This file is from Wikimedia Commons and may be used by other projects.
The description on its file description page there is shown below.
Summary
DescriptionBlackbox AHT.png
English: the driving heat flow Q_1 at intermediate temperature level T_1 will be split in the revalued heat flow Q_2 at high temperature level T_2 and in rejected heat flow Q_0 at low temperature level T_0
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.