Central Utilities is the University of Rochester’s reliable and efficient source of steam, hot water, chilled water, domestic water, natural gas, and electricity for the entire University community. Over the years, there have been continual replacements and updates of equipment and practices to increase the efficiency and output of Central Utilities operations.
One of the primary operations provided by Central Utilities is chilled water for cooling. Chillers are machines that keep water cold at 41-45 degrees F and pump it to buildings such as Strong Memorial Hospital. There the water fills coils positioned for outside air to pass through. The air cools as it passes through the cooling coils, then enters the building supply air ductwork. The chilled water then continues on the loop back to the chillers in Central Utilities, where the cooling process begins again. The Central Utilities Plant and Middle Campus Chiller Plant (MCCP) both provide chilled water to the University. The MCCP is more recent and was built in 2008 with a capacity of 4,000 tons.
Based on existing load, new buildings, and future load analysis, it was determined that the existing campus chilled water system required an increase of 8,000 tons in capacity to provide continued reliable service to campus. In 2011, the MCCP building was expanded to accommodate the new chillers and increased capacity. The project was approved for three more chillers which would increase that output from 4,000 to 12,000 tons. These new chillers are electric, more efficient, and use less energy than the original steam driven chillers. To put into perspective, the coefficient of performance (COP) of the new chillers are at least three times more efficient than typical window unit air conditioners.
Besides the chillers, electric variable speed drives were installed on the chilled water distribution pumps in order to regulate and differentiate heir speed. The variable speed drive changes the speed of the motor depending on demand. It should be as low as possible to be the most efficient and use less power. The previous drives were over 40 years old, mechanical, and not as efficient. Electric chillers with compressor variable speed drives can achieve efficiencies of less than 0.5 kilowatts per ton. Variable speed drives also lead to significant power cost savings because they require less energy to run equipment which saves money, and the payback is typically only a few years. There over 20 variable speed drives in use at Central Utilities on motors ranging from 10 horsepower to as large 900 horsepower.
It is conscientious upgrades like these that show the University’s mindset of environmental responsibility and commitment in all facets of its operations.
By Alanna Scheinerman, Class of 2013