Energy conservation improvements totaling more than $5 million were recently completed on the mechanical HVAC and lighting systems for the 650,000-square-foot Research Facility 1 (R1) research laboratory building on the University of Colorado Denver Anschutz Medical Campus (UCDAMC).
The UCDAMC built R1 in 2003. Throughout the first several years of operation, the facility was unable to maintain safe hood operation while taking equipment offline for maintenance or failure.
In 2009, Cator, Ruma & Associates (CRA) was hired to conserve energy in the building without disrupting the operations of the users, as well as their safety, security, and comfort. As one aspect of this project, CRA evaluated and provided the correct quantity of air required for the laboratories, vivariums, and the linear equipment rooms. This analysis resulted in a decrease of airflow, which reduces fan energy and frees fan capacity for future changes and additional loads. CRA's first proposed solution included rebalancing the system to achieve lower minimum variable-air-volume (VAV) air change rates during occupied and unoccupied times, while still achieving safe airflow in laboratories. Existing building airflows were at a minimum air changes per hour (ACH) rate of 8 to 10 in the open laboratories and 32 ACH within the alcoves (with and without hoods).
During the first phase of the design, CRA reduced air change rates to industry standard minimums in the laboratories and the vivarium, lowering the minimum air change rate to six during occupied and four during unoccupied periods, which provides significant fan energy and reheat energy savings. CRA also installed lighting controls throughout the building. The occupancy sensors in the new lighting control system determine when the unoccupied setback to four ACH occurs. In addition, by installing new cooling-only fan coils in the linear equipment rooms, CRA further reduced the load on the air handling systems. The airflow savings is approximately 85,000 cubic feet per minute (cfm) in the 300,000-square-foot South Tower. Since each exhaust fan is 50,000 cfm and each air-handler is 82,000 cfm, these could now be taken offline while maintaining safety in the laboratories.
The Environmental Health and Safety Department of UCDAMC performed two investigations (before and after) in a pilot laboratory to test the Phase 1 design prior to construction. Using an ethanol bath to release vapor, the department measured multiple points in the laboratory with a photo-ionization detector. The results showed the reduction in air changes was successful and maintained safe airflows.
Phase 2 of the project included a run-around heat recovery system, evaporative cooling in the existing air-handling units, and installing new condensate return systems for the process steam heating system. The construction of Phase 2 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. This long-term outage demanded the airflow reduction be achieved during Phase 1. During project construction, CRA found additional avenues 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. CRA also reprogrammed the exhaust fan variable-frequency drives (VFD) to over speed and achieve the full load amps rated for the motors. This allowed one of the five fans to be disabled while the other four fans maintained safe airflows. CRA's next step was to replace the motors and the VFDs to achieve the maximum speed of the exhaust fans, which increased the available static pressure in the system, further improved the reliability of the exhaust system, and accounted for the increased static pressure drop of the heat-recovery coils.
In the vivarium of the North Tower, the animals were protected during construction by using a bypass supply air ducting system so one of the two air-handling units could run and supply air to the vivarum, while bypassing the new evaporative cooling system being installed in the common ductwork.
At the completion of the project, a vast amount of energy was saved, the occupants encountered minimal impacts and redundancy, and reliability was finally provided for this critical research facility.
Sean Convery joined Cator, Ruma & Associates, Co., a mechanical/electrical engineering consulting firm of 90 people, in 1995, and is a senior associate in the mechanical department. Mr. Convery has a Bachelor of Science in mechanical engineering and is a professional engineer in Colorado. Mr. Convery has a broad array of experience in the design of mechanical systems, focusing on higher education campuses and research laboratories. Recent laboratory projects include the Colorado State University Research Innovation Center (LEED® Gold pending), Front Range Community College Sunlight Peak Science Building (LEED Gold pending), University of Colorado Boulder Systems Biotechnology Building (LEED Gold pending), and UCD Research Complex energy-efficiency upgrades. Mr. Convery was a presenter at the Labs21 2010 Annual Conference and has received engineering excellence awards from the American Council of Engineering Companies in Colorado for his designs at complex biosafety level-3 campuses.
Kenneth Neeper joined UCD in 1997 to supplement staff in the development of the former Army base into a medical campus. Mr. Neeper has a Bachelor of Science in civil engineering and a broad range of experience in operations, programming, design, and construction on large campuses, with a specialization in medical facilities. In his current role as manager of infrastructure, Mr. Neeper has overseen the development of infrastructure, the central utility plant, and parking for 6,000,000 square feet of research, hospital, and educational space. As a project manager, Mr. Neeper also provides construction management services for the renovation of campus research facilities.