The Federal Energy Management Program (FEMP) provides acquisition guidance and federal efficiency requirements for water-cooled ice machines. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law.
Meeting Efficiency Requirements for Water-Cooled Ice Machines
Federal agencies must purchase water-cooled ice machines that are 15% or more efficient than allowed by federal standards and use no more than 25 gallons of potable water per 100 pounds of ice made. These ice machines must be connected to a cooling tower; single-pass cooling using city water is not allowed. If access to a cooling tower is not available or if the cooling tower does not operate year round, then an ENERGY STAR-qualified air-cooled ice machine (ACIM) must be used.
|Table 1. Efficiency Requirements for Federal Purchases|
|WCIM Type||Ice Harvest Rate||Energy Usea||Potable Water Usea|
|Self Contained Unit||50 to 100 lb/24 hours||8.1 kWh/100 lb or less||25 gal/100 lb or less|
|Self Contained Unit||101 to 150 lb/24 hours||7.3 kWh/100 lb or less||25 gal/100 lb or less|
|Self Contained Unit||151 to 200 lb/24 hours||6.6 kWh/100 lb or less||25 gal/100 lb or less|
|Self Contained Unit||200 lb/24 hours or greater||6.5 kWh/100 lb or less||25 gal/100 lb or less|
|Ice Making Head||50 to 300 lb/24 hours||5.3 kWh/100 lb or less||25 gal/100 lb or less|
|Ice Making Head||301 to 400 lb/24 hours||4.8 kWh/100 lb or less||25 gal/100 lb or less|
|Ice Making Head||401 to 500 lb/24 hours||4.3 kWh/100 lb or less||25 gal/100 lb or less|
|Ice Making Head||501 to 750 lb/24 hours||4.1 kWh/100 lb or less||25 gal/100 lb or less|
|Ice Making Head||751 to 1,435 lb/24 hours||3.5 kWh/100 lb or less||25 gal/100 lb or less|
|Ice Making Head||1,436 lb/24 hours or greater||3.4 kWh/100 lb or less||25 gal/100 lb or less|
|a Measured in accordance with AHRI Standard 810-2007 with Addendum 1: Performance Rating of Automatic Commercial Ice Makers.|
Defining the Product Category
This overview focuses on self-contained unit (SCU) and ice making head (IMH) products. SCU models have an ice-making mechanism and storage bin integrated into the same cabinet or housing. SCU models are common in smaller ice machines—those making 500 pounds or less in 24 hours. IMH models do not contain storage bins but are generally designed to fit on top of a variety of bin sizes. These are the most common types of ice machines and range in size from 50 to 4,000 pounds of ice per 24 hours.
This product overview applies to water-cooled ice machines that generate cube ice at 60 grams (two ounces) or lighter. It does not apply to commercial ice machines that make flake or nugget ice or ice machines with remote condensing units and ACIMs.
When buying water-cooled ice machines, specify or select models that meet the efficiency requirements in Table 1.
Federal supply sources for ice machines include the U.S. General Services Administration (GSA) and Defense Logistics Agency (DLA). GSA offers ice machines through its Multiple Awards Schedules program and online shopping network, GSA Advantage! DLA sells them online through DLA EMall.
Water-cooled ice machines should only be used when they can be connected to a cooling tower that operates year round. Federal agencies should not use single-pass or once-through cooling, a practice where potable water is used to remove waste heat from the condenser and then disposed of down the drain. Federal water efficiency best management practices (BMP) advocate against this practice. BMP #9: Single-Pass Cooling Equipment, recommends that ice machines and other equipment using single-pass cooling be modified to recirculate water or be eliminated altogether. In situations where connecting to a cooling tower is not possible or the cooling tower does not operate year round, install ENERGY STAR-qualified ACIMs instead.
Reducing Energy and Water Costs: Save between $582 and $903 by Purchasing Products that Meet or Exceed FEMP-Designated Efficiency Requirements
Lawrence Berkeley National Laboratory (LBNL) calculated the annual energy use, water use and operating cost for a 380-pound capacity, IMH-type WCIM operated 250 days per year (typical for a cafeteria in a federal office building serving two meals a day). The complete cost effectiveness example comparing a less-efficient model, a model meeting FEMP-designated efficiency requirements, and the best-available model from the AHRI Directory of Certified Product Performance is provided in Table 2.
