Extension of Stockland Green Hills Shopping Centre · EXTENSION OF STOCKLAND GREEN HILLS SHOPPING CENTRE Page 4 of 30 4. a Greenstar NCC2016 Reference Building: this model is developed

Dept of Environment & Energy Case Studies – NCC2019 Shopping Centre

Team Catalyst EXTENSION OF STOCKLAND GREEN HILLS SHOPPING CENTRE

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ISSUED 22AUG2018

Team Catalyst ACN 114 572 084 "Driving Sustainability through Teamwork" e: [email protected] m: 0417 405 478

Department of the Environment & Energy

Case Study – NCC 2019

Shopping Centre Extension

mailto:[email protected]



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CONTENTS

contents 2

1 EXECUTIVE SUMMARY ........................................................................................................... 3

1.1 DESCRIPTION .......................................................................................................... 3

1.2 METHOD ................................................................................................................... 3

1.3 RESULTS .................................................................................................................. 4

1.4 COMMENTARY ........................................................................................................ 6

1.5 DISCLAIMER ............................................................................................................ 8

2 BACKGROUND ......................................................................................................................... 9

3 CASE STUDY DESCRIPTION ................................................................................................. 10

4 METHOD ................................................................................................................................. 11

4.1 MODEL EXTENT .................................................................................................... 11

4.2 MODELS ................................................................................................................. 12

4.3 GENERAL MODELLING CRITERIA – GREENSTAR ............................................. 16

4.3.1 OPERATING SCHEDULES ..................................................................................................... 18

4.4 BUILDING FABRIC AND GLAZING ........................................................................ 19

4.4.1 (J1.3) ROOFS .......................................................................................................................... 20

4.4.2 (J1.4) ROOFLIGHTS ................................................................................................................ 21

4.4.3 (J1.6) FLOOR........................................................................................................................... 21

4.4.4 (J1.5) WALLS ........................................................................................................................... 21

4.4.5 (J2) NCC2016 GLAZING CALCULATOR ................................................................................ 22

4.5 J(1.5) NCC2019 WALL GLAZING CALCULATIONS .............................................. 24

4.1 (J1.6) LIGHTING ..................................................................................................... 26

4.2 (J1.5) HVAC SYSTEM ............................................................................................ 27

4.2.1 SYSTEM DESCRIPTION ......................................................................................................... 27

5 RESULTS ................................................................................................................................ 29



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1 EXECUTIVE SUMMARY 1.1 DESCRIPTION

This case study tests the application of the newly proposed “JV2 Green Star” verification method in the proposed NCC2019. The main requirements towards compliance using this approach require that:

• The project is registered for a GreenStar Design and As-Built rating

• Annual GHG emissions of the “Proposed” (or As Built) building are less than 90% of the “Reference” building, when simulated as per the GreenStar simulation requirements (which refer to some NCC DTS requirements), using a valid calculation method, and

• Thermal comfort is predicted to be maintained within ±1 Predicted Mean Vote (PMV) for 95% of occupied floor area for 98% of “hours of operation” for the “Proposed” building

The intent of the case study is to demonstrate how JV2 works and to identify possible changes to design practice that might be needed to comply, by comparing a Reference Building modelled as per Greenstar criteria (which refers to NCC 2019 Sections J1, J5 and J6), against a model developed based on the specifications of the “As Built” building. The newly built extension of Stockland Green Hills shopping centre, located at 1 Molly Morgan Dr, East Maitland has been modelled for this purpose. The proposed extension is a significant addition, increasing the size of the facility from approximately 30,000m2 to about 70,000m2. This project was designed to comply with a 4-star Design and As Built Green Star rating.

1.2 METHOD

The Greenstar “Energy Consumption and Greenhouse Gas Emissions Calculation Guide, May 2016” document has been used to develop the energy models for the Reference and the Proposed (As Built) runs for this case study. It is noted that the original Greenstar submission for the Stockland GreenHills Shopping Centre extension was assessed under the Green Star – Retail Centres v1 Ene-1 Energy Improvement credit and the energy modelling was carried out in line with the Green Star – Retail Centre v1 Energy Calculator Guide (April 2009). NCC2014 JV3 methodology was used to verify compliance for the Building Envelope, while services compliances was assessed using DTS provisions.

For the purposes of this case study, a simplified energy simulation model was developed based on the documentation provided for the shopping mall extension that was carried out on Ground, Upper ground, Level 1 and Cinema levels. Four variations of the simulation model were created for this case study:

1. a GreenStar NCC2019 Reference Building model: this model references the proposed DTS requirements for NCC2019

2. a Greenstar Intermediate Building model: this model tests the compliance of the proposed (As Built) façade, and is required, under the GreenStar system to perform at least as well as the GreenStar NCC2019 Reference Building

3. a Greenstar As Built Building model: this model represents the final “As Built” solution and is used to assess thermal comfort in the proposed building and also to compare its greenhouse gas emissions with the reference model.



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4. a Greenstar NCC2016 Reference Building: this model is developed to highlight the difference between the existing NCC2016 and the proposed NCC2019. Development of this model followed the same process as model 1, except that it references NCC2016

All four models were created using the same geometry, including window dimensions, shading, wall thickness, and zoning.

