edit  watch  

Sharing knowledge to build rich, sustainable lives.

Appropedia is for collaborative solutions
in sustainability, appropriate technology, poverty reduction, and permaculture.

You are encouraged to add to and edit Appropedia -
your site to find, co-create and improve the solutions we need. Our vision and mission.

Contributors have made 389,414 edits and uploaded 31,313 files.
Browse our categories or all 8,210 articles.

edit  watch  

Announcements — more

To catch the rain cover.png You made it happen! Get a paperback on Amazon or digitally at http://www.tocatchtherain.org.


Building a very hot parabolic solar cooker using pedal power tools.
Notice how the focus is the same for the various parabolas.
Aleiha's parabolic solar cooker. The paraboloid is an interesting shape with some amazing qualities. It has the power to concentrate light, electronic waves, sound, etc. to its focus at the center. To find the focal point of a paraboloid, one must use the formula, y=p*x^2, where p is a constant. The variable y is the depth of the dish, and x measures the distance from the center axis to the maximum circumference of the dish. You have to pretend that there is an x axis going through the center of the base of the dish and a perpendicular y-axis passing from the center of the base of the dish to the focal point. The two numbers, x and y, represent a point on the paraboloid, and from that, you are able to determine where the focus is.

Parabolic cookers have been used for centuries now. The idea to concentrate light using curved mirrors was developed by the Greeks, Aztecs, Incas, Romans and Chinese. The Incas used bronze and gold for their mirrors and they built structures that were several stories high. This technology seems to have appeared around the same time for each of the civilizations. It is thought that Archimedes harnessed the technologyW to defend Syracuse from invading Roman fleets in 212 BC.

CCAT's Vermicomposting Bin

Build your own Vermicomposting System!

edit  watch  

Community action news

Parc des Buttes.jpg

Jan 17 Parisian community recognised for its geothermal heating network >[1]

Jan 12 Ireland: Government still not tackling climate change? So sue them [2]

Jan 9 Japan's Seikatsu Club Cooperative challenges consumerism through sustainable consumption [3]

Jan 9 Urban sustainability UK: Urban co-design for better wellbeing and health: Healthy New Town [4]

Jan 9 Climate news 2019: Climate change: 'Right to repair' gathers force [5]

Read More...


Muhammad Yunus at World Economic Forum in Davos, Switzerland, 25 January 2012
I avoid grandiose plans. I start with a small piece that I can do. I go to the root of the problem and then work around it. It's building brick by brick.

Muhammad YunusW
edit  watch  

Visit the Solar Portal

The Sun photographed by the Atmospheric Imaging Assembly (AIA 304) of NASA's Solar Dynamics Observatory (SDO).
Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of the available solar energy is used.

Solar powered electrical generation relies on heat engines and photovoltaics. Solar energy's uses are limited only by human ingenuity. A partial list of solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, daylighting, solar hot water, solar cooking, and high temperature process heat for industrial purposes.To harvest the solar energy, the most common way is to use solar panels.

Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

edit  watch  Selected service learning Projects gallery (refresh)

Engr305 Appropriate Technology Projects: Below are selected service learning projects from Engr305 Appropriate Technology, which is a course on appropriate technology at Humboldt State University taught by instructor Lonny Grafman.

CCAT Clay-straw slip wall

Clay-straw slip wall of CCAT's Greenshed  
CCAT clothes drying

Efficient clothes drying system for CCAT  
CCAT Cold Box

An energy efficient solution to a refrigerator  
CCAT Compost System

CCAT's comprehensive composting system  
CCAT greenhouse natural wall

An aesthetically pleasing natural earthen wall built by clay and straw slip methods  
CCAT greenshed cob wall

Cob wall of CCAT's Greenshed  
CCAT greenshed north wall

Cordwood and mortar wall of CCAT's Greenshed  
CCAT greenshed west wall

Clay-straw slip wall of CCAT's Greenshed  
CCAT greywater marsh (2008)

CCAT's Greywater Marsh 2008  
CCAT greywater marsh (current)

CCAT Greywater Marsh Continued  
CCAT interpretive wind turbine display

Demonstration wind turbine  
CCAT's living roof

Replacing CCAT's living roof  
CCAT MEOW 2012

Refurbishment of CCAT's Mobile Energy Operation Wagon  
CCAT natural concrete stain

Natural concrete stain  
CCAT natural paint project

Interior paints from natural ingredients  
CCAT natural wall construction

Earthen informational kiosk for CCAT  
CCAT pedal powered grain mill

Pedal powered grain mill for CCAT  
CCAT pedal powered TV

Updated version of CCAT pedal powered bicycle  
CCAT rainwater catchment system

CCAT's current rainwater catchment system  
CCAT Raised Garden Beds

Controlled beds of soil above toxic ground  
CCAT remediation zone

A stable slope for planting and attracting beneficial insects  
CCAT Retaining Wall

Retaining wall for slope erosion at CCAT  
CCAT rocket stove

CCAT's improved fuel rocket stove  
CCAT small rainwater catchment

Rainwater catchment for CCAT's cob bench roof  
CCAT's Vermicomposting Bin

CCAT's vermicomposting bin  
edit  watch  

Selected categories

edit  watch  

Construction zone — correct mistakes & flag spam as needed

Newest articles more Wanted pages - click to add info more
Under construction
New pages being developed:
  1. Ground mount fixed tilt PV racking literature review
  2. PV LED streetlights
  3. Show the love
  4. Trishla Foundation
  5. World Day of Social Justice
  6. Greenwich
  7. Modeling of 2D PV Devices
  8. Snow PV Literature Review
  9. Earth shelter
  10. Integrierte Kompostheizungstoilette

Note: Appropedia's newest pages may not yet comply with our policies. Page titles in italics are "redirects," often created when moving a page.

Under construction

Create a new page:

  1. Nutrition
  2. Bacteria‏‎
  3. Human development
  4. Environmental science
  5. Open sustainability
  6. New Urbanism‏‎
  7. Building management systems
  8. Science‏‎
  9. Microgeneration
  10. Environmental design

These red links are invitations for you to contribute your knowledge.

Or create a page on the topic of your choice.

Newest files - images and documents that can be added to pages more

Note: Appropedia's newest files may not yet comply with our policies.

edit  watch  

Please help Appropedia grow!

We want your projects, current works, observations and wisdom! See Contributing content. Improve articles by clicking "edit" at top of the page or section. Our philosophy is: Be Bold and contribute!

Questions? Comments? Visit the Village Pump. Also discuss Appropedia and related topics over on the Permies permaculture forums.

Find us on Facebook, Pinterest, and Twitter. Check our Flickr images and YouTube videos.