Willowdale Community Centre upgrade - energy · Web viewlists the total wall system U-values (after...

Dept of Environment & Energy Case Studies – NCC2019 Willowdale Community Centre

ISSUED 26MAR2018

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

Team CatalystDOCUMENT.DOCX of 35

Department of the Environment & Energy

Case Study – NCC 2019 Proposed Upgrade

Willowdale Community Centre

mailto:[email protected]


CONTENTS_Toc515023158

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

1.1 CASE STUDY DESCRIPTION AND RESULTS...............................................3

1.2 COST IMPLICATIONS.....................................................................................6

1.3 COMMENTARY...............................................................................................7

1.4 DISCLAIMER...................................................................................................9

2 BACKGROUND...............................................................................................................10

3 CASE STUDY DESCRIPTION........................................................................................11

4 METHOD.........................................................................................................................14

4.1 GEOMETRY...................................................................................................14

4.2 CONSTRUCTION SYSTEM...........................................................................16

4.2.1 (J1.3) ROOF....................................................................................................................16

4.2.2 (J1.6) FLOOR..................................................................................................................17

4.2.3 (J1.5) NCC 2016 WALL CONSTRUCTION.....................................................................19

4.2.4 (J2) NCC 2016 GLAZING CALCULATOR......................................................................20

4.2.5 (J 1.5) NCC 2019 COMBINED WALL GLAZING CONSTRUCTIONS............................21

4.3 (J 5) HVAC SYSTEM.....................................................................................25

4.4 (J 6) LIGHTING..............................................................................................27

4.5 SIMULATION PARAMETERS........................................................................28

4.5.1 MODELLING PARAMETERS.........................................................................................28

4.5.2 MODELLING PROFILES................................................................................................29

5 RESULTS AND CONCLUSIONS....................................................................................30

5.1 ENERGY/GHG EMISSIONS..........................................................................31

5.2 COST IMPLICATIONS...................................................................................31

5.2.1 LED LIGHTS...................................................................................................................31

5.2.2 WINDOW SYSTEMS......................................................................................................32

6 COMMENTARY..............................................................................................................33



1 EXECUTIVE SUMMARY1.1 CASE STUDY DESCRIPTION AND RESULTS

The Willowdale Community Centre (WCC) is the social hub of the Willowdale Retirement Living Village. The facility is a single storey structure and consists of a lounge, reception, multipurpose room, some offices and a gym. It has been classified as Class 9b under the NCC, and is located at Denham Court, Western Sydney which falls in NCC Climate Zone 6.

Table 1: Summary of Building details

Building name (if applicable) and address Willowdale Retirement Village

Owner Stockland

Developer Stockland

Builder Ware Building

Architect Integrated Design Group

Services consultants Simpson Kotzman

Leasing agent (if applicable) N/A

Client development manager

End users (if known) Retirement Village

Building classification 9b (Retirement Village Club House)

Deemed building hours of operation.

N/A

: Size Gross Floor Area - 618m2

Number of stories One

Completion date Actual

Construction cost $ 6.05 million

Proposed or achieved environmental certifications and status GreenStar

In small and medium sized building projects, similar to the Willowdale Community Centre, the building industry tries to optimise the building envelope for cost. Therefore, compliance with Section-J is usually tested using a hybrid approach. An energy simulation model is used to test building envelope performance, using DTS compliant services (HVAC and lighting systems) as per clause JV3 (a)(i)(B). For this purpose, building models that “just complied” (Reference building models) with the current 2016 DTS requirement and the proposed 2019 upgrade of NCC Section-J were developed and analysed for the Willowdale Community Centre building design. It is noted that this case study uses DTS compliant HVAC systems for all runs; therefore the impact of changes to HVAC system design and specification has not been investigated.



Four building simulation models the of Willowdale Community Centre have been developed for this case study. These are described below.

NCC 2016 Reference Building: building envelope (J1 and J2), HVAC (J5) and Lighting (J6) are compliant with NCC2016 DTS requirements. Simulation parameters used are from NCC2016. This modelling run sets the reference energy budget for NCC2016

NCC 2016 Proposed Building: building envelope parameters are as per the As Built specifications, HVAC, Lighting and simulation parameters are as per NCC2016. The predicted energy consumption should be less than (or equal to) the reference energy budget for NCC2016 for compliance

NCC 2019 Reference Building: building envelope (J1), HVAC (J5), Lighting (J6) are compliant with the proposed NCC2019 DTS requirements. Simulation parameters are also from the proposed NCC2019 draft. This run sets the reference energy and GHG emissions budget for the proposed NCC2019

Proposed Building: uses the same building envelope parameters as the NCC 2016 Proposed -Building (that is, the As Built specification), while the HVAC, Lighting and simulation parameters are as per the proposed NCC2019 draft

Run Plan NCC 2016 Reference Building

GFA 618m2

NCC 2016 Proposed Building GFA 618m2

NCC 2019 Reference building

GFA 618m2

Proposed Building GFA 618m2

Run Description

Reference building with NCC 2016 DTS compliant Envelope (J1 and J2), HVAC J5, Lighting J6 and NCC 2016 JV3 Sim Parameters

Proposed Building with As Built Specifications for Envelope, NCC 2016 DTS compliant Lighting, HVAC and NCC 2016 JV3 Sim Parameters

Reference building with NCC 2019 DTS compliant Envelope J1 , HVAC J5, Lighting J6 and NCC 2019 JVc SIM Parameters