As per common industry practice, the building shell is delivered by the shopping centre owner (Stockland), and tenancy fitouts are carried out by the tenants. There are four (4) Major tenants at Stockland Greenhills. Two of the Majors have elected to install completely independent HVAC systems for their tenancies. The other two have elected to be supplied with chilled water and heating hot water from the base building (Stockland’s) HVAC plant, with their own air handling equipment. In all these instances the shopping centre owner is not privy to the design details for these systems. This situation is reasonably common in shopping centre developments. The GreenStar scheme deals with this situation by allowing the GreenStar submission to exclude these types of areas: the major tenancies were completely out of the scope of the original Greenstar submission, with neither their services nor their envelope being assessed.

However, NCC compliance is required for all parts of a building. In the application of the JV2 compliance method, it was possible to develop models 1 (GreenStar NCC2019 Reference Building) and 2 (GreenStar Intermediate Building) for the whole facility – including the Majors. It was not, however, possible to develop the 3rd model (the GreenStar AsBuilt Building) for the whole of the shopping centre development, since details for the HVAC systems serving the Majors are not available.

It would therefore seem that the proposed JV2 method may not be an appropriate pathway for testing compliance for large shopping centres, or indeed for any building type where the owner/developer is not responsible for specifying all of the HVAC systems and their overall control strategy. In such cases, the project maybe forced to revert to a hybrid JV3 analysis for whole of building façade compliance, in conjunction with other compliance pathways for the services.

Since the aim of the case study is to test the process for JV2 compliance, the scope of the building models was revised to be consistent with the GreenStar submission. The Majors have been excluded from all four versions of the model and the JV2 procedure has been followed for the remaining spaces – i.e. the mini-majors, speciality shops and common areas. Results for this limited study are summarised in the next section.

1.3 RESULTS

The predicted results are summarised in the table below, and can be interpreted as follows:

The predicted Annual GHG emissions from the Greenstar As Built Model is only 2% less than the GreenStar NCC2019 Reference Building. A further 8% reduction is required for the Greenstar As Built Building model to comply using the JV2 pathway. The least cost route for Stockland to comply with the proposed NCC 2019 via the JV2 route would be to offset these emissions from solar PV electricity, which they are already rolling out across their retail asset portfolio. It is estimated that 384 kW of on-site solar PV is required for compliance. Stockland is installing a 1,000 kW solar PV system at Greenhills, and compliance with the proposed NCC2019 code would be easily achieved, as shown in the results table. (It is worth noting that if the solar installation had not already been planned, the preferred solution would probably have been to show compliance using the JV3 process, which does not require a 10% margin.)



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The Greenstar Intermediate Building (modelled with the As Built façade) is predicted to emit 1% lower GHG emissions than the GreenStar NCC2019 Reference Building model, and therefore satisfies this Greenstar submission process requirement

The Greenstar NCC2019 Reference Building model is predicted to reduce GHG emissions by 46% when compared to the previous code minimum (NCC 2016), i.e., the GreenStar NCC2016 Reference Building. This result can be mainly attributed to the improvements to the minimum performance parameters for services (J5 and J6) in the Draft NCC 2019 proposal. Table 1 lists the input assumptions for both Reference Buildings and the As Built Building.

A PMV (thermal comfort) analysis was carried out for the Greenstar As Built Building model and all occupied (and conditioned) zones were predicted to lie within ±1 PMV during hours of operation. An excerpt of the results (for some of the zones) is provided in the table below.

End UsesElectricity [kWh]

Natural Gas [kWh]

Electricity [kWh]

Natural Gas [kWh]

Electricity [kWh]

Natural Gas [kWh]

Electricity [kWh]

Natural Gas [kWh]

Heating 19 709,921 19 737,201 9 255,265 15 558,713 Cooling 427,249 - 417,747 - 577,468 - 807,560 - Interior Lighting 3,442,105 - 3,442,105 - 3,441,348 - 5,044,290 - Fans 416,593 - 413,324 - 409,399 - 500,986 - Pumps 302,983 - 283,640 - 169,848 - 468,459 - Heat Rejection 71,902 - 70,940 - 76,783 - 88,358 -

Totals, kWh 4,660,851 709,921 4,627,775 737,201 4,674,855 255,265 6,909,668 558,713 Totals Electricity, GJ 16,779 16,660 16,829 24,875 Totals Natural Gas, GJ 2,556 2,654 919 2,011 Totals Electricity, kgCO2e 4,446,452 4,414,897 4,459,812 6,591,824 Totals Natural Gas, kgCO2e 131,696 136,757 47,354 103,646 Totals KgCO2e 4,578,148 4,551,654 4,507,165 6,695,469 Total GHG reduction over 2019REF -1% -2% 46%

Greenstar NCC2019 Reference Building

Greenstar NCC2019 Intermediate Building

Greenstar As Built Building




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1.4 COMMENTARY

No Clause Issue Proposed Solution

1 J5.4 Fan efficiency

Calculations are complex for the differentiation in outcomes

A simpler tabular approach for same fan motor power would be sufficient for DTS

2 J5.7 Pump Systems Calculations are complex for what is a small percentage of total static

Provide max pressure drops for DTS for specific reticulation configurations

Request calculations in specific format if proposed design solutions claims to be better than DTS

REPORT: ZONE THERMAL COMFORT FANGER MODEL PMV [] [GBCA_TENANCY OCCUPANCY]FOR: PEOPLE GROUNDFLOOR:TENANCY2AHU08Values in table are in hours.Time Bin Results

