Tutorial 3 – Heat network

Sympheny V1.1



This tutorial will show you how to implement the following features in your energy model:


> Thermal network modelling: 3 sectors
> Multiple temperature levels


The model includes 3 energy hubs. A district heating connection as well as a connection to a cold-water source are located in sector 2.

Two Network Technology candidates connect the three hubs/sectors: a high temperature (HT) heat network and an anergy network:


For each hub, a system diagram is created on the Sympheny Web App.

Sector 1


Sector 2


Sector 3

Note about the system diagram: to keep it clear, the connection between the network and the hub is not represented. However, whenever a network is displayed on the system diagram (dotted lines) it is implied to be connected to the energy carrier node.




If you’re in need of more information on a certain aspect of the software don’t forget to look into the documentation. Furthermore, if anything is unclear you can find the Help button on the webpage or send an email to: support@sympheny.zendesk.com.


Step 0 – Getting started

The procedure here is the same as for Tutorial 1. You can name the project, Analysis and the scenario, Tutorial 3, Thermal Network modelling and Baseline respectively.


Step 1 - Hubs

The hubs in this tutorial represent 3 sectors of a city.

> Select Add New on the Hubs page, name it Sector 1 and press Add.

> Repeat this procedure for each sector. Each sector will be connected with a cold and hot thermal network (see step 6).

Once you have defined the 3 sectors, you can see and move around 3 hubs in the energy hub diagram on the lower part of the page.

> Press Next on the lower right corner to move to the Energy Carriers (EC) section.


Step 2 – Energy carriers

> Select Add New to define a new energy carrier.

> Assign a Type, a Subtype, and a Name to each energy carrier that you create and Add it.

Find below the list of energy carriers used here.




Heating Energy

Heat 50-60°C

Heat 50-60°C

Heating Energy

Heat 10-20°C

Heat 10-20°C

Heating Energy


District Heat 60°C

Heating Energy

Heat Ambient

Heat Ambient

Cooling Energy


Cold Water Source

Cooling Energy

Cooling 10-20°C

Cooling 10-20°C

Electrical Energy




Step 3 – Energy demands

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Automatisch generierte Beschreibung

Every hub has its own demand in cold and hot heat.

> Thus, for every sector select the hub that requires the energy (Sector 1,2 or 3),

> Then select the energy carrier (Heat 50-60°C or Cooling 10-20°C) related to the demand and name this energy demand (Heat/Cooling Demand).

To make things easier, assume that each sector has the same heat and cooling demand and select the profiles from the database.

> Press Generate Profile and select the following Demand Type – Building Use – Building Age combinations from the Database:

·        Cooling:  Cooling – Multi-family House – Minergie-Renovation

·        Heat 50°C-60°C: Space Heating – Multi-family House – Minergie-Renovation


> Give them an Energy Reference Area of 10’000 [m2] and select Next. This models the demand profiles for 100 multi-family housings with the assumption of 100 [m2] per housing.


The electricity demand of the hub is ignored. The electricity needed to make the heat pump work is determined by the optimization.

> Select Next to move to the Solar Resources section.


Step 4 – On-site resources

No solar resources are needed for this model.

> Select Next to move to the Imports & Exports section.


Step 5 – Energy Imports & Exports

> Insert the following imports in your model:


Energy carrier

Price (CHF/kWh)

CO2 (kg-CO2/kWh)






District Heat 60°C




Cold Water Source





Cold water is imported to sector 3 only to reflect the fact that the cold-water source is situated in the sector 3 and district heat 60°C is imported in sector 2 to reflect that the district heating connection is located in sector 2. Electricity on the other hand is assumed to be imported from the grid to each sector.


Example for electricity:

Example for District Heat 60°C:

No energy exports are needed in this model.

> Select Next to move to the Supply Technologies section.


Step 6 – Supply Technologies

Supply Technologies are divided between Conversion Technologies and Storage Technologies. Let’s go through the ones used for this tutorial.


Step 6.1 – Conversion Technologies common to each sector

Each sector includes the same Water Source Heat Pump and the heat exchanger HEX cooling which links the cold-water network to the Cooling Demand.

> Select Create Custom from the Conversion Technology Candidates tab to add it to every sector.

1.      Water Source Heat Pump

Note that the primary input EC is Electricity and that all 3 hubs are selected.


2.      HEX Cooling

The virtual heat exchanger HEX Cooling models that fact that the EC heat 10-20°C is interchangeable with the EC cooling 10-20°C (same temperature level).

> Don’t forget to tick the Virtual Technology? box.


Step 6.2 – District Heat connection in sector 2

Sector 2 takes heat from the district heating system and forwards it through pipes to the other sectors. Thus, for sector 2 only, add the following conversion technology:


Step 6.3 –Cold water source connection in sector 2

Add the following conversion technology for sector 2:

The electricity usage is meant for the pumps. Therefore, the primary input must be the cold water source, which is then fully transformed to heat 10-20°C , which leads to the output efficiency of 100%).

Here the summary of the Conversion Technology Candidates:

> Select Next to move to the Network Technologies section.


Step 7 – Network Technologies and Links

To create a network, you need to first create the network technology that allows you to create the links between the different energy hubs. All possible links should be specified; the optimizer will select which connections should optimally be installed and their respective dimensioning.

Two networks are needed: one for the cold and another for the hot heat.

> Select Create Custom in the Network Technology Candidates tab and create the following network technology the energy carrier Heat 50-60°C:


> Repeat the same procedure for the energy carrier Heat 10-20°C:


> Press Add New in the Network Link Candidates tab to connect all the hubs together.

> Select the two hubs that should be connected with one another, the Network Technology used (Anergy or HT heat network) and the length of the network link

> Repeat this procedure to link together every hub with both networks. This then gives you the following list:


Length (m)








Select Next to move to Other.


Step 8 – Other

This section allows to include the current interest rate in [%] to the model.

> Set it to 2%.


Step 9 – Review

The review section allows to have an overview over the entire scenario specification and edit a section if it is needed.

> Select Finish Specification & Prepare for Execution to get to the execution of the model.


Step 10 – Execution & Results

Next to the Setup section you can find the Execution section where you select the scenario to be optimized, the two objectives the optimization should be based on and finally the number of points wanted in the pareto front.

> Select the scenario(s) for which you want to execute the analysis (otherwise the execute button will stay grey and cannot be selected) 

> Select Execute to start the optimization.

> Once you receive an email that the optimization is completed, Go to the Results section and Select Download to go through the results of the optimization.

> Click on View results to open the dashboard of your optimal design