Proposed Building with As Built Specifications for Envelope, NCC 2019 DTS compliant Lighting, HVAC and NCC 2019 JVc SIM parameters

EnergyEnd Uses kWh kWh/m2 kWh kWh/m2 kWh kWh/m2 kWh kWh/m2Heating 1,326 2.1 1,337 2.2 6,258 10.1 4,336 7.0Cooling 3,356 5.4 2,459 4.0 9,255 15.0 3,731 6.0Interior Lighting 36,558 59.2 36,558 59.2 14,145 22.9 14,145 22.9Interior Equipment 22,312 36.1 22,312 36.1 22,312 36.1 22,312 36.1Fans 1,916 3.1 1,832 3.0 5,202 8.4 2,794 4.5

- Total End Uses 65,467 105.9 64,496 104.4 57,171 92.5 47,318 76.6Total HVAC 6,597 10.7 5,627 9.1 20,715 33.5 10,861 17.6

Greenhouse Gas Emissions kgCO2-e /GJ 62,455 101.1 61,529 99.6 54,541 88.3 45,141 73.0 % over 2019 REF Allowance 15% 13% 0% -17%

-2% -17%

Section J compliance between Reference and Proposed Building for respective CODEs.

The results are tabulated in the table above and indicate that, for the case of the Willowdale Community Centre:

1. The NCC 2016 Proposed Building model (blue column) performs 2% better than the NCC 2016 Reference Building model (orange column); that is, the Proposed (or As Built) building envelope complies with the NCC 2016 Section-J

2. The NCC 2019 Reference Building model (green column) provides an annual energy budget for the proposed NCC 2019 Section-J, based on the new envelope, lighting, HVAC and simulation parameters. This budget is much lower (13 and 15%) than the predicted annual consumptions for the 2016 runs. The reduction can be seen to be substantially from predicted lighting energy use in the NCC 2019 proposed provisions

3. The Proposed Building model (yellow column) uses the As Built building envelope specifications (that just complied with the NCC2016 provisions with a 2% margin), with all other specifications based on the proposed NCC 2019 draft provisions. Comparison with the NCC 2019 Reference Building indicates that the Proposed Building model emits 17% less GHG emissions. As the difference between these two



models is only building envelope specifications, this result leads to the conclusion that proposed NCC 2019 draft provisions have resulted in a less stringent building envelope

4. The above result also predicts that a building envelope designed to NCC2016 requirements will comply with the draft NCC2019 building envelope specifications. In fact, the relaxation in stringency will allow lower performing glazing to be installed with a resultant cost saving, and potentially opens other options such as allowing the glazing area to be increased.

5. This result should not be generalised, and should be tested for other NCC Class of buildings in other climate zones. However, it does seem to indicate that reductions to GHG emissions claimed for the proposed NCC2019 draft provisions are not due to increases in stringencies relating to the building envelope, (at least for building Class 9b and climate zone 6).

6. Commentary on draft of the Code is provided in Section 6 of this document.



1.2 COST IMPLICATIONSCapital cost implications of the proposed NCC 2019 initiatives for this case study would mainly be in the areas of lighting and windows.

In the case of LED vs CFL lights, LEDs are marginally more expensive at this time, but prices are reducing steadily. It is conceivable that by the time the proposed NCC2019 legislation is implemented, LEDs will be the technology of choice. At this point, the cost differential for a standard 90mm LED downlight fitting with dimmable driver is about 2 – 4 times the cost of an CFL lamp which can fit into a standard (incandescent) lamp mount. Payback has been estimated at 3 – 5 years. Labor cost for installations of either type of downlight are comparable. LED fittings that are “IC” rated are already available in the marketplace. These fittings can have insulation installed directly over them, without the need for cutting holes in the insulation on the ceiling. This one characteristic alone would reduce heating energy consumption, by reducing heat loss from the ceiling in winter.

A review of the NCC2016 glazing calculator results (Table 5) against the window requirements required by the proposed NCC2019 in Table 9 indicates that windows would be cheaper. The effective stringency seems to have been lowered, at least for this case study building configuration (smaller building with low window-to-wall ratios, class 9b, climate zone 6). Only single glazed aluminium windows are required for compliance with the proposed NCC2019 building envelope provisions, while higher performing windows in the SW and E façade were required to comply with the provisions of the existing NCC2016. A saving of about $8,000 was estimated for this project. Single glazed windows are significantly lighter to carry, and the labour component of the installation cost would also be marginally lower. There is also the potential cost differential of wall and roof insulation; however, a quick calculation indicated that the total capital cost saving across the entire project was less than 0.01%, being only the differential cost between two R-value levels of insulation.

The newly proposed whole of façade performance calculation method (if defined carefully so as to reduce confusion, see the Commentary section) allows for performance trade-off between windows and walls, and it would be possible (indeed preferable in some instances) to reduce the wall U-value to easily achievable levels (when thermal bridging is considered) by improving window/glazing specifications to suit. It is anticipated that the market will find the economic “sweet spot” where the cost of labour and materials will be the lowest.



