In-line pumps are among five pump categories covered by the new regulations.
As pump manufacturers in the U.S. design, build and test energy-efficient centrifugal pumps to bring to market, the new Energy Conservation Standards for Pumps, issued by the U.S. Department of Energy (DOE) in late 2015, will be at the top of their minds.
The new standards take effect in 2020 and are based on a metric that incorporates the power consumption of the pump, its motor and any controls. The goals of the new regulations are energy conservation and minimizing carbon emissions and greenhouse gases. According to the Natural Resources Defense Council, pumps meeting the new standards sold in the next 30 years can reduce electricity consumption by about 30 billion kWh. This is the annual electricity use of 2.8 million U.S. households.
To develop the new efficiency standards, the DOE surveyed the market and determined the cut-off efficiency level for each type of pump, taking into account energy savings, consumer benefits and impact to manufacturers. While pumps currently in use will not be affected by the new standards, the 25% of clean water pumps on the market today that do not meet efficiency standards will need to be retired or redesigned to improve efficiency and reduce energy losses if the manufacturer wishes to sell them beyond 2020. According to the DOE, the costs of new materials, pump redesign and compliance testing are estimated at $81.2 million through 2049.
Pumps Affected by the DOE Standards
The standards address up to 70% of commercial and industrial pump energy use. They apply to pumps with an input power at best efficiency point (BEP) between 1 and 200 hp; BEP rate of flow of 25 gal per minute or greater; BEP head of 459 ft or less; temperature between 14ºF and 248ºF; and nominal speeds of 1,800 and 3,600 rpm. These types of pumps are used for a range of applications and can be found in heating and cooling systems, commercial buildings and drinking water treatment plants.
More specifically, the standards target five classes of rotodynamic pumps designated for use in pumping clean water in commercial, industrial, agricultural and municipal applications:
- End-suction close-coupled pumps;
- End-suction frame-mounted pumps;
- In-line pumps;
- Radially split, multistage, vertical, in-line casing diffuser pumps; and
- Submersible turbines (vertical turbine submersible pumps).
Introduction of PEI
To rate the energy performance of pumps, the DOE established a new metric, the pump energy index (PEI). PEI is a ratio of the representative performance of the pump being rated over the representative performance of a pump that would minimally comply with any prospective DOE energy conservation standard for that pump type. A PEI value greater than 1.00 signifies the pump does not comply with the energy conservation standard, and a value less than 1.00 indicates the pump is more efficient than required.
Minimally compliant pump efficiency is determined by a calculation that includes specific speed, the BEP flow in gallons per minute, and a constant that varies by pump type. This determines the Pump Energy Rating, the weighted average of input power to the motor at defined duty points, which is the standard basis for all PEI ratings.
Base-mounted end suction pumps, like this Bell & Gossett model, are now subject to the DOE's Energy Conservation Standards for Pumps.
Testing for Compliance
Many manufacturers are committed to efficiency improvements, so they are redesigning or retooling existing pump lines and testing them for compliance to the new standards.
In 2014, the Hydraulic Institute (HI) created a pump efficiency test standard to meet the needs of the DOE, called HI 40.6. Revised to match all test requirements from the DOE, HI 40.6 was adopted by the DOE and written into the pump rule in 2016.
HI also established a Pump Test Lab Approval Program, HI 40.7, to help manufacturers and other pump test facilities improve current procedures and create testing protocols that are accurate, uniform and repeatable in accordance with the new rules. According to HI, performing tests in a lab that not only applies HI 40.6, but also stands up to an independent third-party audit, will build confidence in the market that the stated efficiencies will be achieved.
Circulator Pumps on Deck
Circulator pumps—relatively small centrifugal pumps designed for hydronic systems—were excluded from the DOE’s Energy Conservation Standards for Pumps. However, as a result of the ruling, the Appliance Standards and Rulemaking Federal Advisory Committee met and unanimously passed a recommendation to form a circulator pumps working group in January 2016.
The circulator pumps working group met throughout 2016 and developed a framework for a separate rule suitable for circulator pumps. The framework includes the following:
- Defining circulator pump;
- Creating performance metrics to rate circulator pumps;
- Formulating test procedures for circulator pumps; and
- Determining standard performance levels for circulator pumps.
The working group negotiated a final term sheet on Nov. 30, 2016, and presented it to the DOE. The working group recommended that the DOE make its best effort to publish the final test procedure and energy conservation standard for circulator pumps by the end of 2017.
These DOE regulations present an opportunity for pump manufacturers to design and launch pumps for HVAC systems that minimize carbon emissions and greenhouse gases and significantly reduce demand for electricity.