solar energy reference
https://web.stanford.edu/dept/cmgm/cgi-bin/drupal/sites/default/files/solar-energy.pdf
https://web.stanford.edu/dept/cmgm/cgi-bin/drupal/sites/default/files/solar-heater.pdf
https://telegra.ph/solar-energy-03-05
https://bitbucket.org/handasaa/workspace/snippets/7qoLax
https://www.pixiv.net/novel/show.php?id=19439313
😁
https://snippet.host/akmikq
http://codepad.org/P7Oig4EE
https://hastebin.com/share/igetecugep.bash
https://www.vingle.net/posts/5448347
https://challonge.com/d4soxlx1