Papers Published

  1. Bejan, A., CONCEPT OF IRREVERSIBILITY IN HEAT EXCHANGER DESIGN: COUNTERFLOW HEAT EXCHANGERS FOR GAS-TO-GAS APPLICATIONS., Journal of Heat Transfer, Transactions ASME, vol. 99 Ser C no. 3 (1977), pp. 374 - 380 .
    (last updated on 2007/04/08)

    Abstract:
    The thermal design of counterflow heat exchangers for gas-to-gas applications is based on the thermodynamic irreversibility rate or useful power no longer available as a result of heat exchanger frictional pressure drops and stream-to-stream temperature differences. The irreversibility (entropy production) concept establishes a direct relationship between the heat exchanger design parameters and the useful power wasted due to heat exchanger nonideality. The paper presents a heat exchanger design method for fixed or for minimum irreversibility number of entropy generation units N//S. In contrast with traditional design procedures, the amount of heat transferred between streams and the pumping power for each side become outputs of the N//S design approach. To illustrate the use of this method, the paper develops the design of regenerative heat exchangers with minimum heat transfer surface and with fixed irreversibility N//S.

    Keywords:
    HEAT TRANSFER - Gases;THERMODYNAMICS - Optimization;