Case Studies > LEED
First Steps to LEED Success: Shell and Core Project, Bagatelle Exclusives, Mauritius
| About | 5-storey office building, total floor area 6,143 m² with LEED Shell and Core certification and energy-efficient design. First LEED energy model completed in-house by Ecolution Consulting. |  |
| By | Thomas Hugo, Building Performance and Sustainability Engineer, Ecolution Consulting | |
| Location | Mauritius | |
| Category | Shell and Core LEED v4 Certification | |
| Highlights |
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This case study presents a LEED modelling project by Ecolution Consulting for Bagatelle Exclusives, a Shell and Core office building located in Mauritius. With DigiConsult serving as the LEED accredited professional, the project features high-performance glazing, efficient lighting, and a roof-mounted photovoltaic (PV) array and has achieved a 33% improvement over the LEED baseline, earning a LEED Certified rating. This summary demonstrates how DesignBuilder’s LEED/ASHRAE 90.1 tools enabled the swift and successful completion of the project.
Figure 1: The Bagatelle Exclusives building viewed from the west.
Project Overview
Bagatelle Exclusives, an office building in Mauritius, was designed and developed as a Shell and Core LEED v4 project. With Mauritius' temperate coastal climate, no heating was required. The building incorporated high-performance glazing and efficient lighting. At the time of certification, the construction of the HVAC systems in tenant office areas had not been completed, so these systems were modelled identically to the baseline building systems per ASHRAE 90.1 (2010). Lighting design for tenant areas was included in the tenant lease agreements. The project achieved a total energy cost saving of 33%, including site-generated renewables, corresponding to 14 LEED points for the Optimize Energy Performance credit.
Figure 3: Output from the Minimum Energy Performance Calculator (MEPC) reporting 14 points for the Optimize Energy Performance credit.
LEED Modelling
Ecolution Consulting conducted energy modelling for ‘Minimum Energy Performance (EAp2)’ and ‘Optimize Energy Performance (EAc2)’ using the whole-building energy simulation method. Shell and Core buildings can only achieve energy efficiency benefits for the unfinished parts of their systems if the design is embedded in signed lease agreements.
- In Phase 1, at the start of the modelling, the design and most of the building construction were already completed. Initially, with no tenant lease agreements, the project did not meet the minimum energy criteria for EAp2. The LEED modelling protocol excludes renewable energy contributions to ensure buildings achieve improved performance through passive design strategies and efficient mechanical, electrical, and plumbing systems.
- In Phase 2, adjustments were made to meet the LEED certification requirements. Efficient lighting and controls were contractually included for tenants, securing the certification and resulting in an excellent score for a Shell and Core building. While efficient VRF systems are recommended for tenants, HVAC systems were not mandated.
Modelling Preparation
Thorough preparation before starting a LEED modelling project reduces the risk of redoing work later. The three main steps below complemented each other and were prepared in parallel with a dedicated project liaison person. Having a reliable contact person within the project team enhanced the efficiency and enjoyment of this work. Preparation for the project included collecting, reviewing, and maintaining a comprehensive list of project information (Step 1). Then, LEED standards and relevant user guides were reviewed (Step 2) to help clarify any uncertainties. Lastly, DesignBuilder’s LEED modelling guide instructions were followed (Step 3).
Figure 4: Prepare for LEED modelling by collecting project information, knowing the requirements, and understanding how DesignBuilder will help you.
DesignBuilder Model and Workflow: Part 1: Proposed Building Model
The process began by modelling the proposed building using as-built documentation, following ASHRAE 90.1 and LEED requirements. Simulation inputs and results were carefully reviewed to ensure the model performed correctly after assigning systems (lighting, HVAC, DHW, etc.) and electricity tariffs. The team found DesignBuilder’s LEED toolset and guidance documents very helpful in guiding them through the process.
Figure 5: Main steps for setting up the Proposed Building model in a new LEED project
The proposed building setup required tariff analysis modelling based on the project's power purchase rates and thermal blocks as defined in ASHRAE 90.1.
Figure 6: Example of tariff charge settings.
DesignBuilder Model and Workflow: Part 2: Baseline Building Model
The next step was to create the baseline model. The embedded LEED tools automated the baseline building model and baseline ASHRAE 90.1 HVAC system generation, significantly reducing setup time for the comparative model. After the baseline building had been generated, minor adjustments were needed, especially for custom space types and HVAC control settings. The automation saved significant time, allowing more focus on exploring energy efficiency improvements, conducting rigorous QA checks, and completing the work more swiftly.
Figure 8: The baseline building model, HVAC system and MEPC report generation are automated
The MEPC report was auto-populated with model inputs and results directly from the DesignBuilder model, significantly reducing the time required for preparing the LEED submission documents. Some fields in the MEPC report required dedicated inputs and explanations to expand on the data held in the energy model.
While working on this project, the modelling team found DesignBuilder's ASHRAE 90.1 and LEED Modelling Guide’s detailed, step-by-step instructions and background information invaluable.
Conclusion
Initially, this LEED modelling project seemed daunting, but with a dedicated and professional team, comprehensive guides, and excellent modelling software, the process was smoother and more enjoyable than expected. Ecolution extends heartfelt thanks to Sarbina and her team at DigiConsult for their outstanding support and commitment, which were crucial in meeting the tight deadlines. This overview of Ecolution's LEED modelling experience with Bagatelle Exclusives demonstrates how firms can successfully navigate the challenges and uncertainties of undertaking new certification modelling projects for the first time.
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About the author Thomas Hugo is an experienced building performance engineer and an ASHRAE-qualified BEMP. At Ecolution Consulting, he led the modelling department, specialising in certification and design modelling work. Thomas studied process engineering and completed his MSc in renewable energy. He has over ten years of experience in building performance modelling with DesignBuilder. Project team: Ecolution Consulting, a sustainability consultancy based in Cape Town, South Africa, who has been greening the local and international built environment with building certifications such as Green Star, LEED & EDGE and modelling since 2011. Bagatelle was Ecolution’s first in-house LEED modelling project, with DigiConsult overseeing the certification as the LEED professionals. Contact: thomas.hugo@designbuilder.co.uk |