US Army Corps

of Engineers

Construction Engineering

Research Laboratory

Recommendations To Improve

Energy Efficiency at the Soo Area

Office, Sault Ste. Marie, MI

Larry Lister and Martin J. Savoie

In terms of energy consumption, the Soo Area

Office, Sault Ste. Marie, MI is the largest facility

under U.S. Army Corps of Engineers Detroit

District oversight. The entire facility at St. Mary’s

Falls Canal is operated and maintained by the

Detroit District, under the supervision of the Soo

Area Engineer. Energy supply for the facility is

unique because the U.S. Hydroelectric Power

Plant is located just north of the locks. The

installation consumes about 3 percent of the

energy from the plant. Natural gas provides

most of the space heating requirements via

cast-iron sectional hot water generators in the

larger buildings, unit heaters in small buildings,

and fire-tube steam boilers in the steam plant.

The U.S. Army Corps of Engineers Detroit

District requested the U.S. Construction

Engineering Research Laboratory (CERL) to

assess potential energy efficiency improvements

at the Soo Area Office. This study evaluated the

facility for energy efficiency and recommended

improvements in energy efficient operations.

CERL Technical Report 99/70

August 1999

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August 1999

3. REPORT TYPE AND DATES COVERED

Final

4. TITLE AND SUBTITLE

Recommendations To Improve Energy Efficiency at the Soo Area Office, Sault Ste.

Marie, MI

6. AUTHOR(S)

Larry Lister and Martin J. Savoie

5. FUNDING NUMBERS

Small Problems Program

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

U.S. Army Construction Engineering Research Laboratory (CERL)

P.O. Box 9005

Champaign, IL 61826-9005

8. PEFORMING ORGANIZATION

REPORT NUMBER

TR 99/70

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES)

U.S. Army Corps of Engineers Detroit District, Soo Area Office

ATTN: CELRE-CO-SO

119 E. Water Street

Sault Ste. Marie, MI 49783

10. SPONSORING / MONITORING

AGENCY REPORT NUMBER

9. SUPPLEMENTARY NOTES

Copies are available from the National Technical Information Service, 5385 Port Royal Road, Springfield, VA 22161

12a. DISTRIBUTION / AVAILABILITY STATEMENT

Approved for public release; distribution is unlimited.

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13. ABSTRACT (Maximum 200 words)

In terms of energy consumption, the Soo Area Office, Sault Ste. Marie, MI is the largest facility under U.S. Army Corps of

Engineers Detroit District oversight. The entire facility at St. Mary’s Falls Canal is operated and maintained by the Detroit

District, under the supervision of the Soo Area Engineer. Energy supply for the facility is unique because the U.S.

Hydroelectric Power Plant is located just north of the locks. The installation consumes about 3 percent of the energy from

the plant. Natural gas provides most of the space heating requirements via cast-iron sectional hot water generators in the

larger buildings, unit heaters in small buildings, and fire-tube steam boilers in the steam plant.

The U.S. Army Corps of Engineers Detroit District requested the U.S. Construction Engineering Research Laboratory

(CERL) to assess potential energy efficiency improvements at the Soo Area Office. This study evaluated the facility for

energy efficiency and recommended improvements in energy efficient operations.

15. NUMBER OF PAGES

 32

14. SUBJECT TERMS

Soo Area Office locks and dams

Sault Ste Marie, MI energy conservation

energy efficiency

16. PRICE CODE

17. SECURITY CLASSIFICATION

OF REPORT

Unclassified

18. SECURITY CLASSIFICATION

OF THIS PAGE

Unclassified

19. SECURITY CLASSIFICATION

OF ASTRACT

Unclassified

20. LIMITATION OF

ABSTRACT

SAR

NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std 239-18

298-102
2 CERL TR 99/70

Foreword

This study was conducted for Commander, U.S. Army Corps of Engineers Detroit

District, under the “Small Problems Program”; Work Unit, “Energy Efficiency

Issues for Soo Area Office.” The technical monitor was Don Erfourth, CELRECO-SO.

