Marriott Corporate Headquarters

John Henderson

Marriott Corporation

Marriott Headquarters

• 1977 construction of ~700,000 square feet

• 1986 addition of ~300,000 square feet

• 8 floors including basement

• Office space operates 7 am to 6:30 pm

• Many areas at ~10% operation 24 hours a day, 7 days a week

Marriott HeadquartersHVAC & Lighting Equipment in

1989

• One 900 ton & one 750 ton electric centrifugal– R-11 refrigerant, 0.86 & 0.92 kW/ton efficiencies– installed in 1977 with original building construction

• Two 450 ton chillers, 0.62 kW/ton, R-11, circa 1986• Two 1000 ton cooling towers• Two 350 horsepower gas boilers, 175°F hot water• ~12,000 fluorescent fixtures, two 40 watt U-tubes

each ~1800 assorted incandescent lamps & spots

Marriott Headquarters Project Scenario

• Virtually no maintenance since 1977

• Half of plant didn’t work• Parts leaked, made noise• Not meeting safety

requirements• Not providing building

comfort

boiler room

Marriott Headquarters“Before” Pictures

sample motor

air handler unit

Marriott Headquarters Project Challenges

• Everything needed attention at once• Large budget for the wrong things• Set strenuous daily goals• Conserved energy wherever possible• Considered many new systems• Most work and analysis done in-house

Marriott Headquarters System Solutions

• Short term, through 1994– cleaned up boiler room– rehabbed equipment - motors, boilers, piping,

air handlers, etc.– converted all chillers to R-123– increased cooling tower capacities to 1200

tons– added heat exchanger for free cooling– put electronic ballasts in lighting fixtures

Marriott Headquarters System Solutions

• Long term, 1994 until today– two new traditional chillers, an ice chiller

and a gas/oil absorber– redesigned chilled water piping for more

effective primary/secondary loops– added window films– extensive rebalancing of air handlers– new motors added– new control system added

Marriott Headquarters Variety of New Chillers

• One 670 ton electric centrifugal chiller – replaced 900 ton chiller– 0.53 kW/ton efficiency, R-123 refrigerant

• One 530 ton combination gas/oil-fueled absorber– replaces 750 ton chiller, used for peak shaving

Marriott Headquarters Variety of New Chillers

• One ice chiller and storage system– converted from 450 ton chiller– 2400 tons of ice, or 350 tons of regular cooling,

0.68 kW/ton efficiency, R-123 refrigerant

• One 400 ton electric centrifugal chiller – replaced 450 ton chiller – 0.53 kW/ton efficiency, R-123 refrigerant

• Total of 1950 tons of total cooling capacity, versus 2550 tons previously

ice chiller

ice tank

Marriott Headquarters Free Cooling

• Condenser water from cooling towers can bypass the chillers

• Cooling towers have variable frequency drives

• Up to 500 tons of cooling provided

• Used during mild weather in spring and fall

Marriott Headquarters Cooling Load Reductions

• Replaced magnetic ballasts of fluorescent lighting with electronic ballasts

• Added tinted films to windows - block sunlight to reduce solar heat gain

• Complete balancing of air distribution system, including exhaust system

• EnergyStar printers - used sleep mode to reduce energy use

Marriott Headquarters Cooling System Improvements

• Just finished adding new motors to air handlers- efficiency improved from 87-89% to

94-95%

• New EMS system- Andover 1986 model combined with

1994 model- computerized control, and help

deciding what systems to run when

Marriott Headquarters Project Timeline

• New facility management in 1989• Plant clean-up began right away and

took 18 months• Plant retrofit work began in 1991• Lighting work in 1992• Window work & AHU balancing in 1994• New chillers installed in 1994

– 1 year of construction

• New AHU motors added in 1998

Marriott Headquarters Financing Structure

• Won 1st place ENCOMP award in 1992 for large buildings - got us noticed

• $1 million from Maryland Public Service Commission through Washington Gas– paid for gas absorber

• $1 million rebate from Pepco – replaced one chiller, lighting retrofits, added

window films

• Sold one 450 ton R-123 chiller• Saved money by using in-house labor• Used almost no cash to finance the project

Marriott Headquarters “After” Pictures

boiler room today

color coded piping

Marriott Headquarters Project Results

• Safe, clean, highly efficient plant • Remarkable system innovation &

flexibility• Reduced peak cooling capacity• Much improved tenant/building comfort• No longer using CFC refrigerants

– first CFC conversion to R-123

• Saving 1.8 MWhrs of electricity per year