DIMOSIM simulation platform

DIMOSIM is a bottom-up, physical simulation platform for district energy systems. It can be used to simulate new or existing districts with or without energy networks. The platform models energy-related equipment on any level of the district (zone, building and district level) and allows thus the simulation of a large number of energy concepts. It has been built for simulating energy concepts as well as to test energy management strategies via emulation techniques. It has a built in stochastical modelling of occupant and equipment behavior.

Application & objectives in THERMOSS project

Provide emulation tool for testing energy management algorithms:

  • CEA: District energy management
  • CSEM: Building energy management

Simulation of the THERMOSS pilots:

  • “before” situation
  • “THERMOSS-inside” situation
  • Assessment of theoretical gains using THERMOSS technologies

The 2 usages of DIMOSIM in THERMOSS

Internal control mode – simulation

In this mode, DIMOSIM simulates the whole district energy system including any energy management or control information. All Thermoss pilot sites are simulated with the aim to compare the “before” and “after” situation.

External control mode – Emulation

In this mode, DIMOSIM simulates the district energy system excluding energy management or control information. This will be provided from an external optimization algorithm on building and or district level.

Some examples of functionalities and usages


Adjacencies are automatically detected from GIS data (visualization by colours)

Solar masks from other buildings

Solar masks are calculated automatically from GIS data of the district for every façade segment. The pictures show examples of masks right bottom and comparisons of the differences by considering or not solar masks (left bottom).

Integrated network generation module

DIMOSIM contains a detailed district thermal network module based on transient plug-flow models. The network can either be imported from available data or automatically generated using a built-in optimization module.

Besttest validation examples

DIMOSIM runs automatically validation tests via the continuous integration modules. DIMOSIM is developed within a Gitlab project with hundreds of unitary tests.

Network generation and sizing

Network generator

The example shows the progress of the optimization module for district networks. In this example, at the end, a secondary network has been constructed from GIS data of roads.

Flow rates in segments

Flow rates in the district network can be visualized for sizing data or at indicated time steps of the simulation. It allows to visually check the operation of the network.

Fig. 1: Sub-ring in the Urberoa pilot

Fig. 2: Main-ring in the Urberoa pilot

Demo site simulation

International Way, Southampton, UK

This site is equipped with hot water radiator heating. In Thermoss, a selection of flats has been equipped with heat interface units (HIU) allowing to reduce return temperatures from each flat to the boiler on the building level. The pilot has been simulated with this DIMOSIM software.

Fig. 3: Google maps

Fig. 4: «BIM» data generated (Qgis display)

Hale Court North, Portsmouth, UK

This site is equipped with hot water radiator heating. In Thermoss, smart thermostatic valves have been implemented with a strategy of optimisating the heating law of the building in real time. The pilot has been simulated with this DIMOSIM software coupled to the CSEM building level optimisation module.

Urberoa, San Sebastian, Spain

This site is equipped with a district heating network for heating and DHW production. The network is based on the main ring and individual sub-rings connecting groups of buildings. District substations allow the delivery from the main ring to the sub-rings. These substations have been improved during Thermoss with heat pumps and solar panels. An optimisation strategy on the district level has been tested in a coupled simulation between DIMOSIM and the CEA optimisation algorithm.

Fig. 5: Google maps

Fig. 6: «BIM» data generated (Qgis display)

Other ongoing work based on DIMOSIM

Online-Coupling of DIMOSIM with ENVIBATE, a microclimatic simulation tool

  • common PHD with University of La Rochelle (LASIE)

Online-Coupling of DIMOSIM with OMEGALPES (MILP optimisation tool) for district energy management optimisation

  • common PHD with University of Grenoble (G2ELAB)

Parsomonious modelling in DIMOSIM

  • common PHD with Mines ParisTech (PSL Research university)

Use of DIMOSIM in POWERDIS, a district simulation platform developed by the French EFFICACITY institute.


  • DIMOSIM has now successfully passed from an internal prototype to a serious tool (Gitlab, continuous integration etc.)
  • Use and improvement in Thermoss but also in several national and European projects
  • Strong partnerships have been created around DIMOSIM with external partners
  • In the frame of the EFFICACITY institute*, Powerdis (with Dimosim as simulation kernel) is supposed to get a reference platform for district simulation
    * EFFICACITY is a national research institute with 30 partners from public and private partners and more than 100 researchers – https://www.efficacity.com/