Interval Start -1.500<= -1.000<= -0.500<= 0.0000<= 0.5000<= 1.0000<= RowInterval End -1.000> -0.500> 0.0000> 0.5000> 1.0000> 1.5000> TotalTotal 0 5.5 1796 1430 418.5 0 3650

----------------------------------------------------------------------------------------------------REPORT: ZONE THERMAL COMFORT FANGER MODEL PMV [] [GBCA_TENANCY OCCUPANCY]FOR: PEOPLE GROUNDFLOOR:AHU26MALL

Interval Start -1.500<= -1.000<= -0.500<= 0.0000<= 0.5000<= 1.0000<= RowInterval End -1.000> -0.500> 0.0000> 0.5000> 1.0000> 1.5000> TotalTotal 0 4 1791.5 1360.5 494 0 3650

----------------------------------------------------------------------------------------------------REPORT: ZONE THERMAL COMFORT FANGER MODEL PMV [] [GBCA_TENANCY OCCUPANCY]FOR: PEOPLE GROUNDFLOOR:TENANCYAHU30

Interval Start -1.500<= -1.000<= -0.500<= 0.0000<= 0.5000<= 1.0000<= RowInterval End -1.000> -0.500> 0.0000> 0.5000> 1.0000> 1.5000> TotalTotal 0 0 1769 1301.5 579.5 0 3650


Interval Start -1.500<= -1.000<= -0.500<= 0.0000<= 0.5000<= 1.0000<= RowInterval End -1.000> -0.500> 0.0000> 0.5000> 1.0000> 1.5000> TotalTotal 0 0 1768 1251 631 0 3650



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No Clause Issue Proposed Solution

3 Clause 3(c)(x) of Specification JVb – Modelling Parameters

The annual greenhouse gas emissions must be calculated for the proposed building and the reference building using the same: unit capacity and sequencing for water heaters, refrigeration chillers and heat rejection equipment such as cooling towers;

This is an existing clause in NCC2016, and should be removed in the NCC2019 redrafting. It removes the possibility of taking advantage of the one significant advantage of an improved building envelope – reduced plant capacity (boilers, chillers, cooling towers, pumps and fans)

4 “Envelope” The NCC define building “envelope” quite specifically. J1.5 is applicable to “wall-glazing” construction, but refers to “envelope” in J1.5a; this is confusing and will lead to incorrect use of the proposed calculation process

It is recommended that terminology for “total system U-value” and “façade solar admittance factor” be carefully, and fully reviewed in relation to “envelope” and “wall-glazing”. The current draft is confusing.

5 “wall-glazing” for retail versus “shop display wall-glazing”

These 2 types of glazing have significantly different stringencies. These stringencies apply to a combination of opaque wall and transparent glazing. However, there is no guidance on how to apportion the opaque wall when the same façade contains both types of glazing

A clear method to be detailed of how the opaque portion of the façade is to be handled must be provide to avoid confusion when applied to practical projects



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1.5 DISCLAIMER

This research case study uses the newly proposed JV2 compliance method, and theoretically tests combinations of building fabric and HVAC systems that have resulted in one of a myriad of compliant solutions with reference to NCC Section-J and GreenStar. The results may not bear any relationship to the actual energy/GHG emissions of the project; results may not be extrapolated to other projects.



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2 BACKGROUND The Department of Environment and Energy has commissioned a series of case studies relating to the changes proposed for upgrade of Section-J for 2019. The objectives for the case studies are to “illustrate the impact of the proposed changes to the NCC, which will then be used as some communication materials for the industry. The case studies need to demonstrate compliance with the current (2016) provisions of Section J, and chronicle any variations in the design needed to meet the 2019 proposed provisions. The intent is to illustrate the practicability of the proposed changes and the ease of compliance; with a secondary intent to test and uncover any deficiencies in the Code, if any”.

Team Catalyst have been commissioned to develop three case studies:

• A large retail shopping centre addition, Class 6, Climate Zone 5

• A nine-unit boarding house complex with communal room, Class 3, Climate Zone 5, and

• A community centre that is the social hub in a retirement living village (RLV), Class 9c, Climate Zone 6

This report details the outcomes of analysing the Shopping Centre extension using the newly proposed NCC 2019 JV2 GreenStar alternate Verification method.



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3 CASE STUDY DESCRIPTION This case study deals with the extension of Stockland’s Green Hills shopping centre, located at 1 Molly Morgan Dr, East Maitland, NSW 2323.

The proposed extension is a significant addition, increasing the size of the facility from approximately 30,000m2 to about 70,000m2. The extension comprises of two levels of shopping, 2 levels of parking, a roof car park and a cinema level. The project was designed in 2014 to target a 4 star greenstar Design and As built rating.

Figure 1: Artist impression of the proposed shopping center extension



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4 METHOD 4.1 MODEL EXTENT

The Greenstar “Energy Consumption and Greenhouse Gas Emissions Calculation Guide, May 2016” document has been used to develop the energy models for the Reference and the Proposed (As Built) cases to verify compliance using JV2. It is noted that the original Greenstar submission for the Stockland GreenHills Shopping Center extension was assessed under the Green Star – Retail Centres v1 Ene-1 Energy Improvement credit and the energy modelling was carried out in line with the Green Star – Retail Centre v1 Energy Calculator Guide (April 2009). NCC2014 JV3 methodology was used to verify compliance for the Building Envelope.

