Fetzer Winery Administration Building
Sustainability - Heating and Cooling

Eight zone building with central VAV system with terminal reheat. Two cooling coils with one using well water bypassed during irrigation and the second tied into the winery's chilled water system. Single boiler for reheat.

CalPass software was used for initial study of thermal mass. Comply24 was used for additional analysis.

"The heating and cooling system looks large and complicated, like most office buildings systems. It is somewhat complicated (and expensive) but the end result is a very very energy efficient system. When cooling is required, air is cooled by running well water through coils (like car radiators) and blowing the building air [around] the coils. Most of the heating and cooling is automatic and transparent to the users, but there are visual cues to what is happening. For example the "casabalanca" types fans in the middle of the building are there to mix the air in the space so that all the hot air doesn't rise to the top in the winter. The clerestory windows will open to flush out the hot air in the summer, and let in cool night time air. The earth walls are a major component of the cooling and heating system, acting like a flywheel to moderate the building temperature. Like an old abode building, the admin. building will be comfortably cool in the summer, and snug and warm in the winter."
— Valley Architects, memo to client

Substantial thermal mass is provided via exterior and interior pise earth walls and partitions.

The natural ventilation elements were designed using ASHRAE methods for stack ventillation. For assurance in sizing HVAC systems for thermal comfort, heat loads from lighting were calculated based on conventional usage, despite the high level of ambient daylighting, providing for generous capacity that would only be used as needed.

The building is moderately instrumented with a permanent performance monitoring system tracking interior and exterior temperature and daylighting amount.

Building commissioning was handled by the routine construction site walkthroughs and follow-up process for occupany issues. No particular post-commissioning system "fixes" were required.

A large rooftop photovoltaic system provides a substantial locally-generated renewable energy component.

A range of alternatives were explored during the design process. A fully passive ventillation approach could provide general comfort, but would be inadequate during heat waves. An air tube cooling approach was abandoned as too costly and not very efficient. Those cooling explorations motivated a decision to include a forced air system for cooling. That choice in turn led to dropping radiant slab heating, which was designed originally, since the same forced air system could handle supplementary heating as well as occassional cooling.

A couple of system components were particular sources of engineering uncertainty. The cold water (well water) cooling coil raised concerns due to unpredicability of well water temperatures, and there were concerns about sizing apertures to achieve daylighting effectiveness without too much heat input.

A challenge in making the best energy engineering design choices for this project was the lack of a systematic framework for evaluating options. The engineers think using the LEED system could have helped address this.

Coordination amoung the design team went well, assisted by strong goals and involvement from the building owner, whose clear presence helped keep the team motivated. Overall communication within the design team was effective.

In actual operations, some building occupants have complained about being too warm sometimes when the HVAC mechanical systems were not in use. Otherwise there have been no complaints, which expresses general comfort and satisfaction with thermal performance.