The paper presents results from the work I2QP. Assume, that we are able to put the system into the interaction with a given environment prepared in two different temperatures. We fix an evolution duration and for both temperatures we perform a process tomography of the quantum channels related to the evolution. Then we calculate the α-fidelities of the channels. We derive an inequality between the experimental data and the partition function of the environment, which bases on our assumptions about the energy spectrum of the environment. If the inequality is not satisfied, our assumption about the energy spectrum of the environment were wrong. To implement the method, one does not to make any assumptions about the Hamiltonian of the system or the interaction term.