Temperature is a physical quantity that expresses the hotness of matter or radiation.
Temperature drop (T1 −T 2) is a direct indication of energy extracted.
For a given resource, it is dependent on T 2 which is in turn dependent on the minimum temperature of the process T1
when the thermal conductivity is low and the coefficient of thermal expansion is large. In unsteady heat-exchange processes the maximum possible temperature drop usually determines the maximum rate at which heat exchange can occur.
A drop of 17 degrees means subtract 17 from given temperature
