Donald Bren School of Environmental Science & Management
Sustainability - Heating and Cooling

"To ensure efficient use of energy, the building was designed to harvest natural light, heating, and cooling. Facing the ocean, the office wing has no air conditioning and instead relies on flow-through ventilation with operable windows and transoms. Daylight harvesting is coupled with a lighting plan that incorporates energy-efficient fixtures and bulbs along with controls for motion and ambient light.

"The operable windows in the office wing have a mechanical interlock (a small sensor in the frame) so that, upon opening, the heaters in the offices are automatically turned off. The ventilation system for the laboratories is the most efficient available. The building is connected to the new multi-building chilled water loop to provide cost-effective cooling for the laboratory wing. The Bren chiller is also able to take on a portion of the total campus load when needed. The estimated savings by participating in this shared system is 85% of the run time on our chiller. Our cooling system consists of three towers with different size fans that stage upon demand. An 85% efficient boiler is used in the building. ...

"The roof-integrated photovoltaic system allows Bren Hall to generate 7-10% of its power cleanly on site.

"Seven to 10% of the School's total energy supply is provided by 240 42-kilowatt photovoltaic panels on the roof.
— Donald Bren School, 'About Donald Bren Hall'

HVAC Engineers:  Flak & Kurtz

Interview with Flak & Kurtz

Energy Performance:  Energy usage is 32% below the California Title-24 standard.

Measurement & Verification:  University did the commissioning, but they worked with the commissioning agent.

Software:  VisualDOE

Thermal Mass:  Concrete building.

Thermal Comfort (Comply with ASHRAE 55-1992):  Did do thermal comfort studies. They do comply with ASHRAE 55-1992

Permanent Monitoring System:  Yes, CO2 sensors on variable air volume (VAV) boxes.

Renewable and Green Energy:  A 42KW rooftop photovoltaic system provides onsite renewable energy.

How did you determine what levels of natural/window ventilation were available relative to what was needed:  Went with 5% of floor area naturally ventillated. Used ECOTECT for the analysis on one room.

Did the owner/architect/engineer have any ideas that you talked them out of?:  Heat recovery from exhaust.

Were you nervous about any particular mechanical system components' ability to perform adequately (ie. Reduced HVAC capacity due to greater thermal performance, use of natural ventilation, mechanical lighting configuration, etc.)?:  The VAV exhaust with Phoenix took a lot of commissioning support.

Did you feel there was enough coordination/communication between the architecture and engineering teams in this project?:  Yes

Did you feel the owner/architect had realistic expectations of the building's energy performance?:  Yes, considering the mild climate they were realistic.

Have you received any negative feedback from the occupants, especially related to unique features of this building? What were they? Could the complaints/problems be resolved?:  There are some spaces where the natural ventillation did not work out. Ask occupant to close shades and turn off computers when not in use. Minimize internal and external gains essentially.

Have you received any positive feedback from the occupants, especially related to unique features of this building? What were they?:  Most students and teachers like it very much

Did the building need any "fixes" to improve the performance, which were not part of the original design?:  Not on F&K stuff

Do you feel you were too "conservative" in any of the features (ie over use of mechanical lighting, oversized HVAC system, etc.):  No, chiller was oversized so it could supplement the campus chilled water loop.

Do you feel that you over estimated the buildings thermal performance and undersized any parts of the mechanical system as a result?:  No other than a few windows for the problem spaces.

"Energy efficiency exceeds California Title 24 (1998) by 30%. Natural ventilation in office wing with operable windows, coordinated with mechanical system; variable volume exhaust system in lab. Energy management and control system; M & V plan. Daylight control, efficient fixtures and motion sensors. 25% (125kW) of the building's energy needs are met by grid power from landfill methane gas; roof-mounted solar panels supply 7% of the energy needed."
— USGBC LEED certification summary

Details

"The laboratory ventilation system uses more than 100 Phoenix Controls Accel® valves. These valves control room pressurization, and exhuast for fume hood, snorkels, and biosafety cabinets. While not a fume hood intensive buildings, Donald Bren Hall optimizes energy savings by using variable air volume (VAV) system and taking advantage of the Phoenix valve's accuracy across a wide flow range, with pressure zones having up to an 8:1 supply air trundown."
— Phoenix Controls press release

Use of Phoenix Valves in Donald Bren Hall — at the Phoenix Controls web site (PDF)
About Donald Bren Hall — at NREL (PDF)