About the Stove

This stove uses dead pine needles as its sole fuel source, and requires no preprocessing steps; simply push the pine needles in, and watch them burn!

Background on Burning Pine Needles
Pine needles are very energy dense (more so than wood), but are difficult to use as a primary fuel because
  • They are difficult to burn in a steady state.  Pine needles are certainly flammable, but they're not easy to control.  Getting a steady burn is a challenge--they like to either burn wildly or not at all.
  • They like to gasify.  When heated or burned, pine needles typically release plumes of gases.  Besides being troublesome from a user interaction and air quality perspective, these gases are also loaded with unused energy.           
The spiral stove burns pine needles, then goes the extra step of burning the gases that are released.


How the Stove Works
Pine needles are plunged into an insulated firebox, where a primary burn occurs.  The needles gasify as they burn, and the gases travel up into the spiral via a central hole.  The draft from the chimney pulls the gases into and around the spiral, and because the spiral is heated by the firebox underneath, the gases ignite and create a secondary burn.  By elongating the burn path of the fuel, we are able to use the energy in the gases to get a clean, efficient burn.
In the top view of the spiral component, note the hole in the center of the spiral.  The gases enter the spiral via this hole and burn as they travel around the spiral, and the exhaust exits out the chimney.


Performance
The current prototype has boiled 5L of water in 16 minutes using less than 600 g of unprocessed, dead pine needles. 

Cost
The current cost estimate for manufacturing this stove in India is $15.85; we expect this cost estimate to go down as we iterate our design.


The Environmental Benefit
Pine needles are a renewable energy source, and harvesting them as a stove fuel
  • reduces deforestation
  • prevents forest fires
  • prevents excess rainwater runoff
  • reduces soil acidification from needle decay
Why harvest wood fuel by cutting from a principal stock of trees, when you could use the fallen refuse?

We are excited about our spiral concept and look forward to developing it further.