Ohsu Claderas Cleaver - Brooks

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Pr of i l esC ustomer Solutions, Ideas, Perspectives Vol. 4, March 199

Cleaver Brooks

A Division of Aqua-C hem, Inc

Universi ty s Central Plant Renovat ionCr ea tes Ef f ic ie ncy, Sig ni f ican t Co st Sav in gs

Or eg o n Hea l t h S ci e n c es Un i v er s i t y s cen t r a l u t i l i t i e s p l a n t f e at u r es tw o C l ea v er - B r o o k s i n d u s t r i a l wa t e r t u b e b o i l e

a l o n g w i t h a 2 00 ,0 00 l b ./ h r d u o - t a n k Sp r a yma s t er deaer a t o r . T h e 4,5 00 -s q u a r e- f o o t f a ci l i t y i s p a r t o f a r e n o v a t i o n

p r o j e ct s t a r t e d i n 1 9 9 6.

Perched majestically atop a hill over-

looking downtown Portland, Oregon

Health Sciences University (OHSU)

has established itself as a virtual pan-

theon to medical research, educationand patient care.

Steeped in tradition tracing back to

the 1800s, OHSU today is one of the

few academic health centers in the

nation not affiliated with a larger,

state university system. The 200-acre

campus is home to schools of medi-

cine, nursing and dentistry, as well as

Oregon's first full-service children's

hospital. Thirty-five buildings are

clustered on the hillside, housing over10,000 students, faculty and profes-

sionals.

In 1995, the university broke away

from the state educational system,

and now stands alone as its own enti-

ty; an independent non-profit corpo-

ration. That independence has crea

freedom and flexibility for the cor

rations decision-makers.

Those decision-makers were puttask in 1996, as the university set

to upgrade its utilities plant. An ev

increasing load, coupled with a s

rounding community sensitive to

environment, provided the ultim

HVAC challenge.


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The 1996 renovation and expansion of

the OHSU central utilities created

many design variables. Due to the

unique uphill layout of the campus,

engineers faced challenges in provid-ing adequate condensate return from

the steam system loop. The communi-

tys desire for green space also meant

the utility would have to be designed

with a low profile in mind, while meet-

ing efficiency and emissions expecta-

tions of facilities management.

With wide steam load demands fluctu-

ating from 15,000 lbs./hr during thesummer months, to 150,000 lbs./hr

during cold winter snaps, facilities

management made the decision to

install an additional industrial water-

tube boiler to work in tandem with an

existing 40,000 lb./hr Cleaver-Brooksindustrial watertube.

They wanted redundancy built into

the system, and with those load fluctu-

ations you can respond faster with

watertubes, said Pacific Energy

Systems Aaron McCabe, lead engi-

neer on the project.

McCabe specialized in steam systemdesign for Pacific Energy Systems, an

engineering firm located in Portland,

Oregon, known for its quality work.

The small building housing the

nal boiler was expanded to

square feet, and a new 60,000 Cleaver-Brooks industrial wate

was added, bringing the new c

plants capacity to 100,000 lb

Across campus, two older water

serve as backup to the central

bringing total system capaci

150,000 lbs/hr.

A 200,000 lb./hr Cleaver-B

Spraymaster duo-tank deaeratoalso added to the system, and pla

the new central plant. The duo

which offers a smaller footprint

two separate tanks, combines a

gallon surge tank and 4,000 g

deaerator tank enclosed in one

for ease of installation and val

floor space savings.

Saturated steam generated at the

plant travels through a common

er at 225 psig and 393 F int

campus loop. A series of reducin

tions are then used to distribut

steam for heat and hot water sy

applications, and for sterilizatio

humidification. While steam tem

tures remain constant, steam pre

is regulated to as low as 3 psig at

points in the loop.

Efficiency, LowEmissions Built inThe magnitude of production dem

on the OHSU plant are evid

through historical data logging. O

annual basis, the utility faces an

age daily load of 50,000 lbs./hr,

consuming some 17,000 to 2

therms of natural gas per dayplant runs on natural gas about 90

Cent r a l p lant p re sents d esign cha l lengesCondensate return, green space among engineering priorities

0 ,0 00 l b ./ h r Cl e a ver - B r o o k s i n d u s t r i a l w a t e r t u b e

l er i s o n e o f tw o wa t e r t u b e s i n t h e OHSU cen t r a l p l a n t .


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periods of peak gas demand in the

winter.

