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From the BIM to the BEM (Building Energy Model), the energy model of the building-installation system

From BIM to BEM (Building Energy Model), the energy model of a buildings technical installation system

The BIM methodology applied to energy performance aspects represents the new revolution: here’s the energy model of a building’s installation system (BEM – Building Energy Model)

In recent years, BIM has been a real trend in the construction industry. Most AEC professionals have heard of Building Information Modeling, but what exactly is it, and why is BIM important?

Many people associate BIM with software, but it is important to clarify that BIM is a methodology that enables the complete management of the entire lifecycle of a project.

BIM is not only geometric modelling (3D BIM); it is a broader approach that also refers to other dimensions of BIM allowing for complete modelling also from the point of view of costs, time, execution capacity, sustainability, etc.

All professionals involved in a BIM project can collaborate and exchange information in real time, resulting in a significant reduction in project design, development, management and execution time. This is just one of the obvious advantages of BIM applied to the construction industry.

Working with a BIM methodology means creating the virtual model of a building and having the possibility to carry out all the involved operations (from planning and construction, to management phase) on that model, while predicting the building performance.

In practice, it is possible to perform simulations on the virtual model and foresee the real model’s response. This brings a huge advantage both in terms of time and costs.

Furthermore, assessing the effects of possible interventions on the virtual model allows to define what the best maintenance intervention will be in an absolute objective manner.

From atoms to bits: Digital Twin, Big Data and IoT

In this context, the concept of Digital Twin has emerged and it is key in Industry 4.0. A digital twin is a digital representation of a physical asset that reproduces the structure and behaviour of that asset in real life. Tests are carried out on the virtual model to simulate and avoid potential problems and/or errors.



Verifying each phase in advance leads to increase efficiency to the entire process.

The shift from atoms to bits started in the last century has taken the current technological evolution to another level. Bits are replacing atoms due to bits lower costs both in terms of storage and processing. Basically, it is more convenient to perform operations on bits (virtual model) than on atoms (real object).

For instance, it is more convenient for a company manufacturing vehicle to create a digital model on which to make tests and simulations so to achieve a satisfactory project, rather than developing prototypes and testing them in wind tunnels.



When the Digital Twin receives data, it can simulate an operational situation and detect eventual malfunctions, thus triggering control mechanisms to identify and solve the problem.
Let’s take an example: Tesla receives information from its cars every day. Hundreds of thousands of cars communicate where they are traveling, the obstacles identified along the way, the engine operation. This huge amount of data (Big Data) allows to build a constantly updated map of roads and to check the presence of structural malfunctions.



A building’s Digital Twin

This same concept can even be applied to building modelling, taking advantage of BIM methodology as a new design approach to the virtual model.

As a matter of fact, different kinds of sensors with different functionalities can be installed in a building:

  • temperature sensors
  • humidity sensors
  • pressure sensors
  • air quality sensor
  • energy consumption control devices
  • brightness sensor
  • proximity tags and sensors
  • access control sensors

Such sensors could generate a considerable amount of data to be transferred in real time to the virtual building.

Additionally, when analysing all these data, the virtual building is able to define the correct functioning of the systems and of all the components in any moment, ensuring comfort and well-being.

IoT (Internet of Things) enabled devices and applications are based on the same principle. The internet of things, in fact, allows objects to communicate with each other, interact with the network and transfer data and information.

In order for the Internet of Things to work properly, it is important to process, collect and analyze large volumes of real time data (eg from sensors, traffic lights, and any connected IoT device).

Hence the need for integrated systems between big data, nosql database and IoT data.

Integrating BIM to BEM



The digital model of a building would contain not only the geometric data but also all the energy data and information, such as systems, type of insulation, opaque building envelope, glazed structures, energy supplies, climatic data, heating, cooling and ventilation aspects.

In this case we could refer to a real energetic model of the building / installation system that allows to exploit the full potential of BIM.



Thanks to the energetic model, the designer will be able to carry out the necessary analyses during the different design phases and to foresee what the real building’s performance will be once it has been built. Thus, optimal design solutions will be identified.

BEM, Building Energy Model, transfers application advantages to thermotechnics and energy performance fields, taking as input a description of a building including geometry, construction materials, and lighting, HVAC, refrigeration, water heating, and renewable generation system configurations, component efficiencies, and control strategies.

Such model leads to innovative scenarios in terms of:

  • design
  • building
  • control
  • management
  • maintenance