A portable heat generating device in which
fuel vapor and an
oxygen supply (e.g. air) are directed through channels contained within a thin, flexible and compliant elastomeric sheet of material. Elongated catalytic heat elements, placed strategically within the channels, spontaneously interact with the fuel-air
stream liberating
heat energy. Means and methods are defined that permit flameless
catalytic combustion to be uniformly extended over the length of each heat element, lowering
power density but maintaining the overall power generated, permitting the use of many types of low temperature materials like plastics, polymers, and elastomers in the construction of the heater. The
heat generation process is started by pumping an air
stream into a reservoir containing a fuel source (e.g.
methanol) thereby saturating the air
stream with
fuel vapor. The
fuel vapor is mixed with a another stream of air to achieve a particular fuel / air ratio and directed into channels within the elastomeric sheet, reacting with the catalytic heat elements to produce flameless
combustion. The warm
exhaust gas is directed to a thermally controlled diverter valve. The valve senses the temperature of the
liquid fuel supply and diverts some or all of the warm
exhaust gas, as necessary, to heat the fuel and keep its temperature within a specified range. Exhaust by-products are passed into a miniature
scrubber module adjacent to the fuel module. The
scrubber absorbs any noxious components in the exhaust stream that may occur during start-up or rapid changes in operating condition.