July 2013 Issue of Wines & Vines
On Campus, Off the Grid
New facility at UC Davis to be carbon neutral, water and energy independent
When the University of California, Davis, Department of Viticulture and Enology opened its teaching and research winery in January 2011, it was the most advanced and sustainable winery in the world. Now, with the addition of the adjacent Jess S. Jackson Sustainable Winery Building, the facility will rise to new heights as the first self-sustainable winery.
• It will be able to operate with reused collected rainwater and energy generated on-site, allowing it to move completely off the water and power grids.
• The pair will comprise the first zero-carbon-emission winery using on-site carbon sequestration to form calcium carbonate.
• It will be the most water-efficient winery ever built, using its processing water at least five times.
• It will be the most chemistry-efficient winery ever built, using and reusing cleaning chemicals at least five times—and it will use green cleaning chemistry, potassium salts and hydrogen peroxide exclusively.
• It will be the most energy-efficient winery with on-site water-based heating and cooling systems that use moderate temperatures generated from solar energy.
• It will be the first winery to be fully solar at peak load on a kilowatt basis, as well as being energy positive on a total kilowatt-hour basis.
The winery and sustainable adjunct building grew out of professor Roger Boulton’s vision of creating a test bed, demonstration and research facility that could provide the basis of future winery operations.
When the winery was built, he took into account many features that couldn’t be implemented initially, but set the stage for their future adoption and application. These include systems for collecting carbon dioxide from both large fermentation vats and small fermentors used for research, on-site generation of nitrogen from the air and plumbing for heating, cooling and a clean-in-place (CIP) system.
Those plans became reality as Boulton shared his vision with the late Jess Jackson and his wife, Barbara Banke, and Jackson’s heirs made the gift to fulfill the dream.
If you build it, they will come
Boulton needed a test bed for the experiments and demonstrations. He thought he’d be able to get loans or donations from many suppliers. “But they didn’t want their equipment to be sitting in the parking lot,” he noted.
After the teaching winery was finished, the Jackson family donated $3 million to provide the adjacent facility that was needed. It’s called the Jess S. Jackson Sustainable Winery Building, but no wine will be made there. Instead, the 8,000-square-foot building will house
advanced water and energy systems for the winery next door. It contains 10 bays, one of which is used for necessary infrastructure like electrical controls. The university also contributed $1 million to the effort.
Cooling and heating
The first step toward sustainability is the building environment itself. The Jackson building is designed without conventional heating or air conditioning. Its massive 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 swing s 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 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 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 year’s worth of rainwater is filtered over a six-month period. This helps spread out the load on the filters and ensures clean water.
4. Nanofiltration membranes allow the chemicals in cleaning solutions to pass through, and both the chemicals and the water can be re-used in cleaning processes. The winery is plumbed for clean-in-place tanks, and 14 new, 2,000-liter teaching tanks should arrive shortly for this purpose.
Boulton hopes to reuse the chemicals and water at least 10 times and to recapture them at 90% recovery. The chemicals used are dilute potassium hydroxide for high-pH cleaning and potassium bisulfate instead of sodium-based caustic, citric acid or other organic cleaners.
Because the winery uses “warmer” cold water rather than below-freezing glycol for cooling tanks, it avoids buildup of tartrates, which would have to be removed from its fermentors with strong base cleaners and high temperatures.
Block emphasizes the importance of the CIP systems and their recycling. “These are techniques long used in dairy, pharmaceutical and brewing,” he says. He should know, having worked in pharmaceuticals before turning to enology. “If your sanitation is bad there, you can kill people. In winemaking, you just produce bad wine.”
There won’t be much wastewater, but it would be low in solids and could be used for irrigation. Organic waste goes to the campus biodigestor, which generates methane (biogas) for heating.
One area of increasing environmental concern is carbon sequestration. Fermentation gives off carbon dioxide, and wineries may have to capture and sequester it in the future.
The UC Davis facility already has the collection system in place, though the CO2 is simply released into the atmosphere at present, which is better than in the winery in any case. It plans to bubble the CO2 through a calcium hydroxide solution, precipitating calcium carbonate, otherwise called chalk.
This chalk has many uses, including drywall, plaster and even toothpaste, but Boulton thinks he may be able to find people who will use that CO2 to nourish algae that produce bio-oils and sugars. They can then return the calcium oxide powder for reuse in the winery.
Two bays that remain open can be used to demonstrate, evaluate and research new technologies as they are developed, noted Block. Normally, the university can’t build for future needs, but as this building (and the winery) were mostly privately funded, this was possible.
At present, the adjoining brewing and food science building isn’t involved. It needs steam, which the winery isn’t generating.
The winery itself was the world’s first LEED Platinum-certified winery and the highest-scoring LEED Platinum building at any university in the world, but the new building can’t be LEED certified because the ratings only apply to occupied buildings. This one will be unoccupied most of the time. It will, however, be certified Net Zero Energy by the Living Building Challenge, only the second building in California to be certified in this way.
One time it’s sure to be busy is when vendors show off their systems at the facility. Block expects most of the systems to be donated or lent and upgraded as improvements are developed. “They can come in on a skid and go out the same way,” he said, noting the large doors and clean layout.
In addition to providing a great demonstration platform, the systems will be secure and protected from the elements.
The department is close to announcing which vendors will provide equipment, much already used in other industries. Though the building is now empty, he expects it will receive s ystems soon.
Block says the department plans to work with the agricultural economics department to help evaluate the results of the tests and help wineries determine which investments make most sense. “Wine companies need information five years before they build a new winery. We hope to help them plan.”
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