Council House 2 (CH2) in review€¦ · HEX 4 Retail PACs HEX 7 HEX 8 Microturbine heat recovery...
Transcript of Council House 2 (CH2) in review€¦ · HEX 4 Retail PACs HEX 7 HEX 8 Microturbine heat recovery...
ECOLI BR I U M • MARCH 201444
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Council House 2 (CH2) in reviewMatthew Hoogland, M.AIRAH, Exergy Australia; and Dr Paul Bannister, M.AIRAH, Exergy Australia
ABSTRACTCouncil House 2 (CH2) is the City of Melbourne’s flagship building for sustainability. The building showcases a number of innovative technologies and has attracted recognition with numerous environmental awards. But how does the building actually perform and what lessons does it have for the broader industry? The City of Melbourne was asking these questions when they invited Exergy to conduct a review of the building’s energy efficiency performance in July 2012.
Exergy’s review focused on the operation of the building’s various systems, including passive chilled beam, tri-generation, thermal storage phase-change material, shower towers and more. Key issues identified mainly pertained to the HVAC commissioning and control strategies applied to these systems not only in isoaltion, but in the complex web in which they come together.
The City of Melbourne is now in the process of implementating the first stage of measures with calculated potential to reduce energy consumption by 25%. Crucial to the success of this project will be a staged process of implementation and measurement to determine how best the building’s systems can complement each other in various modes of operation.
INTRODUCTIONOfficially opened in August 2006, CH2 was Australia’s first 6 star Green Star – Design building, and showcases a number of sustainable building features. The building was designed to set new standards for low energy and high occupant comfort, bringing together a range of innovative technologies not only for the benefit of those to work in it, but also to serve as a sounding board for the broader industry.
But how does the building actually perform? With doubt that the building was achieving its ambitious targets, the City of Melbourne invited Exergy to undertake a review of the building’s energy efficiency performance in July 2012, providing an opportunity to review the performance of the innovative and experimental design features of the building.
The aims of the project were to:
• Quantify the existing performance of the building against NABERS1 Energy benchmarks
• Identify issues impeding energy efficiency performance
• Detail measures to improve the NABERS Energy rating
• Identify lessons that can be learnt from CH2.
The review was based on the findings of a whole building level 2 energy audit conducted by Dr Paul Bannister, M.AIRAH; Matthew Hoogland, M.AIRAH; and Ben Carmichael of Exergy Australia as per the requirements of AS/NZS 3598:2000.
Note that the scope of the review was predominantly targeted at identifying energy efficiency measures to improve the NABERS Energy performance of the building. We acknowledge that there are numerous features of interest within the building. However, in general, our investigation only went as far as that required to improve the efficiency of the core systems that the energy audit revealed to be making a significant impact on the building’s consumption. As such, detailed investigation of the peripheral features of the building such as renewable power sources and automated shading systems were not covered. We also note that water efficiency and indoor environment quality were not included in the scope of the review.
BUILDING FEATURESThe features of CH2 that were intended to contribute to high-level energy performance are listed below. Note that we have divided the features according to the significance with which we observed them having to the building’s current performance:
• Core features:
– Passive chilled beam cooling
– Tri-generation
– Hydronic radiant heating
– Extensive heat transfer and recovery between water loops
– Phase-change material tanks for thermal storage.
• Peripheral features:
– Building integrated wind power
– Solar PV and domestic hot water
– Shower towers
– Electronically actuated windows and shading
– Daylight harvesting.
At the time of CH2’s construction most of these technologies were far from common within Australia’s commercial building industry. And while chilled beam technology and tri-generation systems have since become more widespread, features such as the shower towers and phase-change storage tanks are still relatively uncommon among Australia’s commercial building stock.
Of the building’s array of technologies, arguably most technically significant is the extensive potential for heat transfer between the seven distinct water loops. A water schematic of the site’s servicing is presented in Figure 2. Among others, heat exchangers can be observed between the domestic hot water system and the primary heating water system, the primary heating water system and the primary condenser water system, the primary condenser water system and the supplementary condenser water system, and the supplementary condenser water system and the primary heating water system. Although none of these processes in isolation are particularly unusual, their summation equates to a system of unusual potential and complexity.
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The complexity of CH2’s design, coupled with the industry’s general lack of familiarity with its features has proven to be one of the key challenges for the building’s operation.
Figure 1: CH2 west facing facade (from Swanston St).
Table 1: Heat exchanger (HEX) legend corresponding to Figure 2.
H
H
H
H
C C
C C
CC
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C
C
C
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H HCC
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C
C C
C
C
H
Primary CHW loop
Secondary CHW loop
HHW loop
Shower tower loop
Primary CDW loop
Chilled beam loop
Tenant CDW loop
Heat flow
Cool flow
Boilers
AHUs
Showertowers
L1-9chilled beams
L1-9heating
convectors
L1-9CDW
DHWHEX
PCMtanks
HEX 5
HEX 6
HEX 3
HEX 1
HEX 2
HEX 4
Retail PACs
HEX 7
HEX 8
Microturbineheat recovery
Absorptionchiller
Cooling towers
Screwchillers
Figure 2: Simplified water schematic of HVAC services for CH2, demonstrating the diverse array of water loops and the heat transfer potential between them. Note that each line represents a flow and return path. See HEX legend in Table 1.