1.3 COMMENTARYNo Clause Issue Proposed Solution

1 J1.5(a)

(a) The thermal performance of the glazing and walls forming part of the envelope mustbe assessed—(i) together as wall-glazing construction; and(ii) in accordance with (c) or (g).

definition of “envelope” in Schedule 3 is confusing for this clause:

Envelope, for the purposes of Section J in Volume One, means the parts of a building’s fabric that separate a conditionedspace or habitable room from—(a) the exterior of the building; or(b) a non-conditioned space including—(i) the floor of a rooftop plant room, lift-machine room or the like; and(ii) the floor above a carpark or warehouse; and(iii) the common wall with a carpark, warehouse or the like.

if the whole of wall (and window) parameters are to be employed as per J1.5, then it should be applicable to the “whole façade”, irrespective of conditioned or unconditioned spaces; otherwise it may cause confusion when users are calculating the “Total System U-Value of wall-glazing construction” approach, with the façade for every unconditioned ceiling space and toilet/service areas having to be excluded from the “envelope”.

Spandrels usually span ceiling spaces that are generally unconditioned, and application of thermal bridging requirements becomes contentious.

Similar comments apply for “Façade solar admittance”

2 J1.5(d)(i)(A) Building envelope stringencies for Class 5, 6, 7, 8 and 9b located in climate zones 2 (Brisbane), 4, 5 (Sydney, Perth and Adelaide), 6 (Western Sydney, Melbourne) and 7 (Canberra, Hobart) have exactly the same values of Utotal and Façade Solar Admittance in all orientations when WWR > 20%

The clause is written in a manner that seems to be insensitive to climatic location and ignores passive solar design principles. This has some physical basis for U value (heat gain/loss due to temperature difference being insensitive to orientation) but is more difficult to reconcile for perimeter zones when WWRs become larger



No Clause Issue Proposed Solution

3 J1.6 Floor insulation clause is confusing and will result in many users installing R2.0 insulation in the floor construction. The CIBSE calculations are complicated and it is easy to make mistakes

Should be worded more clearly, or a simple alternate route (preferably tabulated) should be provided;

Clause is more complex than NCC2016

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

The annual greenhouse gas emissions must be calculated for the proposed building andthe reference building using the same:unit capacity and sequencing for water heaters, refrigeration chillers and heatrejection 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)



1.4 DISCLAIMERThis research study uses the building geometry description of the Willowdale Community Centre, and theoretically tests a combination of building fabric and other systems that resulted in one of a myriad of compliant solutions with reference to NCC Section-J. The particular compliance combination arrived at for this study may have no similarities to the as-built building. The findings of this case study may not be generalised to other buildings of similar size or configuration.



2 BACKGROUNDThe 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 9b, Climate Zone 6

This report details the outcomes of analysing the Willowdale Community Centre with the JV3 Alternate Verification compliance requirements for the existing 2016 Section-J, and then with the proposed changes for 2019.



3 CASE STUDY DESCRIPTIONWillowdale retirement village is part of Stockland’s retirement living portfolio. The Community Centre is a single storey structure and consists of a lounge, reception, multipurpose room, some offices and a gymnasium. It is the societal hub of the Willowdale retirement village, and is actively used during the day. It has been classified as Class 9b by the BCA consultant under the National Construction Code (NCC), and is located at Denham Court, Western Sydney which falls under NCC Climate Zone 6. It has been modelled as per its operation, since no profiles are provided for this class of building.

Four building simulation models the of Willowdale Community Centre have been developed for this case study. These are described below.

NCC 2016 Reference Building: building envelope (J1 and J2), HVAC (J5) and Lighting (J6) are compliant with NCC2016 DTS requirements. Simulation parameters used are from NCC2016. This run sets the reference energy budget for NCC2016

NCC 2016 Proposed Building: building envelope parameters are as per the As Built specifications, HVAC, Lighting and simulation parameters are as per NCC2016

NCC 2019 Reference Building: building envelope (J1), HVAC (J5), Lighting (J6) are compliant with NCC2019 DTS requirements. Simulation parameters are from the proposed NCC2019 draft. This run sets the reference energy budget for the proposed NCC2019

Proposed Building: uses the same building envelope parameters as the NCC 2016 Proposed Building (the As Built specification for the NCC2016 Proposed Building), while the HVAC, Lighting and simulation parameters are as per the proposed NCC2019 draft. This run is an indication of what may need to be done to an existing building to comply with the proposed NCC2019

The sections following have calculations that refer to NCC2016, NCC2019 and the Proposed Building, and these values are used to populate inputs to the models described above.



Figure 1 : Willowdale Club House

Figure 2: Site plan

Figure 3: Plan of Willowdale Community Centre



Figure 4: Elevations for Willowdale Community Centre (Top: North, Middle: South, Bottom: West)



4 METHOD4.1 GEOMETRY

A representative building model was developed in the DesignBuilder/EnergyPlus software suite. For both the NCC2016 and draft NCC2019 runs, the same geometry, including window dimensions, shading, wall thickness, zoning, and operation schedules were maintained. The building model has been simplified by removing the swimming pool area from the analysis.

Figure 5 : Layout with appropriate zoning as modelled for both the NCC 2016 and draft NCC 2019 Reference Building runs.



Figure 6 : 3D view of the Willowdale club house model including shading details from the architectural drawings.



4.2 CONSTRUCTION SYSTEMA 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 are tabulated in the following sections.

4.2.1 (J1.3) ROOFThe building design had areas which were covered with a skillion roof, and some areas covered by a pitched roof and ceiling. For both the NCC 2016 and NCC 2019 models, thermal bridging has been accounted for in the calculations.

