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Covered Product Category: Water-Cooled Electric Chillers

The Federal Energy Management Program (FEMP) provides acquisition guidance and Federal efficiency requirements for water-cooled electric chillers, which is 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 Water-Cooled Electric Chillers

The following table describes the minimum efficiency requirements for Federal purchases of water-cooled electric chillers. Note that chiller installations are typically optimized for full-load or part-load operation. Select the requirement (full-load or part-load) that applies to your application, and make sure that the chiller you purchase meets both full-load efficiency and integrated part-load value (IPLV) requirements for that application as shown below.

Table 1. Efficiency Requirements for Federal Purchases of Water-Cooled Electric Chillersa
Compressor Type Capacity (tons) Full-Load Optimized Applications (kW/ton)
products must meet both levels
Part-Load Optimized Applications (kW/ton)
products must meet both levels
Full Load Efficiency IPLV Full Load Efficiency IPLV
Positive Displacement < 75 ≤ 0.75 ≤ 0.63 ≤ 0.80 ≤ 0.60
75 to 149 ≤ 0.71 ≤ 0.61 ≤ 0.79 ≤ 0.51
150 to 299 ≤ 0.68 ≤ 0.58 ≤ 0.72 ≤ 0.50
≥ 300 ≤ 0.58 ≤ 0.54 ≤ 0.64 ≤ 0.48
Centrifugal < 150 ≤ 0.62 ≤ 0.60 ≤ 0.64 ≤ 0.36
150 to 299 ≤ 0.59 ≤ 0.35
300 to 599 ≤ 0.56 ≤ 0.55 ≤ 0.60 ≤ 0.36
≥ 600 ≤ 0.55 ≤ 0.40 ≤ 0.57 ≤ 0.350
All cooling capacities are listed in kW/ton.

aValues are based on standard rating conditions as specified in Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 550/590.


What is Covered by These Efficiency Requirements?

These FEMP-designated efficiency requirements apply to purchases of water-cooled electric chillers of all capacities with positive displacement or centrifugal compressors that will be installed in Federal buildings. 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 $49,700 When You Buy FEMP-Designated Products

FEMP has calculated that a 1,000-ton centrifugal chiller meeting FEMP-designated efficiency requirements will save money if priced $59,200 above the less efficient alternative. The most efficient level saves the average user more money: $142,100 over the course of its lifetime. Similarly, FEMP has calculated that a 400-ton positive displacement chiller meeting the FEMP-designated efficiency requirement will save money if priced $49,700 or less above the base model; the best available model will save money if priced no more than $106,500 above the less efficient alternative. Complete cost effectiveness examples and associated assumptions are provided in Table 2.

Table 2. Lifetime Savings for Efficient Water-Cooled Electric Chillers
1,000-ton Centrifugal Chiller in Full-Load Application
  Base Modela FEMP-Designated Levelb Best Availablec
Full-Load Efficiency (kW/ton) 0.57 0.55 0.52
Annual Energy Use (kWh) 1,140,000 1,100,000 1,044,000
Annual Energy Cost ($) $102,600 $99,000 $93,960
Lifetime Energy Cost ($) $1,687,114 $1,627,917 $1,545,041
Lifetime Energy Cost Savings ($) $59,197 $142,073
400-ton Positive Displacement Chiller in Full-Load Application
  Base Modela FEMP-Designated Levelb Best Availablec
Full-Load Efficiency (kW/ton) 0.62 0.58 0.53
Annual Energy Use (kWh) 496,000 462,400 424,000
Annual Energy Cost ($) $44,640 $41,616 $38,160
Lifetime Energy Cost ($) $734,043 $684,317 $627,488
Lifetime Energy Cost Savings ($) $49,725 $106,555

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".
a The efficiency of the base model is just sufficient to meet ASHRAE Standard 90.1-2010.
b Federal purchases must be of products that meet or exceed FEMP-designated efficiency levels.
c The efficiency of the best available model was obtained during FEMP's market analysis and more efficient products may have been introduced to the market since this information was published.



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 chiller calculator tool. Additional guidance is available from the American Society of Heating, Refrigeration, and Air-conditioning Engineers (ASHRAE).

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

The decision to specify chiller performance using full-load or part-load efficiency (in kilowatt (kW)/ton) levels depends on the application. Integrated part-load value (IPLV) is preferred for more variable loads accompanying variable ambient temperature and humidity, which is the more common situation. Full-load is appropriate where chiller load is high and ambient temperature and humidity are relatively constant (i.e., for baseline chillers). To further optimize selection, compare chillers based on non-standard part-load value (NPLV), which maintains the same weightings as IPLV but allows the designer to prescribe other critical variables for example, entering condenser water temperature, evaporator leaving water temperature, flow rates, etc.). Proper determination of NPLV is described in ARI 550/590-98.


Water-cooled chillers are high-cost products with long operating lives. An energy savings performance contract (ESPC) may be useful to finance a new chiller, with payments based on energy cost savings. For more information, contact your regional FEMP Federal Financing Specialist. Financial incentives may also be available to help offset the higher first cost of an efficient unit. See the FEMP Energy Incentives Programs website for information about incentives available in your area.

Finding More Information

Lawrence Berkeley National Laboratory provided supporting analysis for this product overview.

Updated December 2011