Introduction
The Energy centre Placeholder is an ideal production unit intended for early-stage design before the energy concept has been decided yet. It allows you to already simulate a system without having an actual energy centre concept yet. You can drop it on the canvas as a placeholder for a real production concept and still run meaningful simulations to validate your secondary-side design and control strategy. In subsequent design stages, the placeholder can be easily converted to an inspiration library using the template auto-insertion concept (Ctrl+P).
The energy centre placeholders are available for heating, cooling and changeover as depicted in the figure below.
How to use them
Library location
You can find the energy centre placeholders BCs under “Production” in the corresponding libraries. The libary location is shown in the figure below. As the placeholder is intended for early-stage design, it is also used when starting from Building Simulation Quickstart wizard.
Parameters
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P&ID identifier
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A user-defined label used to identify the placeholder in the P&ID and on the canvas.
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Pressure drop in design
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The pressure drop in design attributed to the placeholder (used in optimise component step).
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Contains distribution pump
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A toggle to indicate if a pump is present in the virtual energy centre
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When disabled: the placeholder has no distribution pump.
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When enabled: an internal pump is activated inside the energy centre placeholder.
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The remainder of the pump parameters are identical to other pump usages, see pumps
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Control connections
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Activation
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Enables/disables the placeholder’s operation in simulation. The activation signal is also used to activate/deactivate the internal pump when present.
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Supply temperature setpoint
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The requested heating supply temperature that the placeholder will deliver in simulation (when active).
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When the supply temperature setpoint is not connected, the design supply temperature will be used as constant supply temperature during simulation.
Simulation behaviour
In simulation, the Heating Energy centre Placeholder acts as an ideal heat source with no maximum capacity or thermal inertia. If the block is active, the simulated supply temperature is simply equal to the requested setpoint temperature. When the block is deactivated, the supply temperature is set equal to the return temperature, not providing any heat flow to the system.
The simulation behaviour of the system is shown in the example figure below. It is clear that the input supply temperature setpoint is directly fed as supply temperature towards the secondary side as read on the sensor.
Placeholders are not actual production units and are excluded from the Pareto analysis. Pareto results may therefore be inaccurate. If you want to use the pareto analysis for your model containing placeholders, replace the placeholder with Fuel boiler with setpoint, electric boiler with setpoint or any other inspiration library template using Ctrl+P
From placeholder to Energy Centre
The Energy Centre placeholder is designed in such a way that it can easily be replaced with an actual energy centre concept from the inspiration library. Instead of manually selecting a template from the inspiration library, you can replace the placeholder using “Ctrl+P” or using the “Template configuration” button 
More information on the template replacement algorithm can be found at template configuration window.
Any energy centre placeholder can be easily converted to an energy centre template using the template replacement mechanism via the template configuration screen
Conclusion
The Heating Energy centre Placeholder is an ideal production unit with unlimited capacity that can be used as placeholder for a real energy centre, primarily intended for early-stage simulations. It always supplies the requested heating supply temperature setpoint (when active), making it useful to validate secondary-side design choices, return temperatures, and control strategies before committing to production technology details.
Once the system’s secondary side is stable, the placeholder can be easily converted to actual energy centre templates to smoothlessly support the energy centre optioneering phase.