We present in this work a generalization of the solution of Gorenstein and
Yang for a consistent thermodynamics for systems with a temperature dependent
Hamiltonian. We show that there is a large class of solutions, work out three
particular ones, and discuss their physical relevance. We apply the particular
solutions for an ideal gas of quasi-gluons, and compare the calculation to
lattice and perturbative QCD results.Comment: 26 pages, 1 figure. To appear in Nuclear Physics