Chill Factor

This week I came across an article that talked about cooling buildings with ice. At first, I thought of the old ice boxes/ice cars that used ice blocks to keep things cold because refrigerant was not invented yet. After reading through the article I saw that more and more buildings are starting to use this method because it cuts down on the AC load of the building. The main concept behind it is to produce ice during the night because electricity costs less during off-peak hours and then use that ice during the day for the cooling needs of the building.

The most common method used is called the “internal-melt ice-on-coil.” A tank is filled with water and a coil is placed in the center filled with a fluid, most common fluid used is a glycol-water solution. The fluid is cooled, during the night, by a chiller and turns the water into ice. During the day the same fluid is re-circulated through the ice it just made to be cooled down. Once the fluid is chilled it can be used directly for cooling or passed through a heat exchanger to transfer energy.

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44 tanks each holding 1,600 gallons of water. A more industrial large scale set up.

Depending on the size of the building, ice cooling can get pretty large, as seen above, so a more common approach is going a partial route.  Using the partial method splits the building cooling needs between the ice method and chillers. With the partial route allows for the chillers to run more in the low peak of energy costs and during the high peaks ice chilling is used.

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Other ways ice cooling can save money for the owner by decreasing the size of ducts, pumps, fans, cooling towers, and power supply infrastructure. They also reduce first costs by allowing chillers and packaged air conditioners to be downsized.

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