FirePit Combusts Without the Smoke
Tom Spendlove posted on September 22, 2017 |
BioLite has developed an airflow injected fire pit that efficiently burns fuel.

As an engineering team, BioLite’s mission is to bring reliable energy everywhere. On their annual off-grid camping trip the group gathered around a campfire each night. Smoke and ash from the fires led to shuffling around the fire pit that felt like ‘musical chairs, but way less fun.’ The idea began back in 2015 to build a fire device that would make the fire cleaner and more experiential. FirePit is the end result of that trip and design, and currently running a highly successful Kickstarter campaign.

FirePit uses air flow control to create less smoke, and allows users to cook with charcoal or firewood. An x-ray mesh around the outside of the device gives 360 degree heat. Smoke was the main focus of the team’s design, and they approached smoke as unburnt fuel. When the particulate matter is ideally burned inside the fire but instead blows out into our clothes or lungs, then the fire is not burning efficiently.

The fire is injected with oxygen from a fan and 51 airjets, and BioLite says that this drives uniform temperature and gas mixing to improve combustion. Heat intensity is controlled directly on the device or through an app, with four levels from OFF to MAX heat. The unit is 27 inches long, 15.8 inches high including the legs, and 13 inches wide. The device weighs 19.8 pounds and the 10,400 milliAmp hour batter is charged through micro USB. The battery can also be used as a charging device in the field, with a USB A output.

Tim Connelly, Senior Project Engineer at BioLite, answered a few questions about the design and development of FirePit. He said the most difficult design decision was the size of the unit. Standard 36 inch fire rings would be large and difficult to control with blowers, and prototyping let the team understand the optimal size for the unit. The rectangular shape was chosen to force the wood positions into parallel arrangement and the airflow to be more predictable. The metal mesh on the outside of the pit was chosen for users to see the combustion process.

Building the system, the air injection pattern required several iterations to get optimum performance from the air flow. The team also had to decide whether or not to use their current thermos electric generation technology with the FirePit. After cost analysis the team decided that the pricepoint with integrated generator would be too high for casual users, and the solution was a standard USB rechargeable battery to drive airflow. These first units sold through Kickstarter, however, will have a solar carrying case to charge the battery and make the FirePits self-reliant.

The greatest manufacturing challenge was size. This is BioLite’s biggest product to date, and the size of the FirePit required the team to find different manufacturing partners able to make larger components. Packaging and shipping the larger pieces also presented challenges.

FirePit is definitely an interesting technology that’s solving a problem that’s bothered me for decades, but I appreciate the company’s dedication to worldwide energy security even more. More than 25,000 households are using BioLite’s technology around the world, and their 2016 Impact Report is filled with status updates on their various projects that reduces the developing world’s reliance on oil and combustion.  The campaign has already blown by its modest funding goal, and ends on October 20, 2017. First units are expected to ship in May 2018.

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