A simplified energy simulation model was developed based on the documentation provided for the shopping mall extension that was carried out on Ground, Upper ground, Level 1 and Cinema levels. Four variations of the simulation model were created for this case study:

1. a GreenStar NCC2019 Reference Building model: this model references the proposed DTS requirements for NCC2019

2. a Greenstar Intermediate Building model: this model tests the compliance of the proposed (As Built) façade, and is required, under the GreenStar system to perform at least as well as the GreenStar NCC2019 Reference Building

3. a Greenstar As Built Building model: this model represents the final “As Built” solution and is used to assess thermal comfort in the proposed building and also to compare its greenhouse gas emissions with the reference model.

4. a Greenstar NCC2016 Reference Building: this model is developed to highlight the difference between the existing NCC2016 and the proposed NCC2019. Development of this model followed the same process as model 1, except that it references NCC2016

All four models were created using the same geometry, including window dimensions, shading, wall thickness, and zoning.

As per common industry practice, the building shell is delivered by the shopping centre owner (Stockland), and tenancy fitouts are carried out by the tenants. There are four (4) Major tenants at Stockland Greenhills. Two of the Majors have elected to install completely independent HVAC systems for their tenancies. The other two have elected to be supplied with chilled water and heating hot water from the base building (Stockland’s) HVAC plant, with their own air handling equipment. In all these instances the shopping centre owner is not privy to the design details for these systems. This situation is reasonably common in shopping centre developments. The GreenStar scheme deals with this situation by allowing the GreenStar submission to exclude these types of areas: the major tenancies were completely out of the scope of the original Greenstar submission, with neither their services nor their envelope being assessed.

However, NCC compliance is required for all parts of a building. In the application of the JV2 compliance method, it was possible to develop models 1 (GreenStar NCC2019 Reference Building) and 2 (GreenStar Intermediate Building) for the whole facility – including the Majors. It was not, however, possible to develop the 3rd model (the GreenStar AsBuilt Building) for the whole of the shopping centre development, since details for the HVAC systems serving the Majors are not available.



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It would therefore seem that the proposed JV2 method may not be an appropriate pathway for testing compliance for large shopping centres, or indeed for any building type where the owner/developer is not responsible for all of the HVAC systems and their overall control strategy. In such cases, the project maybe forced to revert to a hybrid JV3 analysis for whole of building façade compliance, in conjunction with other compliance pathways for the services.

Since the aim of the case study is to test the process for JV2 compliance, the scope of the building models was revised to be consistent with the GreenStar submission. The Majors have been excluded from all four versions of the model and the JV2 procedure has been followed for the remaining spaces – i.e. the mini-majors, speciality shops and common areas. Results for this limited study are summarised in the next section.

The Majors or anchor tenants areas in the GreenHills shopping centre are marked as “Retail Minimajors, Majors_GBCA” in the floor plans presented. These tenancies were excluded from the energy simulation. However, the envelope performance for the reference building includes the facade areas of the majors, as the Wall and Glazing components for each façade has to be assessed under the NCC 2019.

4.2 MODELS

To verify compliance with JV2, three energy simulation building models were developed in the DesignBuilder/EnergyPlus software suite for this case study. A fourth model was developed to verify compliance to NCC2016 using the Greenstar methodology, to provide insights regarding the Section J provisions in the draft NCC 2019 code. These models are described below:

1. NCC2019-GreenStar Reference Building: uses GreenStar “Energy Consumption and Greenhouse Gas Emissions Guide” to develop model inputs, and where it refers to NCC Section-J requirements, it uses the NCC2019 clauses. This model was developed to generate a baseline GHG prediction

2. A Greenstar Intermediate Building Model: this model was developed to test the performance of the proposed (As Built) façade. The model uses the proposed (As Built) envelope parameters and the Reference Building services (J5 and J6) parameters. This mimics the JV3 type scenario and is inbuilt in the Greenstar ENE calculator. The GHG emissions of the Intermediate building cannot be more than that of the Reference building.

3. As Built Building model (Greenstar Proposed Building): based on documentation provided. The predicted energy/GHG outcomes should be at least 10% better than the NCC2019 GreenStar Reference Building to verify compliance with section JV2

4. NCC2016-Greenstar Reference Building: developed in the same manner as the NCC2019 model above but referring to the proposed NCC2016 Section-J requirements. The results provide insights regarding the increased stringency set out in the draft NCC 2019 and its implications.

All four models were created using the same geometry, including window dimensions, shading, wall thickness, zoning, and modelling profiles were maintained.



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Figure 2: Roof Plan of the shopping mall, modelled as flat concrete roof with open carpark.



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Figure 3: Northern facade of the shopping centre including the extension

Figure 4: Western façade of the shopping center



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Figure 5: Southern Façade of the Shopping center

Figure 6: Eastern Façade of the Shopping Center extension

The architectural drawings used to develop the models are attached to the appendix.



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4.3 GENERAL MODELLING CRITERIA – GREENSTAR

The following table summarises the Greenstar modelling requirements for the HVAC plant and the building envelope that were used to develop the simulation models.