Figure 7: Typical flat and pitched roof construction used in both the 2016 and 2019 models



Table 2 : J1.3 Roof and Ceiling Construction

Calculation TypeBridging Material

Bridging %

60mm Anticon R1.3

Insulation (k=0.04) Thickness, mm

Total R value m2-K/W

NCC 2016 Required Total R Value m2-K/W

NCC 2019 Required Total R Value m2-K/W

Proposed Building Total R Value m2-K/W

Unbridged Roof and Ceiling - - Yes 80 R 3.47 R 3.5

Bridged Roof and ceiling Timber 18 Yes 80 R 3.2

Compliance achieved for both NCC 2016 and NCC 2019

R 3.2 @ 0.7 Sol Abs

R 3.2 @ 0.4 Sol Abs

Note: The internal and external film coefficients were accounted for in the total R Value calculations.

The lower value for Solar Absorptance proposed for NCC2019 (0.4 instead of 0.7) can be considered to be an increase in stringency, and is achieved using a lighter colored roof. It is noted that architectural trends over the last few years have already moved in this direction, particularly for metal deck roofs.

4.2.2 (J1.6) FLOORA 250mm thick concrete slab on ground construction was modelled for both the NCC 2016 and NCC 2019 Reference and Proposed building models as represented in the figure below.

Figure 8: Slab on ground construction as modelled



Table 3: NCC 2016 and 2019 Reference Building Floor Construction

Calculation Type

Ground Slab Thickness, mm Required Total R Value m2-K/W

NCC 2016 Slab on Ground 250 No additional insulation required.

NCC 2019 Slab on Ground 250

As per section 3.5 of CIBSE Guide A, the calculated Uf = 0.2 W/m2-K. This complies with Table J1.6 of Draft NCC 2019, for a floor without an inslab heating or cooling system. No Additional insulation Required

Proposed Building Slab 250

No additional insulation required for compliance with NCC 2016 and NCC 2019, J1.6

Slab-on-ground construction for locations in climate zone 6 are calculated to not require any additional insulation for the building being analysed under the proposed provisions for NCC2019.



4.2.3 (J1.5) NCC 2016 WALL CONSTRUCTIONA timber framed Brick Veneer external wall construction was used for both the reference buildings. The typical construction details can be seen in the image below. The NCC 2016 Reference building was simulated without accounting for thermal bridging.

Figure 9: Typical Brick Veneer wall construction

Table 4 : NCC 2016 Reference and Proposed Building wall construction

Wall Type

Required Total System R Value m2-K/W Proposed Building

North, East and West External Envelope Walls R2.8South External Envelope Wall R2.3

Internal Envelope Walls ≤ R1.8

Compliance achieved via JV3 by improving the Glazing

Specification



4.2.4 (J2) NCC 2016 GLAZING CALCULATORTable 5 : Glazing calculator for NCC2016 reference building



Whole window solar thermal performance selections for NCC 2016 are shown in the Glazing Calculator, Table 5 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. Most of the selected combinations can be achieved with single glazed windows, with SW and E facing windows requiring double glazed configurations. Selected whole window U-values range between 2.2 and 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.

Table 6 : Proposed Building (both cases) Glazing Specification

Window TypeTotal System U ValueW/m2K SHGC

All louvred windows and roller door glazing:

6.0 0.7

All remaining glazing: 3.6 0.5

4.2.5 (J 1.5) NCC 2019 COMBINED WALL GLAZING CONSTRUCTIONSPossibly the most significant change in the proposed NCC2019 compliance methods are the manner in which walls and windows are to be analysed. In the current NCC2016, these elements are treated separately, however in the proposed NCC2019 methods, the solar-thermal performance of each façade aspect is tested in a combined manner. There are two alternative calculation methods documented in the proposed NCC2019, and Method 1 has been used for this case study.

The thermal performance of the wall and window system is to be evaluated using a “Total System U-value” using an area-based average. Table 7 lists the total wall system U-values (after accounting for thermal bridging) for wall constructions that have been derived for NCC2019 Reference Building case. The total R-value for walls with window-to-wall ratios (WWRs) less than 20% are fixed at R1.4 (West walls for this case study).



Figure 10 : Typical Brick Veneer wall construction

Table 7: NCC 2019 Reference Building Wall - Total System R Values including Thermal Bridging

Wall Orientation

Bridging Material

Bridging %

Reflective Airgap

Insulation (k=0.04) Thickness mm

Total R value m2-K/W WWR

target Utotal for Wall and Glazing

North Timber 18 Yes 40 R1.4 31% U 2.0South Timber 18 Yes 65 R1.8 42% U 2.0East Timber 18 Yes 40 R1.4 26% U 2.0West Timber 18 Yes 40 R1.4 16% -

Note: The internal and external film coefficients were accounted for in the total R Value calculations.

Calculation of the solar transmission performance for each façade aspect is more complex. The proposed NCC2019 code limits the “Façade Solar Admittance” for each façade aspect, which considers the dimension of each individual window, a Shading Multiplier, the SHGC of each window and the total area of the wall-glazing construction. We have back calculated the limiting SHGC for windows (glazing) in each orientation, since all other parameters are known. The results are detailed inTable 8. The resultant limiting SHGC for each orientation is tabulated in the last column of Table 8. Overall results, paired with a practical U-value for the glazing in each façade of the NCC reference building, are summarised in Table 9 for the nominal North, South, East and West orientations.



