AIR PREHEATER FOR A COMPACT BOILER

摘要

A coil boiler (10) includes an air preheater (26) for recovering energy from exhaust gases to heat secondary combustion air. The air preheater is defined by a compact heat exchange structure. The heat exchange structure provides lateral flow interrupters (36) on a combustion gas side, and transverse flow (35) interruption on the flow resistance to exhaust combination gases is minimized while heat transfer to inlet air is substantially increased through flow interruption. A transverse hair-pin heat exchange coil (100) is also provided. The heat exchange coil is located in plenum space (40) in the boiler surrounding the coil bank (22) of the boiler. The heat exchange coil is connected to an external water supply. Water circulating through the heat exchange coil is heated and delivered to the coil bank as preheated feedwater or is delivered to an end use location.