Living Lab – 749 University Row
Seventhwave is the energy analyst for 749 University Row and a tenant in the building. As a nonprofit firm specializing in energy consulting, research, and education, Seventhwave’s mission is a good fit for the sustainability goals of the building.
Being a tenant allows the firm to actively add to the body of knowledge for the broader community of building professionals. The building has been measured extensively (see seventhwave.org/building-dashboard for an online dashboard).
Measurements are used for a traditional M&V plan that was set up and conducted as part of the design and construction process. Measurement is also used to create a living lab that furthers internal knowledge of cutting edge performance measures.
The first foray into research came when the HVAC system was selected, and the team recognized that it was designing and installing one of just a few water-source VRF systems in the entire Midwest. Funding from local utilities allowed the system to be studied in depth, including flow rates, temperatures, and power consumption at many points.
Though results aren’t final, initial measurements show that the system performs within 8% of rated efficiency, but is underperforming at part load. Ongoing research will investigate what is causing the system to perform or underperform in various scenarios.
The advanced lighting controls in the building are also the subject of significant study and learning. So far, the primary area of research has been demonstrating task tuning. Task tuning is the practice of using dimmable lighting to adjust light levels so that illuminance is appropriate for the activity in the space. Savings from tuning were greater than 20% in two spaces studied in the building, with very little additional effort or cost. (See seventhwave.org/tasktuning for a full report.)
The performance of demand controlled ventilation in a VRF DOAS is also being studied. Tenants use occupancy sensors and CO2 sensors to modulate flow from the DOAS. Research has shown this to be a highly effective practice in buildings where the designer specifies a detailed control sequence, and commissioning includes CO2 sensors and that sequence. (See seventhwave.org/dcv for a full report.)
A few other measurements of interest include:
Though the VRF units are not performing quite to their ratings (see Lessons Learned), the DOAS is over-performing. Ongoing measurement of its heat recovery effectiveness shows an improvement from a design rating of 67% effectiveness to an actual effectiveness of 74% based on real-time measurement of temperature at multiple locations in the unit. This is likely due to decreased airflows from the demand controlled ventilation system; design airflow through the DOAS is 8,800 cfm but DCV allows this value to be 6,950 cfm on average.
Though the building was expected to be cooling dominated, the geothermal system has maintained temperatures below 75°F even in the hottest summer months.
The lower level parking lighting includes occupancy sensors that dim the LED lighting by 60% when nobody is present. Occupancy sensors alone save 53% of the lighting energy in the garage.