Unit Description
HEX-1 HEXtotransfercoolthfromtheprimaryCHWtosecondaryCHW
HEX-2HEXfortransferbetweenthecoolingtowersandthesupplementaryCDWsystem
HEX-3 HEXforheatrecoveryfromtheprimaryCDWreturntoairsideheating
HEX-4HEXforheatinjectionintothesupplementaryCDWsystem(forreverse-cyclePACs)
HEX-5HEXfortransferofcoolthfromtheshowertowerstothechilledbeamnetwork
HEX-6HEXfortransferofcoolthtopre-coolthesecondaryCHWreturnafteritspaththroughHEX-7and/orHEX-8
HEX-7
HEXfortransferofcoolthfromthesecondaryCHWsystemtoeitherofthechilledbeamnetworkdirectlyorviathePCMtanks(paralleltoHEX-8)
HEX-8
HEXfortransferofcoolthfromthesecondaryCHWsystemtoeitherofthechilledbeamnetworkdirectlyorviathePCMtanks(paralleltoHEX-7)
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CURRENT ENERGY PERFORMANCEThe actual energy performance of CH2 does not currently meet the high standard of its design. Our analysis revealed the whole building NABERS Energy performance of the building to be 4.08 stars. With the aid of data obtained from the floor-by-floor sub-metering system we were able to drill down to investigate the weighting of the base building and tenancy on the whole building performance. Our analysis found the base building to be performing at 3.24 stars NABERS. With several major property owners in Australia now reporting average portfolio ratings of 4.5 stars or higher, this is well below the current industry standard for good performance2. At 3.24 stars, the emissions attributable to CH2’s base building services are 68% greater than what they would be if the base building was performing at 4.5 stars.
ENERGY CONSUMPTION ANALYSISInterval data was obtained for the office building’s sole electrical utility meter. The analysis revealed unusual variation in the base load over weekdays and seasons, as presented in Figure 3. With minimal occupation of the building outside of business hours, these observations were tell-tale signs that there may have been frequent HVAC operation occuring outside of the operational hours of the building.
Site inspections were conducted over a course of several months and at various times of the day and night to observe the building in its different modes of operation. The end-use breakdown is presented in Figure 4 as constructed according to the findings of the site inspections. A Sankey flow diagram (Figure 5) was
also produced to help illustrate the diversity of energy sources and complementary systems within the building.
It is noted that the sub-metering system could not significantly inform the breakdown of base building services due to inadequate coverage and poor data quality from some meters.
KEY ISSUESThe key issues preventing CH2 from realising its potential were found to be in the strategies and commissioning of its HVAC controls. Widespread opportunities for optimising control were observed and could broadly be categorised into three groups:
• Priority of cooling modes. One way in which CH2 is unlike most buildings is that it has several different ways of generating cooling to provide to the floors. The source of cooling can either be via absoprtion chiller heat recovery
Whole building NABERS
rating
Estimated base
building NABERS
rating
Estimated tenancy NABERS
rating
Date range
1/7/11to30/6/12
1/7/11to30/6/12
1/7/11to30/6/12
Electricity (kWh) 971,270 571,292 399,978
Gas (MJ) 5,133,122 5,133,122 0
Diesel (Litres) 0 0 0
Hours of occupancy 49.2 49.2 49.2
No. of computers n/a n/a 454
NABERS rating (decimal)
4.08 3.24 5.43
NABERS star rating 4.0stars 3.0stars 5.0stars
Table 2: NABERS Energy performance parameters for July 2011 to June 2012.
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Figure 3: Average daily (above) and seasonal (below) electrical load profiles, highlighting daily and seasonal variation in the base load.
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Fans13%
Pumps15%
Chillers16%
Cooling towers 4%
PAC units8%
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Miscellaneous 0%
Office equipment25%
Office lighting12%
Lifts3% 0
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Cooling towers
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Pumps
Fans
Average summer profileFigure 4: Electricity end-use breakdown for a 12-month period
(above) and an average business day in summer (right).
3513700 MJ
3500 MJ
648000 MJ
2607000 MJ 2525000 MJ
1004400 MJ
154800 MJ
658800 MJ 2322000 MJ 1098000 MJ861000 MJ
1500500 MJ
831000 MJ
505000 MJ
288000 MJ
173000 MJ115000 MJ
478800 MJ
122400 MJ
57600 MJ
327600 MJ
637200 MJ
547200 MJ
152000 MJ
162000 MJ
25200 MJ
58500 MJ
33300 MJ
PCM/reticulationlosses
Solar PV
Utility electricity
supply
Officeequipment
MiscellaneousTotal electricity supply
4,165,200 MJ
Utility gas supply5,133,000 MJ
Officelighting
Base buildinglighting
Car parklighting
Heatrejection
Fieldcooling
Fieldheating
Coolingtowers
Lighting
Fans
Pumps
Chillers
Flue losses
Microturbine
Heat recoveryHVAC electrical
Showertowers
PACunits
327600MJ
Boilers
Standinglosses
Solarhot water
Domestichot water
Combustionlosses
Reticulationlosses
electricity [MJ]
gas [MJ]
hot water energy [MJ]
heat (losses) [MJ]
Condenser water [MJ]
Chilled water [MJ]
Rejected heat [MJ]
Figure 5: Sankey flow diagram. This diagram demonstrates the flow of energy into the building and throughout its sub-systems. The diversity of energy sources and uses within the building is evident, as well as the degree of energy transfer and heat
recovery between the range of sub-systems. Note that thermal energy flows in the CHW and CDW networks are not quantified.
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from the micro-turbine, the screw chillers, the cooling towers or the shower towers. Production of cooling can either be after-hours and stored within phase-change material (PCM) tanks or delivered directly during occupied hours. Observations of the building through a range of conditions revealed that the system often failed to prioritise the most efficient cooling mode available. This regularly resulted in significant energy wastage overnight for charging of PCM tanks, which proved to be the issue responsible for the overnight operation (Figure 3). More importantly though, poor consideration of cooling modes meant the building was largely operating without an economy cycle, thus leading to excessive use of the electric chillers.
