UCSF Genentech Hall
Sustainability - Heating and Cooling

Genentech Hall uses a built-up HVAC system with chiller efficiency of 0.45 kW/ton and variable volume air supply control, with premium efficiency electric motors, and an cooling tower approach temperature of 8°F. Together with efficiencies in building envelope and lighting, this efficient HVAC system results in 22.5% overall energy savings compared to minimum Title 24 requirements.

"Variable volume supply and exhaust systems offer substantial energy savings over traditional constant volume systems. These systems rely on electronic variable speed drive (VSD) motor controllers to reduce airflow and fan electricity use." — PG&E TEAP report

The conventional practice base case for evaluating this building was considered to include a packaged HVAC system with chiller efficiency of 0.75 kW/ton and constant volume air supply control, with standard efficiency electric motors, and an approximate cooling tower approach temperature of 15°F.

The large built-up HVAC system includes three water cooled chillers and four boilers (two steam and two hot water), with variable frequency drive (VFD) pumps and fans throughout.

The mininum air flow level maintained for occupied hours is cut in half for unoccupied hours, using two control system setpoints (i.e. 8 airchanges per hour and 4 airchanges per hour). Maximum and minimum temperature levels are similarly relaxed for unoccupied hours.

Trace was used for HVAC load calculations, and Gayner used their own software for room level calculations.

In the early occupancy stage, engineers initially worked with the facilities staff on some minor issues. The building systems were not holding building temperature very well in some areas, running a little cold. The balance on the reheat coils was found to be incorrect, until they were readjusted, which fixed the problem.

During the commissioning process, duct static pressure appeared excessive on exhaust and was noisy. It was determined that some turning vanes were not installed by a contractor, and the problem was solved by installing the missing vanes. Smoke/fire dampers actuators slipped and had to be fixed. Some tricky issues of interaction among automatic air lock doors had to be worked out.

A cogeneration plant was considered intensively but not implemented.