A building digital twin or a digital replica of a building is a virtual model that collects real-world information about various building structures from wireless technologies like sensors, drones and many more. In construction projects, a digital twin is used to conducts design tests, gain valuable insights and record experiences without affecting the building structure. It can also be used to improve the building’s performance during its entire life cycle, while reducing ownership costs like construction, maintenance, renovations, etc.
LEED (Leadership in Energy and Environmental Design) is a globally recognized green building certification system, which verifies that a building was designed and built by implementing strategies aiming at higher performance across metrics like energy savings, reduced emissions, indoor environmental quality, etc. LEED certification applies for all building types, commercial as well as residential.
Depending upon the different types of building projects, there are several rating systems provided under the LEED certification system. Building owners who seed LEED certification can use digital twins to simulate several design options for maximizing the credits earned under the LEED scoring system. Below are the LEED certification rating systems:
Building Design and Construction – BD+C
Interior Design and Construction – ID+C
Operations and Maintenance – O+M
Neighborhood Development – ND
Each rating system has a unique set of prerequisites and the corresponding credits based upon the building occupancy classification. A digital twin allows the building owners to compare all these design options in multiple scenarios.
LEED certification required accumulation of at least 40 points, including the prerequisites of the rating system with their corresponding credits. There are 3 main certification level awarded based on the minimum score limit:
Silver – 50 points
Gold – 60 points
Platinum – 80 points
LEED Credits with a Digital Twin
The LEED certification rating system offers the following 2 options along with technical requirements:
Prescriptive Requirement: They have very specific instructions, but the designed flexibility offered is very limited. Using only this approach, the building LEED certification can become highly expensive.
Performance-Based Approach: Since this approach doesn’t require the use of prescriptive features, it offers high design flexibility. However, a building simulation is required as proof when opting for LEED credits based on performance.
The following points are some of the simulation proofs required for the performance-based approach:
Sustainable Sites – Proof of reduced pollution reduction.
Energy and Atmosphere – Proof for validating minimum energy performance and possible optimization beyond the minimum.
Indoor Environment Quality – Simulation results for air pollutant levels for ventilation intake, construction material emission, illuminance levels of natural light.
A digital twin can also be used for improving the performance areas where LEED certification does not mention simulation modeling. Energy efficiency is one such areas where building owners can score points that contributes towards a LEED certification.
BD+C – 18 points
ID+C – 25 points
O+M – 20 points
Homes – 29 points
As mentioned above, the minimum score for LEED certification is 40 points. Thus, building owners can earn points from the energy efficiency feature alone. The combination of energy efficiency and building performance can allow owner to achieve higher certification levels (Silver, Gold or Platinum).
Design Comparison with a Digital Twin
Comparing several design options for a LEED certificate can be a time-consuming task with the conventional methods. However, a digital twin allows comparing multiple design options in a much faster and efficient way. For eg. A digital twin can simulate several configurations for HVAC systems and building envelopes to determine the configuration offering the highest energy efficiency. This in turn allows building owners to maximize the credits earned for a LEED certificate.
In most cases, building featured that improve the overall performance achieve synergy. However, in some cases, these features are mutually exclusive of each other. At design level, digital twin allows MEP engineers to eliminate the ineffective features and thus combine the features that collectively maximize the building performance. This greatly increases the chances of earning more certification credits.