> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How to determine the heat flow on a specific part of your model

## Objective:

Learn how to determine the heat flow on a specific part of your model.

## Applies to:

* Thermal analysis
* Simulation
* Heat Exchangers

## Procedure:

1. After running a [**Thermal Analysis**](/help-articles/knowledge-base/structures/how-to-run-a-thermal-analysis) use the results to create a **Heat Flux Point Map.**

2. Define a region that intersects with the areas you want to determine the heat flux in. For example, a **Box from Corners**, thickening a CAD surface, or any other volume.

3. Use the **Filter Points by Volume** block with the **Heat Flux Point Map** and Region as inputs.

4. Extract the values from the Properties of the filter block and post-process as you need to (average, sum, etc.)

![The nTop notebook example of how to create a Heat Flux Point Map. The image also shows the Thermal Analysis model.](https://files.learn.ntop.com/help-articles/structures/4408190379923.png)

And that's it! You've successfully determined the heat flux on a specific area.

Are you still having issues? Contact the [support team](https://support.ntopology.com/hc/en-us/requests/new), and we'll be happy to help!

## Download the Example file:

* [Example file](https://files.learn.ntop.com/Support%20Article%20Example%20Files/Knowledge%20Base/Simulation/Heat%20Flow%20on%20Part%20of%20Model%20Example.ntop)

## Keywords:

*points calculate heat flow filter thermal flux how-to sum*