• Optimisation of HVAC parameters. A number of the temperature, flow and pressure set-points that the building’s air and water systems were operating to were fixed in spite of variable demand conditions. Examples included constant-pressure control for chilled water and heating hot water pumps, constant-flow control for air-handler fans, and constant water temperature control for chiller plant condenser water.
• Tuning of HVAC operation. A range of smaller operational issues were identified that summed up to a reasonable quantity of lost energy for the site. Such issues included general exhaust fans running when not required, car park ventilation fans running irrespective of CO set points, pumps running when there was no heating/cooling within the fluid they were circulating, heat exchangers (HEX) opening the primary valve without the secondary valve, and so on.
A comprehensive revision of the strategies and commissioning of the HVAC controls was recommended to address these issues, including improved economy cycle operation, vairable set-points for key water and air systems, and a general tightening up of HVAC control to avoid wasteful operation.
However, the physical components of a system must be operating reliably for controls measures to achieve their full potential. Observations of CH2’s plant suggested the system was generally in good working condition, but there was evidence of a modest range of less visible issues that may have been preventing optimum performance. The majority of these issues were consistent with the usual failure modes of commercial HVAC systems, including air within the water networks, instances of dubious sensor accuracy, valves failing to seal, compromised HEX efficiency and poor performance of PCM tanks. A tune-up process was recommended to help mitigate the risk they posed to the performance of the building.
EXAMPLES OF CONTROL OPPORTUNITIESA series of screenshots from the BMS are presented below with notes against the opportunities they highlight.
Erroneous cooling system operation during business hours
Figure 6 demonstrates the building’s cooling system operating on July 27, 2012. The following opportunities for improvement were observed:
• As noted in the yellow circle labelled “A”, the outside air conditions at this time were 12.5°C and 72%RH,
corresponding to a wet bulb temperature of approximately 10°C. In these cool conditions, the cooling towers are capable of providing sufficient cooling to the building, with no need for the chilled water plant. This opportunity exists for most of winter but was overlooked by the system’s control strategy.
• As noted in the green circles labelled “B”, there were a number of pumps operating at this time apparently for no purpose. The absorption chiller had faulted out of operation, preventing the cooling system from providing any cooling. However, the failure was not communicated to the pumps, and thus they were each running to circulate room-temperature water throughout the building.
PCM charging with chilled water
Figure 7 demonstrates the chilled water system operating at 04.00 on November 21, 2012. The chillers were found to be operating overnight to charge the PCM tanks. This operation appeared to occur regularly throughout the shoulder and summer months between the hours of 00.00 and 06.00 on business days. The design intent of the PCM charging process is to take advantage of cool overnight conditions and charge the tanks with the cooling towers to avoid having to use the electric chillers during the day. If the PCM tanks are performing ideally, charging them via the electric chillers overnight should not result in a significant loss of energy. However, there did appear to be a high level of energy loss associated with this operation.
Figure 6: Cooling system operating when “free cooling” is available from ambient conditions.
Figure 7: Chilled water system operating at 04.00 to charge the PCM tanks.
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Logs of the charging and discharging process were plotted against the average tank internal temperature in Figure 8.
The following observations were made:
• While the charging process (signified by the decreasing tank temperature) lasted for approximately five hours from 00.00 to 05.00, the tanks were fully discharged (signified by increasing tank temperature) after one hour upon start-up.
• The temperature is continuously decreasing during the charging process. The temperature of a PCM remains constant while the material is undergoing a phase change (changing from liquid to solid). That the tank temperature was continuously decreasing during the charging process implied that there was no phase change within the tank; i.e., the chilled water was merely cooling the material down in its existing phase (most likely liquid). The thermal storage capacity of the tank relies on the material’s nature to absorb coolth as it changes from liquid to solid phase; thus the tanks provide minimal storage without the phase-change process.
Erroneous operation of heating plant and air-handling plant
Figure 9 demonstrates the outside air-handling plant operating on October 18, 2012. Several issues were observed with its operation:
• As circled in red and labelled “A”, the heating pump had been engaged for the air-handling plant despite the mild ambient
conditions (18.4°C). Heating should not be required in an office building with ambient conditions above 18.0°C.
• As circled in yellow and labelled “B”, the system elected to operate the heat reclaim pump from the condenser water loop to serve the heating needs of the air handlers at this time. However, the temperature of the flow into the HEX, out of the HEX, into the AHUs and out of AHUs was each measured at 19.5°C, indicating there was no transfer of heat occurring in the system and thus the pumps were not achieving anything.
• As circled in green and labelled “C”, the heating hot water network was engaged at this time. Inspection of the BMS heating demand indicated that the AHU system was registering a demand on the heating hot water plant despite not using the heating hot water.
Constant speed pumping
Figure 10 presents the operation of heating (in red) and cooling (in blue) reticulation in the building on October 18, 2012. We noted these pumps operating at the same speed across a range of different internal and ambient conditions. Introducing dynamic resets to the pressure set-points was recommended to help them turn down to meet demand, which would also apply more broadly to other air and water systems as well.
MEASURES FOR IMPLEMENTATIONThe report was delivered in December 2012, with recommendations made for wholesale revision to the HVAC controls in addition to a suite of hardware tuning items and minor retrofits. With budget awarded for FY13/14, at the time of writing the City of Melbourne and Exergy are in the planning phase for implementation of the first stage of measures. They are presented in Table 3.
