The influence of the number of stages on the heat source temperature (t(hs)) of desiccant wheel dehumidification systems that adopt water or refrigerant as cooling/heating media is examined in this paper. Under the same working conditions, when the exergy provided by the hot water (E-h) or the power input of the compressor (P) are reduced, thy can also be reduced. To reduce E-h and P, the exergy destruction of the desiccant wheels and heat exchangers should be reduced. The influence of stage number on the exergy destruction of the desiccant wheels is not significant when A(r) and F-r are equal to 1. However, stage number has a significant influence on the exergy destruction of the heat exchangers. For water-driven systems, as stage number increases, t(hs) (inlet temperature of the hot water) does not always decrease. The optimal stage number varies according to the water's total mass flow rate. A (m(c)c(pw))/(m(a)c(pa)) value of around 4 and the number of stages being 2-4 are preferable, with thy being around 55 degrees C and t(hs) being higher than 18 degrees C. When refrigerant is used, as the number of stage increases, t(hs) (condensing temperature) decreases. In this scenario, a 4-stage system with COP around 4.5 is preferable. (C) 2015 Elsevier Ltd. All rights reserved.