The making of wine

The wine grapes are produced in hundreds of vineyard areas in the surrounding counties, then trucked to the winery where they are crushed, drained, and the juice is placed in vats for fermentation.

Following fermentation, the wine is piped into storage tanks for aging. The insulated tanks each hold up to 600,000 gal of wine. They comprise a storage farm stretching out for half a mile, tied together by an intricate pipeline and valving system.

Some of the tanks are held at low temperature by mechanical refrigeration systems, as temperature control of the aging wine is an important quality control measure.

At maturity, the wine is piped into a highly automated bottling plant. Here, it is bottled and placed in corrugated shipping cases. The finished wine cases are stacked up to 30 ft high by product type in huge warehouses awaiting shipment.

Just one of the warehouses covers an astonishing 30 acres, and has four railroad spurs running into it for bulk rail shipment. In a typical week, this single facility ships 1.2 million cases of wine.

Time's a-changing

Steve Babb, a mechanical maintenance supervisor for Gallo, explained the importance of temperature control in the warehouse.

“We know that holding the wine at a near-constant temperature maintains its quality. That’s why the warehouse is air conditioned,” he said.

Recently, Gallo made a decision to upgrade the air conditioning system at the large warehouse to improve efficiency and reduce maintenance costs.

Dale White, existing building services manager at Trane’s Sacramento commercial sales office, worked with Gallo in evaluating options for upgrading the air conditioning at this warehouse. “Gallo was concerned because the building had an aging system and they needed to know what way to go in the future,” he said.

The giant warehouse had 109 rooftop units of various types. “Because of the age of the units, the maintenance costs were going up every year,” said White. “Plus, they had been added in increments as the building was expanded, so there were a lot of different models spread around the roof. That made maintenance even more challenging.”

The decision by Gallo was an initial project involving replacement of the first 46 of the rooftop units with a Trane Company 500-ton, single-stage, Model ABSC steam absorption chiller and a gas-fired boiler. A second stage (scheduled for a later date) would involve an additional 1,000-ton chiller and boiler to replace the balance of the rooftop units.

Step one toward efficiently cooled wine

The first stage alone is expected to save $10,000 per year in maintenance expenses, and reduce operating costs for that part of the air conditioned space by 30%.

The chilled water from the absorption machine feeds 13 Trane Number 35 “Modular Climate Changer” air handlers, each of which features a 35-sq-ft cooling coil, and is equipped with economizers for use when outside temperatures are below 60°F.

Gallo decided to use steam absorption chillers because the local utility, Pacific Gas & Electric, has an attractive summer rate for natural gas.

According to Gallo’s George DePonte, “This is a near-ideal interruptible gas application. We can tolerate occasional interruptions because of the tremendous thermal flywheel effect of the wine in storage. The temperature of the warehouse only goes up a couple of degrees with a day-long outage.”

The steam for the absorber is currently generated in a dedicated boiler, but Gallo is also considering using waste heat from a company glass bottle manufacturing plant as an alternative steam source.

“This would involve construction of a fairly lengthy steam pipeline and is currently in the study stage. We’ll see what happens,” said DePonte.