optimising building performance - city of melbourne...18-28 c,
TRANSCRIPT
Presented by
22/05/2012
Optimising Building Performance
Dr Paul Bannister
Where does the energy go?HVAC technologiesLighting technologiesOffice equipmentOther technologiesConclusions
Overview
Where does the Energy Go?
HVAC consists ofChillersCooling towersBoilersCogen/trigenFans and PumpsPackage unitsHVAC control systemAnd some other bits and pieces
HVAC Technologies
Optimum chiller technologies<300kW – scroll300-700kW – magnetic bearing VSD centrif700-1000kW mag bearing VSD centrif, small VSD screw1000-2000kW VSD screw, VSD mag bearing centrif
Savings – up to 50% relative to 10-15 year old technologiesEconomics: long payback, coordinate with routine replacement if possible. Note: R22/R123 (HCFCs) are becoming obsolete
Chiller Hardware
Don’t run when they aren’t neededOutdoor temperature lockout
Operate at higher chilled water temperaturesOperate at lower condenser water temperaturesStage up and down at the right timeEconomics: great
Chiller Operation
Hardware:Replace old tired cooling towersUse induced draft towers not forced draft towersVariable speed fans
OperationSpread load out across multiple towersOptimise temperature set-point in conjunction with chillers
Cooling Towers
Hardware:Replace tired old boilersEliminate steam boilers as far as possibleUpgrade burners to fully modulating burnersUse condensing boilers
OperationTune the burner regularlyTurn off as much as possibleReduce operating temperature when loads permit
Boilers
Hardware:Not a magic bullet, and very expensiveSizing a critical issueCan you actually use the waste heat?
OperationConsider third party operation and managementMaximise run hours during peak electricity cost periods to get returnDon’t create false loads to justify thermal useNot a substitute for efficiency
Cogen/trigen
Hardware:Replace stuffed bearings and sagging V-belts Use VSD control not guide vane
OperationSet up controls to minimise operating speed and pressure to meet loadTurn off when not needed
Fans
Hardware:Replace stuffed bearingsUse VSD control not throttling valves
OperationSet up controls to minimise operating speed and pressure to meet loadTurn off when not needed
Pumps
Hardware:Replace dying unitsInstall condenser water shut-off valves
OperationTurn off when not neededWiden dead bandsRefrigerant chargeFilter cleaning
Water Cooled Package Units
Hardware:Replace with inverter units
OperationTurn off when not neededWiden dead bandsRefrigerant chargeFilter cleaning
Air Cooled Package Units
Hardware:Replace pneumatic systems
OperationSee operational measuresWiden dead bandsCommission!Time-of-use control
HVAC Controls
Outside air controlOptimise economy cycleMinimise unnecessary outside air
Air FiltersClean regularlyUse high energy efficiency filters (Eurovent standard)
Other HVAC Bits and Pieces
Halogen downlightsReplace with LED (with care!)
Metal HalideConsider LED replacements if control possible
FluorescentAim for <9W/m² in office spaceT5 or T8 with electronic ballastGrid spacing and design important
Lighting is a DESIGN issue
Lighting Technologies
Time of use control is paramountManual switches rarely effectiveTime-clocks tend to longer hours than necessaryUse occupancy sensors
Manual on, auto-off Zone size <250m²
DimmingGood theory but often unsuccessfulKeep focussed on the time of use control!
Lighting Control
Time of use control is paramountWorking week is less than a third of the hours in a weekTurn off!!
Use low-power PCs (laptops and some desktops; thin client)Use power management settings
Screen savers do not save energy
Office Equipment - Computers
Time of use control is paramountUse power management settings
Avoid excess equipmentUse central print stations, MFDs
Kitchen equipmentUse 3+star fridges, etcTime-clock boiling water/ chilled water units
Office Equipment - General
Don’t over-conditionASHRAE air-on recommendations:
18-28°C, <60% RH, 5.5°C<dewpoint<15°CMake sure air goes through not around the racks
“Hot aisle/cold aisle” approachEnsure that separate conditioners are not fightingVirtualise/modernise serversRemove old, underutilised servers
Office Equipment – Server Rooms
Upgrade technologyMassive costBenefit can be >40%
Tune operating parameters to match real-occupancyDon’t over condition the lift motor roomUpgrade the lights in the lift carsTurn off some lifts overnight (remarkably difficult)
Other Equipment – Lifts
Convert electric to gas or heat pumpReduce tap flowsTurn off circulation pump out of hours
Other Equipment – Domestic Hot Water
Wide range of possible upgrades for all technologyIn each case measures may be
Hardware – longer paybacksOperational – shorter paybacks
Remember: Most buildings have many operational savings availableImproved efficiency frequently means better service
Conclusions
