OpenIDEO is an open innovation platform. Join our global community to solve big challenges for social good. Sign Up / Login or Learn more

Self sufficient lawn mower

A group of engineers and business students from George Mason University are developing EcoMow, a small self-fueled mower and grass pellet harvester. It uses the grassy biomass that it harvests as fuel, and processes the biomass that it does not use into a dried pellet form which can be used for other applications such as heating or power generation.

Photo of Ramiro Sanchez Caballero
2 1

Written by

How does it work?
It uses the grassy biomass that it harvests as fuel, and processes the biomass that it does not use into a dried pellet form which can be used for other applications such as heating or power generation.
 
Unlike many conventional mowers that use a rotating blade, the EcoMow uses an electrically driven bar cutter. This allows the mower to operate without the need to maintain the kinetic energy required in a rotary blade system. The bar cutter is followed by pelletizer that presses the grass into pellets in a manner similar to a meat grinder except that higher pressures and temperatures are used.
The formed pellets obtained by harvesting are dropped into a collection bin where they are progressively dried with hot air from the gasifier. Dried pellets are then converted to a fuel gas in a device called a gasifier.
 
The gasifier is a partial combustion type, using high temperature to convert the gas pellets to a fuel usable in a conventional gas engine. The fuel is filtered, cooled, and mixed with air before it is used. An internal alternator generates power for electrically driven components and computer control, guidance, and communications.
 
The gasifier is modeled after an imbert downdraft design with its top sealed to prevent oxygen from getting in. Very wet biomass (such as grass) can be processed as long as the material is dry by the time it reaches the pyrolysis zone. Pyrolysis is the physics behind the gasifier, which consists of the decomposition of bio material in the presence of heat, but without oxygen. Hydrogen gas and gaseous hydrocarbons are liberated, leaving primarily carbon char. The output is highly flammable gas.

Where else can this technology be used?
By lowering the cost barrier to using biomass fuel sources, they expect to provide an eco-friendly renewable solid fuel technology that can be retrofitted into existing vehicles.
 
This technology could be attractive to multiple market segments, and the value will be different for each segment. In established economies it can significantly shift energy use from fossil fuels to biomass sources while lowering the energy cost. And in developing economies it can lower the barrier to implementing local fuel production sources for power, heating, and equipment.

 
Reference:
http://www.ecomowtech.com/

 

Please indicate which type of energy is most relevant to this post

  • Biofuels

2 comments

Join the conversation:

Comment
Spam
Photo of Will Rice

oh man thats cool. does the moisture of the grass matter?

Spam
Photo of Ramiro Sanchez Caballero

hi will!
The gasifier is designed in such way that very wet biomass (such as grass) can be processed since it will get dry by the time it reaches the pyrolysis zone.