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C O VER ST O RY cinder-block walls provide high thermal mass, and an air gap separates them from the R60 insulation. The roof contains enough insulation to have an R80 rating. "We specified that we never wanted the building to drop below 50°F or rise above 80°F," said UC Davis Viticulture & Enology Department chair David Block, who, like Boulton, is a chemical engineer by training. The temperature requirements were a tall order for Davis, which endures many days with temperatures above 100°F throughout the summer. Temperature is controlled by night air cooling in summer and warm day heating in winter. Windows near the peak of the slanted ceiling and low in the walls open automatically to introduce cool air at night during the summer by natural circulation, through a fan that introduces the air. Hot or cold water can be circulated to heat or cool the floor slab of the building via tubes within the slab. The water temperatures range between 40°F and 120°F. The water can also cool or heat fermentation vats in the winery; heavily insulated pipes run underground between the buildings. At present, the campus supplies hot and cold water for the tanks. No glycol is used in the winery. All water piping is made from expensive, high-density polyethylene; the school didn't want pipes containing chlorine such as popular PVC (polyvinylchloride) due to concern regarding formation of TCA (trichloroanisole) contaminants. Naturally, the roof contains photovoltaic arrays to gather energy during the day, but it also mounts a Cogenra solar hot water system using a parabolic reflector. Even the surface of this reflector contains solar cells. Two large, heavily insulated tanks store the 120°F hot water. A solar electricity-operated icemaker cools water to 40°F for the fermentors and the building. In the future, the department hopes to add a buried rock bed that could be cooled or heated by air to provide a reservoir for cooling or heating. One day this spring, when the outside temperature was above 90°F, Block said that the interior temperature was 67°F without any mechanical assistance. Daily 40°F swings in the outdoor air temperature result in inside temperature variations of about 4°F. Hydrogen from water To supplement the energy supply, the winery will have a system for breaking down water into oxygen and hydrogen. The hydrogen can operate a fuel cell to provide electricity at night or, if needed, to supplement the solar energy during a peak during the day. The hydrogen also can be used to operate vineyard vehicles and forklifts. One possibility, in fact, is to use a fuel-cell car like that made by Honda to generate electricity. Block says one fuel cell produces 100 kW of mechanical power, enough for more than 50 kW of electricity. The whole building is designed to avoid large spikes in demand for electricity that result from starting large pumps or fans. Instead, it seeks gradual changes with slower processes like smaller pumps that operate longer. The building uses mostly natural light during the day, though fluorescent lamps are provided for nighttime or intense work that requires it. The winery doesn't use cold stabilization for wines, as the research wines aren't treated for shipping. Water treatment Water use is a major rationale for the facility in view of projected future shortages and restrictions. "I believe the time will come when a county planning department won't let you build a winery without these features," declared Boulton. He added, "That's not due to climate change, but population growth and declining aquifers." It rains mostly during the winter in Davis, and the winery will have sufficient water storage for a year's needs. Between the two buildings are four 40,000-gallon tanks for collecting rainwater that is now used The Jackson family donated $3 million for the Jess S. Jackson Sustainable Winery in honor of the late vintner. primarily for irrigation and flushing toilets. In the future, six more tanks will be added for process water collected off the roofs of the main institute building and purified. Four different systems are used to process water: 1. The passive solar hot system. 2. The chilled water system using a solar-powered icemaker. 3. Reverse osmosis membranes to filter rainwater before it is used as process water. No chemicals or ozone are required since bacteria can't pass through the membranes. And, since rainwater doesn't contain chemicals such as silica, the membranes should last a long time. The main contaminants in rainwater are dust and bird droppings, which are easily removed with coarser microfilters. Filtered water is constantly looped through the winery for cleaning, and the David Block (left) is department chair of the Department of Enology and Viticulture at the University of California, Davis. Roger Boulton is a professor and holds the Stephen Sinclair Scott Endowed Chair in enology. Both have PhDs in chemical engineering. Win es & Vi n es JU LY 20 13 29