SESSION 10811:00am – 12:30pm

Energy Efficiency in Existing Buildings and Tenant Improvements

Presenter: Rod Yeoh

PrincipalOmicron Architecture

Engineering Construction

Session Co-sponsored by

Omicron AEC+ Architecture, Engineering, & Construction+ Established in 1998+ Now almost 200 office and field staff+ Head office in Vancouver+ Office in Calgary, Satellite offices in Victoria,

BC & Toronto, ON+ Integrated Project Delivery focus + Market Sectors – Institutional/Commercial,

Retail, Renewals, Office Interiors, Residential/Oilsands

Outline

+ Existing Systems+ Evaluate Equipment+ Reduce Loads+ “Right-size” Equipment+ Energy Efficiency

Trends+ Re-commissioning

Existing Systems+ Most large office buildings in

downtown areas have Central Plants– Central Chiller plant– Central Boiler plant (or steam from Central

Heat)

Existing Systems+ Air Handling Systems

– Central or Floor by Floor• Free cooling available with outside air

Existing Systems

+ Terminal Systems– VAV Terminal Units

• with or without re-heat– Fan Coil Systems

• 4 Pipe and 2 Pipe

Existing Systems

+ Terminal Systems– Underfloor

distribution system– Induction Systems

Existing Systems+ Smaller office buildings (usually

outside of downtown core)– Water Source Heat Pumps

Existing Systems+ Smaller office buildings

– Rooftop VAV• Typically with

electric/hydronic re-heat coils

– Fan powered mixing boxes

• Maintains constant volume to space by mixing return air

Existing Systems+ Smaller office buildings

– Multi-zone• Hot Deck• Cold Deck• Dampers mix zone

supply temperatures as required

• Good thermal comfort

• Not so good efficiency

Existing Systems+ Smaller office buildings

– Rooftop VVT• Variable Volume,

Variable Temperature

• “Polls” zones and supplies heating or cooling as required

• Correct zoning is very important

Evaluating Equipment+ ASHRAE Tables

– Data based on Surveys done in the US in 1978 by ASHRAE. Updated in 1986

– Estimates based on time to replacement, not failure– Various reasons for replacement

• Failure• General Obsolescence• Reduced reliability• Maintenance costs• Energy use• Environmental conditions

Evaluating Equipment+ ASHRAE Tables

– Equipment life is extended with good maintenance

Evaluating Equipment

+ Lawrence Livermore National Laboratory (LLNL) & Whitestone Research have done studies of equipment service life to failure of various types of equipment

+ Contributing Factors towards longer LLNL service lives– Complete and consistent maintenance schedule– Regular condition assessments– Replace equipment on down slope of failure

distribution

Evaluating Equipment

Evaluating Equipment

Evaluating Equipment

Evaluating Equipment

Evaluating Equipment

+ Vibration testing– Can identify issues

with bearings, wear, unbalance

– Can identify problems earlier than other methods

– Can prevent catastrophic failure in equipment

Analysis of existing equipment

Evaluating EquipmentAnalysis of existing

equipment+ Infrared

Thermography– Detects “hot

spots” in electrical components and equipment

– Can help identify electrical issues in HVAC equipment

Reduce LoadsEnvelope Upgrades+ IF the Building is already having envelope issues,

or needs to be re-roofed, increasing insulation or replacing glazing may make sense

Reduce LoadsEnvelope Upgrades+ Study for CoV – Green Retrofits

– Glazing upgrades can save over 20% of total energy costs per year for a typical downtown office tower

– Balance with incremental cost of higher performance glazing if already planning a glazing replacement

