optimising building performance - city of melbourne...18-28 c,

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

Presented by

22/05/2012

Questions?

Dr Paul Bannister paul@xgl.com.au 02 6257 7066