Simulate an active network with a central pump

Cold district heating, part 5: simulation of an active network with a central circulation pump

Overview ▶ 0:11

Passive network as the starting point for conversion to an active network — Starting point: passive network with decentralized pumps that is converted into an active network with a central pump

This tutorial demonstrates how to convert a passive network with decentralized circulation pumps into an active network with a central pump. The conversion is done in just a few steps.

Replacing the systems ▶ 0:36

Replacing the decentralized heat pump with pump by a variant with a valve — Replacing the decentralized heat pump: from the variant with a pump to the variant with a valve

Starting from the previous example with decentralized heat pumps and circulation pumps:

Select the decentralized heat pump with pump.
Click Replace.
Select a decentralized heat pump with valve from the database.
Copy the element so that it can be edited.
Repeat the procedure for all other system types.

Structure of the new system ▶ 1:18

System editor with heat pump and valve instead of circulation pump — New system: heat pump with valve (instead of circulation pump) to regulate on a 3 Kelvin temperature difference

The new system consists of:

Heat pump with the corresponding pressure loss
Valve (instead of the circulation pump), which regulates on a fixed temperature difference of 3 Kelvin

The consumer side is now passive — no decentralized pump is required any more.

Installing the central pump ▶ 2:06

System editor of the probe field with an installed central pump — Central pump with defined head installed in the probe field and connected

The network still needs a circulation pump, which is now placed centrally in the probe field:

Open the probe field in the system editor.
Delete the existing connection line.
Drag a pump with defined head into the system.
Connect the elements.
Confirm with OK.

The network has now been converted into an active system.

Performing the steady-state calculation ▶ 2:48

Steady-state calculation with central pump instead of decentralized pumps — Steady-state calculation with the central pump selected as the supply option

Open the steady-state calculation dialog.
For the supply, select a central pump instead of decentralized pumps.
Start the calculation.

The pressure loss at the worst point should hardly differ from the passive system, since only the pump has been swapped.

Pump sizing ▶ 3:25

Pump sizing with system curve and pump selection from the database — Pump sizing: system curve and selection of a suitable pump from the database

Click Details > Pump sizing.
The system curve is displayed.
Select a suitable pump from the database.
Click Assign pump.

The pump is stored in the system with the corresponding curve and head.

Running the simulation ▶ 4:44

Simulation settings with 14 days of simulation time — Simulation over 14 days for a quick check of the active network with central pump

Switch to the simulation.
Set the simulation time (e.g. 14 days for a quick check).
Start the simulation.

Evaluating the results ▶ 5:07

Results with temperature difference at the consumers and pump diagram — Results: temperature difference at the consumers and pump diagram with constant pressure increase (0.8 bar)

In results mode, check in particular:

Temperature difference at the consumers: The configured 3 Kelvin should be reached. If not, the pump must be re-sized or the pressure increase adjusted.
Pump diagram: The central pump runs with a constant pressure increase (e.g. 0.8 bar).

The system has now been successfully converted into an active network with a central pump.