Table 8: Detailed calculation for wall-window solar performance for façade aspect in the four orientations required for NCC2019. “Aw” is the total window area per wall. P, H and G are the shading geometry characteristics, as defined in Figure J1.5 of the NCC.

Total Window Area

Window Height P H G P/H G/H

Sw- Shading Multiplier from Table J1.5e Aw * Sw

Wall Area

FSA (Façade Solar Admittance) Limiting Value from Table J1.5c

SHGC = FSA x Total Wall Area / sum(Aw x Sw)

Games Entrance 4.32 2.4 0 0 1.0 4.3

High Level Window x 11 12.1 1.2 1.9 1.4 0.2 1.4 0.2 0.5 5.7High Level Window 1.2 1.2 1.9 1.4 0.2 1.4 0.2 0.5 0.6Reception Window 2.9 2.9 0.0 0.0 1.0 2.9Lobby Windows x 3 7.3 2.7 4.0 2.7 0.0 1.5 0.0 0.4 2.6Village Manager x 3 4.1 2.7 0.0 0.0 1.0 4.1Multipurpose x 5 10.8 2.7 0.6 2.7 0.0 0.2 0.0 0.8 8.6Library 2.5 1.0 0.0 0.0 1.0 2.5Totals 31.2 172 0.13 0.72

Office 2.7 1.5 0.0 0.0 1.0 2.7Well Being 2.7 1.5 0.0 0.0 1.0 2.7Hairdressing 1.9 1.2 0.0 0.0 1.0 1.9Gym 3.8 2.7 1.0 3.8

Library 2.7 1.0 0.0 0.0 1.0 2.7Reception 21.4 4.3 9.0 4.3 0.0 2.1 0.0 0.4 7.5Sales Office 3.8 4.3 9.0 4.3 0.0 2.1 0.0 0.4 1.3Totals 22.6 93.9 0.13 0.54

Corridor Entrance 11.0 2.7 1.0 2.7 0.0 0.4 0.0 0.6 7.1Gym 3.8 2.7 0.0 0.0 1.0 3.8

Multipurpose 7.2 2.4 10.0 2.7 0.3 3.7 0.1 0.4 2.9Lobby Window 1 2.7 2.7 4.0 2.7 0.0 1.5 0.0 0.4 0.9Lobby Window 2 7.2 2.4 4.0 2.7 0.3 1.5 0.1 0.4 2.9Lobby Window 3 2.4 1.5 4.0 2.1 0.6 1.9 0.3 0.6 1.4Totals 18.9 113 0.13 0.77

Circulation 1.1 1.0 0.0 0.0 1.0 1.1

Lobby x 4 19.6 2.7 1.4 3.6 0.9 0.4 0.3 0.9 17.4Totals 18.5 123 0.13 0.86

North East (Wall Azi 26°)

North (Wall Azi 356°)

North West (Wall Azi 296°)

West (Wall Azi 266°)

NCC 2019 North Wall SHGC = 0.77

NCC 2019 North Wall SHGC = 0.86

South (Wall Azi 175°)

South West (Wall Azi 206°)

South East ( Wall Azi 116°)

East ( Wall Azi 86.1°)

NCC 2019 East Wall SHGC = 0.72

NCC 2019 South Wall SHGC = 0.54



Table 9: Summary of window performance parameters by orientation for the proposed NCC2019 Reference building, calculated as per section J1.5. Note: Acronyms are defined in Table 8. Aw*Sw is the sum of the product of the window area and shading multipliers, for each cardinal orientation.

Orientation Aw*SwWall

area m2

FSA limit (Table J1.5c)

SHGC limit

U-value W/m2-K WWR

North 18.9 112.8 0.13 0.77 4.9 31%South 22.6 93.9 0.13 0.54 4.0 42%East 31.2 171.9 0.13 0.72 5.7 26%West 18.5 123.2 0.13 0.86 5.8 16%

From Table 9 above it is clear that single pane window systems with metal frames are all that are required to pass the NCC2019 J1 stringencies for this case study building.



4.3 (J 5) HVAC SYSTEMIn practise, for buildings of this size and class, a “hybrid” compliance approach is typical, and this will continue to be the case for the draft NCC 2019. In this “hybrid” compliance process, the JV3 method is used to optimise the façade, with a DTS compliant HVAC system modelled. No HVAC configuration changes are made between reference and proposed building model runs; such a procedure proves compliance of the building envelope. The HVAC (and lighting) contractor then provides a Section-J compliance certification via the DTS route for their design.

For this case study a series of DTS compliant, reverse cycle electric heat pumps have been modelled, one system per thermal zone as shown in the schematic in Error: Reference source not foundFigure 11. This HVAC configuration is referred to as a Packaged Terminal Heat Pump (PTHP) in the EnergyPlus (USDOE) energy simulation calculation engine. Since the COPs for this size of equipment is governed by MEPS (Minimum Energy Performance Standards), these values are the same for both the NCC2016 and proposed NCC2019 runs at this time.

The system schematic shows an outside air section, Direct eXpansion (DX) cooling and heating coils, a fan section, and an electric defrost/heating coil. Figure 12 to Error: Reference source not foundFigure 14 are screen captures of the detailed input required. The system uses electricity for both heating and cooling, and is common in buildings of this size, in this climate zone.

