The campus electrical service originates at the Heating/Chilling Center. Two separate (preferred and alternate) primary, sources of 7.2/12.5 KV are provided from Wisconsin Public Service (WPS) to weather-protected 15KV switchgear. The switchgear consists of two 15KV main circuit breakers (preferred and alternate), metering and six (6), 15KV feeder breakers. In order to transfer from one source to the other, WPS is required to de-energize the services, while the campus electricians mechanically make the switch over.
Two of the feeder breakers serve the Heating/Chilling Center. One serves the facility substation in the basement and the other feeds an oil-ﬁlled exterior transformer, which serves a 4160 V chiller on the ﬁrst ﬂoor. The remaining four feeder breakers serve the following groups of buildings: 1) Lab Science, Environmental Sciences and Instructional Services. 2) M.A.C. Hall, Kress Events Center, Physical Plant, Sports Lighting, Parking and Street Lighting. 3) Rose Hall, Wood Hall and Cofrin Library. 4) Student Services/Union, Theater Hall, Studio Arts and the Weidner Center. The primary distribution system is composed of 15 KV shielded polyethylene insulated cables run in ducts, encased in concrete, with manholes every 250 FT or less. The system is a basic multiple loop system, where the loops are operated open with sectionalizing switches pad mounted outdoors to permit feeding the entire load on the loop from either terminal. There is one spare switch terminal available at a pad- mounted switch located adjacent to manhole P-8 and one spare switch terminal available at a pad mounted switch adjacent to P-15. Not all the facilities are on the loop; some are radial fed. The loop system is preferred by the Facilities Management Department.
All the residence hall buildings in the northeast corner of the campus are served directly from WPS services at less than 600V. These buildings are separately metered.
The main switchgear is original equipment installed in 1970, but is in fair condition. The main breakers were cleaned in 2001. There are no spare breakers and the space within the switchgear yard is full and not expandable without fencing and wall revisions. The cables and sectional switches were installed in 1985 and the campus has not experienced any problems with this system.
Power Distribution (Normal Power):
The facilities on campus each have their own service transformer located in a vault, which provides the building with 480/277 V or 120/208V, 3 phase, 4-wire power. Some of the transformers are original and others have been upgraded or replaced. The metering and distribution equipment within the facilities varies in type and condition depending upon the age of the system and the amount of upgrades or additions done in the past. Rose Hall and Wood Hall do not have main disconnects on the secondary side of their service transformers.
Power Distribution (Emergency Power):
Many of the campus facilities have emergency stand-by generators. The smaller units (100 KW and smaller) are natural gas type. The larger units are diesel type with associated fuel storage tanks. The generators are 480 V or 120/208 V depending upon the normal service to the building. The Lab Sciences building has two generators; a newer diesel unit, which serves the Lab Sciences, and an older natural gas unit, which serves Environmental Sciences and Instructional Services buildings.
Uninterruptible Power Systems:
The Instructional Services Building contains the Campus Main Telecommunications Network equipment. The equipment is connected to individual UPS units. There is no main shut-off for the banks of UPS’s.
Site Roadway, Pathway, and Parking Lighting:
The campus pathway lighting was replaced in the mid 1990s with “Kim” semi-cut-off ﬁxtures on pedestrian scaled poles in all locations except for the plaza lighting of the library. The “Kim” ﬁxtures are in good shape and provide adequate illumination. The roadway lighting ﬁxtures are cobra head style ﬁxtures arm mounted to poles. In the late 1970s, to reduce energy consumption, every other ﬁxture was removed and the remaining ﬁxtures were retro ﬁtted with high-pressure sodium lamps.
Cofrin Library Lighting
As lighting on campus is updated, fixtures should be cut-off type and should conform to the International Dark-Sky Association Standards.
Central Heating/Cooling Plant:
The campus is set up with a central boiler, chiller, and compressed air distribution system via an underground “walk-through” tunnel. The central plant is actually located at the south end of campus, across Highway 54/57. The tunnel extends to the north with a partial section of tunnel extending to the east, while the main tunnel artery feeding existing buildings runs to the west and then to the north ending at the Theatre Hall. The piping in the tunnel is sized for a campus of almost twice the existing size. A majority of the equipment in the central plant has been replaced. Existing equipment which is original has been well maintained and is in very good shape. All utilities are metered separately, however the steam, chilled water, and compressed air utilities supplied to the campus by the plant are not metered.
The student residential housing complex at the northeast corner of campus uses gas, water, sewer, and electric. The water is distribute from the campus system while the sanitary is a separate feed. The electric and gas are separate feeds to this area from WPS corporate mains.
The chilled water system has three chillers, a 1400-ton electric chiller, 1200-ton electric chiller and a 725-ton steam turbine chiller. The turbine chiller is not used and needs some repairs. Each of the chillers has a circulating pump which pumps into the primary variable ﬂow campus chilled water distribution system. This loop distributes chilled water to the campus through the underground tunnel system.
