Putting the Chill on Ice Maker Energy Consumption
By Staff -- Foodservice Equipment & Supplies, 12/1/2007 12:00:00 AM
Across the United States, commercial facilities such as restaurants, hospitals and hotels operate more than 1.2 million ice makers. Together they consume more than 9.4 billion kilowatt-hours (kWh) of electricity each year and rack up more than $800 million in annual electricity bills. The energy efficiency of new ice makers has improved considerably over the past decade, and foodservice operators can now choose from many efficient models. Some of these newer models provide substantial energy savings with little or no incremental cost over less-efficient models, creating a “win-win “situation for the operator. With new state and federal standards coming into effect, the number and diversity of energy-efficient ice makers will continue to increase.
Foodservice operators can select an ice maker that uses one of three different types of condenser:
Air-cooled ice makers use the most energy but tend to cost less than water-cooled models. The air-cooled units also use less water, with their energy use per 100 pounds (45 kilograms) of ice ranging from 4.6 kWh (for machines making 1,500 pounds of ice per day) to 20.4 kWh (for self-contained machines making 50 pounds of ice per day).
Water-cooled models tend to be more efficient than air-cooled units. Their energy use per 100 pounds of ice ranges from 3.4 kWh (for machines making 1,800 pounds of ice per day) to 10.5 kWh (for self-contained machines making 150 pounds of ice per day). These units do not place any additional burden on air-conditioning loads, because they discharge the heat removed in making the ice outside the building.
Remote air-cooled condensers transfer the heat generated by the ice-making process outside of the building. Like water-cooled units, they reject heat outside of conditioned spaces and, therefore, do not increase air-conditioning loads. Their energy use per 100 pounds of ice ranges from 4.2 kWh (for machines making 1,650 pounds of ice per day) to 8.8 kWh (for machines making 400 pounds of ice per day). They also reduce noise levels inside by up to 75 percent, but these units generate extra installation costs for running lines to a remote location.
The Consortium for Energy Efficiency (CEE) has created voluntary standards for commercial ice maker energy and water efficiency. These can be found, along with a list of ice makers that meet the standards, on the CEE web site at www.cee1.org. In some cases, high-efficiency ice makers have little or no incremental cost vs. less-efficient models. For example, a search for air-cooled ice makers with approximately 1,200 pounds of capacity showed that a model meeting CEE Tier 1 standards was the most expensive, $120 (or 2 percent) more than a baseline model, whereas models meeting the Tier 2 and Tier 3 standards cost $250 (3 percent) and $350 (5 percent) less than the baseline model, respectively.
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When shopping around for a new ice maker, operators should pick a machine with a capacity that meets their needs. Oversizing an ice maker can increase energy consumption due to excessive standby losses. On the other hand, larger ice makers generally consume less energy per unit of ice than smaller ones. It is important to pick a unit that most closely matches your quantity requirements. Ice machines are designated by the amount of ice that they can produce in a 24-hour period, under reference conditions of 70º Fahrenheit (F., 21º Celsius [C.]) ambient temperature and 50ºF. (10ºC.) inlet water temperature. Typical sizes are 250, 400, 500, 650, 800, 1,000, 1,200, and 1,400 pounds per 24 hours, but some machines can make several tons of ice per day. Actual capacity varies with both ambient temperature and water temperature. Manufacturers usually recommend using the capacity listed at the test conditions used by the Air-Conditioning and Refrigeration Institute (ARI): 90ºF. (32ºC.) ambient air and 70ºF. (21ºC.) water. Selecting equipment based on the capacity at those conditions will ensure adequate ice production under most conditions encountered in operation.
New U.S. federal and state standards will continue to push ice maker efficiency upwards. Federal energy-efficiency requirements taking effect in 2010 will be the same as the current voluntary CEE Tier 1 standards. California's 2008 energy-efficiency standards for commercial ice makers are also the same as the current CEE Tier 1 standards. Both the federal and California standards will include water-efficiency requirements. Canada will strengthen its ice maker standards in 2008 as well — see the Natural Resources Canada Office of Energy Efficiency web site, www.oee.nrcan.gc.ca, for more information.
Energy Star efficiency levels for ice makers go into effect Jan. 1, 2008. These initial levels cover only air-cooled ice makers and those that make cube ice, which means they exclude cube- and nugget-producing machines. They mirror CEE Tier 2 standards for the specified machines. The Energy Star program has stated its intention to include flake and nugget machines once a test standard is available and adequate data are collected for deriving performance requirements. For more information, see the Energy Star web site: www.energystar.gov.
Several U.S. states offer incentives for ice maker efficiency: California, New York, Vermont and Wisconsin. Some U.S. and Canadian cities also offer ice maker efficiency incentives, including Austin, Texas; Oakland, Calif.; Las Vegas; San Diego; Seattle; and Toronto, Ontario.
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