Theoretical study on a cross-flow direct evaporative cooler using honeycomb paper as packing material

A cross-flow direct evaporative cooler, in which the wet durable honeycomb paper constitutes as the packing material, is investigated. The system is expected to act as both humidifier and evaporative cooler to create a comfortable indoor environment in arid regions. A mathematical model, including the governing equations of liquid film and gas phases as well as the interface conditions, has been developed. The interface temperature of falling film has been predicted and discussed in detail. Analysis results indicate that there exists an optimum length of the air channel, which results in the lowest temperature, and the system performance can be further improved by optimizing the operation parameters, such as the mass flow rates of feed water and process air, as well as the different dimensions of the honeycomb paper.