Pinch Analysis online

The goal of a Pinch Analysis is to find the optimal way to connect heat sources and sinks through heat exchanger networks, enabling the internal use of waste heat.

The key to effective integration lies in cascading the use of waste heat according to temperature levels, meaning waste heat is always utilized at the highest possible temperature to avoid losing potential. For example, waste heat at 300 °C from combustion gases should not simply be used for producing hot water at 50 °C.

The result of a Pinch Analysis is a comprehensive overview of which heat and cooling demands can be efficiently interconnected. This theoretical optimum reveals the minimum external cooling and heating requirements, as well as the maximum feasible cooling supply temperature and minimum heating supply temperature.

In practice, additional constraints may limit certain types of heat recovery, but a systematic Pinch Analysis often provides highly cost-effective strategies for improving energy efficiency, potentially reducing energy consumption by up to 30%, often with payback periods under two years.

The most time-consuming step in a Pinch Analysis is gathering and preparing data on all heating and cooling requirements.

Important parameters include energy capacity, heat transfer medium (e.g., air, water, steam), volume flow, and temperatures. Each requirement is considered a process stream and categorized as either a Cold Stream (requiring heating) or a Hot Stream (requiring cooling).

It is crucial to separate the process from the energy supply; for instance, if a raw material like milk is heated from 20 °C to 80 °C, this raw material itself is classified as a Cold Stream, not the heating medium used.

After data collection, Pinch Analysis relies primarily on graphical methods. The main diagrams used are the Hot and Cold Composite Curves and the Grand Composite Curve.

The Composite Curves combine all Hot Streams and all Cold Streams into a single curve for each, representing the total heating and cooling demand. Overlapping areas indicate potential for heat recovery due to temperature differences, while the sections to the left and right reflect the required external heating and cooling demand.

The Grand Composite Curve represents the remaining energy requirements after maximizing internal heat recovery. It shows where and at what temperature levels external heating or cooling is still needed, serving as a valuable tool for integrating heat pumps into industrial processes.

See our blog post on pinch analysis for more basics.