The work was performed by the Energy Branch (CF-E), of the Facilities Division

(CF), U.S. Army Construction Engineering Research Laboratory (CERL). The

CERL principal investigator was Martin J. Savoie. Larry M. Windingland is

Chief, CECER-CF-E, and L. Michael Golish is Chief, CECER-CF. The CERL

technical editor was William J. Wolfe, Information Technology Laboratory.

The Director of CERL is Dr. Michael J. O’Connor.
CERL TR 99/70 3

Contents

SF 298.................................................................................................................................................... 1

Foreword ............................................................................................................................................... 2

1 Introduction ................................................................................................................................... 7

Background .........................................................................................................................7

Objectives............................................................................................................................8

Approach.............................................................................................................................8

Scope ..................................................................................................................................8

Mode of Technology Transfer...............................................................................................9

Units of Weight and Measure..............................................................................................9

2 Electrical Energy Use................................................................................................................. 10

Description ........................................................................................................................10

Recommendations ............................................................................................................11

3 Buildings...................................................................................................................................... 13

Administration and Davis Buildings...................................................................................13

Description...................................................................................................................................13

Assessment .................................................................................................................................13

North Warehouse and South Warehouse. ........................................................................14

Description...................................................................................................................................14

Assessment .................................................................................................................................14

4 Floating Plants............................................................................................................................ 16

Description ........................................................................................................................16

Problem.............................................................................................................................17

High Electrical Use ......................................................................................................................17

Temperature Control ....................................................................................................................17

Humidity Control ..........................................................................................................................18

Insulating the Cabins ...................................................................................................................18

Proposed Solution.............................................................................................................19
4 CERL TR 99/70

5 Central Heating Plant................................................................................................................. 20

Description ........................................................................................................................20

Problems ...........................................................................................................................21

Feedwater System Deaerator ......................................................................................................21

Feedwater Pumping System ........................................................................................................22

Recommendations ............................................................................................................23

6 Air Compressors for Ice Control.............................................................................................. 25

Description ........................................................................................................................25

Recommendation..............................................................................................................25

7 Summary and Recommendations........................................................................................... 26

Distribution
CERL TR 99/70 5

List of Figures

Figures

1 North warehouse lighting...........................................................................................12

2 Warehouse unit heater...............................................................................................15

3 Floating plant equipment. ..........................................................................................16

4 Tug docked in boathouse...........................................................................................17

5 Steam plant boilers....................................................................................................20

6 Steam plant deaerator and blowdown heat exchanger. ............................................22

7 Steam plant – external water treatment system. .......................................................23

8 Utility tunnel. ..............................................................................................................24
CERL TR 99/70 7

1 Introduction

Background

In terms of energy consumption, the Soo Area Office, Sault Ste. Marie, MI is the

largest facility under U.S. Army Corps of Engineers Detroit District oversight.

The entire facility at St. Mary’s Falls Canal is operated and maintained by the

Detroit District under the supervision of the Soo Area Engineer. The facility has

four locks: MacArthur, Poe, Davis, and Sabin. The Poe lock has the largest capacity of the four locks and is the most active. The locks serve many different

types of vessels, varying in size from small passenger vessels and work boats, to

large ships carrying more than 72,000 tons of freight in a single cargo. Approximately 12,000 vessels pass through the locks each year. A proposed new

lock is envisioned in the area now occupied by the Davis and Sabin Locks.

Energy supply for the facility is unique because the U.S. Hydroelectric Power

Plant is located just north of the locks. The 20 megawatt (MW) plant generates

over 150 million kilowatt hours of electric power each year. The first priority for

the power generator is the lock operations. The remaining power is purchased

by a private power company (Detroit Sault Electric Co.) and distributed to homes

and business in Sault Ste. Marie and surrounding communities. About 3 percent

of the energy from the plant is consumed by the installation. Primary use for

electric power on the facility includes:

• exterior and interior lighting

• floating plant equipment

• domestic water heating

• interior space heating (remote buildings only)

• air compressor plant

• dewatering pumps for lock maintenance

• process loads for hydroplant and steam plant operations

• electric vehicle charging

• electrically-driven lock gate operators

• building loads (receptacle loads for typical office equipment).