Meeting those production demands,

while still hitting the design criteria

for efficiency, low emissions and an

environmentally-friendly central plant

were crucial obstacles to hurdle in the

renovation project.

This community likes its green

space, and Cleaver-Brooks helped us

design our plant to be low profile,

said Bill Botieff, manager of utili-

ties/energy management at OHSU. He

pointed to examples such as reduced

stack heights and low emission burn-

ers as key design elements.

The industrial watertubes are fitted

with low emission Coen QLN burn-

ers, designed to match combustion

air-to-fuel mixture precisely for high-

er ultimate efficiencies. The 60,000

pound boiler/burner package provides

fuel-to-steam efficiencies of 83.4 per-

cent on natural gas at full fire, and

86.3 percent on No. 2 oil. The burners

meet low NOx guarantees without theuse of flue gas recirculation an

option that was very attractive to

OHSU facilities staff.

The newest Cleaver-Brooks boiler is

fitted with a rectangular, finned tube,

counterflow stack economizer to help

heat pretreatment water and further

enhance efficiency.

The outstanding efficiency perfor-mance of the central plant has trans-

lated into significant costs savings. An

aggressive insulation program on the

high pressure steam piping, along

with close monitoring of chemical

usage, condensate systems, fuel and

electricity all have helped produce

savings.

Weve saved in excess of $2 millionin the last two years on our overall

utilities bill, Botieff said. Its

phenomenal...our administrators are

impressed.

The university has actually received

awards from the community for being

low polluters. Because it is deemed a

potential polluter by Oregons

Department of Environmental

Quality, OHSU is permitted to release

500 tons/yr into the atmosphere in its

air quality control district. In reality,

the central plant is only emitting about

3 tons/yr, according to Botieff.

Location of the new central utility,

elevated some 600 feet above most of

the buildings on campus it serves, also

created unique design challenges for

the condensate return system. The

steam system was designed for 85

percent steam recovery in the form of

condensate, with 15 percent makeup.

That collection system was a real

challenge because youve got all these

different buildings that you have to

collect from, and an 1,800-foot con-

densate return pipe coming back,

McCabe said.

McCabe said specification ofoversized deaerator was, in part,

ten with the overall condensate r

balance in mind.

We were looking for surges in

densate returns, so with the duo

wed have a reservoir to even ou

help balance the flow as bes

could, he added.

Due to the length and height o

condensate run, maintaining sy

design condensate return tem

tures of 180 F was also a con

Botieffs Heat Plant Coordin

Jerry Witt, has worked closely w

Cleaver-Brooks representatives

Cole Industrial in Beaverton, Or

to remedy the situation.

The problem was we didnt wa

have to use the steam to heat the w

going to the deaerator, Witt

With the C-B guys, and our

neers, we are overcoming that i

condensate system.

Using a heat recovery device o

boiler blowdown water is just o

the creative ways C-B personne

the OHSU staff have alleviated

condensate temperature concerns

The central plant is now in its

consecutive year without

unplanned shutdown of the steam

tem. Botieff credits his facilities

and its attention to maintenance d

in achieving the performance lev

(Continued on Back)

Weve saved inexcess of $2 millioin the last two yea

on our overallutilities bill.

The OHSU cen t r a l p l a n t i s s er v ed b y a

2 00 ,0 00 l b ./ h r Sp r a ym a s t er d u o -

t a n k d e a er a t o r .


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And, although like most modern-day

boiler rooms the OHSU plant utilizes

a computer building automation sys-

tem, Botieff said his staff never loses

sight of the importance of hands-on

maintenance.

We know the mechanics of the sys-

tem, he said. Technology wont

solve everything. Whatever readings

we can gather off the boiler via com-

puter, that gives us an instantaneous

view of whats going on with that

boiler. But theres still mechanical

oversight we dont want to lose sight

of.

Botieff said he has been pleased with

the central plants evolution, from

design and installation, to perfor-

mance. Its been a total team effort,

he added. We think were unique

here in Oregon to be integrating

building automation, steam and

chilled water product. And that has

not been an easy task.

Pr of i l es is a quarterly publication o f C leaver-Broo ks D ivision, Aq ua-Chem, I nc.featuring ideas, solutions and installation scenarios from our customers.

Cleaver Brooks

Milwaukee, WI (414) 359-0600 www.cleaver-brooks.c

[email protected]

Cl e a ver - B r o o k s R ep r es en t a t i v e St

Fa r nes o f Co l e I ndu s t r i a l he l p s OH

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Ohsu Claderas Cleaver - Brooks

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