Are you looking forward to using alternative solutions to meet the building's energy efficiency requirements or planning to get a Green Star Rating for Ecologically Sustainable Development (ESD)? 

Regardless of your choice, you will need to undertake energy modelling according to the relevant guidelines. Besides elemental provisions, you can comply with the NCC energy efficiency requirements using JV3 or JV3 Modeling solutions. 

However, sometimes, building developers aim to obtain some Green Stars as evidence of sustainable design. So, do you need to change your energy model in such a case to match the NCC guidelines? 

This article will discover the discrepancies and similarities between Green Star and JV3 Assessment energy models. 

Should You Keep Your Energy Model?

You don't have to change many modelling items when you try to assess whether your Green Star energy model complies with the NCC Section J energy efficiency requirements via JV3 or JV3 Modeling. 

These items include geometry, operating profiles, occupancy density, thermal zones, internal heat gains from appliances, the number and sizes of windows, and many more aspects of a building. 

What are the Major Changes When Migrating from Green Star to the JV3 Model?

If you desire to obtain the Section J Report while complying with the NCC energy efficiency requirements through the JV3 performance solution, you should change the following criteria:

Lighting controls

NCC and Green Star modelling guidelines don't require a reference project to install lighting control sensors. However, if control devices are suggested in the proposed project, it's recommended to look up and compare the adjustment factors within at least two references. 

It's important because the description and adjustment factors differ when comparing the two references. 

Let's understand this with the help of an example. If a building project requires a motion detector in a toilet, NCC allows for an adjustment factor of 0.4. On the other hand, Green Star allows for an adjustment factor of not more than 0.9.

Although the adjustment factors for lighting control devices, as specified by Green Star, seem more conservative, it's ideal to always check to not allow for less than the mandated value. You should always double-check only if considering undertaking JV3 Modeling. 

However, double-checking is unnecessary if you migrated your model from JV2 modelling. It is recommended that you consult building consultants for the JV3 assessment and BASIX report. 

Air quality 

Compliance with the Green Star minimum expectation for air quality requires the fresh air flow rates supplied by the ventilation system to be increased than the industry standards for non-residential buildings. The building must improve the outdoor air by 50% in each space in the regularly occupied areas. 

Although building developers can keep these increased rates for the proposed projects of Green Star and JV3 models, these increased outdoor flow rates are not allowed for the JV3 model reference project. 

You can't increase reference fresh air flow rates by more than 20% of what is required in Part F4. For example, a bar's minimum outdoor airflow rate is 10 L/s/person. According to Green Star's minimum expectation for air quality, you can go 50% more than that (15L/s/person), with NCC allowing you to go for 20% or less (12L/s/person). 

When it comes to large commercial buildings, this discrepancy between the proposed and reference project ventilation rates might create a significant gap in thermal energy compliance. In such a case, a good control strategy would be to use the CO2 sensors for demand-controlled ventilation, especially in crowded spaces. 

Final Words

Green Star and BASIX Report serve as Australia's trusted mark of quality and energy efficiency for sustainable building design, construction, and operation. 

However, no matter what energy efficiency standard you consider following, you can achieve your aim by following the appropriate energy modelling solution like JV3 modelling. 

When migrating from Green Star to JV3 modelling, you must make the above-discussed changes to design and construct energy-efficient buildings.