A summary of important clauses in Section J5 considered for DTS compliance of the DX (PTHP) system (for the proposed NCC2019 clauses) are discussed below:

Each zone can be individually controlled by its system; the thermostat is set to 21C for heating and 24C for cooling; there is no mixing of hot and air streams, nor is reheating applicable for this system configuration; the individual PTHP sizes are well below that required for economy cycle (varying from less than 1 kW to about 4 kW), so only minimum fresh air is modelled; being a packaged system a constant speed fan is modelled. No pumping or water based requirements need be considered. No ducting requirements were considered as each DTS compliant DX system was modelled as having an in-room fan coil unit that delivers conditioned air directly into the space, without any ducting. The only consideration really is to ensure that the fan wire-to-air efficiencies meet or exceed the J5.4 requirements, using the equation in clause (b) (ii), and the MEPS compliant systems modelled were calculated to comply with DTS requirements.

The systems were autosized for each run based on a selected set of monthly design day temperatures and coincident wet bulb temperatures. Part load performance curves adjust the efficiency of the PTHP system based on capacity, as well as on supply air and environmental conditions.

The As Built HVAC systems in the building are similar to the DTS (PTHP/DX) systems that were modelled. They are 3 pipe VRV/VRF systems (reverse cycle heat pumps). However, some units are ducted 4 way supply FCUs. These systems have not been modelled as the focus on this case study has been on compliance of the building envelope. DTS compliance for the As Built systems would have been provided by the mechanical contractor. A separate case study (on shopping centre) will provide details on HVAC system compliance for the proposed NCC2019.



Figure 11: PTHP/DX System as represented in DesignBuilder / EnergyPlus

Figure 12 : DX Cooling Coil Inputs for all cases



Figure 13 : PTHP component input detail for all cases

Figure 14: Supply Fan Inputs for all cases

4.4 (J 6) LIGHTINGAs noted earlier, the focus of this case study is on testing compliance of the building envelope using a “hybrid” JV3 approach. Therefore, the lighting system design is not considered for this case study. However, the lighting power densities allowed under the respective codes have been input to the respective NCC reference building models for the purpose of testing building envelope compliance.

A summary of the lighting power density calculations for both NCC2016 and proposed NCC2019 codes is listed in Table 10 after adjustments for the room aspect ratio. Lighting



adjustment factors are not considered for either building model, as the lights are assumed to be manually switched as was generally the case for the proposed design.

Table 10: Lighting Power Density comparison for DTS provisions of NCC 2016 and draft NCC 2019

Room TypeRoom Height Area Perimeter

Room Aspect ratio

NCC 2016 nominal LPD

Adjusted for Room aspect ratio (simulated)

NCC 2019 nominal LPD

Adjusted for Room aspect ratio (simulated)

Reception 4.7 68.6 39.3 0.37 10 16.0 3 4.8Multi Purpose (High) 4.7 18.0 21.0 0.18 10 17.8 3 5.3Circulation 4.7 58.0 40.0 0.31 8 13.3 2.5 4.1Lounge 4.7 68.1 31.6 0.46 10 15.3 3 4.6Library 2.7 18.4 16.0 0.42 10 15.6 4.5 7.0Multi Purpose (Low) 2.7 31.0 23.6 0.49 10 15.1 3 4.5Village Manager 2.7 21.6 17.6 0.46 9 13.8 4.5 6.9Mail Room 3.9 18.0 22.3 0.21 9 15.8 4.5 7.9Servery 3.9 25.2 20.8 0.31 8 13.3 3 5.0Sales Office 3.9 20.0 17.2 0.30 9 15.0 4.5 7.5office 2.7 18.9 17 0.41 9 14.1 4.5 7.1Wellbeing 2.7 16.1 15 0.40 9 14.2 4.5 7.1Circulation 1 2.7 62.0 73 0.31 8 13.2 2.5 4.1Circulation 2 2.7 16.6 22.6 0.27 8 13.5 2.5 4.2Hairdressing 2.7 16.8 16.4 0.38 9 14.4 4.5 7.2Gym 2.7 32.5 22.8 0.53 10 14.8 3 4.4Pool and Equip 2.7 60.0 37.2 0.60 5 7.2 1.5 2.1Games 2.7 30.3 22 0.51 10 14.9 3 4.5Kitchen 2.7 18.0 18.8 0.35 8 12.9 3 4.9

The calculations in Table 10 show that LPD values for the proposed NCC2019 are much more stringent than in NCC2016, and will result in a significant reduction in GHG emissions from the NCC2019 Reference building model.

4.5 SIMULATION PARAMETERS4.5.1 MODELLING PARAMETERS

Table 11 captures the differences and similarities for many of the internal load and operational inputs to the simulation model between the existing NCC 2016 clauses and those proposed for the draft NCC 2019, as applicable to this case study.

In summary, infiltration rates have been reduced, thermostat settings for cooling and heating have been tightened (to reflect practise). Equipment and occupant loads are the same for both codes.



