Most Americans are too young to remember the icebox. It was the forerunner of the modern refrigerator, though much smaller, made of wood, lined with tin or zinc and insulated with cork, sawdust, straw or seaweed. It contained a block of ice (delivered to your home by the ‘ice man’) and it kept a family’s fruit, meat, milk and butter cold as long as the ice held out.

Today, a number of corporations are applying this great-grandfather technology to cool their giant office buildings and reduce their giant-sized air conditioning bills. Credit Suisse, for example, is cooling 1.9 million square feet of office space at the Met Life tower, a historic building that was New York’s tallest in the days before the Empire State Building. The system took about four months to construct and company engineers say it is extremely efficient. Colleen Long of the Associated Press, reports on The Discovery Channel that: “Because electricity is needed to make the ice, water is frozen in large silver tanks at night when power demands are low. The cool air emanating from the ice blocks is then piped throughout the building more or less like traditional air conditioning. At night the water is frozen again and the cycle repeats.

Ice storage at Credit Suisse lowers the facility’s peak energy use by 900 kilowatts, and reduces overall electric usage by 2.15 million kilowatt-hours annually — enough to power about 200 homes.In case you’re thinking about converting your home AC system over the weekend and giving the ice man a call, please note that the Credit Suisse project cost $3 million, although incentives were provided by New York State’s Energy Research and Development Authority.