Control Technology and Energy Recovery
Any attempt to evaluate the amount of heat energy required to bake a fixed weight of dough gives rise to wide variations owing to such variables as dough structure and formulation, mode of bake, e.g. hearth or panned, temperature control gradients and rate of removal of moisture, which in turn, for the most part, involve oven design. Anderson (Bakers Digest, 40(6), 60, 1966) found that by increasing the final-proof temperature, and lowering the baking temperature, thus limiting moisture loss, the energy requirement was reduced to 162.2 Btu from 256.6 per pound of bread under controlled conditions. Johnson and Hoover (Bakers Digest, 51(5), 58, 1977), analysed total energy requirements for baking, and estimated the following Btu requirements per pound of bread. Oven start-up 77.4; heating during baking 77.0; evaporation of moisture 179.7; starch gelatinization 2.0; heating of pan 34.8; insulation loss 45.4, and flue-gas losses 122.4. These results are based on industrial data obtained from a daily production of 80 0001b of bread, the total energy input for 11b of bread being 528.9 Btu. Therefore, the two main loss sources in the total balance are: moisture evaporation 34.3%, and flue-gas losses 23.2%, which together constitute more than 50% of Btu requirements.
KeywordsControl Technology Energy Recovery Valve Plate Photoelectric Cell Magnetic Valve
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