Science Technology Ice Bear: Thermal Storage for Cheaper AC By Lloyd Alter Design Editor University of Toronto Lloyd Alter is Design Editor for Treehugger and teaches Sustainable Design at Ryerson University in Toronto. our editorial process Facebook Facebook Twitter Twitter Lloyd Alter Updated October 11, 2018 Migrated Image Share Twitter Pinterest Email Science Space Natural Science Technology Agriculture Energy Temperatures are breaking records across North America and Europe. Every old power plant that can crank out a kilowatt is working overtime, burning coal and gas like mad, shuffling power all over a grid that is on the verge of collapse. Time to look again at a post John did in cooler times a year ago, for an idea whose time has really come. The Ice Bear connects up to a conventional air conditioning system, but uses it to make ice at night when the power is cheap and melts all day to keep you cool. Each unit can take 5 to 10 tons of cooling off the peak load. It is not saving a watt of energy for the owner (see below the fold), but it saves lots of money because off peak power is cheap, and it is great for the environment because peak power is expensive and dirty. The problem with electricity is that you can't store it (except with batteries) but people have been storing ice for thousands of years. Every air conditioning system should have this. ::Ice BearJohn Laumer explains in engineerspeak why it actually does save energy overall: "There is an inaccuracy in the statement you made that not a 'watt is saved'. Electrical engineers understand this innately so it seldom gets written about. If you were to plot, for an individual fossil fuel plant, efficiency on one axis and percent of peak capacity produced on the other axis, the resulting line is slightly curvilinear (sinusoidal or "s" shaped if you will). At the start of this curve, nearest the ordinate, slope is relatively flat: efficiency stays relatively low as output increases. After a bit more output, efficiency ramps up. At about 85% of peak capacity (the sweet spot that you operate at during the night time as a "base load" plant), efficiency is optimal. After that the curve flattens out again, getting progressively less efficient as you move toward to pinnacle of output."