Natural gas provides most of the space heating requirements via cast-iron sectional hot water generators in the larger buildings, unit heaters in small buildings and fire-tube steam boilers in the steam plant. A new steam plant was con-
8 CERL TR 99/70

structed in 1996, located between the Poe and Davis locks, to generate high pressure steam for operating two 70-ton stiffleg derrick hoist machines for the Davis

and Sabin Locks, to deice the locks during the winter, and to provide heat to facility construction projects. An ancillary use is to heat the administration and

Davis buildings.

At the request of the Commander, U.S. Army Corps of Engineers Detroit District, U.S. Construction Engineering Research Laboratory (CERL) staff made a

site visit to the Soo Area Office, Sault Ste. Marie, MI to assess potential energy

efficiency improvements.

Objectives

The objectives of this study were to evaluate the facilities at the Soo Area Office,

Sault Ste. Marie, MI for energy efficiency, and to make recommendations for improvements in energy efficient operations.

Approach

1. CERL engineers made a site visit to the Soo Area Office on 15 April 1999.

2. Lock personnel gave CERL personnel a detailed tour of the facility.

3. CERL engineers surveyed the facility’s electrical energy use, its buildings, floating plants, central heating plant, and air compressors.

4. Soo Lock engineering, and operations and maintenance personnel were interviewed.

5. The condition of the facility components was summarized, and recommendations

made for improved energy-efficient operations.

Scope

This study specifically focused on conditions at the Soo Area Office. However,

some information in this study may be applicable to similar lock-and-dam facilities.
CERL TR 99/70 9

Mode of Technology Transfer

This information will be forwarded directly to the Corps of Engineers Detroit

District, Soo Area Office, Sault Ste. Marie, MI, and will also be made publicly

available through the CERL Internet website at the following URL:

http://www.cecer.army.mil/techreports

Units of Weight and Measure

U.S. standard units of measure are used throughout this report. A table of conversion factors for Standard International (SI) units is provided below.

SI conversion factors

1 in. = 2.54 cm

1 ft = 0.305 m

1 yd = 0.9144 m

1 sq in. = 6.452 cm2

1 sq ft = 0.093 m2

1 sq yd = 0.836 m2

1 cu in. = 16.39 cm3

1 cu ft = 0.028 m3

1 cu yd = 0.764 m3

1 gal = 3.78 L

1 lb = 0.453 kg

1 hp = 9.803 kW

1 psi = 6.89 kPa

°F =(°C x 1.8) + 32
10 CERL TR 99/70

2 Electrical Energy Use

The Soo Area Office Point of Contact (POC) was Don Erfourth, tel. (906) 635-

3468

Description

The primary source of end-use energy at the Soo Area Office is electricity. The

Soo hydroplant generates 20 MW of power that is sold to and feeds the upper

peninsula (Detroit Sault Electric Co.) grid. About 3 percent of the energy from

the plant is consumed by the installation. End-use applications include:

• Exterior lighting, which currently uses high pressure sodium luminaires.

• Floating plant support, which includes all electrical power required when

docked. End-uses are electrical space heating, equipment (strip) heating,

lighting, and all on-board operations such as electronic (receptacle) loads and

equipment (connected) loads (pumps, hoists, cranes, etc.).

• Domestic water heating in most buildings. Chapter 3 includes more detail on

the buildings’ energy use.

• Interior space heating (remote buildings only). Chapter 3 includes more detail on the buildings’ energy use.

• Interior lighting, which currently uses energy-efficient T12 technologies.

• Air compressor plant (3 x 350 hp), which is used for hydraulic lock gate operations, and also seasonally for bubbling air near the lock gates to keep

them clean of ice and snow and for some process compressed air loads.

• Pumping, for which large pumps are used intermittently to dewater the locks

for maintenance.

• Miscellaneous process loads, which include hydroplant and steam plant operations, electric vehicle charging, electrically-driven lock gate operators.

• Miscellaneous building loads, which include receptacle loads such as office

equipment, copy machines, etc.