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Table 1 HVAC System Design Parameters as per Table 24, Section 14.1 of the Energy Consumption and Greenhouse Gas emissions Calculation Guide, 2016

Design Load Parameter Greenstar NCC2016 Reference Building model

Greenstar NCC2019 Reference Building model

As Built Building model

As Proposed Project As Proposed Project As per design


As Proposed Project As Proposed ProjectAs per design - Green Star Energy CalculatorGuide Appendix B


As Proposed Project As Proposed ProjectAs per design - Green Star Energy CalculatorGuide Appendix B

As per Table J6.2a (and adjusted for Room aspect ratio)

As per Table J6.2a (and adjusted for Room aspect ratio)

As per design - Green Star Energy CalculatorGuide Appendix B

As per Part F4 As per Part F4 As per design

As per Part J1 Building Fabric and Part J2 Glazing

As per Part J1 Building Fabric and Glazing As per design

As per Section JV3(d)(i)(F) As per Section JVb 2.(d) As per design

For perimeter zones,1 ACH when plant is ON1.5 ACH for all zones when plant is OFF

For all zones,0.7 ach when plant is OFF0.35 ACH all other times

0.5 ACH for perimeter zones and 0 ACH for internal zones

Operation Schedules As per As Built model As per As Built model

As per Section 14.3 of the Energy Consumption and Greenhouse Gas emissions Calculation Guide, 2016

Williamtown.rmy

4m2 / person

Tenancies 70 W + 60 WFoodcourt (seating) and Restaurants 80 W + 80 W

Speciality Retail and Mall areas 5W/m2Minimajors and Majors 40W/m2

Restaurants and Food Retail 60W/m2

Design weather conditions(summer dry bulb and wet bulb, and winter dry bulbtemperatures; solar radiation)

Room design temperature and humidity (where applicable)

Room occupant density

Occupant heat gain (sensibleand latent)

Equipment heat gain (sensible and latent)

Summer set point: 24°C dry bulb Winter set point: 21°C dry bulb

Infiltration rate

See Lighting Load Table

Lighting heat gain

Outdoor air rate 7.5l/s per person; in compliance with AS 1668.2

Building envelope

See Building Fabric and Glazing Section



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The Greenstar Intermediate building was modelled with the same parameters as the Greenstar NCC2019 Reference building except for the building envelope. The “As Built” envelope that was documented was modelled, mimicking the JV3 process to test the compliance of the façade.

The infiltration rate tabulated above is as per the Greenhouse Gas emissions calculations Guide. The proposed “As Built” building is set with the Greenstar prescribed infiltration rate, while the NCC 2019 and NCC2019 Greenstar models refer to the NCC provisions as mentioned in Table 2.

4.3.1 OPERATING SCHEDULES

The following are the operating schedules listed in section 14.3 of the energy consumption and Greenhouse gas emissions calculation guide, 2016.

0%

50%

100%

1 3 5 7 9 11 13 15 17 19 21 23

Greenstar Retail centre public spaces operational profiles - 7 day schedule

Occupancy Lighting Equipment HVAC

0%

50%

100%

1 3 5 7 9 11 13 15 17 19 21 23

Greenstar Retail centre back of house operational profiles - 7 day schedule




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4.4 BUILDING FABRIC AND GLAZING

A detailed description of the type of construction for each building element is presented in this section. The performance criteria specified in Section J1 and J2 of NCC 2016 and Section J1 of Draft NCC 2019, compared against the proposed (As Built) building envelope is summarised below.

Construction for each of these three models is listed on a separate line in the following sections. The Intermediate Building model has the same envelope performance parameters as the Greenstar Proposed “ As Built” building.

0%50%

100%

1 3 5 7 9 11 13 15 17 19 21 23

Car park and loading dock operational profiles - 7 day schedule




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4.4.1 (J1.3) ROOFS

The roof construction is primarily concrete with insulation on the underside of the roof as shown in the figures listed in this section.

Figure 7 : Concrete wall and Roof with insulation fixing details as per construction drawings provided

Table 2: NCC 2016, NCC 2019 Reference Building and Greenstar Proposed Building Roof and Ceiling construction

Roof Type Code Requirement Bridging Material Insulation (k=0.04) Thickness, mm

Total R value m2-K/W

NCC 2016 Concrete Roof with underside insulation R 4.2 none 160 R4.2NCC 2019 Concrete Roof underside insulation R 3.7 none 135 R3.7Greenstar Proposed Concrete Roof with underside insulation 150 R4.0



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4.4.2 (J1.4) ROOFLIGHTS

Table 3: Roof Light Transmittance values modelled for 2016 and 2019 Greenstar Reference Building and Greenstar Proposed Building

4.4.3 (J1.6) FLOOR

The entire ground floor conditioned area sits above a carpark. The table below summarises the floor constructions used in the three models.

Table 4: NCC 2016, NCC 2019 Reference Building and Greenstar Proposed Building Floor construction

4.4.4 (J1.5) WALLS

The wall constructions used in the NCC 2016 Greenstar Reference Building Model and the Greenstar Proposed building model are listed below. For the Intermediate building model and the Proposed building model , all external wall insulation was removed. The model was simplified as the design had allowed for only small discontinuous wall areas to be insulated.

