Update. Reader Erich W\u00e4lde comments:\u00a0<\/strong><\/p>\n> Unlike a deep-water reservoir, a bag put under sand would not try to float, so there would be no need for complex anchors at the bottom.<\/p>\n
This is not entirely correct. The bag will work it’s way up! Around the edges some sand will always travel from “above” the bag to “below” the bag — unless the bag has considerable “flaps” around it, which will extend well into the neighboring area, i.e. complex anchoring, I’m afraid.<\/p>\n
Other example: I bought a house several years back. In the garden there is an underground tank, which was used to store oil (heating). Heating was changed to use natural gas rather than oil, so the tank became unused. In order to fully abandon its operation, we had to get it cleaned out AND we had to show that the tank is not in the parking lot. If it were there, then it would have to be filled up with concrete or sand. Otherwise it would work it’s way up, very slowly, due to its buoyancy force. This is in Germany and local administration knows about each underground tank. Its well regulated.<\/p>\n
So: You can’t trick physics \ud83d\ude42<\/p>\n","protected":false},"excerpt":{"rendered":"
Reader Paul Blais sends us an interesting idea: “I’ve been following your website for years and I like it very much. I’ve been reading your article from 2018 about off-grid compressed air energy storage and I’ve been thinking about a possible solution regarding the varying pressure problem which you mention about small scale, low pressure […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[],"_links":{"self":[{"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/posts\/4570"}],"collection":[{"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/comments?post=4570"}],"version-history":[{"count":3,"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/posts\/4570\/revisions"}],"predecessor-version":[{"id":4609,"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/posts\/4570\/revisions\/4609"}],"wp:attachment":[{"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/media?parent=4570"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/categories?post=4570"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.notechmagazine.com\/wp-json\/wp\/v2\/tags?post=4570"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}