Exergy analysis is either applied for the identification of system irreversibilities via the calculation of exergy losses and exergy destruction, or for the assessment of system performance by calculating the exergy efficiency. As the system under consideration here is characterized by cyclic operation (fig 1) two approaches to exergy analysis are imaginable. Firstly, each cycle stage could be subject to an exergy analysis which would require taking into account the exergy of the sorption material and the adsorbate.

with Ew=E3=E4=0 during the desorption stage and Ei=E2=0 during the pre-cooling stage due to zero mass flow rate. The overall exergy balance for the cycle can then be expressed by equation 7.

£(( + E3 + E. ) — + E4 ) = Ed [J] (equation 7)

The average exergy destruction rate of one heat exchanger can be obtained dividing by the cycle time. The exergy efficiency can be expressed as the relation of exergetic product to the exergetic input. Identifying the increase in exergy between fresh air inlet and supply air outlet during adsorption as the system exergetic product, the exergy efficiency is given by equation 8.