THERMAL AND HYDRAULIC PERFORMANCE OF A MODIFIED 2-STAGE EVAPORATIVE COOLER

The thermal and hydraulic performance of a modified two-stage evaporat ive cooler is evaluated. Variables considered are the mode of operatio n, packing thickness, mass flow rate of the water flowing to the preco oler, and the mass flux of water flowing over the packing media. The e ffectiveness of the system increased with the increase of the mass flo w rate of water flowing to the precooler, decreasing the mass flux of water flowing to the packing, and with the increase of the packing thi ckness. The effectiveness of the system with structured packing was hi gher than that with sheathy leaf base or natural fiber packing. The ai r-side pressure drop per unit length in the direction of air flow was nearly constant when the structured packing was used. For the sheathy leaf and natural fiber packings, the air pressure drop increased at a uniform rate as the mass flux of water flowing over the packing increa sed. The air pressure drop was lowest for the setup with the structure d packing. (C) 1996 Elsevier Science Ltd.