A JV3 assessment is a performance-based pathway used to demonstrate energy efficiency compliance for commercial buildings under Section J of the National Construction Code (NCC). JV3 involves using energy modelling software to compare the proposed building’s energy performance against a reference building designed to meet Deemed-to-Satisfy (DtS) requirements.
Below is a detailed explanation of the JV3 modelling process:
1. Data Collection: Plans, Specifications & Climate Information
Building Plans and Design
- Floor plans (building geometry and layout)
- Elevations (window types, locations, and shading details)
- Window schedules (window sizes and types)
- Site plan (nearby shading structures and building orientation)
- Electrical plans
Building Specifications and Materials
- Floor insulation, roof insulation and wall insulation
- Glazing types (tint, Low-E, double-glazing, frame material)
- HVAC systems (heating, cooling, ventilation)
- Types of lighting and shading devices
Local Climate Data
- Temperature
- Humidity
- Solar exposure
2. Reference Building Modelling (Deemed-to-Satisfy)
Creating a Reference Model
A reference building is modelled according to the Deemed-to-Satisfy (DTS) provisions outlined in Section J of the NCC. This reference model uses default standards for each building element, such as insulation, glazing, and shading, as specified in the National Construction Code (NCC).
Baseline Energy Use
The energy consumption of the reference building is calculated using the modelling software, and this serves as the benchmark for the which the proposed building will be compared.
3. Proposed Building Modelling
Modelling the Proposed Building
The proposed building is modelled based on the real-world design specifications provided by the architects and engineers. This includes the insulation, glazing, HVAC systems, and other design elements as per the construction plans.
Interaction of Building Elements
The proposed building model considers the interaction between different building components. For example, shading devices can reduce heat gain, thermal mass (stores heat) can regulate temperatures, and changes to the materials/shading can impact overall energy consumption.
Incorporation of Additional Energy-Saving Features
If necessary, energy-saving measures such as the installation of solar photovoltaic (PV) panels or the use of high-efficiency HVAC systems can be factored into the proposed model. These features can help offset energy use in other parts of the building, allowing greater design flexibility.
4. Energy Simulation
Running Simulations
Both the reference building and the proposed building undergo energy simulations using advanced software such as EnergyPlus or IES VE.
The software simulates energy usage for the entire year, accounting for various factors such as:
- Internal heat gains from occupants, lighting, and equipment
- External heat gains from solar radiation
- Heat transfer through walls, roofs, windows, and floors
- HVAC system performance and efficiency
- The effect of shading, thermal mass, and other design features
Energy Use Comparison (Greenhouse Gas Emissions)
The total energy consumption of the proposed building is compared to the reference building. This includes energy used for heating, cooling, ventilation, lighting, and other building services. The proposed building must achieve lower total Greenhouse gas emissions than the reference building.
Thermal Comfort
The proposed building must also meet preset thermal comfort targets to ensure a comfortable internal temperature is achieved for the occupants. The software will determine if the HVAC systems, insulation and glazing systems are sufficient to ensure that a comfortable temperature can be maintained. ANSI/ASHRAE Standard 55 sets out the guidelines that the simulations must following, with the Predicted Mean Vote (PMV) being the most commonly used metric to show compliance.
5. Design Optimisation (if necessary)
Adjusting the Building Design
If the proposed building’s energy consumption exceeds that of the reference building, adjustments must be made to the design to achieve compliance. This could involve:
- Better insulation in walls, floors and/or roofs
- Upgrading glazing to reduce heat transfer
- Optimising the shading strategy (shading devices, and/or eaves)
- Incorporating renewable energy sources, such as solar panels
Rerunning the Simulation
After making the adjustments, the building model is re-simulated to ensure it meets or exceeds the energy performance of the reference building.
6. Final Compliance & Report
Compliance Confirmation
Once the following criteria are met, the building is deemed compliant with the NCC:
- Proposed building’s energy use is confirmed to be lower than or equal to the reference building’s energy use; and
- The building meets the thermal comfort targets for occupancy comfort
If the building meets both criteria, it is considered to meet the NCC’s energy efficiency requirements under the JV3 pathway.
Final Report Preparation
A detailed report is then prepared, which includes:
- A description of the building
- The insulation and glazing requirements
- Requirements for HVAC systems
- Supporting results of the simulations for both the reference and proposed buildings
7. Submission to Authorities for a Building Permit
Report Submission
The JV3 report is submitted to the relevant authorities, demonstrating that the proposed building complies with the energy requirements in Section J of the NCC.
Key Factors in JV3 Modelling
- Thermal Performance of Building Materials: The ability of walls, roofs, floors, and windows to resist heat transfer (insulation and glazing performance).
- Building Geometry and Orientation: The shape, size, and orientation of the building affect solar gains and energy use.
- Shading and External Structures: The impact of shading devices and nearby buildings or structures on heat gain.
- HVAC and Lighting Systems: The efficiency of heating, cooling, and lighting systems plays a significant role in the building’s overall energy use.
- Internal Heat Loads: Heat generated by occupants, appliances, and lighting affects cooling requirements.
JV3 Assessments
The JV3 pathway allows greater design flexibility whilst ensuring compliance with the NCC’s energy requirements for commercial buildings. By using simulation software (such as EnergyPlus) to model performance, JV3 allows for trade-offs between building components and the incorporation of renewable energy.
This process ensures that compliance with the NCC is demonstrated, whilst allowing the design team greater design flexibility. Our consultants can help your design team explore these trade-offs with ease.
To order a JV3 report or to determine which energy efficiency report is best for your commercial project, talk to our experienced energy efficiency consultants today.
1300 864 944
Energy@greenchoiceconsulting.com.au