Reduce LoadsEnvelope Upgrades+ Heating and Cooling Calculations and Energy

Simulations should be performed+ In some instances, increasing insulation could

actually increase energy use

Reduce LoadsLighting+ Lighting Loads in

the past– Up to 4 watts per

square foot+ New Lighting

– Can be under 1 watt per square foot

Reduce LoadsLighting+ Replace T12 lights

with T8 or T5+ Magnetic ballasts to

electronic+ Occupancy sensors+ Daylight sensors &

controls+ Most likely strategy

in Tenant Improvements

Reduce LoadsOther Cooling Loads+ Computers

– CRT Monitors – 110 Watts operating– LCD Monitors – 30-40 Watts operating

Reduce Loads

Heating Loads+ Ventilation Air

– Check existing ventilation levels

• May be over/under ventilating

– ASHRAE 62-2007 Requirements

• 17 cfm per person required for office space

• 7 cfm per person required for reception areas

Reduce LoadsHeating Loads+ Ventilation Air

– Heat Recovery on Ventilation systems

• Enthalpy Wheels• Air to Air Heat

Exchangers• Glycol loops• Heat pipes

Reduce LoadsMotor Loads+ Demand Controlled Ventilation+ Variable Speed Drives on VAV

systems & Pump systems

“Right” Size Equipment+ Once Loads are

Reduced– Look at replacing

main plants: chillers, boilers, rooftop units

– Don’t just replace with same size

– Size to suit new loads

– Add Redundancy

“Right” Size Equipment

+ Evergreen Building– Replaced Glazing– Reduced lighting

loads– Reduced Chiller Size

by 15%– Reduced Boiler size

by 10%

New Equipment Efficiencies

+ Average efficiency of a chiller installed in 1980-1990 – 0.85-0.90 kW/ton– Could be as high as 1.2

kW/ton+ Old chillers can also get

oil logged – keep adding refrigerant with oil in it, reduces efficiency by up to 10%

New Equipment Efficiencies+ New Centrifugal Chillers have an efficiency of

0.40-0.50 kW per ton+ Efficiency can go down to as low as 0.25 kW

per ton with VFD chillers

New Equipment Efficiencies+ VSD or small jockey motors on Cooling

Tower fans+ Water Side Economizers

– CoV Study – if no air side economizing, simple payback in as little as 4 years – different for other locations

New Equipment Efficiencies+ Old boilers were rated

at 70% to 80% efficiency

+ New near condensing boilers are rated at up to 86% efficiency

+ CoV Study– New mid-efficiency

boilers – 7 year simple payback – could be quicker in Alberta

New Equipment Efficiencies+ New condensing boilers

are rated at up to 98% efficiency– At more practical return

water temperatures, more like 90%

+ Review type of heating system and boiler return temperatures for condensing

New Equipment Efficiencies

+ Motor efficiency

Horsepower Standard (%) High Efficiency (%)

1 78.0 82.5

5 84.0 89.6

10 84.0 91.1

15 87.5 91.7

25 90.2 93.0

50 91.7 94.1

250 94.1 95.8

New Equipment Efficiencies+ VAV Systems

– Older systems use variable inlet vanes or other mechanical means to vary airflow

– New systems (or retrofits) use VFDs– Full floor Tenant Improvement

New Equipment Efficiencies

+ VAV Systems– Power varies

as cube of fan speed

System Efficiencies in TI’s+ Duct & Pipe insulation

– Can pay back in as little as 3-5 years+ Energy efficient (Energuide)

equipment and appliances

System Efficiencies in TI’s+ Controls

– Re-commissioning– Calibration– Adding DDC or setback control– Morning warm-up or pre-cooling

+ Sub-metering

New Equipment Efficiencies+ Financial Incentives and Rebates

– Province of Alberta• “Light it Right” Program

(www.lightitright.ca)– Restaurant– Retail– Multi-unit Residential– Office/Hotels– Warehouse/Recreational Facilities– Rebates for lighting & controls

Energy Efficiency Trends+ Dedicated Outdoor Air Systems

– Separating space conditioning and ventilation loads+ Displacement Ventilation and Underfloor Air

Distribution systems

Energy Efficiency Trends+ Radiant Heating and Cooling Systems

Thermal Comfort

Fred Kaiser Building UBC

Energy Efficiency Trends+ Variable Refrigerant Flow (VRF, VRV)

Systems

Energy Efficiency Trends

+ Co-generation– Generate Heat and

Power at the same time– By-product heat can be

used for cooling through absorption chillers

– Generally more efficient for large or district plants

Energy Efficiency Trends+ Renewable Energy

– Solar• Photovoltaics• Solar Hot Water• Direct solar heating/Solar Wall

– Wind– Green Power certificates

Re-Commissioning+ Re-commissioning of Building

Systems (RCx)– The Office of Energy Efficiency

(NRCan) has cited studies that show that re-commissioning can improve energy efficiency by 5-15%, with a payback under 2 years.

