R1, a 650,000-square-foot laboratory, houses flexible laboratory, lab support spaces, and offices. The University of Colorado Anschutz Medical Campus realized that relative to energy consumption, R1 was under-performing in comparison to other buildings on the campus.
This was partly due to the inability to recover energy from building systems, excess pressure drop in air handling systems due to unnecessary sound attenuation devices, and inefficient use of lights in the facility. The University undertook a major effort to decrease energy consumption while increasing the comfort and safety of occupants. The results were astounding—the energy conservation improvements resulted in an annual savings of roughly $900,000, a considerable amount of steam, and 1.4 million kWh of electricity.
Innovative Application of Technology
Cator, Ruma & Associates (CRA) acted as the prime consultant for this project, providing mechanical and electrical engineering design to rework systems that were not performing to their best potential. Many factors had to be taken into consideration, such as the condition and performance of existing systems, occupant safety and comfort, and budget. A summary of the design follows.
Phase I: During the first Phase of the design, air change rates were reduced to industry standard minimums in the laboratories, lowering the minimum air change rate to six during occupied periods and to four for unoccupied periods, which provided significant fan energy and reheat energy savings.
To confirm that reductions in airflow would not compromise researcher safety, tests were performed prior to construction by the UCD Environmental Health and Safety Department, which proved that the reduced airflows would still maintain a safe environment.
Lighting controls were installed throughout the building. The occupancy sensors in the new lighting control system determines when the unoccupied setback to four ACH occurs. In addition, installing new cooling-only fan coils in the linear equipment rooms further reduced the load on the air handling systems. The airflow savings is approximately 85,000 cfm in the South Tower (300,000 SF).
Phase II: This phase of the project included a run-around heat recovery system, evaporative cooling in the existing air-handling units for the South Tower, as well as the vivarium in the North Tower. Installation of new condensate return systems for the process steam heating system in both Towers was also accomplished. The construction of Phase II required an exhaust fan and an air-handler to be out of commission for several days in order to install the heat recovery coils and the evaporative cooling system.
This long-term outage demanded the airflow reduction be achieved during Phase I. During the construction of the project, additional avenues were found to improve the reliability of the system during outages, such as removal of sound attenuators that were not needed, thereby increasing the available static pressure in the system.
Phase III: Phase III was very similar to Phases I and II, and was performed in the North Tower. Cator, Ruma completed approximately 50% of the required work due to available funding.