Additionally, ICE II uses three high-efficiency ammonia screw compressors, each providing 88.4 tons of refrigeration, with the refrigeration equipment designed to balance electrical demand between grid power and onsite renewable energy, allowing significant power savings. Compressors are only run during peak hours when they are driven by solar cells.

Consistency of power--and thus of temperature--is critical. To ensure that the building will remain cold for a reasonable period of time even in the event of a power failure, the walls were made nine inches thick and the roof 12 inches thick.

"If the power went out today, it wouldn't be a problem for three days, maybe four before we have a problem," Hamann says.

Other elements of sustainability include density: at 60 feet tall, the building is twice the height of other warehouses, and allows more storage--7.5 million cubic feet--without occupying a larger footprint. The freezer's interior was designed with narrow aisle racking to maximize space. Radio frequency technology eases locating items, which are then retrieved by electric forklifts that recharge their batteries with energy generated by the weight of the product being lowered. All rainwater is collected on the site's seven acres and used to run the refrigerators.

Other technologies used include a cool roof, increased ventilation, carbon dioxide monitors, reflective concrete, and water re-use and conservation measures, among others. SDG&E awarded a $150,000 Savings by Design incentive, as well as an Emerging Technologies incentive of $94,773 to offset the cost of light-emitting diode light fixtures that are activated by motion sensors and a complex refrigeration controls energy management system. The office building also boasts stained concrete rather than carpet, and large amounts of daylight to reduce power needs.

The result is 62% more energy efficient than a baseline cold storage facility, with 73% of the building's energy provided through renewable resources. Hamann predicts an annual savings of more than 3.4 million kilowatt hours, saving more than $408,000 annually and preventing 3,683 metric tons of carbon dioxide from entering the atmosphere.

The Hamann building is not the first to make cold storage sustainable: a Budweiser storage facility in Antioch, CA, uses an array of solar panels to offset some 60% to 70% of its power, saving about $100,000 annually. But the ICE Building takes sustainability to the ultimate level: In fact, the company missed Platinum certification by just two points, which were impossible to get, Hamann explains, because the building is not situated on a brownfield, nor is it near public transit, among other possibilities.

Some experiments have not completely worked. Though the San Diego area is not known for its high winds, Hamann put wind generators on the building to see if ocean breezes hitting a 60-foot-high exterior wall would produce significant power.

"The power [produced] is close to what was projected," Hamann says. "But the payback is not what I'd call practical."

But the experimentation was part of the fun, he notes. "For the most part, if it made sense, we did it," Hamann says. "I love doing these kinds of projects."