Figure 11 demonstrates the measures improving the base building’s rating to 4.5 stars. However, it is important to note that the savings were conservatively calculated as what we expected to be available from an “install and leave it” type approach. We anticipate that an intensive process of monitoring and tuning will reveal greater potential from the building’s existing systems.
Crucial to the success of this project will be a functioning sub-metering system to inform a critique of each of the building’s
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Figure 9: Air-handling plant engaging the heating system in mild conditions.
Figure 8: PCM charging and discharging process on the 14/11/12 demonstrating the disparity between charging
and discharging times.
Figure 10: Constant speed pumping control for heating and cooling systems.
F O R U M
features as they are plugged in and out of the control strategy. This process will serve to provide a blueprint for how the building’s complex array of sub-systems can best collaborate with each other. Furthermore, with this information the building will finally be in a position to provide feedback to the industry on the performance of the experimental technologies it features.
CONCLUSIONS1. CH2 is currently performing well below its potential due to
the state of the HVAC controls. It appears that the complexity associated with the building’s web of relatively unfamiliar sub-systems has led to a range of flawed strategies and operational issues.
2. The building is an excellent illustation of the importance of optimising control strategies and commissioning control behaviour for sub-systems, not only individually but also in their operation as a whole system and under numerous scenarios.
3. The building is expected to achieve 4.5 stars NABERS base building performance with the measures currently intended for implementation. Further improvement is expected to be realised with intensive monitoring and tuning.
4. Upgrade of the building’s sub-metering system, combined with a staged process of implementation and measurement is necessary not only to optimise the building’s operation but also to inform the industry on the performance of its more experimental technologies. This review marks the beginning of a project from which much more will hopefully be learnt regarding the performance of its many features. ❚
FOOTNOTES1. National Australian Built Environment Building Rating
System, www.nabers.gov.au2. See annual reports available online for CPA,
GPT Group and DEXUS. Each accessed 21/01/2014: http://www.cfsgam.com.au/au/property/cpa/Investor_
Centre/Reports_and_presentations/ http://www.gpt.com.au/Sustainability/Our-Environment/
NABERS-Ratings
http://dexus.com/investor/home.aspx
ACKNOWLEDGMENTSWe would like to acknowledge the keen assistance of Michele Leembruggen (Sustainability Branch), Allen McCowan (Property Services) and their colleauges within the City of Melbourne, as well as Matt Waller of Transfield Services and Peter Collins of Schneider Electric.
2.5 3 3.5 4 4.5 5 5.5 6Base Building NABERS Energy Rating
Monitoring and tuning
Existing rating
HVAC re-commissioning
Optimise after hours DHW servicing
Sub-metering and monitoring
HVAC controls revision
Upgrade CDW system to variable flow
BOH lighting controls
Figure 11: Base building NABERS improvement path.
Measure%
Energy saving
Payback (yrs)
Base building NABERS
star impact
HVAC controls revision of
re-commissioning19.7% 5.2 1.14
Upgrade supplementary CDW system to variable flow
1.4% 9.3 0.13
Optimise after-hours DHW
servicing3.9% 8.1 0.06
Back-of-house lighting controls 0.3% 22 0.02
Sub-metering verification and
monitoringn/a n/a n/a
Total 25.2% 7.2 1.36
About the authors
MatthewHoogland,M.AIRAH,isaseniorconsultantwithExergyAustraliabasedinMelbourne.Emailhimviamatt@xgl.com.au
DrPaulBannister,M.AIRAH,isthemangingdirectorofExergyAustralia,[email protected]
Table 3: Short-to-medium term measures for implementation.
DA27 + DA28Green Star recoGnition
Purchase online at www.airah.org.au
DA27 BUILDING COMMISSIONING
BUILDING COMMISSIONING DA27
••• 24
••• 25
The commissioning manager can assist the owner and
building designers define the POR, the content of which is
discussed in Section 5.
3.4.3. Assemble commissioning teamThe next step is to put together the commissioning team.
The role of the commissioning team is to oversee the entire
commissioning process.
The commissioning team will:• Provideaforumforintertradecommunication.• Provideamechanismfortheclearallocationofproject
responsibilities.• Participateincommissioningreviews.• Assistwithnon-conformanceresolution.• Approvethecommissioningandtuningplans.
• Approvethecommissioningreport.
The commissioning manager chairs the commissioning
team meetings and is ultimately responsible for assigning
commissioning task responsibilities and signing off on
required verification steps.Stakeholders that should be represented on the commissioning team include:• Owner’srepresentative.• Facilitymanagementstaff.• Maintenancemanager.• Occupantortenantrepresentative.• Maincontractor.
• Buildingservicessubcontractors.• Specificequipmentmanufacturers.• Buildingdesignersandarchitect.• Controlscontractororsupplier.• Buildingservicesdesigners.Not all of these stakeholders will be available at thebeginningoftheproject.Themake-upofthecommissioning team will evolve over the course of the
projectaskeystakeholdersbecomeinvolvedintheprocess,
anddependingonthecontractualstructureoftheproject.
