Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
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Spring 2011
Insulated copper piping brings glycol from Williams Selyem’s solar collectors down to four, 175-gallon storage tanks with internal heat exchangers (1). The tanks feed the preheated water into the winery’s propane-fueled water heater (2), reducing the amount of propane needed to keep water hot, or to heat water in the propane tank for winery needs.
An external heat exchanger uses the heated glycol from the solar thermal system to heat water for the hot water loop at Kunde, boosting the temperature of hot water going to the boiler. Water can remain hot to 200°F in the storage tank for up to three days (it loses about 1°F per hour if no new hot water is introduced). The solar thermal system, at its peak production, should be able to generate up to 4,000 gallons of hot water for daily use at Kunde.
“The system’s efficiency is highly dependent on the amount of solar radiation, and the daytime temperature,” Fish reports. “On hot, sunny days, the storage tank will reach 200°F by early afternoon if we start from 60°F. On cooler, overcast days it may only reach 80°F to 100°F.”
Hot water from the boiler is piped to Kunde’s caves for barrel washing, and to the bottling
line for sterilization. Early morning bottling runs take maximum advantage of the hot water generated the previous afternoon.
Fish planned that Kunde personnel try to do barrel washing on days when hot water is not needed to sanitize the bottling line, or in the afternoon when the solar thermal system is at top efficiency. The winery is researching the use of a steam generator as a method for sanitizing the bottling line and barrel cleaning. Pre-heated water from the solar thermal system could be used to feed the steam generator, cutting hot water use significantly.
Kunde’s solar thermal system also pre-heats domestic hot water for the winery building, and a high-efficiency, tank-less, hybrid hot water heater was installed to boost the solar-heated water when necessary.
Solar thermal system maintenance is performed by washing down the roof panels to remove dust two to three times per year, checking the glycol level every other year, and periodically inspecting the system for damage or leaks.
Williams Selyem Estate Winery
The new Williams Selyem Estate Winery center on Westside Road outside Healdsburg took three years to complete, and while crush and primary fermentation are still performed at nearby Allen Ranch, the new building contains barreled wine and case goods, a bottling line, and visitor center.
A 54kW solar PV system was installed by One Sun (Graton, CA) as two carport rooftops (one on the west side of a parking lot, and one on the east side). 226 PV panels are fixed at a 4-degree tilt, and seven string inverters convert DC current produced by the panels to AC current for use in the winery. The PV system is expected to power 25% to 35% of the facility’s electrical needs, and earned a 30% federal tax credit and PG&E’s CSI solar PV rebate.
A solar thermal system, installed by SunWater Solar (Richmond, CA), was activated in July 2010. The system components on the outside of the building are:
  • 14 Heliodyne Gobi 408 collectors facing due south, with 448 square feet of collector area;
  • 1.5-inch copper piping (L piping) with Armaflex neoprene insulation (3/4-inch wall) jacketing on the exterior.
Inside the winery, the system has:
  • 4 Rheem 175-gallon solar hot water storage tanks with heat exchangers;
  • 1 multi-speed solar pump;
  • 1 mixing valve (controlling hot water temperature to prevent scalding);
  • 1 Wi-Fi solar differential control (interface with online monitoring capabilities);
  • 1 small expansion tank (5 to 10 gallons, to hold excess glycol, which expands with heat, so that it will not exceed the capacity in the pipes and collectors).
The 14 collectors mounted on the winery roof absorb the sun’s rays, heating the glycol that circulates between the collectors and the four water storage tanks in the mechanical room. The heated glycol travels through piping from the collectors to the heat exchangers inside each solar hot water storage tank.
As the heated glycol passes through a heat exchanger, the heat is transferred to the water stored in the tanks. A pump pushes the cooled glycol back up to the collectors. The solar water tanks feed the winery’s propane-fired water heater with solar pre-heated water, significantly reducing propane consumption.
The solar differential control is the “brains” of the thermal system. It turns the pumps in the solar thermal system on and off, and also logs system data. Because the control utilizes Wi-Fi (wireless Internet connectivity), winery operations can view system data anytime, on any computer that has an Internet connection.
Hot water produced by this system is used for barrel washing, wash-down of tanks, equipment, and floors at the facility, and bottling line/bottle sterilization before filling. It is also used for heating barrel storage rooms when needed, and for sterile cleaning (including four commercial dishwashers in the visitor center).
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