Table 11: Comparison between DTS provisions of NCC 2016 and proposed NCC 2019

Building Element NCC 2016 DTSModel Input NCC 2016 Reference building Draft NCC 2019 DTS

Model Input NCC 2019 Reference Building

Equipment 5W/m2 averaged; 8760 h y 5W/m2 averaged ; 8760 h yOccupancy 75W &55W y 75W & 55W yDensity 10m2 / person y 10m2 / person y

Infiltration

1.5ACH when plant is OFF in all zones1 ACH for perimeter zones and 0 for center zone when plant Is ON y

0.7 ACH when plant is OFF for all Zones0.35 ACH when plant is ON for all zones y

Thermostat18 to 26 to all conditioned zones y 18-25 to transient zones y

21-24 to all other zones ySchedules User Schedule y User Schedule y

4.5.2 MODELLING PROFILESAs no modelling profiles are described in either code for Class 9b – communal building within an aged care accommodation – they have been developed based on the actual building operation, and are used for NCC2016 and proposed NCC2019 building models. These modelling profiles are depicted in Figure 15

0%

20%

40%

60%

80%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Weekday Occ Weekend Occ Lighting All DaysHVAC All Days Equipment All Days

Figure 15 : User defined modelling profiles, based on actual building operation, used for both the NCC 2016 and draft NCC 2019 Reference Buildings (all simulation runs for this case study report use these profiles)



5 RESULTS AND CONCLUSIONSTable 12: Modelled results for Willowdale Community Centre project

Run Plan NCC 2016 Reference Building

GFA 618m2

NCC 2016 Proposed Building GFA 618m2

NCC 2019 Reference building

GFA 618m2

Proposed Building GFA 618m2

Run Description

Reference building with NCC 2016 DTS compliant Envelope (J1 and J2), HVAC J5, Lighting J6 and NCC 2016 JV3 Sim Parameters

Proposed Building with As Built Specifications for Envelope, NCC 2016 DTS compliant Lighting, HVAC and NCC 2016 JV3 Sim Parameters

Reference building with NCC 2019 DTS compliant Envelope J1 , HVAC J5, Lighting J6 and NCC 2019 JVc SIM Parameters

Proposed Building with As Built Specifications for Envelope, NCC 2019 DTS compliant Lighting, HVAC and NCC 2019 JVc SIM parameters

EnergyEnd Uses kWh kWh/m2 kWh kWh/m2 kWh kWh/m2 kWh kWh/m2Heating 1,326 2.1 1,337 2.2 6,258 10.1 4,336 7.0Cooling 3,356 5.4 2,459 4.0 9,255 15.0 3,731 6.0Interior Lighting 36,558 59.2 36,558 59.2 14,145 22.9 14,145 22.9Interior Equipment 22,312 36.1 22,312 36.1 22,312 36.1 22,312 36.1Fans 1,916 3.1 1,832 3.0 5,202 8.4 2,794 4.5

- Total End Uses 65,467 105.9 64,496 104.4 57,171 92.5 47,318 76.6Total HVAC 6,597 10.7 5,627 9.1 20,715 33.5 10,861 17.6

Greenhouse Gas Emissions kgCO2-e /GJ 62,455 101.1 61,529 99.6 54,541 88.3 45,141 73.0 % over 2019 REF Allowance 15% 13% 0% -17%

-2% -17%

Section J compliance between Reference and Proposed Building for respective CODEs.

Table 12 is a listing of predicted performance for four modelled building configurations. These are:

NCC 2016 Reference Building: building envelope (J1 and J2), HVAC (J5) and Lighting (J6) are compliant with NCC2016 DTS requirements. Simulation parameters used are from NCC2016. This modelling run sets the reference energy budget for NCC2016

NCC 2016 Proposed Building: building envelope parameters are as per the As Built specifications, HVAC, Lighting and simulation parameters are as per NCC2016 The predicted energy consumption should be less than the reference energy budget for NCC2016 for compliance

NCC 2019 Reference Building: building envelope (J1), HVAC (J5), Lighting (J6) are compliant with the proposed NCC2019 DTS requirements. Simulation parameters are also from the proposed NCC2019 draft. This run sets the reference energy and GHG emissions budget for the proposed NCC2019

Proposed Building: uses the same building envelope parameters as the NCC 2016 Proposed Building (that is, the As Built specification for the NCC2016 Proposed Building), while the HVAC, Lighting and simulation parameters are as per the proposed NCC2019 draft. This run is an indication of what may need to be done to an existing building to comply with the proposed NCC2019



5.1 ENERGY/GHG EMISSIONSThe results are tabulated in the table above and indicate that, for the case of the Willowdale Community Centre:

1. The NCC 2016 Proposed Building model (blue column) performs 2% better than the NCC 2016 Reference Building model (orange column); that is, the Proposed (or As Built) building just complies with the building envelope provisions of NCC 2016 Section-J

2. The NCC 2019 Reference Building model (green column) provides an annual energy budget for the proposed NCC 2019 Section-J, based on the new envelope, lighting, HVAC and simulation parameters. This budget is much lower (13 and 15%) than the predicted annual consumptions for the 2016 runs. The reduction is substantially due to the increased stringency in the NCC 2019 proposed lighting provisions

3. There is a predicted 15% reduction in GHG emissions between the NCC 2019 Reference Building (green column) and the NCC 2016 Reference Building (orange column). This is a pleasing result, indicating that application of the proposed NCC2019 requirements would reduce GHG emissions from buildings similar to Willowdale Community Centre in climate zone 6, which includes Western Sydney and Melbourne, both heavily populated areas in Australia

4. The Proposed Building (yellow column, modelled with the as-built envelope and DTS lighting, HVAC and simulation parameters as proposed for NCC 2019) comfortably complies with the NCC 2019 energy budget. Since this envelope is unchanged from the “NCC 2016 Proposed Building Run”, which only just complied with the envelope provisions of NCC 2016, this indicates that proposed NCC 2019 provisions have resulted in a less stringent building envelope compared with NCC 2016.

