MEETING OF COUNCIL - Town of Cambridge

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COUNCIL MINUTESTUESDAY 26 FEBRUARY 2013System Evaluation CriteriaThese systems were evaluated against key criteria:-• Technical suitability;• Whole of life costs;• Current code compliance;• Environmental impacts; and• Spatial considerations and disruption upon Town's operationFollowing this evaluation four options were shortlisted as follows:-ID System InitialCapitalCost20 Year LifeCycle CostEstimatedGreenhouse GasEmissions (TonnesCO 2 /Annum)1 Air cooled chiller system $1,020,000 $3,740,000 149(Like for like replacement).2 Water cooled chiller only. $1,300,000 $3,730,000 1263 Variable Refrigerant Volumesystem (VRV).4 Water cooled chiller systemwith gas heating.$1,040,000 $2,450,000 92$1,720,000 $2,620,000 57The initial capital costs include a 10% contingency, allowance for phasing of works andpotential disruption during normal business hours. They also include professional fees fordesign documentation, tender and contract administration. Note: the initial capital costs arealso included in the 20 year life cycle costs.The VRV system (Variable Refrigerant Volume) is the preferred option, predominantly due to:-• Low capital costs;• Greater economic life;• Lower operational costs; (Life Cycle Costs)• Does not require the provision of any gas services for heating;• Low environmental emissions;• System meets current BCA standard;• Providing greater comfort control;• System flexibility; and• VRV systems can be prioritised and staged over more that one year for construction.An option to simply replace the system "like for like" was reviewed and whilst it has minormeasurable benefits it was rejected due to:-• High "Whole of Life" costs;• Comprises of part system replacement only;• Existing inefficient electrical heating which does not meet current BCA standards; and• Higher environmental emissions.• Should works be required on the building system, BCA compliancy is not met.The annual environmental emissions have been estimated on normal working hours, Mondayto Friday.H:\CEO\GOV\COUNCIL MINUTES\13 MINUTES\FEBRUARY 2013\C CR.DOCX 129
COUNCIL MINUTESTUESDAY 26 FEBRUARY 2013Variable Refrigerant Volume System (VRV)Variable Refrigerant volume systems operate like a normal direct expansion (DX) airconditioning system but have the ability to control the volume of refrigerant by varying thespeed of the compressor. This makes them far more efficient than normal large scalerefrigerated air conditioning systems.It also means that the building can be divided into smaller sections which need only be enabledwhen required which is very advantageous when considering after hours use of specific areassuch as the rangers Office and Council Chambers.They also have the advantage of being able to provide simultaneous heating and cooling todifferent areas which allows individual comfort control at a very high level and can beincorporated with an Economy Cycle to deliver genuine future energy savings.Economy CycleEconomy cycles measure the conditions within the building against outside ambient conditionsand utilise the fresh air when advantageous. This not only results in lower operating costs dueto energy savings but can also greatly improve conditions within the building for the occupantsdue to the increased amount of fresh air.An economy cycle has the potential to reduce cooling plant energy costs by up to 20% whichwill significantly lower the greenhouse emissions associated with the building and subsequentlyits carbon foot print.Although an economy cycle has been incorporated in the existing system, it has been addedonto the original design and does not take full advantage of the potential savings available.Any new air conditioning system installed in the building will require installation of a trueeconomy cycle to conform to current BCA/NCC Section J5 requirements.Systems with lower carbon footprints such as geothermal were considered, however, it wasnoted that there was significant capital cost differences (>$1m) over preferred options andmuch longer payback periods (>10 years) before they came into parity with more conventionaloutcomes. It is also noted that the significant technical risks associated with these systems areproving challenging elsewhere.Attachment 1 provides an extract from the full consultancy assessment.POLICY/STATUTORY IMPLICATIONS:The Town's Asset Management Policy 5.4.9 adopted in April 2012 includes as a principle thatconsideration be given to life cycle costs prior to a decision being made to replace an asset.The preferred system has strong credentials in this regard.FINANCIAL IMPLICATIONS:The scope of the consultancy, to be undertaken in this (2012/13) financial year includesfinalisation of design, preparation of tender documents and completion of a pre-tender estimateof capital costs. It will be necessary to undertake works in 2013/14 as the risk and completesystem failures are increasing.A funding amount of $300,000 is currently held in the Asset Management reserve. During thelast three budgets, $100,000 has been allocated each year for this air conditioning upgrade.H:\CEO\GOV\COUNCIL MINUTES\13 MINUTES\FEBRUARY 2013\C CR.DOCX 130
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MEETING OF COUNCIL - Town of Cambridge

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