Architectural Simulation of Hybrid Energy Harvesting: A Design Experiment in Lanzarote Island

This study conducts research on an architectural design based on energy harvesting technology. The research subject is a pergola-style structure to be built in a square in Arrecife, the Spanish territory of Lanzarote Island. The architectural design based on the energy harvesting technology developed in this research utilizes solar energy. To install a solar panel on the roof of the pergola, the optimal tilt angle from January to December was derived by using a function that considered the latitude and solar declination value of the study site, and the amount of renewable energy generation was calculated. The architectural design based on energy harvesting also utilizes wind power. To transform wind power into renewable energy, piezoelectric materials that trigger renewable energy with the micro-vibrations generated by wind power are applied to the architectural design. The amount of energy generation was calculated considering the wind power and wind direction in the location where the pergola should be built; in addition, this calculation used information from prior studies on piezoelectric materials. This article is significant, as it has developed an architectural design where hybrid energy harvesting technology that utilizes two types of natural energy (solar and wind) is applied to a building façade.

Long-Term Global Solar Radiation Prediction in 25 Cities in Morocco Using the FFNN-BP Method

This article presents different combinations of input parameters based on an intelligent technique, using neural networks to predict daily global solar radiation (GSR) for twenty-five Moroccan cities. The collected measured data are available for 365 days and 25 stations around Morocco. Different input parameters are used, such as clearness index KT, day number, the length of the day, minimal temperature Tmin, maximal temperature Tmax, average temperature Taverage, difference temperature ΔT, ratio temperature T-Ratio, average relative humidity RH, solar radiation at the top outside atmosphere TOA, average wind speed Ws, altitude, longitude, latitude, and solar declination. A different combination was employed to predict daily GSR for the considered locations in order to find the most adequate input parameter that can be used in the prediction procedure. Several statistical metrics are applied to evaluate the performance of the obtained results, such as coefficients of determination (R2), mean absolute percentage error (MAPE), root mean square error (RMSE), normalized root mean square error (NRMSE), mean bias error (MBE), test statistic (TS), linear regression coefficients (the slope “a” and the constant “b”), and standard deviation (σ). It is found that the usage of input parameters gives highly accurate results in the artificial neural network (FFNN-BP) model, obtaining the lowest value of the statistical metrics. The results showed the best input of 25 locations, 12 inputs for Er-Rachidia, Marrakech, Medilt, Taza, Oujda, Nador, Tetouan, Tanger, Al-Auin, Dakhla, Settat, and Safi, seven inputs for Fes, Ifrane, Beni-Mellal, and Meknes, six inputs for Agadir and Rabat, five inputs for Sidi Ifni, Essaouira, Casablanca and Kenitra, four inputs for Ouarzazate, Lareche, and Al-Hoceima. In terms of accuracy, R2 of the selected best inputs parameters varies between 0.9860% and 0.9920%, the range value of MBE (%) being from −0.1076% to −0.5931%, the RMSE between 0.1990 and 0.4580%, the range value of the NRMSE between 0.0355 and 0.8938, and the lowest value MAPE between 0.0019 and 0.0060%. This technique could be used to predict other parameters for locations where measurement instrumentation is unavailable or costly to obtain.

Development and Implementation of a Low-cost Automatic Dual-axis Solar Tracker through Hardware/Software Embedded Program Control

A solar tracker is a system that is used for the mechanical orientation of solar payloads (collectors and photovoltaic panels) towards the sun. A simple, low-cost, but effective open-loop dual axis solar tracking system was developed in this work. The tracker is an embedded system that consists of a microcontroller integrated with other components in an electronic circuit to coordinate the activities of the circuit in driving out and in the motor shafts of electrically powered linear actuators used to move the payload. The work is divided into two parts: hardware and software. The hardware part consists of two movable (tilting and axial moving) rectangular frames fixed together and used to hold the payload and two electrically powered linear actuators (jacks) used to move the rectangular frames in the tilting and axial directions. The software part was a code written in the C programming language following an algorithm developed from measured parameters of the jacks and the sun’s position and embedded into a microcontroller. The testing of the dual-axis solar tracker was done by measuring a parabolic trough collector’s position with respect to the sun hour angles and solar declination angles and comparing the values with the calculated angles for two days. The results obtained showed that the tracker followed the sun with deviation of ±2o (percentage errors that ranged between 0.01% and 3.26%).

