Pinch Analysis
Pinch analysis is a systematic method for minimising energy use in a process by matching hot and cold streams for heat recovery around the 'pinch point' — the location of the tightest temperature approach. It sets the thermodynamic targets for minimum heating and cooling utility.
Developed for process integration, pinch analysis plots the combined heating and cooling demands of a process as composite curves. Where the curves come closest is the pinch, which divides the process into a heat-deficit region above and a heat-surplus region below. The golden rules — do not transfer heat across the pinch, do not use hot utility below it, do not use cold utility above it — yield the minimum theoretical energy bill and guide the design of heat-exchanger networks.