Modelling flow through a heating station

[karli_aau]

I have an issue where i would like to model a district heating station so that it has two different families. One for the secondary side (temp 80/50) and the other for the primary side (temp 95/53). I have also modeled heaters and set my system up so that there is preset flow in the heaters. Then I connect a number of heaters into the substation. After that in the substation i´d like to sum the flow from two lines (i used a parameter with a formula) and then exit that summed flow on the other side of the substation so that it would then flow continiously to the primary side. 

Now there are two issues that i´m facing right away. First is that for some reason the formula is not summing the flow-s in the model. Although when i test it inside the family it works. But not in the model. The second issue is that the flow directions seem to be in the opposite direction when i inspect the system with the system inspector tool. And also to me it seems that it doesn´t understand that it should flow through the substation, but it rather flows from the secondary side connector to the other. I´ve also tried to link connectors, but i can´t seem to link two connectors into one outlet connector.

The project can be downloaded from here: https://www.dropbox.com/transfer/AAAAADHJnpU7-96Y7RJ7mL97dSDw2th-jd1jndZd3XEqkKMGga4kNQI 

I would really appreciate all kinds of help on this thing! 

[karli_aau]

I´m also adding a link with a small video. The issue of parameter formula working in a family but not in a project can be seen here https://www.dropbox.com/t/pzniBiIRAffqm9PJ  

[fabiosato · Accepted solution]

Hello,

I made some adjustments and it seems to be working.

First uncheck Enable analysis for closed loop.

Then I changed the inlet connectors of the secondary to calculated.

Please check the attached file

[karli_aau]

Super! That seemed to solve the problem. Could you explain further what removing that tick exactly did? 

[fabiosato]

Hello,

Unfortunatelly I don´t know exactly what are the differences, I hope sombedy else may have the answer. Sorry

[iainsavage]

The hydronic network calculation setting allows you to calculate hydraulic performance for complete loops and hence give a flow and pressure value for the pump. By unticking the box I presume each supply and return system is treated as a single system rather than as a circulating supply/return loop and for pump sizing you would then need to add the values together yourself.

https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/CloudHelp/cloudhelp/2019/EN...

https://knowledge.autodesk.com/support/revit-products/learn-explore/caas/CloudHelp/cloudhelp/2019/EN...