Air conditioning is one of the nation’s top energy hogs, particularly in the warmer regions. When a heat wave is approaching, energy utilities know to kick their extra generation capacity into gear, and prepare for potential blackouts. But Ice Energy thinks it can make a big difference by storing power overnight, to run air conditioning units during the day.

The concept is simple: Electricity is plentiful and cheap at night, when demand is low, so the “Ice Bear” energy storage unit spends all night making ice. When the sun begins to beat down, a conventional air conditioning unit sucks in frosty air from the Ice Bear, rather than running an energy-intensive compressor pump.

The idea of using ice is rather different from the solution a number of startups have suggested, which is efficiency — simply turning the heat or cold air off, or lower, when demand is peaking. But the end result of using less peak power is more or less the same, and consumers who are used to their own ways will likely prefer plunking an Ice Bear on the roof of their office and continuing to wear full suits in sweltering weather.

A similar idea is to tap into solar power for air conditioning, because the heat is hottest when the sun is also the highest, and can thus provide the most power. One innovative idea is to use solar-generated steam on an absorbent heat exchanger, which produces cool air; a company called Sopogy is working to commercialize that concept.

However, Ice Energy has attracted far more financing to date. The company is announcing today a $33 million tranche in its second venture funding round from Energy Capital Partners, part of a larger $150 million round that should see Ice Bears begin to be deployed around the country. The Windsor, Colo. company took $25 million in its previous round.