The marginal cost of this electric energy is quite low, which negatively impacts

the economic cost-effectiveness of electrical energy efficiency projects. In spite of

this impediment, Mr. Erfourth has initiated and executed a large number of energy-saving projects. These include a base-wide mercury-to-high pressure sodium (HPS) conversion that cut exterior lighting energy use by over 60 percent
CERL TR 99/70 11

with no impact on exterior lighting levels. Lighting in the Administration

Building and the Davis Buildings was replaced 3-4 years ago and the most energy-efficient T12/magnetic ballast fluorescent technologies available at that

time were used in those applications. Future interior lighting upgrades (if undertaken) should consider T8/electronic ballast technologies, which are now

technically mature and have become the Government standard for new construction. Based on economics, and the small sizes and distributed locations of many

of the buildings, further replacing existing interior electric heating with other

fuel-based heating sources is not recommended. Better thermostatic and/or time

clock control of these electrically heated structures are and should continue to be

considered on an individual basis based on occupancy and the need for maintenance or replacement of faulty systems.

Individual behavior patterns can dictate the efficient use of electricity to a large

extent because humans directly control many of the end uses themselves. A significant part of the installation Energy Manager’s job (on larger posts) is in fact

to teach energy awareness. Discussions with personnel across the installation

indicated that the diligence Mr. Erfourth has shown toward energy efficiency in

their departments has impacted their behavior and subsequently has reduced

electricity use across the installation. This personal effort is a large part of why

the Soo Area Office exhibits such exemplary energy behavior patterns. While

there is no way to account for the amount of energy being saved by this individual, his impact was evident and his performance is to be highly commended. He

appears to view every project being implemented at The Soo s an opportunity to

increase energy efficiency

Recommendations

Replace existing fluorescent lighting systems with T8/electronic systems at the

next time of building rehab or wide-scale lighting replacement. Replacement of

the functioning T12 luminaires is not warranted on economic grounds alone.

Consider increasing light levels in the utility tunnel, and installation of a lighting control system for the utility tunnels running parallel to the locks. Such a

system must be carefully designed to allow workers to not be trapped inside the

tunnels if lights go out. This is unlikely to have a positive economic payback, but

these tunnels reportedly have lights on quite often when there is nobody working

or traversing the tunnel. Light levels were slightly restrictive in the tunnel, allowing plenty of light to walk from point-to-point in the tunnel but not enough in

many places to do close work or perform repairs
12 CERL TR 99/70

Continue to monitor space heater control condition in remote structures to ensure that controls are working as intended and are not set too high. Install DDC

monitoring and control system for floating plants operations (see separate section below).

Upon failure of existing systems, replace warehouse lighting (Figure 1) with

T8/electronic ballasted luminaires. The 8-ft fixtures should be replaced with 4-ft

strips. It is recommended that the system be master/slave wired so that a single

ballast is driving 3 or 4 lamps.

Figure 1. North warehouse lighting.
CERL TR 99/70 13

3 Buildings

The following buildings were toured and inspected by CERL engineers:

• Administration Building (incl. control tower)

• Davis Building

• North Warehouse

• South Warehouse

• Hydroplant

• Steam Plant (new)

• Boathouse.

The first four main buildings cited above comprise a large percentage of the

normally occupied and conditioned square footage. A majority of the office-based

personnel work in or are based out of these four buildings. A short summary of

the observations in these areas follows.

Administration and Davis Buildings

Description

These historic buildings house a number of administrative and engineering staff at

the Soo. The Administration Building (built in 1896) occupies an area of 23, 292 sq

ft, and the Davis Building (built in 1914) covers 8898 sq ft. The Administration

Building also contains the control tower used to oversee navigation and lock operations. These buildings are heated by steam radiators connected to either central

plant steam or a backup steam boilers installed in 1988. The backup boiler is used

during the late spring and early fall when the seasonally-operated process steam

plant is no longer in use.

Assessment

The use of the “end-of-pipe” steam by both the Administration and Davis Buildings is

an extremely efficient way to heat these buildings during the coldest months. The

building heating system appeared to be in very good condition. Building renovations

currently underway will replace the old windows with energy efficient units. Light-
14 CERL TR 99/70

ing systems are described in the above section. No further energy conservation efforts are warranted in these buildings.

North Warehouse and South Warehouse.

Description

New boilers have been installed to serve the North and South Warehouses. The

existing North Warehouse brick building envelope, along with its overhead doors

and windows is rather leaky. Operation of this building requires frequent overhead door opening year-around.