|Table 2. Cost Effectiveness of 380-lb Capacity IMH-Type WCIM|
|Best Available||FEMP-Designated||Less Efficient|
|Annual Ice Production||95,000 lb||95,000 lb||95,000 lb|
|Energy Use Rate||4.30 kWh/100 lb||4.84 kWh/100 lb||5.70 kWh/100 lb|
|Annual Energy Use||4,085 kWh||4,598 kWh||5,415 kWh|
|Annual Energy Cost||$367.65||$413.82||$487.35|
|DOE Discount Factor – Electricity||6.19||6.19||6.19|
|Lifetime Energy Cost||$2,275||$2,562||$3,017|
|Potable Water Use||23.2 gal/100 lb||25.0 gal/100 lb||30.0 gal/100 lb|
|Condenser Water Use (make-up)||8.5 gal/100 lb||8.0 gal/100 lb||8.0 gal/100 lb|
|Annual Water Use||30,115 gal||31,350 gal||36,100 gal|
|Annual Water Cost||$135.50||$141.10||$162.45|
|DOE Discount Factor – Water||6.23||6.23||6.23|
|Lifetime Water Cost||$844||$879||$1,006|
|Total Operating Cost||$3,120||$3,441||$4,023|
|Lifetime Operating Cost Savings||$903||$582||--------|
Using current federal guidelines (NISTIR 85-3273-27), LBNL calculated that during its seven-year life the FEMP-designated model saves approximately 5,720 kWh of electricity, 33,250 gallons of water and $582 over the less-efficient model. During the same time period, the best-available model saves approximately 9,310 kWh of electricity, 41,895 gallons of water and $903 over the less-efficient model. In food service facilities that prepare three meals a day, seven days per week (e.g., military bases, VA medical centers, federal prisons) the savings will be greater.
Products meeting FEMP-designated efficiency requirements or ENERGY STAR performance specifications may not be life cycle cost effective in certain low-use applications. For most other average or high-use applications, purchasers will find that energy-efficient products have the lowest life cycle cost.
Complying with Contracting Requirements
Legislation and the Federal Acquisition Regulations (FAR) require federal agencies to specify and buy ENERGY STAR-qualified products or, in categories not included in the ENERGY STAR program, products that meet or exceed FEMP-designated efficiency requirements. Agencies that follow requirements to buy efficient products can realize substantial operating cost savings and help prevent pollution. As the world's largest consumer of most commercial products, the federal government can help pull the entire U.S. market toward greater energy efficiency, while saving taxpayer dollars.
These requirements apply to all forms of procurement, including construction guide specifications and project specifications; renovation, repair, maintenance, and energy service contracts; lease agreements; acquisitions made using purchase cards; and solicitations for offers. Energy-efficiency requirements should be included in both the evaluation criteria of solicitations and the evaluations of solicitation responses.
FAR Part 23.206 requires federal agencies to insert the clause at FAR section 52.223-15 in solicitations and contracts that deliver, acquire, furnish, or specify energy-consuming products. FEMP recommends that agencies incorporate efficiency requirements into both the technical specification and evaluation sections of solicitations. Agencies may claim an exception to these requirements through a written finding that no ENERGY STAR-qualified or FEMP-designated product is available to meet the functional requirements, or that no such product is life cycle cost effective for the specific application.
Buyer Tips: Selecting Efficient Products
The type of ice maker purchased has energy use implications. IMH-type WCIMs do not contain storage bins but are generally designed to accommodate a variety of bin sizes. Federal buyers need to be aware that the additional energy use associated with the storage bins is not included in the reported energy consumption for these products. Since SCU have an ice-making mechanism and storage bin integrated into the same cabinet or housing, the energy use associated with the storage is included in the reported energy use.
Due to their high electricity demand, ice machines should be operated during off-peak hours if possible. This requires purchasing larger storage bins and installing a clock or timer to prevent the machine from making ice during peak hours (usually between 12 p.m. and 6 p.m.). This operating strategy reduces the demand charges resulting in additional cost savings.
User Tips: Using Products More Efficiently
Proper maintenance of water-cooled ice machines is important, especially of solenoid valves that control the flow of water through the condensers. When these valves fail in the open position, water flows through the condensers regardless if it is operating or not. This unnecessarily increases loads on cooling towers.
Hard water leaves mineral deposits or scale on the evaporator plate and other components of the ice-making mechanism. Commercial ice machines typically include a self-cleaning function that periodically rinses scale off these components. In most cases, the owner or service technician can adjust the frequency of the cleaning function to accommodate differences in water quality. It is common to find ice machines with self-cleaning set to maximum regardless of water quality. It is necessary to check and adjust the setting to match the water quality in your area.
Lawrence Berkeley National Laboratory provided supporting analysis for this product overview.
Updated August 2014