Customer question
Please could you let me know how your new Wild Woodgas stove compares to the other models (Woodgas LE, XL) in terms of heat output, burn times and fuel consumption?
Wild Stoves technical response
There are 2 ways of addressing this question: from a practical perspective (how they perform in the field in practice) and from a lab-data perspective.
First, practically:
- all models are high quality double-walled woodgas stoves and burn cleanly using similar principles of preheating secondary air
- the LE and Wild WGS are likely to be fairly similarly powered (around 3kW), being of similar size, though it's likely the LE has the slight edge as the forced air causes it to burn slightly more vigorously
- the XL is approx 3.6kW.
- the LE and Wild Woodgas have similar-sized combution chambers so take a similar amount of wood. The LE is likely to burn through its wood slightly quicker due to the forced air; while the Wild WGS is slightly gentler so the wood should last longer. The actual amount of heat delivered over the burn probably varies little.
- the LE and XL will not burn without the batt pack attached / with flat batteries; the Wild Woodgas requires no batteries for optimum performance.
Secondly, from a theoretical & research perspective:
- turbulence generally increases the quality of combustion (and therefore efficiency) and the LE and XL have the edge here as they inject air into the base of the chamber and inner top edge. However, the passive air flow on the Wild Woodgas and other passive stoves (like the Bushbuddy) is remarkably effective - as evidenced by the 'jets' of yellow flames emerging from the air holes.
And finally a little general info on Woodgas stoves...
There are a few publications comparing the performance of many different stoves available, including the Test Results of Cookstove Performance (2011, Aprovecho Research Centre). This shows that wood gas stoves:
- produce just 22% of the carbon monoxide compared with an open fire (compared with a rocket stove which produces 26%)
- produce a fraction of particulates (basically smoke) of an open fire - just 15% - a reduction of 85%! (Rocket stoves reduce particulates by around 40%)
- Are the most efficient kind of wood cooking stove tested, beaten only by alcohol and propane stoves.
Wild Stoves technical support welcomes comments on posts: please add these below.
Comments
WS Technical Response
Yes, and sorry for the delay in replying.
1. A camping butane gas cooker boiled 500ml water in the MSR 775ml pot in 4.5 minutes
2. The Trangia, with no regulator and after warming up for 2 minutes boiled 500ml of water in its smallest pot in 8.5 minutes.
3. The Wild Woodgas Stove powered on wood pellets boiled 500ml of water in 5 minutes.
The wood pellets used in the boiling test are fairly high density fuels and give a good steady long (and easily repeated) burn. Softer woods like chunks of pine would burn more intensely and more quickly and you would expect to shave a little time off this boiling time with them.
Hope that helps! Do feel free to share any further test results.
JR
We're planning to do some water boiling tests to establish the relative performance of the different stoves - we'll be sure to post results here.
WS Technical Response
Thanks for the follow-up question. Good question.
It's true that woodgas stoves (WGS) are among the most efficient and clean-burning stoves out there, but there are still advantages to rocket stoves which, I think, make them a better option for regular garden cooking. Although the smoke and CO emissions may be slightly higher from rocket stoves, their benefits include:
- little or no fuel preparation required: you can just feed long sticks into the front of a rocket stove, nudging them in as they burn. This is in contrast to a WGS which requires wood to be chopped into pieces a few inches long, to fit into the small combustion chamber. Rocket stoves often need a little less tending than WGS, and are a bit less fussy about how well seasoned wood is.
- longevity: the rocket stoves Wild Stoves sell are designed for tough conditions in the cities and countryside of developing countries. They are built from materials designed to last many years being used everyday. Most camping WGS are exceptional quality, but built to be lightweight an engineered with leisure use in mind, and so do not have the same life as well-designed rocket stove
- Sturdiness: our rocket stoves are sized for family cooking, so have a sturdy cast-iron hob, which can support large pots and pans of all shapes and sizes. Easily big and powerful enough to cook for a decent sized family in large pots. Camping WGS are designed to cook smaller volumes of food in billies, and their smaller 'footprint' makes them less stable.
As with everything in life, there are swings and roundabouts, and in the case of cooking stoves performance always needs to be balanced with practicality. Despite the wonders of wood gas stoves, rocket stoves have made the greatest impact in developing countries, where many hundreds of thousands have been sold and disseminated in recent years. The time spent preparing fuel for cooking on has been a significant factor in people tending to choose rocket stoves over WGS.
Hope this helps.
So what advantages do rocket stoves have?