Assessment

Because of this use pattern, a more energy-efficient approach to space heating

would be to replace the overhead steam-fed unit heaters (Figure 2) with gas-fired

infrared heaters. Note, however, that the cost-effectiveness is probably not worthy of energy conservation funding. Lighting is of older T12 type, with a number

of 8-ft luminaires still in place. Replacement with T8 and electronic ballasts is

recommended at the time of the next building renovation. The “Recommendations” section in Chapter 2 (p 11) gives further details.
CERL TR 99/70 15

Figure 2. Warehouse unit heater.
16 CERL TR 99/70

4 Floating Plants

The POC for the floating plants was Ed Hallquist, tel: (906) 632-3311.

Description

The fleet of floating plants used by Soo Area Office personnel consists of six

boats that are used on the river during normal workday activities and are docked

at the installation on nights and weekends (Figure 3). In winter, when the

channel is closed, most of the boats are docked until spring. There is dock space

for two boats under cover in the boathouse (Figure 4). While docked, these boats

are connected to installation electrical power at a series of pedestals. Workers

remain on board the boats and work during business hours throughout the winter.

Figure 3. Floating plant equipment.
CERL TR 99/70 17

Figure 4. Tug docked in boathouse.

Problem

High Electrical Use

The floating plants consume a substantial amount of installation electricity that

is used by resistance heaters for space conditioning. At the present time, however, this appears to be unavoidable. Maintaining the worker comfort and space

conditioning requirements in the interior cabin areas of these boats is quite

challenging. There are two separate functions of the space heaters: (1) to provide temperature control (heat) during winter conditions, and (2) to provide humidity control when outside conditions start to moderate. During these latter

conditions, the workers are forced to overheat the interior areas to ensure that

the dew point is not exceeded on interior surfaces, tools, winches and cranes, and

electronic equipment.

Temperature Control

The cabin walls and interior areas below deck are made of plate steel, and the

walls and ceilings are insulated. This makes temperature control during the

winter expensive because of: (1) the low R-value of the walls, and (2) the fact
18 CERL TR 99/70

that the interior air temperatures must be kept substantially warmer than normal to compensate for human body radiant loss to the extremely cold surfaces.

As the surface temperatures rise with outside air, the amount of radiant cooling

near the occupants decreases and comfort can be achieved at a lower interior

temperature. Without the means to automatically control temperatures, the occupants set the heat for the requirement in the morning and late day, and open

hatches midday when they get too warm.

Humidity Control

According to Mr. Hallquist, humidity is a major problem with the operation of

the floating plants. The problem is caused because the water that the boats sit

in stays very cold much later in the season than the air does, and the conductive

nature of the cabins and hull keeps the interior surfaces cooler than the warmer

air that starts to occur as spring arrives. Since this air is often saturated, the

dew point is easily achieved on the interior surfaces of the boats and large

amounts of condensation result. Workers told numerous stories of electronic

(and other) equipment damaged by moisture, lost work time due to cleaning and

oiling tools, and safety problems due to wet cables on winches and cranes. To

control this, personnel are forced to overheat the cabins to absorb the humidity,

and then open doors and windows in an attempt to achieve comfortable working

temperatures. The best way to efficiently account for this and simultaneously

save installation energy is to install a control system to regulate electric heaters

in response to either temperature or humidity requirements.

Insulating the Cabins

Spray-on bonded cellulose and fiberglass marine hull board has been installed on

the interior ceiling and walls of the derrickboat, S/V Bray and the two harbor

tugs. The insulation is not continuous in any of the plant due to the problems

previously noted. This has helped the thermal comfort situation, but has caused

other problems. First, the large temperature difference that sets up across the

insulation allows the dewpoint to be reached inside the insulation. Under humid

conditions, this causes moisture retention and mold growth in the insulation,

which also deteriorates its thermal properties. Second, the choices for insulation

materials are limited by fire and marine-rating restrictions. And third, a safety

problem has been noted on the deck areas above which insulation has been

placed. In many cases, the heated side of the deck plate has been insulated. The

supporting angle iron framing projects below the insulation and transmits heat

to the deck. The frost on the deck melts in long stripes above the framing so that

moisture runs and freezes over the insulated plate. As a consequence, the deck

develops ice, which causes a slip hazard. These interrelationships and compet-
CERL TR 99/70 19

