As cold weather approaches, many fireplaces and wood-burning stoves are pressed into service. The idea of sitting next to a fire is comforting, though comfort has not always been the prime reason for fireplaces and stoves. For thousands of years, open fireplaces with chimneys warmed and fed, everyone from kings to paupers with most of the fire’s heat going up the chimney instead of into the room.
Reducing flow into the chimney, as well as a poorly designed or blocked chimney, could allow smoke into the room, making an unpleasant indoor environment. It wasn’t until the late 17th century that significant advancements started improving ventilation and efficiency of fireplaces. The 18th century brought several more advancements. Baffling, which were added by Benjamin Franklin and some of his contemporaries, kept hot exhaust gasses in contact with cooler room air, improving heat transfer. Work to improve wood-burning heaters continues, especially in modern pellet-type heaters.
These problems of home heating may seem old, but they are not simple. Understanding the impact of a wood-burning heater, even excluding the chemical changes due to combustion, involves three invisible factors: air movement, heat transfer, and radiation. Hand calculations can identify general trends, but they require costly assumptions to work in a 3-dimensional space. Use of analysis tools makes these three invisible factors visible.
The results of analysis not only produce answers, they also produce questions. What would happen if that chimney were larger? Should it be closer to the front of the fireplace? Should the fire grate keep the fire up higher? What would happen if the back of the fireplace was more reflective? Further analysis can quickly answer these questions, resulting in a better final product.
Finally, the analysis process reduces time to market. Wood-fired heating products have been in continuous improvement for hundreds of years; but movement from concept to market today won’t wait for extended physical testing cycles. Visualizing design factors and accelerating product improvement cycles will put better products in customer hands faster.
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