After the action "Compute design flows" you go to the next step "Select pipes"

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“Select pipes” button in Hysopt

In the figure below, an example of the Hysopt pipe selection for steel pipes is shown. The selected pipe diameter and the corresponding pipe length is given in meter. The total pipe length is shown in the right top corner. The user can manually override the Hysopt pipe selection. In the example below, the DN 80 pipe selection was manually changed to DN 100 pipes.

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Hysopt pipe selection - Output example

Pipe types

Following standard pipe types are available in the Hysopt software.

• Steel pipes (welded): NBN EN 10255

• Steel pipes (precision): NBN EN 10305-1 and NBN 10305-2

• Copper pipes: NBN EN 1057

• Multilayer: NBN EN ISO 21003-2

• Epoxy

• HDPE 100 SDR 11

• External steel pipes : Cibse CP1

• External PEX pipes : Cibse CP1

You can change the pipe type when selecting a pipe on the canvas.
You can add custom pipe types if desired via the Select pipes | Pipe settings

Standards for pipe sizing

For the moment, Hysopt supports three standards for pipe sizing

• WTCB / Buildwise (Belgium)

  • based on report 14 Ontwerp en dimensionering van centrale-verwarmingsinstallaties met warm water.

  • default

  • using a “maximum pressure drop per meter“ criterium

• ISSO (Netherlands)

  • based on publication 18 ISSO is verhuisd

  • validated by ISSO

  • using the “gradual speed reduction“ method, a combination of the “maximum pressure drop per meter“ and “maximum velocity“ criterium as explained in the standard

  • be aware that the standard allows you to deviate from the currently used values, as explained in Select pipes | ISSO

• Cibse (UK)

  • based on code of practice CP1 https://www.cibse.org/knowledge-research/knowledge-portal/heat-networks-code-of-practice-for-the-uk-cp1-2020

  • only available via custom upload, see Select pipes | CIBSE guide CP1 (2020) for pipe sizing (underground pipe network)

  • using a “maximum velocity“ criterium as explained in Select pipes | CIBSE guide CP1 (2020) for pipe sizing (underground pipe network)

You can select the desired standard via the Select pipes | Pipe settings

You can also choose to deviate from the standards, and create your own custom pressure profile, as explained in Select pipes | Custom pressure profiles

ISSO

The ISSO standard allows three types of

• Constant speed (constante speed)

• contstant friction or constant pressure drop (constante wrijving)

• gradual speed reduction (geleidelijke snelheidsreductie)

CIBSE guide CP1 (2020) for pipe sizing (underground pipe network)

The CIBSE CP1 (2020) guide is widely used and recognized in the UK for sizing heat network pipework.

At this moment, the Hysopt software only supports pipe sizing based on maximum velocity, maximum pressure drop per meter, or target pressure drop per meter. However, CIBSE CP1 recommends pipe sizing based on typical (or target) velocity which is currently not supported by the Hysopt software.

As a workaround to size pipes according to the recommendations from CIBSE CP1 (2020), we have created excel sheets to design pipes based on the max velocity method, providing very similar results as to the typical velocity calculation presented in the CIBSE CP1 (2020) guide.

We have two different pressure profile tables for CIBSE CP1 (2020). The first pressure table contains the ‘typical velocity’ that is listed in the CIBSE CP1 (2020). However, in CIBSE CP1 (2020) they have made a comment that higher velocities are allowed. For this reason, we have made a second pressure profile which allows 30% more flow velocity compared to the typical velocities in CIBSE CP1 (2020) for the external steel pipe. This pressure profile table can also be found below. The excels are thoroughly tested and can be implemented in our software as per the method explained above.

You can upload these pressure profiles as described in Select pipes | Custom pressure profiles

Pressure profile CIBSE CP1 (2020)

A. Table with typical velocities from CIBSE CP1 (2020)

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B. Table with 30% higher allowed maximum velocities for pipetype “external steel pipe”

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Custom pressure profiles

If you like, you can create your own pressure profiles and implement your own practice / standard.
The Hysopt software supports 3 methods for pipe sizing:

• Maximum velocity

• Maximum pressure drop per meter

• Target pressure drop per meter

Both velocity and pressure loss serve as 'hard' filtering criteria. Pipe diameter is never selected when the pressure loss is larger than the maximum, or the velocity is larger than the maximum velocity. When target pressure losses are supplied, the pipe diameter is selected from the set of diameters that are allowed (by the above criteria), and which has the smallest deviation from the target pressure loss. Summarized this means: that when both are supplied the most restrictive is applied and a "0" value is ignored.

You can change the pressure profiles via the Select pipes | Pipe settings

Pipe settings

The user can change the pipe types and the pipe selection profile by first clicking on the button in the top right corner of the screen stating "model settings".

A popup window will appear where the user can change different design options including the pipe types and pressure profiles. The user can add or modify the pipe types and the pressure profiles by exporting the excel sheets, changing them, and importing them again. This way, any standard or best practice for pipe selection and/or pipe physical properties can be implemented and applied in our software.