ing effects make the use of insulation a problem. The use of insulation actually

makes the decks more dangerous from accumulated ice and frost

Proposed Solution

CERL engineers recommend the design and installation of a direct digital control

system (DDC) to control the temperature and humidity conditions inside the

floating plant cabins, and to monitor critical conditions inside the cabins such as

valve freezing, high water (water leakage), and lack of power or heat. The pedestals are already equipped with LAN drops that will provide the communications between the warehouse office and the docked plants. The design of such a

system should be done by an independent, third-party engineering consulting

firm that specializes in DDC control systems and is familiar with a number of

vendors products. CERL has experience with dealing with such firms, and is

available to work with Detroit District and Mr. Hallquist to define the control

requirements for this project.
20 CERL TR 99/70

5 Central Heating Plant

The facility tour was provided by Mr. Ricky Southwell, Plant Supervisor.

Description

The plant consists of three, 150-hp fire-tube boilers (Figure 5) manufactured by

Superior Boilers. The plant went into operation in 1996. Output is rated at

5,175 lb/hr steam at 150 max pressure. The plant’s primary function is to provide direct steam heat to the locks to keep ice off the gates. When the plant is

on-line it also provide steam to some of the buildings for space heating. The

plant was offline for the spring/summer season. The system will typically use

about 4,000 to 5,000 gal of water in an 8-hour period. The water conditioning

system is designed to provide a maximum of 30 gal/min to the DA tank. There

are three feedwater pumps rated at 7 1⁄2 Hp, 3450 rpm, 30 GPM. The feedwater

pumps are Lockwood Products, Atlanta, GA model HG08-3

Figure 5. Steam plant boilers.
CERL TR 99/70 21

Problems

Feedwater System Deaerator

A potential problem exists in the feedwater system. Apparently, the original design had sought to obtain make-up water at around 50 °F from new ground water wells. These wells were removed from the project because it was determined

that they were not cost effective. Instead, make-up water was obtained from the

water passing through the locks. This water is very close to 32 °F while the

plant is in operation. There is a small make-up water preheat system which uses

continuous blowdown water from the boilers. However, this system is not large

enough to prevent very cold water from entering into the Deaerater (DA) tank,

causing thermal shock and preventing the DA from functioning correctly. The

DA tank head temperature has been seen to drop from 230 to 180 °F.

The purpose of a deaerating heater (deaerator, see Figure 6) is to remove noncondensable gases and dissolved oxygen from the feedwater. A properly operating deaerator will have no more than 10 ppb (parts per billion) O2 in the outlet

water. Deaerators are subject to thermal cycling and corrosion. Proper operation of deaerators is extremely important because of their critical function in protecting the boiler system from corrosion. Catastrophic failure of deaerators is

usually attributable to cracks forming longitudinally and transversely to the

heat affected zones of the welds. Deaerators are potentially a great danger because of their location at the top of the heating or power plant. To ensure that

deaerators provide safe reliable service, they require periodic visual inspections

of their internal and external surfaces. If visual inspection reveals cracking,

then a company specializing in deaerator inspection must perform an ultrasonic

examination of the entire vessel and wet fluorescent magnetic particle examinations of the heat affected zones of the welds before certification to determine if

continued operation of the vessel is safe. Repairs must be subjected to post-weld

heat treatment and hydrostatic testing before certification.

Particular attention should be given to deaerator venting practice. Venting

should be held to the minimum required to preclude oxygen entrainment in the

feedwater. When intermittently operating condensate pumps are used, look for

any tendency toward the creation of a vacuum when a pump starts. If this happens, the installation of a small continuously operating, float throttled, condensate pump (in parallel with intermittently operating pumps) will ensure a condensate flow at all times. If there are a number of intermittently operating

condensate pumps, it may be possible to convert one of them (if of small enough

capacity) to continuous throttled operation.
22 CERL TR 99/70

Figure 6. Steam plant deaerator and blowdown heat exchanger.

Feedwater Pumping System

Another potential problem existing in the feedwater pumping system. The

pumps may be cavitating and experiencing extensive cycling. This problem may

be caused by the DA tank being located too low in elevation above the pumps.