Re-Commissioning+ New DDC Control

systems– Can Increase

Efficiency • Ensuring systems are

operating as intended• Resetting setpoints to

optimize energy use• Optimal start up

routines • Track changes in

energy usage and report exceptions

Re-Commissioning+ Check trends on DDC system

– entering and leaving chilled/heating water temperature versus setpoint/setback/schedule

– equipment schedule — on/off — versus time of day– zone temperature & setpoints versus time of day.

Re-Commissioning+ BC Hydro Continuous Optimization Program

– Will pay for re-commissioning in addition to installation of pulse meter and energy management software

Prioritizing Capital Projects+ Life Cycle Cost

Assessment– Analysis should include

all Costs in life of component

– Life Cycle Cost (LCC) as “the total discounted dollar cost of owning, operating, maintaining, and disposing of a building or a building system” over a period of time.

Prioritizing Capital Projects+ Life Cycle Cost Assessment

– For One time costs:

Prioritizing Capital Projects+ Life Cycle Cost Assessment

– For Recurring costs:

Prioritizing Capital Projects+ Life Cycle Cost Assessment

– Summarize Alternatives

Prioritizing Capital Projects+ Life Cycle Cost Intangibles

+ Issues such as IAQ and thermal comfort affect productivity

+ Productivity cost is very hard to quantify

+ Original Construction 2%+ Maintenance Costs 6%+ Personnel Costs 92%

Prioritizing Capital Projects

+ Life Cycle Cost Example

Prioritizing Capital Projects+ Life Cycle Cost Example

Evaluating Old Equipment10 Tips for increasing chiller efficiency

1. Keep a daily log– A log builds a history of operating conditions,

including temperature, pressure, fluid level and flow rate.

2. Keep tubes clean – Chiller efficiency declines rapidly when tubes

become fouled. The compressor's approach temperature, the difference between the temperature of the fluid leaving the heat exchanger and the saturation temperature of the refrigerant being cooled or heated, is a good indicator of heat transfer efficiency

Evaluating Old Equipment

10 Tips for increasing chiller efficiency

3. Treat condenser water– Condenser water loops using open cooling sources,

such as atmospheric cooling towers, require water treatment to prevent fouling. Erosive conditions, for example, sand flowing through the tubes at high velocity, may pit tubes

4. Reduce entering water temperature– Lowering the temperature of the water entering the

condenser can improve the chiller's efficiency

Evaluating Old Equipment

10 Tips for increasing chiller efficiency

5. Control water velocity– Too low a flow rate leads to laminar flow, reducing

heat transfer. Too high a flow rate leads to vibration, noise and erosion. Flow rates should be kept between 3 – 12 feet per second velocity in tubes. Confirm with Manufacturer.

6. Maintain refrigerant charge – Low refrigerant charge, usually resulting from leaks,

causes the compressor to work harder and achieve less cooling effect.

Evaluating Old Equipment

10 Tips for increasing chiller efficiency

7. Purge non-condensables – Air and moisture are two non-condensables that can

leak into low-pressure chillers. Non-condensables can reduce chiller efficiency by as much as 4% at 60% load and 7% at 100% loads

8. Analyze compressor oil – High moisture levels can indicate a purge unit

problem, which has a significant effect on efficiency

Evaluating Old Equipment

10 Tips for increasing chiller efficiency

9. Check wiring – check chiller electrical connections, wiring and

switchgear for hot spots and worn contacts.

10. Modulate speed – Under the right operating conditions, variable speed

drives offer significant energy savings. Variable speed drives also act as "soft starters" to reduce the motor's inrush current

Thanks! Any Questions?

Please visit the Tradeshow for over 250 exhibits and food services!

Wednesday : 9:30am – 4:00pmThursday: 9:30am – 3:00pm