University of Nebraska-Lincoln’s Nebraska Innovation Campus (NIC) Centralized Renewable Energy System (CRES)

In 2012, the developer for the University of Nebraska-Lincoln’s Nebraska Innovation Campus (NIC) started to explore methods to increase the sustainability of the new buildings on the campus. The concept of utilizing the treated wastewater effluent from the City of Lincoln’s Theresa Street Wastewater Treatment Plant (WWTP) was developed to provide renewable energy to the future buildings on NIC. The system is known as the Centralized Renewable Energy System (CRES). The concept for this project was initiated in 2012. The project is now complete and was placed in operation on August 19, 2014.NIC will consist of 2.2 million square feet of building space to house businesses and research facilities. This amount of building space requires significant energy to heat and cool the facilities. The challenge was to provide energy in an efficient and renewable manner that would attract companies with a sustainable mindset to occupy the space.CRES is an innovative approach to heating and cooling buildings; using the heat from the City of Lincoln’s treated wastewater allows the capability of heating and cooling 1.8 million square feet of space. Water that would normally be discharged into the Salt Creek from the treatment plant is pumped to a heat-exchanger building where a series of plate-and-frame heat exchangers are used to decouple the effluent water from the closed loop CRES water that is pumped around campus. The effluent water and the CRES water do not mix. Only thermal properties is transferred between the two systems. The effluent water is then returned to the treatment plant discharge point into Salt Creek. The effluent water temperatures range from 57–75 degrees Fahrenheit (°F), depending on the time of day and the time of year. This temperature of the water is more stable than the temperatures of a typical closed-loop geothermal heat pump loop where temperatures can range from the low 40s to the upper 90s. This temperature stability adds to the CRES efficiency and electrical energy savings.This CRES project is a sustainable design solution that provides a benefit to social acceptance of the development of NIC. Not only does the project reduce the amount of natural gas and electricity consumption at NIC, but it is also being used by the University of Nebraska to attract businesses that want to utilize renewable energy sources. The attraction of these types of businesses helps create jobs for the community and keeps a highly technical work force within the City of Lincoln and the state of Nebraska.