Constant Pressure Compressed Air Storage

June 29, 2020 by kris de decker Filed Under: Energy storage

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 vessels.

What about using a constant pressure reservoir? My idea is to use a long airtight bag stored in a trench and covered with sand, that would inflate and deflate pushing the sand up and down. The height of the sand column would determine the inside pressure of the bag, which would remain constant across it’s whole inflation range. The sand would also act as a thermal mass, taking and restoring heat to the air.

I’ve read that similar storage ideas exist [1] but involve putting the bags deep underwater, which is not practical for off-grid purposes. 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.”

[1] http://euanmearns.com/a-review-of-underwater-compressed-air-storage/

Update. Reader Erich Wälde comments: 

> 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.

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.

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.

So: You can’t trick physics 🙂

The Future is Public: Remunicipalisation

May 29, 2020 by kris de decker Filed Under: Public services

“Resistance to privatisation has turned into a powerful force for change. (Re)municipalisation refers to the reclaiming of public ownership of services as well as the creation of new public services. In recent years, our research has identified more than 1,400 successful (re)municipalisation cases involving more than 2,400 cities in 58 countries around the world.”

“But this book is about more than just numbers. It shows that public services are more important than ever in the face of the climate catastrophe, mounting inequalities, and growing political unrest. Together, civil society organisations, trade unions, and local authorities are crafting new templates for how to expand democratic public ownership to all levels of society and opening up new routes to community-led and climate conscious public services.”

“The Covid-19 crisis has made clear the disastrous effects of years of austerity, social security cuts, and public service privatisation. But it has also demonstrated that public services and the people who operate them are truly the foundation of healthy and resilient societies. As privatisation fails, a growing international movement is choosing (re)municipalisation as a key tool for redefining public ownership for the 21st century.”

Read more and download the book. Via Aaron Vansintjan.

Mental Resilience: The Art of Survival

May 9, 2020 by kris de decker Filed Under: Random, War

“Following the 21st century radical changes on this planet, we have realized it was high time for us to give new contribution based on evidence from the siege of Sarajevo experience (1992-1996), to the urgent need of establishing a resilience module – for the sake of terrified individuals and unprepared societies alike. Extreme urban conditions produced a parallel civilization in which creativity was a basic necessity. The process of adaptation left no space for stagnation and helplessness. Work was the law of mental and physical survival.

“Working towards resilience kept people’s minds occupied – work eliminated thoughts that could destroy their motivation. It was necessary to establish a balance in the extreme urban conditions of life. This was done through creating peaceful, simple, normal situations, according to one’s personal needs. During the siege, the continuation of normal life in the city, the continuation of creativity, was as important as bread or medicine or water for all citizens of Sarajevo.”

“In this book we are not presenting a theory, but a real life evidence of an open mind potential to win in the face of the unknown, the new, the uncertain and the unthinkable. We believe that citizens who lived the Sarajevo siege present an example of hope for mankind facing serious threats and the changes so far unthinkable on this planet of ours.”

Read more and download the book: The Art of Survival. Extreme Conditions and Human Resilience: The Siege of Sarajevo 1992-1996, Suada Kapiç. Thanks to Jere Kuzmanic.

Quarantine is the future big tech wanted us to want

April 27, 2020 by kris de decker Filed Under: Quotes

In some ways, a pandemic is the ideal proof-of-concept for the particular utopia that the tech industry has tried to build. Social distancing plays to digital technology’s immediately tangible strengths: ubiquitous and sanitary access to other people, maximum convenience, broad consumer choice, and endless entertainment at low cost. As the coronavirus brought countless global systems to a halt, the internet kept working, heroically filling the gaps. Some longtime critics of the tech industry, having spent much of the past decade complaining about its toxicity, seemed ready to acknowledge a silver lining if not praise it outright.

But rather than prove that nearly anything is possible with an internet connection, the quarantine is calling attention to what digital technology can’t do. It was easier to think of the domestic cozy, online-first existence as not only possible but preferable when it was strictly a lifestyle choice. Being forced to live it, many of us are now discovering how much of the physical world we have taken for granted. Without distinct places for doing different activities like work and exercise, and bombarded by an accelerated news cycle, we’re losing our sense of time as well as space. Spatial variation helps structure the rhythms of everyday life and without the structure imposed by commuting, gathering with friends, and doing errands outside the house, days blur together and scheduling begins to feel arbitrary.

Read more: Home Screens, Drew Austin, Real Life Mag, April 27, 2020.

Generating Light from Darkness

April 13, 2020 by kris de decker Filed Under: Lighting, Random

Night-time power generation analogous to photovoltaics would be an enabling capability for applications such as lighting and wireless sensors. We demonstrate a low-cost power generation device based on thermoelectric generators where the cold side radiates heat to the cold of space by facing the night sky. The power generated is sufficient to maintain a LED at night, enabling battery-free off-grid lighting. [Read more…]

Self-Sufficiency Defies Common Sense

April 9, 2020 by kris de decker Filed Under: Low-tech living, Random

Many dream of financial self-sufficiency, but only few are prepared to go as far as Lasse Nordlund. In the early 1990s, Nordlund began an experiment living as self-sufficiently as possible. Eventually, he was able to sustain himself and his family with a budget of mere 30 to 50 euros per year, living in a small town in North Karelia, located in Eastern Finland, growing and preparing everything else from scratch, all by himself.

Nordlund is exceptional due to the depth of his experiment. What is also exceptional are the swarm of comments on the 2008 Helsingin Sanomat article covering the self-sufficient practices of Nordlund and his family. In little over a week, the article gathered 451 comments. A civic debate on radical self-sufficiency larger than this is hard to come by. Nordlund saved these comments for later research. Our study based on this material was published in the Kulttuurintutkimus journal in 2017.

Image: Lasse Nordlund, by Marko Ulvila (CC BY-SA 4.0)

[Read more…]