Numerical simulation of heat and mass transfer in adsorbent beds with annular fins

A transient two-dimensional numerical model of combined heat and mass transfer in the adsorbent bed of a silica gel/water adsorption chiller is presented for a cylindrical bed with annular fins. The bed transient transport behaviors are discussed for all cycle phases. Complex flow patterns are found for isosteric heating and cooling phases due to the simultaneous occurrence of the adsorption and desorption processes. Furthermore, the effects of bed configurations such as fin spacing, bed height, and particle size on the performance of the system are examined. Results show that fins in general reduce the COP of the system; however, for a given total cooling power, the bed size can be reduced dramatically, when fins are employed at the cost of slightly lower COP. It is also shown that there is an optimum particle diameter associated with each bed configuration that maximizes the COP, TCP, and SCP of the system.

► Flow patterns, temperature and uptake distributions are examined in a finned bed.
► Increasing the fins number and decreasing the fins height reduce the cycle time.
► At a given fin height, SCP increases with the increase in fins number.
► Fins in general slightly reduce the COP of the cooling cycle.