EPOC (Excess Post-exercise Oxygen Consumpion) and TRIMP (Training Impulse) are used to quantify training load. They accumulate exponentially to training intensity. The key difference is that EPOC decreases during the recovery breaks while TRIMP only accumulates upwards. Also EPOC is scaled in Training Effect (0.0-5.0) helping the interpretations while TRIMP scores doesn’t have automatic classification.
You can read more about the Training Effect, EPOC and TRIMP from here.
See also the video about EPOC from here.