Low elevation can result in NPSH at the pump inlet which causes cavitation. In

designing these systems, the minimum recommended elevation of DA tanks

above the feedwater pumps is 7 ft. The existing DA tank is only about 4 ft above

the pumps.

The boilers also experience load surges from the steam users, which causes low

water problems at the boilers. Surge tanks are often installed ahead of feedwater heaters to prevent surging problems

The external water treatment system (Figure 7) is a typical sodium zeolite softening system. This system may also be experiencing surge problems from rapid

demands by end-use equipment, which could be solved by using a surge tank.
CERL TR 99/70 23

Figure 7. Steam plant – external water treatment system.

The internal water treatment program is reviewed twice per year by the water

treatment chemical supplier. The operating staff also checks the boilers 3

times/week (Monday, Wednesday, Friday). Sulfites are added at the boiler and

are maintained between 60-30. P-alkalinity is maintained at 400-600. Conductivity is maintained at 2000-2500. The internal water treatment should be adequate for steady state operation, but may become deficient if the boilers experience large fluctuations in steam demand.

The steam distribution system is located in tunnels that run alongside the locks

(Figure 8). No condensate is returned to the boiler plant. There were no signs of

pipe leakage or damage in the tunnels.

Recommendations

• Boiler system design should be assessed to determine corrections for DA and

feedwater problems.

• Boilers should be inspected/tuned-up to ensure efficient operation.

• Boiler operators should receive onsite training (which could be combined with

the boiler tune-up/inspection activity).

• Boiler lay-up procedures should be reviewed to optimize equipment life.
24 CERL TR 99/70

Figure 8. Utility tunnel.
CERL TR 99/70 25

6 Air Compressors for Ice Control

Description

Three 350 hp electric air compressors supply air for a bubbling system to control

ice blockage at the gates. The bubbling system is needed during the spring and

fall. Two air compressors will run 24 hrs/day when ice is present in the locks.

Space heating for the Compressor Building is provided by waste heat from the

compressors with back-up from electric heaters. The compressors were not in

operation during the site visit, but appear to be well maintained.

Recommendation

Conduct a distribution leak inspection and repair lines, if required.
26 CERL TR 99/70

7 Summary and Recommendations

This study evaluated the facilities at the Soo Area Office, Sault Ste. Marie, MI

for energy efficiency, and makes the following recommendations for improvements in energy efficient operations:

1. Lighting.

a. Replace existing fluorescent lighting systems with T8/electronic systems at

the next time of building rehab or wide-scale lighting replacement.

b. Consider increasing light levels in the utility tunnel, and installation of a

lighting control system for the utility tunnels running parallel to the locks.

c. Continue to monitor space heater control condition in remote structures to

ensure that controls are working as intended and are not set too high.

d. Upon failure of existing systems, replace warehouse lighting (Figure 1) with

T8/electronic ballasted luminaires.

2. Buildings. Because of the use pattern of frequently opened overhead doors, a

more energy-efficient approach to space heating would be to replace the overhead

steam-fed unit heaters with gas-fired infrared heaters. However, note that the

cost-effectiveness of this change may not justify the expenditure of energy conservation funding.

3. Floating Plants. Install a direct digital control system (DDC) to control the temperature and humidity conditions inside the floating plant cabins, and to monitor

critical conditions inside the cabins such as valve freezing, high water (water

leakage), and lack of power or heat.

4. Central Heating Plant.

a. Boiler system design should be assessed to determine corrections for DA and

feedwater problems.

b. Boilers should be inspected/tuned-up to ensure efficient operation.

c. Boiler operators should receive onsite training.

d. Boiler lay-up procedures should be reviewed to optimize equipment life.

5. Air Compressors for Ice Control. Conduct a distribution leak inspection and repair

lines, if required.
CERL TR 99/70 27

USACERL DISTRIBUTION

US Army Corps of Engineers Detroit District

ATTN: CELRE-DE (5)

US Army Corps of Engineers Soo Area Office

ATTN: CELRE-CO-SO (2)

Chief of Engineers

ATTN: CEHEC-IM-LH (2)

ATTN: CEHEC-IM-LP (2)

ATTN: CECC-R

ATTN: CERD-L

ATTN: CERD-M

Defense Tech Info Center 22304

ATTN: DTIC-O (2)

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