The influence of recycle on a parallel-plate heat exchanger with insulation sheet inserted for double-pass operations

The influence of recycle on a parallel-plate heat exchanger of inserting in parallel an insulation sheet to divide an open duct into two channels for double-pass operations with uniform wall temperature has been studied analy tically. The results are represented graphically and compared with those in an open duct (without an inserted insulation sheet) and a double-pass with out recycle. Substantial improvement in heat transfer is obtainable by empl oying such a double-pass device with external refluxes, instead of using an open conduit with single-pass operations and using double-pass operations without recycle. The effect of insulation-sheet location on the enhancement of heat transfer efficiency as well as on the increment of power consumpti on, has been also discussed. (C) 2001 Elsevier Science Ltd.