Table 5: NCC 2016 Reference Building and Greenstar Proposed Building Wall construction

TypeRoofLight Shaft Index % of Floor Area

U ValueW/m2K SHGC

NCC 2016 Roof Light<1

5 3.4 0.34

NCC 2019 Roof Light <1 5 3.9 0.20Greenstar Proposed Roof Light

5 4 0.35

Floor Type Code Requirement for Envelope Floors

Bridging Material

Insulation (k=0.04) Thickness, mm


NCC 2016 250mm Concrete Floor with underside insulation

R 2 none 70 R2

NCC 2019 250mm Concrete Floor underside insulation

R 2 none 70 R2

Greenstar Proposed 250mm Concrete Floor

- - - R0.33

Wall Type Code Requirement for Envelope Walls

Bridging Material

Insulation (k=0.04) Thickness, mm


NCC 2016 190mm Concrete Block wall with insulation

R 2.8 none 70 R2.8

NCC 2016 200mm Concrete Wall with insulation

R 2.8 none 70 R2.8

Greenstar Proposed Wall - metal 90 R2.4



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4.4.5 (J2) NCC2016 GLAZING CALCULATOR



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Whole window solar thermal performance selections for NCC 2016 are shown in the Glazing Calculator, as presented above. Care has been taken to specify window performance combinations that are readily achievable, and a minimum number of differently performing windows are selected. The combination of windows is designed to result in a “just pass” set of selections. All of the selected combinations can be achieved with single glazed windows, with whole window U-values not needing to be any better than 6.0 W/m2-K.

It is worth noting that window systems for commercial buildings are procured differently from residential buildings. It is possible to select standard size, AFRC rated windows with WERS labels for residential buildings. Window systems for commercial buildings are more “bespoke” with the window supplier combining glass products and framing sections to achieve a specified window system performance.



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4.5 J(1.5) NCC2019 WALL GLAZING CALCULATIONS

The following tables list the wall R values derived from the draft NCC2019 combined wall glazing calculations. For the simulations, the minimum calculated R value has been set as per the Combined Wall-Window Glazing calculations table. In Table 6 : First Floor Combined Wall and Window Glazing Calculations as per J1.5(d)(i) and Table J1.5c, the left hand side section details the actual calculations for the combined wall – glazing stringency. The right-hand side section explains the construction system that was used to comply with the DTS requirements. A higher R value of R1.7 was used for the wall construction for the Greenstar NCC2019 Reference building. This is because, following Table 2b, Specification J1.2c, the minimum insulation in combination for a steel stud frame is R1.34, which when calculated for a 200mm Concrete wall with 92mm steel stud and minimum insulation resulted in a total system R value of R1.7.

Table 6 : First Floor Combined Wall and Window Glazing Calculations as per J1.5(d)(i) and Table J1.5c

Table 7: Wall and Glazing Combined calculations for Roof Lobby as per J1.5(d)(i) and Table J1.5c

Table 8: Wall and Glazing combined calculations for all other opaque facades as per Table J1.5c

Total R Value Achieved - Metal Framed Wall as per Table 2b, Specification J1.2c, NCC 2019

OrientationFirst Floor

UwindowW/m2-K

WWR target Utotal W/m2-K

R-wallm2-K/W

Wall Construction Stud Depth and spacing mm

Bridging Material

R value of bridged R1.25 Insulation

Calculated Total R Value of metal framed concrete wall including bridging

North 6.0 28% 4.3 0.3 200mm Concrete Wall 92 / 600 2mm steel 1.34 1.7

East 6.0 11% 1.4 200mm Concrete Wall 92 / 600 2mm steel 1.34 1.7South 6.0 13% 1.4 200mm Concrete Wall 92 / 600 2mm steel 1.34 1.7West 6.0 8% 1.4 200mm Concrete Wall 92 / 600 2mm steel 1.34 1.7

2.4Target U Total 4.3

Draft NCC 2019 Combined Wall -Window Glazing Calculations

North Wall total R value set to R 1 as per J1.5 (d)(iii)(A)

Calculated AWA for First Floor


OrientationRoof Lobby

Uwindow WWR target Utotal

R-wall Wall Construction Stud Depth and spacing

Bridging Material


Calculated Total R Value of metal framed concrete wall including bridging

North 3.5 50% 2.0 1.9 200mm Concrete Wall 92 / 600 2mm steel 1.51 1.9East 5.8 28% 2.0 1.9 200mm Concrete Wall 92 / 600 2mm steel 1.51 1.9West 6.0 27% 2.0 1.9 200mm Concrete Wall 92 / 600 2mm steel 1.51 1.9South 6.0 16% 1.4 200mm Concrete Wall 92 / 600 2mm steel 1.51 1.9

AWA for Roof Lobby 1.93 Target U Total 2.00



Ground and Cinema

Uwindow WWR target Utotal

R-wall Wall Construction Stud Depth and spacing

Bridging Material


Calculated Total R Value of metal framed concrete Block wall including

All Orientations 0.0 0% 1.4190 mm Concrete Block Wall

92 / 600 2mm steel1.34 1.7




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Table 9 : Façade SHGC calculated as per J1.5(d)(ii) for the four orientations for First Floor

Two tables are presented above, one tabulating the calculation methodology, while the other table is to clarify the actual SHGC number used in the NCC2019 Reference building model simulation. This is because, the calculations results in impractical and incorrect numbers as shown in the row, Shgc Façade Total. The Shgc number can only be a maximum of 0.89 for single pane clear uncoated glass. This anomaly is particularly expressed when the window to wall ratio is less than 75%.

