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Best Practice Guide |
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Food and Beverage Growers and Processors |
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Case StudyVineyard 29Location: St. Helena, California
Vineyard 29, located in Napa Valley's St. Helena, produces about 15,000 cases of premium wine each year, 6,000 for itself and 9,000 for eight other wineries. Vineyard 29's grapes are primarily grown on Vineyard 29's three acre home vineyard and the nearby 16 acre Aida Vineyard. Vineyard 29 is a young vineyard, first planted in 1989. In 2000, Chuck and Anne McMinn purchased the vineyard and began plans to design and construct a state-of-the-art winery onsite. Their goal was to minimize the environmental impact of wine production while simultaneously improving the quality of wine produced. The resulting facility, completed in 2003, consists of a 17,000 sq. ft. winery built of stucco-faced concrete block with two stories and a mezzanine, and 13,000 sq. ft. of climate-controlled caves. Today, Vineyard 29 is the most technologically advanced winery in Napa Valley, yet adheres to Old World winemaking ideals. Production at Vineyard 29 peaks for two months per year during harvest season. For the rest of the year, Vineyard 29's primary energy loads are refrigeration for barrel storage and lighting. Design and Construction
Vineyard 29's design team included architects from the Lail Design Group and engineers from Axiom Engineers. From the very beginning, regular meetings of the entire design team helped translate the McMinns' environmental commitment into actual plans and construction. Energy-efficient building systems were planned from day one. Lighting, for example, is completely controlled by motion sensors. Most of the winery is unconditioned, relying instead on natural ventilation for temperature control. Double-paned thermal windows with low emissivity and shade provided by architectural elements help alleviate solar heat gain indoors. A master control system for lighting and heating, ventilating, and air conditioning (HVAC) relies on motion sensors to detect occupancy levels, but can also be programmed with a digital timer that recognizes time of day and day of week. System performance is tracked continuously, and the McMinns are always looking for new ways to improve energy and resource efficiency. One tool to assist this overall plant optimization is the USGBC LEED certification process, which the McMinns hope will help identify additional areas of savings as well as recognize their achievements thus far. Interior Lighting
Vineyard 29 was designed to maximize daylighting throughout the winery. Every workstation is lit by natural light, supplemented as necessary by Title-24 compliant light fixtures controlled by occupancy sensors. Ample windows, doorways, and other openings also allow each person working at the vineyard to enjoy views of the outdoors. In the barrel storage, lighting is controlled by occupancy sensors and follows guests and staff as they move through the caves. A tan-colored stucco was selected for the interior finish, which helps reflect the artificial light and reduces by half the amount of lighting fixtures needed - fewer fixtures means less cooling loads for the refrigeration system, another energy-saving benefit. Winery Climate Control A carved cut into the hillside was structurally reinforced so that the building could be backed into the hill. The rear portion of the winery sits two-thirds below the grade; inside, 30 to 40 foot ceilings form one large volume of space in which the temperature is tempered by the thermal mass of the hill itself, rarely getting too hot in the summer or too cold in the winter. Vent shafts in the rear work with front-facing windows and doors to push hot air through the interior and out the shafts, creating a chimney effect. Other architectural elements aid climate control within the winery. The building's front is north facing, which helps the entire building block solar radiation. Louvers and low-emissivity windows reduce solar heat gain through windows, but also let in ample natural light. The cogeneration system provides mechanical heating or cooling as needed in extreme weather. Waste heat captured in a heat exchanger feeds a hot water loop, which supplies fan coil units during cold winter months. A forced-air fan system blows radiated air into eight different zones, each controlled by occupancy sensors and the master control system. Cooling is provided similarly by the adsorption chiller, which transforms waste heat into chilled water. Process Cooling and Production Area Climate Control At times, water colder than 37ºF is needed. In these cases, water is pre-chilled by the adsorption chiller to 37ºF, the lowest temperature possible, and then further chilled by a backup electric chiller. Otherwise, no electricity is used for process or space cooling. Gravity-fed System Reduces Use of Pumps and Motors To help manipulate gravity flows, Vineyard 29 can lift or lower special tanks with an industrial elevator and forklift. Special trap doors, hoses, and conduits are also used to move wine between the crush pad, production, barrel storage, and bottling areas. Caves and Climate Control