Itisessentialhowever,thatallkeyprojectparticipantsare
included at the earliest possible stage to ensure that the
owner’sexpectationsandindividualprojectcommissioning
responsibilities are clearly allocated and understood. It is
also essential that once these stakeholders are engaged in
theproject,theactionsandresponsibilitiesthathavebeen
delegated to them and the commissioning expectations of
them are clearly communicated to them and understood
and accepted by them.Periodic meetings of the commissioning team are essential
toasuccessfulbuildingcommissioningprocess.Morefrequent team meetings are generally required during the
later stages of construction, testing and handover as this
isthephaseoftheprojectwhenmosterrorsorconflicts
can arise and when there is the least amount of time and
resources available to resolve them.3.4.4. Pre-design meetingAnimportantstepintheprocessistoholdapre-design
meeting of the commissioning team. This is an opportunity
for the commissioning manager and owner to introduce all
stakeholders, explain the commissioning process, allocate
all responsibilities (clarifying any overlaps), coordinate the commissioning activities, and clearly outline the expectations for all parties.
The owner should fully empower the commissioning manager at this time to ensure that all stakeholders in the
projectarefullyawareoftheowner’sexpectationswithregardtobuildingcommissioning.Thepre-designmeeting
is also an opportunity for commissioning team members to
sharelessonslearnedfrompreviouscommissioningprojects.
3.4.5. Roles and responsibilitiesNotallprojectstakeholders(e.g.specialistcontractors
andsubcontractors)willbeengagedintheprojectat
this early stage however, their roles and responsibilities
still need to be allocated and defined at this point. Once
thesestakeholdersareengagedintheprojectandjoin
the commissioning team they should be asked to sign off
or confirm the roles and responsibilities that have been
allocated to them. These roles and responsibilities should
be detailed as part of the conditions of contract, not after
the awarding of the contract or subcontract works.3.4.6. Define scope of workOneofthepre-designdeliverablesofthecommissioning
teamisawell-definedandagreedscopeofworkforthe
projectsothatthedesignphasecanbecarriedout.The
scope of work will form part of the commissioning plan.3.4.7. Draft commissioning plan (outline)Once the scope of work has been defined, an outline of the
commissioning plan will be developed by the commissioning
manager. The commissioning plan is a document that evolves
withtheprojectandisreviewedandupdatedatseveralstages
duringtheproject.Seefigure3.2.Developinganoutlineofthecommissioningplanatthepre-designstagehelps
the commissioning team to focus on the commissioning
requirementsofthedesignstageoftheproject.The commissioning plan serves as a focus point for the commissioningteamthroughouttheproject.Atpre-design
stage it will specify the design related commissioning tasks
andschedules.Atdesignstageitwillspecifytheconstruction
relatedcommissioningtasksandschedules.Atconstruction
stage it will specify the handover related commissioning
tasksandschedules.Athandoverstageitwillspecifythe
building tuning related commissioning tasks.
Figure 3.2: Commissioning Plan updated after each phase
Finalcommissioningplan
Install
Test
Design
Outline
The commissioning process
Figure 3.1: The Commissioning Process
• Assign a commissioning manager• Document owner’s requirements• Assemble commissioning team
• Pre-design commissioning meeting• Draft scope of work• Outline commissioning plan
Pre design
• System design reviews• Design review reports• Commissioning ream review
• Design issues and changes• Commissioning specification• Updated commissioining plan (Design)
Design
• Construction documentation review• Systems installation / site review• Building documentation review
• Documenting issues and changes• Finalise test procedures• Updated commissioning plan (Install)
Install
• Test reports• Diagnostic monitoring• Functional tests and TAB
• Integrated tests• Building preformance tests and seasonal tests• Updated commissioning plan (Test)
Test
• Final building documentation• Training• Operations review and building tuning
• Final commissioning report• Lessons learned at meeting
Handover
• Tuning and maintenance• Persistance strategies• Continuous commissioning
• Recommissioning• Retrocommissioning• Replacement
Owning
DA27 BUILDING COMMISSIONING
BUILDING COMMISSIONING DA27
••• 24
••• 25
The commissioning manager can assist the owner and
building designers define the POR, the content of which is
discussed in Section 5.
3.4.3. Assemble
commissioning team
The next step is to put together the commissioning team.
The role of the commissioning team is to oversee the entire
commissioning process.
The commissioning team will:
• Provideaforumforintertra
decommunication.
• Provideamechanismfortheclea
rallocationofproject
responsibilities.
• Participateincommissioningrev
iews.
• Assistwithnon-conform
anceresolution.
• Approvethecommissioningan
dtuningplans.
• Approvethecommissioningrep
ort.
The commissioning manager chairs the commissioning
team meetings and is ultimately responsible for assigning
commissioning task responsibilities and signing off on
required verification steps.
Stakeholders that should be represented
on the commissioning team include:
• Owner’srepresentative.
• Facilitymanagementstaff.
• Maintenancemanager.
• Occupantortenantrep
resentative.
• Maincontractor.
• Buildingservicessubcon
tractors.
• Specificequipmentmanufacturer
s.
• Buildingdesignersanda
rchitect.
• Controlscontractororsu
pplier.
• Buildingservicesdesign
ers.
Not all of these stakeholders will be available at
thebeginningofthepro
ject.Themake-upofthe
commissioning team will evolve over the course of the
projectaskeystakeholde
rsbecomeinvolvedintheprocess
,
anddependingonthec
ontractualstructureoft
heproject.
Itisessentialhowever,th
atallkeyprojectparticip
antsare
included at the earliest possible stage to ensure that the
owner’sexpectationsan
dindividualprojectcom
missioning
responsibilities are clearly allocated and understood. It is
also essential that once these stakeholders are engaged in
theproject,theactionsa
ndresponsibilitiesthatha
vebeen
delegated to them and the commissioning expectations of
them are clearly communicated to them and understood
and accepted by them.
Periodic meetings of the commissioning team are essential
toasuccessfulbuilding
commissioningprocess.More
frequent team meetings are generally required during the
later stages of construction, testing and handover as this
isthephaseoftheproje
ctwhenmosterrorsorconflicts
can arise and when there is the least amount of time and
resources available to resolve them.
