Abstract- In this study, a solar assisted rotary coal dryer is analyzed in terms of exergy economy and environment (3E). In the analysis two different heat sources are utilized. In the first one, a natural gas burner is used for producing the required heat for coal drying. In the second one, a parabolic solar system is employed as a heat source for drying same amount of wet coal. First of all, design parameters of a rotary coal dryer are investigated and economic operation range, the effects of some parameters are determined for the given type of coal. The effects of the dry bulb temperature at the inlet of the dryer are investigated. The second law efficiency of the dryer is calculated. For the parabolic solar system an economic analysis is carried out to estimate the payback period of the investment, which is found to be 6.6 years without heat storage. Also, by applying solar system to the coal dryer, reduced CO2 emissions are found.