these comets have never been in the traditional cloud at great distances from the Sun.

3. Note on Solar Radiation

1888 ◽  
Vol 14 ◽  
pp. 118-121
Author(s):  
John Aitken
Keyword(s):  
Solar Radiation ◽  
The Sun ◽  
Geological History ◽  
Conservation Of Energy ◽  
Vast Amount ◽  
Chemical Theory ◽  
Energy Theory ◽  
The Many ◽  
Different Sources

In the many theories that have been advanced to explain the comparative constancy of solar radiation in long past ages as evidenced by geological history, it has been generally assumed that the temperature of the sun has not varied much, and to account for its not falling in temperature a number of theories have been advanced, all suggesting different sources from which it may have received the energy which it radiates as heat. Since the chemical theory was shown to be insufficient to account for the vast amount of heat radiated, other theories, such as the meteoric theory and the conservation of energy theory, have been advanced.

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