English: Temperature (K) vs. heat load (W) diagram of hot stream (H₂O entering at 20 bar, 473.15 K, and 4 kg/s) and cold stream (R-11 entering at 18 bar, 303.15 K, and 5 kg/s) in a counter-flow heat exchanger. Created using MATLAB and NIST REFPROP. "Pinch" is the point of minimum temperature difference between the hot and cold streams, in a temperature vs. heat load diagram.