Influence of fermion determinant on the temperature dependence of gluon condensates

The contribution of the fermion determinant to the gluon condensates at a f inite temperature is calculated in the framework of the grand partition fun ction for a weak-interacting instanton medium of a disordered phase. It is found that the temperature behavior of both chromomagnetic and chromoelectr ic gluon condensates depends sensitively on the flavor number. The more the flavors are, the faster the gluon condensates decrease. In the three-flavo r case, the gluon condensates would be vanish (or the scale invariance woul d be restored) approximately at the temperature of 180 MeV.