There are two primary chilled water pumps, 300 HP variable speed pump, and a 150 HP variable speed pump. The 150 HP pump can easily maintain the system ﬂow for one chiller, but not two. The 300 HP pump can handle three chillers on line. There were ﬂow restrictors installed in the distribution piping from the chilled water mains to each of the buildings to help balance the ﬂow and maintain pressure in the main piping system. The original pumping system used a primary distribution pump and building secondary pumps. This system was removed due to problems maintaining a return water temperature differential and over pumping the loop. There have been no issues with cooling of any of the buildings on campus as long as they maintain 45F water temperature.
The underground piping system has a capacity of 320,000 gallons. This storage ability allows for one hour of peak load capacity. The campus currently drops the loop temperature at night to below 39 degrees and uses that capacity during the day by demand limiting the chillers. Past campus operation has been to demand limit to a maximum of one chiller. With the increase in new buildings and remodeling on campus, the campus load on a peak day is actually 2,700 tons by calculation. The actual load by diversity is 2,400 tons. This requires that both chillers operate to maintain system temperature through the day. By continuing their demand limit concept, they essentially lose capacity on their buildings before noon with only one chiller operating.
By operating the existing two chillers at full load and utilizing the underground sub-cooled loop, the campus can add 400 tons or 15 percent capacity without additional equipment. The piping and primary variable speed drive pump system could actually support a third pump and chiller which would allow the campus load to grow by 50 percent.
There is a 6” compressed air pipe which runs through the underground tunnel system feeding pneumatic air to each building. Compressed air is primarily used for the temperature control system. This system also provides air for the art and woodworking classes in Studio Arts and the laboratories in the Laboratory Science Buildings. All of the buildings on campus are connected to the main air compressor system, except for the recent building, M.A.C. Hall, which has its own separate air compressor. There are two 25 HP air compressors in the central heating/cooling plant distributing 100 lbs. pressure throughout the tunnel system. Only one compressor is required to operate to maintain load. There are no capacity problems with this existing system.
The steam system utilizes two 60,000 lb/hour boilers (one is decommissioned), one 30,000 lb/hour boiler, and an 8,000 lb/hour summer boiler. The summer boiler is slated for replacement by three 15,225lb/hr high efficiency boilers in 2005. Steam is distributed at 100 lb. pressure and is reduced in pressure at each of the buildings to 15 lb. pressure for use in the heating systems.
The steam system has a large de aerator and water conditioning system for maintaining the physical condition of the equipment and piping. There is a condensate return piping system which utilizes individual building condensate pumps to return the condensate back to the boiler plant. The typical temperature of the re-turn water is 160 degrees. Approximately 90 to 95 percent of the water is returned back to the de aerator system.
A calculated maximum peak load for the campus is 45,000 lbs/hour and the actual operating capacity with diversity is 38,000 lbs/hour. The summer load is approximately 8,000 lbs/hour during the peak summer months which allowed minimal operating time on the old summer boiler. An 18,000 lbs/hour load is anticipated in the spring and fall months.
The existing boiler equipment and piping system can easily support a campus of twice its current size.
There are 12” and 10” city water mains which feed the campus from the south. There is also an 8” main that comes off Nicolet Drive on the northeast side of cam-pus. One of the water meter pits (12” service at the south-west) has been decommissioned by the city due to pipe failures. The water system is a semi-circular loop which is not connected at the south end. Many of the buildings are fed with 3” or 4” distribution piping from the main which will not accommodate adding a ﬁ re protection system in the future. The city water pressure to the building is 45 psi and is marginal for system requirements.
Some of the buildings have water softeners, although the water system is from the Green Bay Water Department which has a lower mineral content than surrounding areas. Many of the buildings have back ﬂow preventers installed to protect the main water system. Maintaining and sizing of these is critical. The campus is at the end of the city water mains. There is a 16” high pressure water main at the east side of campus, installed in 1982, to serve the new residential and institutional construction north of campus. This main is available to supply campus, utilizing a pressure regulator. Division of State Facilities (DSF) has initiated a water survey to clarify future water main needs.
There is a natural gas pipe which is extended throughout the campus. This pipe is separate from the tunnel piping system. The natural gas piping feeds the emergency generators in designated buildings, classrooms in the Laboratory Building and the Studio Arts building. The natural gas is distributed at a high pressure and reduced in pressure at each of the buildings. The natural gas piping system that feeds the campus originates from the physical plant meter.
There is a separate 2” gas main which feeds the UW-Housing residence hall buildings and the Union building kitchen loads.
Storm and Sanitary:
There are two main storm and sanitary distribution points for the campus. The two sanitary pipes are connected to the city mains in Nicolet Drive. The two storm pipes discharge to the Waters of Green Bay. One set is extended from south of campus and the other is from the north. The storm and sanitary systems are ad-equate and will accommodate future expansion. The Union has grease separators to protect the piping system. There are also various other storm water discharges to Mahon Creek and City water easements. The UW-Green Bay housing area has a separate 8” sanitary main.
There is a concurrent and separate UW System Stormwater Study being conducted by OMNNI Associates which will provide for water retention and ﬁltering of the storm water systems on campus.