Effects of Receiver Parameters on Solar Flux Distribution for Triangle Cavity Receiver in the Fixed Linear-Focus Fresnel Lens Solar Concentrator

The objective of the study is to investigate and optimize the solar flux uniformity of a fixed linear-focus Fresnel lens solar concentrator using a triangle cavity receiver. The effects of receiver parameters including the vertical distance from the cavity opening plane to the Fresnel lens f, receiver internal surface absorptivity αab, end reflection plane reflectivity ρr, solar declination angle δ and solar angle ω on the uniformity factor (UF) of a triangle cavity receiver were carried out. The effects of receiver parameters are evaluated with a significance test of critical factors. The results showed that the increase in f and δ would result in an increase in the UF. The average UF with f = 600, 625, 650, 675 and 700 mm, respectively, are 0.5030, 0.5858, 0.6337, 0.6576 and 0.6784 for ω in range of 0–60°. Moreover, the UF increases as αab decreases when other receiver parameters are constant for the δ of 0–8°. The ρr has a limited effect on the UF until δ becomes relatively larger and ω becomes relatively smaller. Furthermore, ω effects are most significant on the UF, followed by δ, f and αab. Setting a suitable f is the most economical and effective way to improve the UF.

THE DISTINCTIONS OF THE BEGINNING PRAYING TIME CALCULATION BY RINTO ANUGRAHA

Praying (Shalat) is a fundamental ritual for moslem. Moslem must have deep understanding about praying time in doing Shalat. In this era, many astronomy and falak scholars make a guideline or formula of an algorithm of the beginning of praying time calculation. One of them is a physic lecturer from Gajah Mada University who concern about calculation, specifically about Islamic astronomy (Falak). He designs algorithm of the beginning of praying time schedule on his book “Mekanika Benda Langit (Celestial Mechanics)” and his personal blog to access the program of the beginning praying time calculation. This work is a kind qualitative research which use library research method. By using descriptive explanatory method, the author will scrutinize factor which differ the calculation of the beginning praying time by Rinto Anugraha that will be compared to the beginning of praying time by Ministry of Religious Affairs of Indonesia. In this study, the authors analyzed that the solar declination data and the equation of time used were calculated manually by looking for initial data from Julian Day. The program presented in the early Rinto Anugraha prayer time algorithm based on modern astronomy is very friendly for the user. In the implication of hisab, Rinto Anugraha uses a constant sun height of -18 ° for the evening prayer time and -20 ° for the dawn prayer time.

Teaching Astronomical Concepts Relevant to Earth and Climate Sciences with AstroGeoVis 1.0 : Leveraging Scientific Computing and Dynamic Visualizations

<p>Solar irradiance is one of the defining factors determining Earth’s climate and habitability. Thus, comprehension of Earth’s orbital parameters, and the resulting apparent motions of the Sun on the celestial sphere and spatio-temporal patterns of insolation, is an important part of climate literacy. The Earth orbit v2.1 model (Kostadinov and Gilb, 2014, GMD) focused on 3D Earth orbit, Milankovitch cycles and insolation visualization and analysis with research and pedagogical applications.  Here I introduce <em>AstroGeoVis v1.0</em> – software that performs astronomical visualizations relevant to Earth and climate science, with a focus on the apparent motions of the Sun on the celestial sphere and related concepts, with primarily pedagogical applications in mind. Specifically, <em>AstroGeoVis v1.0</em> computes solar equatorial and local horizontal coordinates (using the Meeus (1998) algorithms) and uses first principles to compute and visualize various phenomena such as the terminator, daily path of the Sun on the celestial sphere, shadow geometry, the equation of time and the analemma, seasonality and daylength. Instantaneous irradiance on a randomly oriented solar panel is computed and used to determine annual energy production and optimize panel orientation, demonstrating numerical integration and optimization. This component of <em>AstroGeoVis v1.0</em> is particularly relevant in the context of the increasing importance of solar renewable energy and sustainable practices such as passive building design, requiring that an increasing number and variety of professionals be familiar with Sun-Earth geometry and related concepts.</p><p><em>AstroGeoVis v1.0</em> was written in MATLAB© and is open source. I provide multiple examples and ideas for classroom use, including a complete exercise in which students track solar declination throughout the semester via shadow length and azimuth measurements. The software has multiple pedagogical advantages, e.g. figures are dynamic and can be re-created by the instructor, for example for a specific latitude, some are 3D and have pan/tilt/zoom capability. The scientific code itself can be inspected, modified and improved by instructors and students as needed, i.e. it is intended that the code as well as the visualizations will be used in instructional settings. This makes <em>AstroGeoVis v1.0</em> applicable in pedagogical settings at many levels, across many disciplines, e.g. physical geography, oceanography, meteorology, climatology, Earth system science, physics, astronomy, mathematics and computer science. Earth sciences, like many other disciplines, have increasingly become highly quantitative and computational in nature, dealing with large numerical data sets (e.g. climate model development and analysis). <em>AstroGeoVis v1.0</em> is intended to help students master not only astronomical concepts relevant to Earth and climate sciences, but also acquire scientific computing and data analysis skills, which are becoming increasingly indispensable for a wide variety of careers.</p>

Technical analysis of an oven with coupled receiver for scheffler solar concentrator tested under cloudy weather conditions

