A new approach to the effectiveness method for the simulation of desiccant wheels with variable inlet states and airflows rates

Exponential correlations to predict the dependence of effectiveness parameters of a desiccant wheel on the airflow rates and on the rotation speed

“…As expected, and also according to the previous work of Ruivo et al [12], the effectiveness parameters h h and h j depend on the airflow rates, thus justifying the search for appropriate correlations. The classical analysis of the performance of heat exchangers suggests the proposal of an exponential-type correlation to take into account the influence of the airflow rate.…”

“…This assumption significantly simplifies the problem of predicting the global performance of the desiccant wheel, but according to previous tests conducted by the authors [12] its validity is questionable.…”

“…However, a recent work [12] demonstrated that the effectiveness method supported by constant-effectiveness values provides results with unacceptable accuracy in a significant number of cases within the expected range of operation, even in those cases with constant airflow rates and constant rotation speed of the desiccant wheel. A probable reason for the contradictory conclusions of Refs.…”

“…1 requires the use of a pair of effectiveness parameters. As referred in Ruivo et al [12], one of the effectiveness parameters here used is…”

“…[12], including: (i) a new pair of intuitive effectiveness parameters, (ii) a 2D interpolation procedure that accounts for the dependence of the effectiveness parameters on the inlet airflow conditions (EIPIS approach) and (iii) a simple correlation of exponential type for predicting the effectiveness parameters in cases of Effectiveness Interpolation Procedure for the effect of the Inlet States F1, F2 characteristic potentials h specific enthalpy of moist air (J kg À1 ) k f coefficient used in Ref. [12] …”