The 13,000 sq. ft. of caves at Vineyard 29 take advantage of the natural characteristics of Napa Valley's climate, soil, and rolling hills, while making the most of state-of-the-art refrigeration and energy systems. Caves require substantially less energy for climate control than conventional aboveground cold storage because of their superior thermal mass, which blocks solar heat gain in the summer and helps retain cool air inside. At night, air vents open to allow cool outdoor air to enter. During the day, condensers and an adsorption chiller (powered by waste heat from the cogeneration system) keep humidity and temperatures within precise presets. The adsorption chiller is a unique energy-saving technology. Vineyard 29 installed a 30-ton adsorption chiller developed by Nishiyodo Kuchouki Company - the first of its kind in the United States. This chiller requires only 0.20 kilowatts to operate which powers digital controls and two small pumps. The compressor - the most energy-intensive part of a conventional absorption chiller - is eliminated. Besides energy savings, adsorption chillers have a number of advantages over absorption chillers. First, costs and risks associated with chemical inputs are reduced - a silica gel (good for thirty years) replaces lithium bromide as the absorbent/adsorbent and water is used as a refrigerant instead of freon or ammonia. Second, the design prevents corrosion or crystallization of internal parts, and so requires less maintenance. Finally, adsorption chillers operate well under a wider set of parameters - hot water inputted can be as low 122ºF, eliminating the need for a backup boiler, and the temperature of chilled water outputted can range as low as 37.4ºF. Cooling Tower - Electrostatic Water System Cogeneration System Using Microturbines A dual 60-kilowatt microturbine cogeneration system was designed for and installed at Vineyard 29; two Capstone microturbines generate electricity from natural gas with about 28 percent efficiency. Waste heat from the microturbines both recovered with a heat exchanger to heat domestic and process water, and used to power an adsorption chiller that provides cooling capacity for the winery's heating, ventilating, air conditioning, and refrigerating (HVACR) system, including wine tanks and caves. A backup boiler and electric chiller provide added reliability, but are rarely needed. When heating and cooling capacity is factored in along with electricity generation, the cogeneration system has a total system efficiency of over 80 percent (utility or "grid" power has an efficiency of about 30 percent, by comparison). Besides significantly better generation and transmission efficiencies, the cogeneration system considerably reduces greenhouse gas emissions per megawatt-hour of electricity compared with emissions associate with "grid" power. Total energy cost savings are estimated between $24,000 and $39,000 per year. Conventional electricity and natural gas purchases would have been between $62,000 to $64,000 per year, whereas the cogeneration system costs about $25,000 to $38,000 per year (depending on the cost of natural gas). Payback on the McMinns' investment is expected in less than six years. Although the McMinns are enthusiastic about their cogeneration system, they admit that the system's complexity and substantial capital outlay may deter others from following suit. Computer controls and software are "buggy, like software everywhere," explains McMinn. He recommends that owners expect to fine-tune the software over the course of several years in order to fully optimize the system. Water Conservation Efforts
Vineyard 29 has a self-contained water delivery and wastewater disposal system - no water leaves the property, and all water is provided onsite by a well. Wastewater is processed onsite in a septic system, then deposited into a leach field, where it percolates through the soil for further purification, eventually and safely replenishing groundwater supplies. Landscaping is irrigated using an evapotranspiration system based on current weather conditions. The automated drip irrigation system is connected to a weathervane system that tracks weather conditions, and then applies preprogrammed algorithms to determine how much additional irrigation is needed. Because the vineyard is central to Vineyard 29's operations, it is watered manually. However, moisture probes are used to measure and monitor moisture levels at 10 different sites in the vineyards at four different depths at each site from surface to up to six feet underground. Real time data loggers transmit this information from the vineyards wirelessly to a central data collection site, which then puts it on a web page accessible anywhere in the world with an Internet connection. |