3.4.4. Pre-design meeting
Animportantstepintheproce
ssistoholdapre-desig
n
meeting of the commissioning team. This is an opportunity
for the commissioning manager and owner to introduce all
stakeholders, explain the commissioning process, allocate
all responsibilities (clarifying any overlaps), coordinate
the commissioning activities, and clearly outline the
expectations for all parties.
The owner should fully empower the commissioning
manager at this time to ensure that all stakeholders in the
projectarefullyawareof
theowner’sexpectation
swith
regardtobuildingcommissioning.Th
epre-designmeeting
is also an opportunity for commissioning team members to
sharelessonslearnedfro
mpreviouscommissioningpro
jects.
3.4.5. Roles and responsibilities
Notallprojectstakehold
ers(e.g.specialistcontra
ctors
andsubcontractors)wil
lbeengagedinthepro
jectat
this early stage however, their roles and responsibilities
still need to be allocated and defined at this point. Once
thesestakeholdersaree
ngagedintheprojecta
ndjoin
the commissioning team they should be asked to sign off
or confirm the roles and responsibilities that have been
allocated to them. These roles and responsibilities should
be detailed as part of the conditions of contract, not after
the awarding of the contract or subcontract works.
3.4.6. Define scope of work
Oneofthepre-designde
liverablesofthecommissioning
teamisawell-definedandag
reedscopeofworkfort
he
projectsothatthedesig
nphasecanbecarriedo
ut.The
scope of work will form part of the commissioning plan.
3.4.7. Draft commissioning
plan (outline)
Once the scope of work has been defined, an outline of the
commissioning plan will be developed by the commissioning
manager. The commissioning plan is a document that evolves
withtheprojectandisre
viewedandupdatedats
everalstages
duringtheproject.Seefig
ure3.2.Developinganou
tline
ofthecommissioningplanatthepre-
designstagehelps
the commissioning team to focus on the commissioning
requirementsofthedesignstageo
ftheproject.
The commissioning plan serves as a focus point for the
commissioningteamthroughout
theproject.Atpre-desig
n
stage it will specify the design related commissioning tasks
andschedules.Atdesign
stageitwillspecifythec
onstruction
relatedcommissioningtasksandsched
ules.Atconstruction
stage it will specify the handover related commissioning
tasksandschedules.Atha
ndoverstageitwillspecif
ythe
building tuning related commissioning tasks.
Figure 3.2: Commissioning Plan updated after each phase
Final
commissioning
plan
Install
Test
Design
Outline
The commissioning process
Figure 3.1: The Commissioning Process
• Assign a commissioning man
ager
• Document owner’s requireme
nts
• Assemble commissioning te
am
• Pre-design commissioning
meeting
• Draft scope of work
• Outline commissioning plan
Pre design
• System design reviews
• Design review reports
• Commissioning ream review
• Design issues and changes
• Commissioning specification
• Updated commissioining pla
n (Design)
Design
• Construction documentatio
n review
• Systems installation / site re
view
• Building documentation rev
iew
• Documenting issues and ch
anges
• Finalise test procedures
• Updated commissioning plan
(Install)
Install
• Test reports
• Diagnostic monitoring
• Functional tests and TAB
• Integrated tests
• Building preformance tests
and seasonal tests
• Updated commissioning plan
(Test)
Test
• Final building documentati
on
• Training
• Operations review and build
ing tuning
• Final commissioning report
• Lessons learned at meeting
Handover
• Tuning and maintenance
• Persistance strategies
• Continuous commissioning
• Recommissioning
• Retrocommissioning
• Replacement
Owning
APPLICATION MANUAL
THE AUSTRALIAN INSTITUTE OF REFRIGERATION, AIR CONDITIONING AND HEATING
BUILDING COMMISSIONING
DA27
DA27 Building Commissioning and DA28 Building Management and Control Systems have been recognised in a recent GBCA technical clarification. This means that Australian industry can work with processes and documents that they understand. References are to Australian law, Australian regulations, Australian Standards and Australian practices – and all in a language and vernacular that Australian industry can understand.
DA28 BUILDING MANAGEMENT & CONTROL SYSTEMS BUILDING MANAGEMENT & CONTROL SYSTEMS DA28
••• 62
••• 63
as-installed drawings reflect what has been corrected
to gain a more efficient and manageable building system.
10.9. System management
10.9.1. System access
It is important to decide who has access to the BMCS
controls. The following stakeholders generally need some
form of access to system settings:
• System operators – Day to day operational tasks.
• Maintenance providers
– System interrogation, monitoring.
• Building tuning team – Fine tuning control loops
• Specialist or vendor representatives
– Updates and fixes.
The level of access and authority to make changes
must be clearly identified and defined for each individual.
10.9.2. Change management
It is important for BMCS, or any DDC control system, that
a formal change management system is put in place.
Unauthorised changes and quick fixes are common
reasons why system controls operate inefficiently. Only
specified people should be given access to the BMCS
and the responsibility or authority for changing controls
settings, control routines, and controls logic should be
nominated.
• Control settings – Changing set points and targets,
room temperature settings, set back temperatures.
• Control routines – Changing parameters
associated with systems control philosophy.
• Control logic – Changing code
in the controller programming.
When making changes to system operating
controls or settings, it is important to consider all
of the consequences of the change made. The system
should be set up to record and show who was logged
onto the system, what changes if any were made, and
the underlying reasons why the changes were made.