Most of the solar collectors experiments are carried out under clear-sky conditions to evaluate the maximum performance of collectors, even though this condition is not critical for some uses, such as cooking. The optical and thermal performance of a solar oven heated by Scheffler concentrator is here analyzed in more adverse weather conditions. The receiver for conversion and heat transfer of the concentrated solar energy is coupled to an oven specially developed for this work. The Scheffler concentrator geometry is a lateral cut angled 43.23° of a paraboloid matrix, and it works in a two-axis tracking system, to always maintain its focal image at the stationary receiver with the progression of the Earth rotation and solar declination movements. A model for distributing the daily radiation over the hours is used to compare the results. The time-constant experimental method is considered. The heating and cooling tests were carried out at the official local time. The maximum temperature achieved by the absorber was 328°C, and the maximum average temperature in the oven was 150°C. The results for heat loss factor were evaluated, and the trends for thermal efficiency and optical efficiency factor were analyzed for the system considered

MEASUREMENT AND FORECASTING OF MATERIALS SAMPLES’ TEMPERATURE DURING WEATHERING IN DIFFERENT CLIMATIC ZONES

The relation between standard meteorological parameters and surface temperature of samples exposed directly to the sun and in a sheltered environment has been studied using 6–8-year timeframe. The following materials have been used: KMKU-3.150.U0.1 carbon fiber reinforced polymer, KMKS-4.175.Т10 glass fiber reinforced polymer, and D16-AT aluminum alloy substrate with black and white EP-140 epoxy coating . Outdoor weathering has been conducted at Gelendzhik and Moscow testing sites of the All-Russian Institute of Aviation Materials (VIAM). It has been shown that it′s possible to use a multilinear model to estimate the temperature of the materials′ surfaces during their weathering in different climatic regions. The following parameters for 1–12 months’ timeline have been used to estimate samples’ temperature at different locations: air temperature, total solar radiation, solar declination, and solar hour angle.

An Overlooked Construction Manual for the Quadrans Vetustissimus

This article presents an edition and brief analysis of the previously overlooked text De compositione quadrae, which is transmitted as part of a scientific miscellany assembled at Worcester Cathedral Priory no later than 1140. De compositione quadrae offers hitherto unavailable information on the construction of the so-called quadrans vetustissimus, a version of the universal horary quadrant circulating in Latin Europe during the eleventh and twelfth centuries. It is particularly noteworthy for its description of a graphical method of inscribing the months of the Julian calendar on the quadrant’s cursor, which successfully approximates the sine function that determines the change of solar declination in the course of a year.

An empirical model of nitric oxide in the upper mesosphere and lower thermosphere based on 12 years of Odin SMR measurements

Nitric oxide (NO) is produced by solar photolysis and auroral activity in the upper mesosphere and lower thermosphere region and can, via transport processes, eventually impact the ozone layer in the stratosphere. This work uses measurements of NO taken between 2004 and 2016 by the Odin sub-millimeter radiometer (SMR) to build an empirical model that links the prevailing solar and auroral conditions with the measured number density of NO. The measurement data are averaged daily and sorted into altitude and magnetic latitude bins. For each bin, a multivariate linear fit with five inputs, the planetary K index, solar declination, and the F10.7 cm flux, as well as two newly devised indices that take the planetary K index and the solar declination as inputs in order to take NO created on previous days into account, constitutes the link between environmental conditions and measured NO. This results in a new empirical model, SANOMA, which only requires the three indices to estimate NO between 85 and 115 km and between 80∘ S and 80∘ N in magnetic latitude. Furthermore, this work compares the NO calculated with SANOMA and an older model, NOEM, with measurements of the original SMR dataset, as well as measurements from four other instruments: ACE, MIPAS, SCIAMACHY, and SOFIE. The results suggest that SANOMA can capture roughly 31 %–70 % of the variance of the measured datasets near the magnetic poles, and between 16 % and 73 % near the magnetic equator. The corresponding values for NOEM are 12 %–38 % and 7 %–40 %, indicating that SANOMA captures more of the variance of the measured datasets than NOEM. The simulated NO for these regions was on average 20 % larger for SANOMA, and 78 % larger for NOEM, than the measured NO. Two main reasons for SANOMA outperforming NOEM are identified. Firstly, the input data (Odin SMR NO) for SANOMA span over 12 years, while the input data for NOEM from the Student Nitric Oxide Experiment (SNOE) only cover 1998–2000. Additionally, some of the improvement can be accredited to the introduction of the two new indices, since they include information of auroral activity on prior days that can significantly enhance the number density of NO in the MLT during winter in the absence of sunlight. As a next step, SANOMA could be used as input in chemical models, as a priori information for the retrieval of NO from measurements, or as a tool to compare Odin SMR NO with other instruments. SANOMA and accompanying scripts are available on http://odin.rss.chalmers.se (last access: 15 September 2018).