November 22nd 2022

Irish Life: Pathways to Net-Zero using Sleeping Digital Twins

Irish Life: Pathways to Net-Zero using Sleeping Digital Twins

IES have been working with one of Ireland’s leading life, investment and pensions companies, Irish Life, using their Sleeping Digital Twin process to breathe new life into existing compliance models and help create net-zero roadmaps for multiple buildings across their portfolio.

IES have been supporting the net-zero ambitions of one of Ireland’s largest pensions company, having recently created four calibrated digital twins of commercial buildings within their portfolio, using its Sleeping Digital Twin process. 

The process recognises that 3D design and BIM models already exist for a large proportion of the existing building stock. However, typically these remain nothing more than a snapshot in time. Often created during the design/refurbishment phase, or for compliance purposes (such as Part L, BER, LEED or BREEAM), they are discarded once the building is handed over, representing a massive loss of potential to building owners once their buildings enter the operation phase.

At IES, we refer to these existing models, many of which have been created in our own Virtual Environment (VE) software, as Sleeping Digital Twins. A massive untapped resource for the buildings sector, these dormant models can be re-awoken into fully-fledged, accurate and reliable performance digital twins. Opening up the potential to optimise the performance of buildings in real time, evaluate future ‘what-if’ scenarios and technologies, and perform a variety of analyses around energy, health and wellbeing, comfort, costs, decarbonisation and more.

All four of the buildings selected in this project had previously been modelled by IES for compliance purposes. The client therefore recognised that they could utilise these existing Sleeping Digital Twins to start creating a plan to achieve net-zero status across their portfolio, knowing that these much more accurate models would allow them to test and compare different decarbonisation interventions with a much higher degree of confidence in the results. IES were chosen for this project due to their previous experience in modelling the buildings, as well as its extensive energy modelling experience in the construction sector in Ireland, since all 4 buildings were located in Dublin city centre.   

The client wanted four Digital Twins to help inform the best route to Net-Zero for their portfolio, selecting buildings that were representative of the overall portfolio and some of which had historical requirements. The buildings chosen included:

  • 2 offices: both in Dublin city centre
  • 1 retail: located on Grafton Street
  • 1 warehouse: located in Dublin city centre

IES used energy modelling workflows to evolve the archived models, initially created for Irish BER compliance, into fully-fledged performance digital twins that could support the decarbonisation analysis. The first step was ensuring that the models were upgraded to more accurately reflect the building HVAC systems and their components in operation, to better understand current performance and how this can be optimised. Detailed HVAC design involves precise management of plant components, but ensuring these work to the best possible degree requires a modelling analysis encompassing performance curves, activation thresholds and scheduling. 

IES consultants have a wealth of experience in taking BER & LEED models to the next level in HVAC performance, meaning they were able to model the design and then report on plant sizing and load matching to refine performance. IES provided schematic and 3D visual representations of the HVAC systems’ performance, which provided a clear communication on the opportunities and risks associated with the 4 buildings to the client. Through this approach, the digital twin uncovered the real energy consumption of the HVAC systems integrated within the four buildings. 

Additionally, a digital twin involves calibration of a physics model, which is the replacing of building assumptions within an energy model with data from energy bills or onsite metering. This produces a realistic digital twin to represent the building in operation. In this project, IES followed a six-step process to integrate the relevant data within the four building models before using the calibrated digital twins to test a range of energy saving measures or renovation strategies which took account of the requirements of listed buildings, if applicable. 


Figure 1 shows the dashboards IES created to show the baseline consumption of the targeted buildings. This is a key first step to decarbonisation.

For all 4 buildings the following steps were taken:

  • Task 1: Onsite surveys
  • Task 2: Assessment of existing building information and data
  • Task 3: Checking inputs of models 
  • Task 4: Digital twin creation 
  • Task 5: Monthly Calibration with energy data
  • Task 6: Testing different renovation and decarbonisation scenarios

Figure 2 shows the interactive tool created to test different renovation scenarios to help the client reach net-zero status for each of their buildings.
Figure 3 shows the decarbonisation pathways in a real-time dashboard to allow the client to track their progress towards Net-Zero.

The final reports and tools produced by IES contained a decarbonisation roadmap highlighting specific renovation and operational measures that can be implemented within these buildings (and also replicated elsewhere in the client’s portfolio) to achieve their goals. To reach net-zero, large-scale interventions need to be implemented for each building. Therefore, IES educated the client on the following steps which  they may need to consider to take some of the existing buildings within their portfolio to net-zero:

  • Change the heritage/historical character of the buildings and thus change their exterior appearance, including windows, frames, possibly structure. 
  • Consider renovation measures that will make the building fully inaccessible for a number of months for structural and HVAC changes. 
  • Replace HVAC systems they currently have installed and propose completely new ones. 
  • Then to achieve net-zero status, installing renewables (Solar PV, battery storage, wind turbine etc.). 

The Digital Twins created in this project provide lasting digital assets which the client can continue to use in future projects. Their work with IES is ongoing to ensure the best route to decarbonisation for their buildings.

Anonymised project outputs can be accessed via the links below:

Decarbonisation Roadmap Dashboard
Interactive City Model for Dublin Portfolio

For more information on our Sleeping Digital Twin service, please visit https://www.iesve.com/sleeping-digital-twin