10.9.3. Documenting changes
Ideally a building tuning plan should be in place to
introduce a standardised process for managing changes
to the control system. All changes that are authorised
should be fully documented and the building
documentation and BMCS information updated as
appropriate.
10.9.4. Verifying systems
Even with strong policies in place, it may be difficult
to guarantee that unauthorised changes have not been
made and it is worthwhile to periodically verify and sign
off that rogue control strategies or changes have not been
implemented.
10.10. Post occupancy
evaluation
Also termed building performance evaluation, this
activity focuses on determining how well the building
is meeting its defined operating requirements and assesses
the level of satisfaction or dissatisfaction of building
occupants and users.
Post occupancy evaluation usually focuses on energy
usage figures and occupant evaluation surveys, although
criteria will vary from facility to facility.
Any evaluation process needs to include a formal
evaluation of the building performance information
and survey results, generally by a tuning or building
performance team.
10.11. Performance review
The specific requirements of the building or individual
spaces may change over time and there should be
some form of review to adjust systems to the specific
requirements. Where no particular changes have occurred,
systems will still need to be finetuned. Minor changes
may lead to a recommissioning program whereas major
changes in the operating requirements may lead to system
or building retrocommissioning.
• Fine tuning – Uses tests and procedures
as detailed in the building tuning manual.
• Recommissioning – Uses the same tests and
procedures as utilised for the original commissioning
program.
• Retrocommissioning – Uses new tests and
procedures developed specifically for the new
or modified system.
10.12. Recommissioning
Recommissioning begins with a review of the project
operating requirements (POR) to determine what, if any,
changes have occurred. The POR needs to be updated
or confirmed prior to any recommissioning activities
commencing.
If changes have occurred, systems are reviewed to
establish if corresponding changes to equipment,
controls or operation procedures are required.
Systems are then fully surveyed and a list of findings
or issues compiled.
System trend logs or functional performance tests may
be used to determine if the systems meet the performance
defined in the reviewed and updated project operating
requirements (POR).
10.13. Upgrades
Replacement strategy – scheduling the replacement
of inefficient equipment with modern high efficiency
alternatives (always review the load requirements for changes).
This Appendix provides a broad overview of control system
fundamentals and explains some of the common terms
used when discussing control systems. For more detailed
technical information on any of this material refer to CIBSE
Guide H Building Control Systems or similar publications.
Manual control requires direct control of a system by
human intervention. Automatic controls function without
direct human intervention once set in motion. Automatic
controls act to maintain a predetermined set point in
response to changing conditions.
At its most fundamental, a control system comprises
a sensor, a controller, a controlled device, a process,
and a feedback to the system. Closed loop systems
have a direct feedback via the sensor; open loop systems
have no direct feedback. The set point is the desired
or pre-set value of the variable for the feedback loop
to compare against, e.g. the temperature of a space
or the pressure of a fluid.
Figure A1: Basic control loop
A sensor detects and measures a variable and sends this
information to the controller. Sensors typically measure
temperature, pressure, humidity, velocity, flow, illuminance,
movement, substance concentration, electrical resistance, or
electronic voltage. Sensor output becomes controller input.
The controller receives the information from the sensor
and uses a pre set logic or control algorithm to compute
an output signal which it sends to the controlled device.
Controller output becomes controlled device input.
The controlled device receives the information from the
controller and acts on it to make the required change to
the system. Examples of controlled devices are modulating
valves and dampers, lighting dimmers, variable speed
motors (that drive fans, pumps and compressors), electrical
or electronic switches and capacitors.
A sensor, controller and controlled device can all live
in the same box or they can be in three separate places.
They need to be connected to communicate, connections
can be wired or wireless. Sensor output becomes
controller input and controller output becomes device
input. A thermostat is both a sensor and a controller; a
thermostatic valve is a sensor, a controller and a controlled
device. The load or process typically includes building
ventilation, cooling, heating, lighting, transport, and
security access.
Figure A2: DDC inputs and outputs
A direct acting control action means the output increases
with increases in the measured variable.
A reverse acting control action means the output
decreases as the measured variable increases.
Examples of controllers are thermostats, programmable
timers, microprocessor controls, direct digital control
systems (DDC), and building management and control
systems (BMCS). How the controller functions, its internal
logic, determines the relationship between the controllers
input and output. This is called the control response.
Typical control responses employed in building HVAC are:
• Two position – This is essentially an on/off control
based on the specified set point and differential.
The output is off when the set point is reached,
and on when the difference between the set point
and the measured variable (the differential) reaches
the specified value.
Controls fundamentalsAppendix A
CCD
CoolingCoil
S
Controller
ControlledDevice
ChilledWaterSupply
ChilledWater Return
Controlled Medium
(Air temperature)
NormallyOpen
Sensor
CSController
Into DDCOut of DDC
OUTPUTLOGIC
INPUT
CDControlledDevice
Sensor
DA28 BUILDING MANAGEMENT & CONTROL SYSTEMSBUILDING MANAGEMENT & CONTROL SYSTEMS DA28
••• 62
••• 63
as-installed drawings reflect what has been corrected
to gain a more efficient and manageable building system.10.9. System management10.9.1. System accessIt is important to decide who has access to the BMCS
controls. The following stakeholders generally need some
form of access to system settings:• System operators – Day to day operational tasks.• Maintenance providers – System interrogation, monitoring.• Building tuning team – Fine tuning control loops
• Specialist or vendor representatives – Updates and fixes.
The level of access and authority to make changes must be clearly identified and defined for each individual.10.9.2. Change managementIt is important for BMCS, or any DDC control system, that
a formal change management system is put in place.
