The CaCO 3 fouling behavior in both re-circulated cooling water and pool boiling systems have been studied.Fouling morphology was also analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM).The fouling characteristics

as well as removal of fouling

for both induction period and post-induction period

were investigated in cooling water system.The results show that the removal performed in induction period will reduce fouling

while fouling will increase for the removal performed in post-induction period.Fouling morphology changed in the presence of inhibitor of 5mg·L -1PAA in cooling water system.For the CaCO 3 fouling formed in pool boiling system

it was found that main crystal forms changed from calcite in the absence of PAA to aragonite and vaterite in the presence of PAA.Step bunching was found by AFM on the crystal surface of CaCO 3.Fractal dimension analysis shows that in the presence of inhibitor of PAA

fractal dimension increased for CaCO 3 fouling morphologies formed in both heat transfer systems.