5. The above result also predicts that building envelopes designed to NCC2016 requirements will comply with the draft NCC2019 building envelope specifications. This result should not be generalised, and should be tested for other NCC Class of buildings in other climate zones. However it does seem to indicate that reductions to GHG emissions claimed for the proposed NCC2019 draft provisions are not due to increases provisions relating to the building envelope, (at least for building Class 9b and climate zone 6).

6. It is noted that this case study uses reference HVAC systems for all runs; therefore the impact of changes to HVAC system design and specification has not been investigated

5.2 COST IMPLICATIONSCapital cost implications of the proposed NCC 2019 initiatives for this case study would mainly be in the areas of lighting and windows.

5.2.1 LED LIGHTSIn the case of LED vs CFL lights, LEDs are marginally more expensive at this time, but prices are reducing steadily. It is conceivable that by the time the proposed NCC2019 legislation is implemented, LEDs will be the technology of choice. At this point, the cost differential for a standard 90mm LED downlight fitting with dimmable driver is about 2 – 4 times the cost of an CFL lamp which can fit into a standard (incandescent) lamp mount. Payback has been estimated at 3 – 5 years. Labor cost for installations of either type of downlight are comparable. LED fittings that are “IC” rated are already available in the marketplace. These fittings can have insulation installed directly over them, without the need for cutting holes in



the insulation on the ceiling. This one characteristic alone would reduce heating energy consumption, by reducing heat loss from the ceiling in winter. (However, these savings are not represented in this case study as the overall level of roof insulation is assumed to be similar in both of the “proposed” building runs).

5.2.2 WINDOW SYSTEMSA review of the NCC2016 glazing calculator results (Table 5) against the window requirements required by the proposed NCC2019 in Table 9 indicates that windows would be cheaper. The effective stringency seems to have been lowered, at least for this case study building configuration (smaller building with low window-to-wall ratios, class 9b, climate zone 6). Only single glazed aluminium windows are required for compliance with the proposed NCC2019 building envelope provisions, while higher performing windows in the SW and E façade were required to comply with the provisions of the existing NCC2016. A saving of about $8,000 was estimated for this project. Single glazed windows are significantly lighter to carry, and the labour component of the installation cost would also be marginally lower. There is also the potential cost differential of wall and roof insulation; however a quick calculation indicated that the total capital cost saving across the entire project was less than 0.01%, being only the differential cost between two R-value levels of insulation.

The newly proposed whole of façade performance calculation method (if defined carefully so as to reduce confusion, see the Commentary section) allows for performance trade-off between windows and walls, and it would be possible (indeed preferable in some instances) to reduce the wall U-value to easily achievable levels (when thermal bridging is considered) by improving window/glazing specifications to suit. It is anticipated that the market will find the economic “sweet spot” where the cost of labour and materials will be the lowest.



6 COMMENTARY


1 J1.5(a)

(a) The thermal performance of the glazing and walls forming part of the envelope mustbe assessed—(i) together as wall-glazing construction; and(ii) in accordance with (c) or (g).

definition of “envelope” in Schedule 3 is confusing for this clause:

Envelope, for the purposes of Section J in Volume One, means the parts of a building’s fabric that separate a conditionedspace or habitable room from—(a) the exterior of the building; or(b) a non-conditioned space including—(i) the floor of a rooftop plant room, lift-machine room or the like; and(ii) the floor above a carpark or warehouse; and(iii) the common wall with a carpark, warehouse or the like.

if the whole of wall (and window) parameters are to be employed as per J1.5, then it should be applicable to the “whole façade”, irrespective of conditioned or unconditioned spaces; otherwise it may cause confusion when users are calculating the “Total System U-Value of wall-glazing construction” approach, with the façade for every unconditioned ceiling space and toilet/service areas having to be excluded from the “envelope”.

Spandrels usually span ceiling spaces that are generally unconditioned, and application of thermal bridging requirements becomes contentious.

Similar comments apply for “Façade solar admittance”

2 J1.5(d)(i)(A) Building envelope stringencies for Class 5, 6, 7, 8 and 9b located in climate zones 2 (Brisbane), 4, 5 (Sydney, Perth and Adelaide), 6 (Western Sydney, Melbourne) and 7 (Canberra, Hobart) have exactly the same values of Utotal and Façade Solar Admittance in all orientations when WWR > 20%

The clause is written in a manner that seems to be insensitive to climatic location and ignores passive solar design principles. This has some physical basis for U value (heat gain/loss due to temperature difference being insensitive to orientation) but is more difficult to reconcile for perimeter zones when WWRs become larger




3 J1.6 Floor insulation clause is confusing and will result in many users installing R2.0 insulation in the floor construction. The CIBSE calculations are complicated and it is easy to make mistakes

Should be worded more clearly, or a simple alternate route (preferably tabulated) should be provided;

Clause is more complex than NCC2016

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

The annual greenhouse gas emissions must be calculated for the proposed building andthe reference building using the same:unit capacity and sequencing for water heaters, refrigeration chillers and heatrejection 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)


Willowdale Community Centre upgrade - energy · Web viewlists the total wall system U-values (after...

Documents

Transcript of Willowdale Community Centre upgrade - energy · Web viewlists the total wall system U-values (after...