Unauthorised changes and quick fixes are common reasons why system controls operate inefficiently. Only
specified people should be given access to the BMCS
and the responsibility or authority for changing controls
settings, control routines, and controls logic should be
nominated.• Control settings – Changing set points and targets,
room temperature settings, set back temperatures.• Control routines – Changing parameters
associated with systems control philosophy.• Control logic – Changing code in the controller programming.When making changes to system operating
controls or settings, it is important to consider all of the consequences of the change made. The system
should be set up to record and show who was logged
onto the system, what changes if any were made, and
the underlying reasons why the changes were made.10.9.3. Documenting changesIdeally a building tuning plan should be in place to introduce a standardised process for managing changes
to the control system. All changes that are authorised
should be fully documented and the building documentation and BMCS information updated as appropriate.
10.9.4. Verifying systemsEven with strong policies in place, it may be difficult to guarantee that unauthorised changes have not been
made and it is worthwhile to periodically verify and sign
off that rogue control strategies or changes have not been
implemented.
10.10. Post occupancy evaluationAlso termed building performance evaluation, this activity focuses on determining how well the building
is meeting its defined operating requirements and assesses
the level of satisfaction or dissatisfaction of building occupants and users.
Post occupancy evaluation usually focuses on energy
usage figures and occupant evaluation surveys, although
criteria will vary from facility to facility.Any evaluation process needs to include a formal evaluation of the building performance information and survey results, generally by a tuning or building performance team.
10.11. Performance reviewThe specific requirements of the building or individual
spaces may change over time and there should be some form of review to adjust systems to the specific
requirements. Where no particular changes have occurred,
systems will still need to be finetuned. Minor changes
may lead to a recommissioning program whereas major
changes in the operating requirements may lead to system
or building retrocommissioning.• Fine tuning – Uses tests and procedures as detailed in the building tuning manual.
• Recommissioning – Uses the same tests and procedures as utilised for the original commissioning
program.• Retrocommissioning – Uses new tests and
procedures developed specifically for the new or modified system.
10.12. RecommissioningRecommissioning begins with a review of the project
operating requirements (POR) to determine what, if any,
changes have occurred. The POR needs to be updated
or confirmed prior to any recommissioning activities commencing.
If changes have occurred, systems are reviewed to establish if corresponding changes to equipment, controls or operation procedures are required.Systems are then fully surveyed and a list of findings
or issues compiled.System trend logs or functional performance tests may
be used to determine if the systems meet the performance
defined in the reviewed and updated project operating
requirements (POR).
10.13. UpgradesReplacement strategy – scheduling the replacement of inefficient equipment with modern high efficiency alternatives (always review the load requirements for changes).
This Appendix provides a broad overview of control system
fundamentals and explains some of the common terms
used when discussing control systems. For more detailed
technical information on any of this material refer to CIBSE
Guide H Building Control Systems or similar publications.Manual control requires direct control of a system by
human intervention. Automatic controls function without
direct human intervention once set in motion. Automatic
controls act to maintain a predetermined set point in
response to changing conditions.At its most fundamental, a control system comprises
a sensor, a controller, a controlled device, a process, and a feedback to the system. Closed loop systems have a direct feedback via the sensor; open loop systems
have no direct feedback. The set point is the desired
or pre-set value of the variable for the feedback loop
to compare against, e.g. the temperature of a space or the pressure of a fluid.
Figure A1: Basic control loopA sensor detects and measures a variable and sends this
information to the controller. Sensors typically measure
temperature, pressure, humidity, velocity, flow, illuminance,
movement, substance concentration, electrical resistance, or
electronic voltage. Sensor output becomes controller input.The controller receives the information from the sensor
and uses a pre set logic or control algorithm to compute
an output signal which it sends to the controlled device.
Controller output becomes controlled device input.The controlled device receives the information from the
controller and acts on it to make the required change to
the system. Examples of controlled devices are modulating
valves and dampers, lighting dimmers, variable speed
motors (that drive fans, pumps and compressors), electrical
or electronic switches and capacitors.A sensor, controller and controlled device can all live in the same box or they can be in three separate places.
They need to be connected to communicate, connections
can be wired or wireless. Sensor output becomes controller input and controller output becomes device
input. A thermostat is both a sensor and a controller; a
thermostatic valve is a sensor, a controller and a controlled
device. The load or process typically includes building
ventilation, cooling, heating, lighting, transport, and security access.
Figure A2: DDC inputs and outputsA direct acting control action means the output increases
with increases in the measured variable.A reverse acting control action means the output decreases as the measured variable increases.Examples of controllers are thermostats, programmable
timers, microprocessor controls, direct digital control systems (DDC), and building management and control
systems (BMCS). How the controller functions, its internal
logic, determines the relationship between the controllers
input and output. This is called the control response.Typical control responses employed in building HVAC are:• Two position – This is essentially an on/off control
based on the specified set point and differential. The output is off when the set point is reached, and on when the difference between the set point and the measured variable (the differential) reaches the specified value.
Controls fundamentals
Appendix A
C
CD
CoolingCoil
S
Controller
ControlledDeviceChilledWaterSupply
ChilledWater Return
Controlled Medium(Air temperature)
NormallyOpen
Sensor
CS
Controller
Into DDCOut of DDC
OUTPUTLOGIC
INPUT
CD ControlledDevice
Sensor
APPLICATION MANUAL
THE AUSTRALIAN INSTITUTE OF REFRIGERATION, AIR CONDITIONING AND HEATING
DA28BUILDING MANAGEMENT
AND CONTROL SYSTEMS
(BMCS)