{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,28]],"date-time":"2026-01-28T22:00:53Z","timestamp":1769637653818,"version":"3.49.0"},"reference-count":30,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2025,2,8]],"date-time":"2025-02-08T00:00:00Z","timestamp":1738972800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Union","award":["823802"],"award-info":[{"award-number":["823802"]}]},{"name":"European Union","award":["10.54499\/UIDB\/50022\/2020"],"award-info":[{"award-number":["10.54499\/UIDB\/50022\/2020"]}]},{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia (FCT)","award":["823802"],"award-info":[{"award-number":["823802"]}]},{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia (FCT)","award":["10.54499\/UIDB\/50022\/2020"],"award-info":[{"award-number":["10.54499\/UIDB\/50022\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Applied Sciences"],"abstract":"<jats:p>To computer-simulate solar-concentrating facilities, an accurate knowledge of the Sun\u2019s position as a function of latitude, longitude, time and date is required. In this work, it is reported first a simplified description of a general algorithm, developed by the astronomy community to accomplish that. Our implementation of this algorithm (included in our Light Analysis Modelling package) has been successfully validated against well trusted astronomy data. The software was then used to produce a wide range of results for 2024, for two well-known research facilities, the most northern (J\u00fclich, Germany) and the most southern (Protaras, Cyprus) heliostat fields listed in the official SFERA-III EU project. This includes altitude and azimuth data, sunrise and sunset data, analemma curves, angular speed data and geocentric Sun trajectories around the observer\u2019s position. Other ray-tracing techniques are also reported to help simulate the Sun vectors reaching the solar devices. The truly inspiring results obtained show how important this type of software is, from the scientific and industrial point of view, to better understand our relationship with our neighbor star, the Sun.<\/jats:p>","DOI":"10.3390\/app15041739","type":"journal-article","created":{"date-parts":[[2025,2,10]],"date-time":"2025-02-10T04:44:03Z","timestamp":1739162643000},"page":"1739","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Computer Modelling of Heliostat Fields by Ray-Tracing Techniques: Simulating the Sun"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1608-4387","authenticated-orcid":false,"given":"Jos\u00e9 Carlos Garcia","family":"Pereira","sequence":"first","affiliation":[{"name":"Departamento de Engenharia Qu\u00edmica, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]},{"given":"Gon\u00e7alo","family":"Domingos","sequence":"additional","affiliation":[{"name":"IDMEC\u2014Instituto de Engenharia Mec\u00e2nica, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4730-3765","authenticated-orcid":false,"given":"Lu\u00eds Guerra","family":"Rosa","sequence":"additional","affiliation":[{"name":"IDMEC\u2014Instituto de Engenharia Mec\u00e2nica, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/0038-092X(76)90033-5","article-title":"Solar thermal power system based on optical transmission","volume":"18","author":"Hildebrandt","year":"1976","journal-title":"Sol. Energy"},{"key":"ref_2","unstructured":"(2024). 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