Table 10: Façade total SHGC calculated as per table J1.5a for the four orientations of the Roof Lobby

Table 11: Actual “As Built” Glazing performance used in the Greenstar Intermediate Building and the Greenstar Proposed Building model

For the Intermediate building model and the Proposed building model, all external wall insulation was removed. The model was simplified as the design had allowed for only small discontinuous wall areas to be insulated.

First Floor North East South WestModelled SHGC 0.89 0.89 0.89 0.89

First Floor North East South WestFaçade Total 2590.0 1173.8 2331.15 1035.7Aw x Sw Total 726.0 123.5 302.0 85.5FSA 0.62 0.62 0.62 0.62Shgc Façade Total 2.21 5.89 4.79 7.51Modelled SHGC 0.89 0.89 0.89 0.89

Roof Lobby North East South WestFaçade Total 128.2 342.8 128.77 342.9Aw x Sw Total 63.5 95.5 20.0 92.0FSA 0.13 0.13 0.13 0.13Shgc Façade Total 0.26 0.47 0.84 0.48



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4.1 (J1.6) LIGHTING

Lighting power density as per the DTS provisions were applied to the two Reference cases, and the As Built (Proposed) design is also listed. These were incorporated in the respective simulation models.

Table 12: Lighting Power Density comparison for DTS provisions of NCC 2016 and draft NCC 2019 and proposed design

Retail SpaceRoom Height m Area m2 Perimeter m

Room Aspect ratio

NCC 2019 LPD W/m2

Adjusted for Room aspect Ratio W/m2

NCC 2016 LPD W/m2

Adjusted for Room aspect Ratio W/m2

Proposed Lighting LPD W/m2

Avg Tenancy 4.6 176 60 0.64 16 22 22 31 22Avg Mini Major 5 1190 138 1.72 16 16 22 22 16Avg Major 5 4795 270 3.55 16 16 22 22 16Avg Food Retail 4.6 156 50 0.68 6 8 22 30 8Carpark 2 8 2Mall Areas 16 22 8Back of House 2.5 8 2.5



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4.2 (J1.5) HVAC SYSTEM

4.2.1 SYSTEM DESCRIPTION

The HVAC system designed for the extension of the shopping centre is a water cooled, chilled water system, with gas fired boilers for heating. The air side of the HVAC system consists of air-handling units (AHUs) and some smaller fan coil units(FCUs). The AHUs have economiser cycles specified, and provide conditioned supply air to thermal zones via variable air volume (VAV) terminal units fitted with hot water reheat coils, that are ducted to diffusers.

The GreenStar documentation prescribed a number of detailed HVAC system configuration and performance requirements for the Greenstar Reference building models. These were incorporated into the simulation models. The main HVAC plant characteristics are summarised below.

The “Major” tenants have their own systems, and these are not considered within the model as discussed earlier. Therefore, the modelled systems supply the “Speciality” shops and the “Mini Major” tenants.

AHU fan efficiencies were calculated using the equation documented in Section J5.4. An extract of the table is reproduced below. It can be seen that the efficiency values lie within a small range irrespective of the size, and it is felt that a simpler approach maybe more user friendly.

The HVAC system was modelled in detail, and an extract of the plant side model schematic representation is reproduced below.

Item GreenStar Reference As Built

Number of chillers 3 4Chiller capacity ratio 15%, 45%, 45% equal sizes

Chiller design COP

NCC2016=4.2, NCC2019=5.0/5.8 for low

load/main chillers 5.5

Number of boilers 2 2Boiler efficiency NCC2016=0.85, NCC2019=0.9 0.9

motor kW a P Log P b N EfficiencyAHU name tag in model less than 10 0.85 4.56 10 1 10.5 64 0.49

more than 10 0.85 1.1 30 1.477 2.6 64 0.54AHU GROUND MALL AHU SUPPLY FAN 10.4 0.85 1.1 10.4 1.017 2.6 64 0.53AHU 38 MALL AHU SUPPLY FAN 3.4 0.85 4.56 3.4 0.527 10.5 64 0.48AHU MM203 AHU SUPPLY FAN 12.9 0.85 1.1 12.9 1.112 2.6 64 0.53AHU 42 AHU SUPPLY FAN 1.5 0.85 4.56 1.5 0.181 10.5 64 0.46AHU 30 AHU SUPPLY FAN 6.4 0.85 4.56 6.4 0.803 10.5 64 0.49AHU MM101 AHU SUPPLY FAN 5.3 0.85 4.56 5.3 0.721 10.5 64 0.48



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Figure 8: An extract of the HVAC Plant and Systems as represented in the simulation model; only two AHUs and two FCUs are shown for clarity. The Plant side has three chillers, two cooling towers and two boilers as stipulated for the Greenstar Reference building model

An example static calculation for a typical AHU used in the project is provided below. These values were incorporated into the simulation models.

Other DTS criteria that are relevant for the energy model were incorporated, eg., reheat was limited to 7.5C.

