The university's Central Utility Plant (CUP) produces steam and chilled water on the Anschutz Medical Campus for the university, UCH, TCH, and the City of Aurora. The steam produced is used for heating, humidification, sterilization, and testing. The chilled water produced is used for comfort and equipment cooling.
The CUP is more energy efficient, reliable, and offers operational savings as compared to having decentralized boilers and chillers. By having all of the boilers and chillers located in the CUP, larger and more efficient boilers and chillers were purchased. As more steam and chilled water is produced, the cost per 1,000 lbs of steam and ton hours of cooling decreases.
The boilers are operated as efficiently as possible. Fuel is purchased at the lowest possible cost. Maintaining a proper water treatment program that eliminates scale inside of all of the boilers maximizes heat transfer. All of the boilers have economizers installed on them that use some of the waste heat from the flue gas to preheat the feedwater going to the boilers 30F to 40F. All of these items reduce energy costs.
The chillers are operated as efficiently as possible. The condenser water that circulates between the chillers and the cooling towers is cooled down to 60 F as often as possible versus the design temperature of 75 F. Doing this along lowers the chiller operating cost by 15% to 25%. Maintaining a proper water treatment program that eliminates scale inside of all of the chillers and cooling towers thus maximizing heat transfer. All condenser water tubes in all of the chillers are cleaned annually to ensure that heat transfer is maximized. The speed of all of the large chilled water pumps and the cooling tower fans are controlled by variable frequency drives (VFD). The VFD’s are programmed to operate at the slowest possible speed. At outside air temperatures of 55 F or lower, the pressure in the chilled water system is reduced. All of these items reduce energy costs. The latest technology in water treatment control allows chemical to be pumped with precision into the condenser water system. An acid feed system pumps acid into the condenser water system to lower the PH. This allows the water to be cycled 8 to 10 times versus the normal 4 to 5 times. These two items save water. The cooling towers evaporate many millions of gallons of water annually. This water is metered and through an agreement with the City of Aurora, the CUP is not charged sewer charges on this water that is evaporated. This item saves sewer charges.
The CUP is staffed 24 hours a day, seven days a week. The CUP Shift Operations personnel are well trained to respond to operational issues quickly. Decentralized boilers and chillers are not typically overseen by an Operator. If there were to a failure in a decentralized plant, response would be slower and the possibility of equipment damage would be very likely.
For information on the Engineering Services section of Facilities Management, please email my.CU.edu Roen, Phone 303-724-1103.