Last year, BSH made news with its plant oil cooker for developing markets, addressing the problem of indoor air pollution caused by traditional cooking fires. Interestingly, Philips Design was working on the same problem, but chose a different solution. Instead of changing the fuel it sought to improve the wood-burning process.
The Philips Woodstove uses a built-in fan and is said to greatly improve the burning process: fuel (wood or charcoal) consumption is reduced to about one-third, smoke pollutions to one-tenth and volatile organic compound (VOC) emissions to about one-hundredth.
Philips claims to have solved the biggest problem of this type of cook stove: how to efficiently power the fan. A rechargeable battery powers the fan at start-up. Then the thermoelectric generator takes over, powering the fan as well as recharging the battery. It took some development time to achieve the proper electrical efficiencies with the unit. The generator is said to be made of P-type and N-type alloys of bismuth and tellurium sandwiched between ceramic plates, which are heated on one side by the fire and cooled on the other side by the fan. A control unit regulates the generator and controls the fire itself.
The project was transferred from Philips Research (the central research department where the laserdisc and the CD were invented) to Philips DAP (Domestic Appliances and Personal Care). In the spring of 2007, DAP will complete a 450-unit test project in India. Philips says that, in earlier tests, users were reluctant to return the stoves.