Pinch Analysis

Pinch analysis is the thermodynamic basis for the core OpenPinch workflow. The main objective is to determine how much heat can be recovered internally before external heating or cooling utilities are required.

OpenPinch uses pinch analysis to answer three primary questions:

  • What is the minimum hot utility target?

  • What is the minimum cold utility target?

  • Where is the pinch-constrained temperature region?

Thermal Framing

In OpenPinch terms:

  • hot process streams release heat as they cool

  • cold process streams require heat as they warm

  • utilities satisfy whatever part of the thermal load cannot be recovered internally

The package reports this through summary metrics such as:

  • Hot Utility Target

  • Cold Utility Target

  • Heat Recovery

  • Hot Pinch

  • Cold Pinch

Analysis Dataflow

The core OpenPinch solve path can be read as one analysis-dataflow diagram:

input files / schemas
    -> validated streams, utilities, and options
    -> prepared Zone hierarchy
    -> direct and/or indirect targeting services
    -> target models attached to zones
    -> TargetOutput summaries and graph payloads
    -> tables, plots, Excel export, and dashboard views

This matters because the same prepared model feeds the CLI, the PinchProblem wrapper, the service layer, and the packaged notebooks.

Minimum Approach Temperature

OpenPinch uses dt_cont as the main continuous temperature-approach assumption for streams and many utility calculations.

Conceptually:

  • a larger dt_cont makes heat recovery more conservative

  • a smaller dt_cont increases the apparent recovery potential

  • the pinch location and utility targets depend on this assumption

The package supports both base and active dt_cont values on runtime streams, so zone-level multiplier studies can alter the effective shift while preserving the original input.

What The Pinch Represents

The pinch is the temperature region where the process is most constrained with respect to heat recovery under the chosen temperature-approach assumptions.

Practically, this means:

  • utility targets are determined by the interval cascade through this constrained region

  • graph interpretation often starts here when a case is difficult to improve

  • direct and indirect integration workflows both depend on the same broad idea, but they apply it at different system scopes

What OpenPinch Adds Beyond The Textbook Core

Classical pinch targeting is the starting point, not the whole package. OpenPinch extends the workflow with:

  • hierarchical zone modeling

  • indirect / site-level targeting

  • multiple graph views

  • optional Heat Pump and refrigeration workflows

  • optional turbine cogeneration post-processing

  • programmatic and file-backed workflows over the same core engine