The Federal Energy Management Program (FEMP) provides acquisition guidance and Federal efficiency requirements for air-cooled electric chillers, which are a FEMP-designated product category. 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 Energy Efficiency Requirements for Air-Cooled Electric Chillers
The following tables describe the efficiency requirements that air-cooled chillers must meet. Note that chiller installations are typically optimized for full-load or part-load operation. Select the requirement (full-load or part-load optimization) that applies to your application, and make sure that the chiller you purchase meets both full-load and integrated part-load value (IPLV) requirements for that application as shown below.
|Table 1. Efficiency Requirements for Federal Purchases: Air-Cooled Electric Chillersa|
|Full-Load Optimized Applications
products must meet both levels
|Part-Load Optimized Applications
products must meet both levels
|Chiller Capacity||Full Load Efficiency||IPLV||Full Load Efficiency||IPLV|
|< 150 tons||≤ 1.15 kW/ton
(≥ 10.40 EER)
|≤ 0.96 kW/ton
(≥ 12.50 EER)
|≤ 1.25 kW/ton
(≥ 9.56 EER)
|≤ 0.78 kW/ton (≥ 15.39 EER)|
|≥ 150 tons||≤ 0.94 kW/ton
(≥ 12.75 EER)
|≤ 0.80 kW/ton
(≥ 15.07 EER)
|You may choose to use either the cooling capacity (kW/ton) or the Energy Efficiency Ratio (EER; Btu/watt) to determine a product's compliance.b|
a Values are based on standard rating conditions as specified in Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 550/590. Only packaged chillers (i.e., none with remote condensers) are covered.
Defining the Covered Product
This FEMP-designated product category applies to air-cooled electric chillers installed in Federal buildings. This includes leased spaces occupied by Federal tenants and for which the Federal government will pay the utility costs. Product performance must be measured in accordance with AHRI 550/590: Standard for Performance Rating Of Water-Chilling and Heat Pump Water-Heating Packages Using the Vapor Compression Cycle.
Reducing Energy Costs: Save More Than $59,000 by Purchasing Products That Exceed the FEMP-Designated Efficiency Requirement
FEMP has calculated that a product meeting FEMP-designated efficiency requirements saves money if priced no more than $59,860 above the less efficient alternative. The most efficient level saves the average user more money: $159,200. The complete cost effectiveness example and associated assumptions are provided in Table 3.
|Table 3. Lifetime Savings for an Efficient 200-ton Air-Cooled Chiller In Full-Load Application|
|Base Modela||FEMP-Designated Levelb||Best Availablec|
|Full-Load Efficiency (EER)||9.56||10.40||12.17|
|Annual Energy Use (kWh)||501,987||461,538||394,412|
|Annual Energy Cost ($)||$45,179||$41,538||$35,497|
|Lifetime Energy Cost ($)||$742,903||$683,042||$583,701|
|Lifetime Energy Cost Savings ($)||—||$59,861||$159,202|
Notes: Examples assume 2,000 full-load operating hours per year, Federal electricity price of $0.09/kWh, 23 years of operation, and 3% discount rate. Future electricity price trends and a 3% discount rate are based on Federal guidelines (NISTIR 85-3273-26) and are from the Annual Supplement to NIST Handbook 135 and NBS Special Publication 709, Energy Price Indices and Discount Factors for Life-Cycle Cost Analysis - 2011.
Products meeting FEMP-designated efficiency requirements or ENERGY STAR® performance specifications may not be life cycle cost effective in certain low-use applications. For standard applications, purchasers will find that energy-efficient products have the lowest life cycle cost.
Operating conditions vary from facility to facility. To help determine cost effectiveness in operating conditions different from the example, see the FEMP Web-based air-cooled chiller calculator. Additional guidance is available from the American Society of Heating, Refrigeration, and Air-conditioning Engineers.
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, 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.
Federal Acquisition Regulation (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. Additional information on Federal requirements is available.
Buyer Tips: Choosing Efficient Products
When deciding on a chilled water system, designers must choose between air- and water-cooled chillers. Air-cooled systems eliminate the need for a cooling tower, reducing installation and maintenance costs. However, air-cooled chillers are substantially less efficient than water-cooled models (see FEMP's Covered Product Category: Water-Cooled Electric Chillers). To compare air- and water-cooled options, a detailed life cycle cost analysis can be performed using Building Life Cycle Cost (BLCC) software available through FEMP.
Lawrence Berkeley National Laboratory provided supporting analysis for this product overview.