Numerical study on performance of a desiccant cooling system with indirect evaporative cooler

Solid desiccant indirect evaporative cooling, driven by low-grade heat source, is an ideal alternative for conventional vapor compression systems to provide a thermal comfort condition in the humid area. Based on the coupled heat and mass transfer, the mathematical model, is developed to evaluate the performance of the hybrid system in terms of coefficient of performance (COP) and Em. The sub-models were validated by comparing their results with the experimental results. The effects of the operating parameters, as well as the number of transfer units (NTU) on the performance of both heat exchanger and indirect evaporative cooler are numerically investigated. The results show that the optimum process inlet temperature and humidity should be less than 35 °C and 18 g/kg, respectively; Em value is almost independent of the inlet air face velocity, regeneration air temperature, NTUHE and working air mass ratio; Increase in NTUHE or NTUIEC within a certain range (NTUHE ≤ 3, NTUIEC ≤ 6) both can improve the COP of the system; The working air mass ratio in indirect evaporative cooler can affect on the amount of air supplied to the room and the COP of the system, but almost can not affect the basic air conditions.