You can see the 2 papers:

1) http://www.sciencedirect.com/science/article/pii/S1876610212015731

2) http://www.sciencedirect.com/science/article/pii/S1878029612002484

oooooh thank you Mr.Mohamed Hamdy and if you have more information about that ,your help would be highly appreciated

please refer the following article link:

T.S. Ge, Y. Li, R.Z. Wang, Y.J. Dai, A review of the mathematical models for

predicting rotary desiccant wheel, Renewable and Sustainable Energy

Reviews 12 (2008) 1485-1528.

You may also find the following paper link:

Z. Gao, V.C. Mei, J.J. Tomlinson, Theoretical analysis of dehumidification

process in a desiccant wheel, Heat and Mass Transfer 41 (2005) 1033-1042.

I have used something similar with the reference (Roy Holmberg) in this paper. Works good.

Please find the following article:

Z. Gao, V.C. Mei, J.J. Tomlinson, Theoretical analysis of dehumidification

process in a desiccant wheel, Heat and Mass Transfer 41 (2005) 1033-1042.

Following may also helpful to you.

T.S. Ge, Y. Li, R.Z. Wang, Y.J. Dai, A review of the mathematical models for

predicting rotary desiccant wheel, Renewable and Sustainable Energy

Reviews 12 (2008) 1485-1528.