Fan Total Pressure Drop Pa comments

Heating Coil 50 2 row coilCooling coil 130 6 row coilFilter section 95 medium dirty filterDuct Length 150 measuredBends multiplier 1.4Supply sub-total 485

Return Static Duct Length 150Bends multiplier 1.4Return sub-total 210

Total Fan Static 695



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5 RESULTS Table 13: Predicted energy consumption and GHG emissions for the three scenarios

The predicted results are summarised in the table above, and can be interpreted as follows:

The predicted Annual GHG emissions from the Greenstar As Built Model is only 2% less than the GreenStar NCC2019 Reference Building. A further 8% reduction is required for the Greenstar As Built Building model to comply using the JV2 pathway. Since the building has been recently upgraded, and the HVAC system is also newly commissioned, the least cost route for Stockland to comply with the proposed NCC 2019 via the JV2 route would be to offset these emissions from solar PV electricity, which they are already rolling out across their retail asset portfolio. It is estimated that 384 kW of on-site solar PV is required for compliance. Stockland is installing a 1,000 kW solar PV system at Greenhills, and compliance with the proposed NCC2019 code would be easily achieved, as shown in the results table. (It is worth noting that if the solar installation had not already been planned, the developer would have had to show compliance using the JV3 process, which does not have this 10% margin.)

The Greenstar Intermediate Building (modelled with the As Built façade) is predicted to emit 1% lower GHG emissions than the GreenStar NCC2019 Reference Building model, and therefore satisfies this Greenstar submission process requirement

The Greenstar NCC2019 Reference Building model is predicted to reduce GHG emissions by 46% when compared to the existing code minimum (NCC 2016), i.e., the GreenStar NCC2016 Reference Building. This result can be mainly attributed to the improvements to the minimum performance parameters for services (J5 and J6) in the Draft NCC 2019 proposal.

The As Built model is predicted to generate 2% lower GHG emissions compared to the GreenStar NCC2019 Reference Building model. This indicates that current practise in the retail sector may already at the level of the proposed NCC2019 provisions. Clearly the proposed NCC2019 provisions are aligned to reflect good engineering practise for large buildings, from the point of view of services, particularly lighting and HVAC systems.

End UsesElectricity [kWh]

Natural Gas [kWh]

Electricity [kWh]

Natural Gas [kWh]

Electricity [kWh]

Natural Gas [kWh]

Electricity [kWh]

Natural Gas [kWh]

Heating 19 709,921 19 737,201 9 255,265 15 558,713 Cooling 427,249 - 417,747 - 577,468 - 807,560 - Interior Lighting 3,442,105 - 3,442,105 - 3,441,348 - 5,044,290 - Fans 416,593 - 413,324 - 409,399 - 500,986 - Pumps 302,983 - 283,640 - 169,848 - 468,459 - Heat Rejection 71,902 - 70,940 - 76,783 - 88,358 -

Totals, kWh 4,660,851 709,921 4,627,775 737,201 4,674,855 255,265 6,909,668 558,713 Totals Electricity, GJ 16,779 16,660 16,829 24,875 Totals Natural Gas, GJ 2,556 2,654 919 2,011 Totals Electricity, kgCO2e 4,446,452 4,414,897 4,459,812 6,591,824 Totals Natural Gas, kgCO2e 131,696 136,757 47,354 103,646 Totals KgCO2e 4,578,148 4,551,654 4,507,165 6,695,469 Total GHG reduction over 2019REF -1% -2% 46%


Greenstar NCC2019 Intermediate Building

Greenstar As Built Building




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A PMV (thermal comfort) analysis was carried out for the Greenstar As Built Building model and all occupied (and conditioned) zones were predicted to lie within ±1 PMV during hours of operation. An excerpt of the results (for some of the zones) is provided in the table below.

REPORT: ZONE THERMAL COMFORT FANGER MODEL PMV [] [GBCA_TENANCY OCCUPANCY]FOR: PEOPLE GROUNDFLOOR:TENANCY2AHU08Values in table are in hours.Time Bin Results

Interval Start -1.500<= -1.000<= -0.500<= 0.0000<= 0.5000<= 1.0000<= RowInterval End -1.000> -0.500> 0.0000> 0.5000> 1.0000> 1.5000> TotalTotal 0 5.5 1796 1430 418.5 0 3650

----------------------------------------------------------------------------------------------------REPORT: ZONE THERMAL COMFORT FANGER MODEL PMV [] [GBCA_TENANCY OCCUPANCY]FOR: PEOPLE GROUNDFLOOR:AHU26MALL

Interval Start -1.500<= -1.000<= -0.500<= 0.0000<= 0.5000<= 1.0000<= RowInterval End -1.000> -0.500> 0.0000> 0.5000> 1.0000> 1.5000> TotalTotal 0 4 1791.5 1360.5 494 0 3650


Interval Start -1.500<= -1.000<= -0.500<= 0.0000<= 0.5000<= 1.0000<= RowInterval End -1.000> -0.500> 0.0000> 0.5000> 1.0000> 1.5000> TotalTotal 0 0 1769 1301.5 579.5 0 3650


Interval Start -1.500<= -1.000<= -0.500<= 0.0000<= 0.5000<= 1.0000<= RowInterval End -1.000> -0.500> 0.0000> 0.5000> 1.0000> 1.5000> TotalTotal 0 0 1768 1251 631 0 3650

Documents

Extension of Stockland Green Hills Shopping Centre · EXTENSION OF STOCKLAND GREEN HILLS SHOPPING CENTRE Page 4 of 30 4. a Greenstar NCC2016 Reference Building: this model is developed