Practical Winery
65 Mitchell Blvd, San Rafael, CA 94903
phone: 415-453-9700 ext 102
email: Office@practicalwinery.com
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September/October 2008
WINEMAKING
Incorporating study results
The two PG&E studies show that electrodialysis is the clear energy-efficiency winner for the clarification process. However, the studies also show that makingmodest changes to the cold stabilization process can significantly increase efficiency for this commonly used method.
Since insulation potentially accounts for the majority of cold stabilization energy savings, winemakers are encouraged to insulate tanks. In fact, according to a PG&E Non- Residential New Construction study prepared by Applied Technology Services, simply installing three inches of insulation around tanks can cut energy use by almost 95%. This supports the dramatic drop in electricity — from 1,200 to 22 Wh per gallon — between the two test sites in the Emerging Technologies studies.
In addition to energy savings, electrodialysis offers the benefits of less processing time and reduced wine loss. Although these benefits go beyond the scope
Table III: Electrodialysis stabilization measurement points
Measured parameter Logging method Logging interval
Wine inlet temperature data logger 15 min.
Wine outlet temperature data logger 15 min.
Wine initial conductivity winery personnel Start
Wine final conductivity winery personnel End
Wine initial pH winery personnel Start
Wine final pH winery personnel End
Energy consumption of ED system data logger 15 min.
Water consumption winery personnel 1 per batch
ED pump on/off status data logger Varies
of the study, winemakers are reminded to take these into consideration when weighing the pros and cons of adopting electrodialysis technology. Other considerations such as space, time, and winemaking style must be taken into account.
The nuances and long-term plans of each winery will influence the most appropriate method.Winemakers must be especially aware that adopting electrodialysis technology results in increased water consumption that necessitates increased wastewater treatment and associated costs.
Fetzer Vineyards was in a unique position in that they already employed multiple water conservation methods and it was therefore easy to accommodate extra waste water. Winemakers who do not have this capability must be prepared for increased water related expenses. To that end, PG&E will conduct a study in which winery wastewater treatment practices will be examined and benchmarked.
"We are aware that electrodialysis uses more water than traditional stabilization," says Fetzer's Thrupp. "However, the relatively small increase in water for this technology is addressed and compensated for by ongoing water conservation practices throughout the winery, bottling facility, and vineyards. In addition, the water is treated on-site through aeration ponds and is reused in the vineyards and landscaping."
PG&E supports the adoption of electrodialysis technology forwine stabilization as an energy efficiency tool, and encourages winemakers to insulate tanks to save energy in the cold stabilization process. To that end, PG&E is currently offering incentives for adopting non-mobile electrodialysis technology or for insulating wine tanks. To find out how PG&E can evaluate your possible energy savings using electrodialysis technologies, call the PG&E Business Customer Service Center (800/468-4743) and ask for the project manager in your area.
[Steve Fok, PE, has been managing power generation, environmental compliance, and energy efficiency projects at PG&E for 29 years. Steve can be reached at 415/223-4735 or SKF2@pge.com.]
Table IV: Cold stabilization measurement points
Measured parameter Logging method Logging interval
Outdoor air temperature data logger 15 min.
Barrel room ambient temperature data logger 15 min.
Stabilization tank surface temperature data logger 15 min.
Stabilization tank well temperature data logger 15 min.
Wine temperature winery personnel 2 per day
Stabilization tank level winery personnel 2 per day
Wine conductivity winery personnel Varies
Wine pH winery personnel Varies
Glycol flow rate (at bypass pipe) spot measurement Once
Glycol supply temperature data logger 15 min.
Glycol return temperature data logger 15 min.
Cooling tower fan motor current data logger 15 min.
Cooling tower fan on/off status data logger 15 min.
Glycol supply pump power spot measurement Once
Condenser pump power spot measurement Once
Chiller compressor power (idle) spot measurement Once
Energy consumption of chiller system data logger 15 min.