Section 431.345 - Energy conservation standards and effective dates(a) Each compressor that is manufactured starting on January 10, 2025 and that: (1) Is an air compressor,(2) Is a rotary compressor,(3) Is not a liquid ring compressor,(4) Is driven by a brushless electric motor,(5) Is a lubricated compressor,(6) Has a full-load operating pressure greater than or equal to 75 pounds per square inch gauge (psig) and less than or equal to 200 psig,(7) Is not designed and tested to the requirements of The American Petroleum Institute standard 619, "Rotary-Type Positive-Displacement Compressors for Petroleum, Petrochemical, and Natural Gas Industries,"(8) Has full-load actual volume flow rate greater than or equal to 35 cubic feet per minute (cfm), or is distributed in commerce with a compressor motor nominal horsepower greater than or equal to 10 horsepower (hp),(9) Has a full-load actual volume flow rate less than or equal to 1,250 cfm, or is distributed in commerce with a compressor motor nominal horsepower less than or equal to 200 hp,(10) Is driven by a three-phase electric motor,(11) Is manufactured alone or as a component of another piece of equipment; and(12) Is in one of the equipment classes listed in the Table 1, must have a full-load package isentropic efficiency or part-load package isentropic efficiency that is not less than the appropriate "Minimum Package Isentropic Efficiency" value listed in Table 1 of this section. Table 1-Energy Conservation Standards for Certain Compressors
| Equipment class | Minimum package isentropic efficiency | [ETA]Regr
(package isentropic efficiency reference curve) | d
(percentage loss reduction) |
| Rotary, lubricated, air-cooled, fixed-speed compressor | [ETA]Regr + (1 - [ETA]Regr) * (d/100) | -0.00928 * ln2(.4719 * V1) + 0.13911 * ln(.4719 * V1) + 0.27110 | -15 |
| Rotary, lubricated, air-cooled, variable-speed compressor | [ETA]Regr + (1 - [ETA]Regr) * (d/100) | -0.01549 * ln2(.4719 * V1) + 0.21573 * ln(.4719 * V1) + 0.00905 | -10 |
| Rotary, lubricated, liquid-cooled, fixed-speed compressor | .02349 + [ETA]Regr + (1 - [ETA]Regr) * (d/100) | -0.00928 * ln2(.4719 * V1) + 0.13911 * ln(.4719 * V1) + 0.27110 | -15 |
| Rotary, lubricated, liquid-cooled, variable-speed compressor | .02349 + [ETA]Regr + (1 - [ETA]Regr) * (d/100) | -0.01549 * ln2(.4719 * V1) + 0.21573 * ln(.4719 * V1) + 0.00905 | -15 |
(b) Instructions for the use of Table 1 of this section:(1) To determine the standard level a compressor must meet, the correct equipment class must be identified. The descriptions are in the first column ("Equipment Class"); definitions for these descriptions are found in § 431.342 .(2) The second column ("Minimum Package Isentropic Efficiency") contains the applicable energy conservation standard level, provided in terms of package isentropic efficiency.(3) For "Fixed-speed compressor" equipment classes, the relevant Package Isentropic Efficiency is Full-load Package Isentropic Efficiency. For "Variable-speed compressor" equipment classes, the relevant Package Isentropic Efficiency is Part-load Package Isentropic Efficiency. Both Full- and Part-load Package Isentropic Efficiency are determined in accordance with the test procedure in § 431.344 .(4) The second column ("Minimum Package Isentropic Efficiency") references the third column ("[ETA]Regr"), also a function of full-load actual volume flow rate, and the fourth column ("d"). The equations are provided separately to maintain consistency with the language of the preamble and analysis.(5) The second and third columns contain the term V1, which denotes compressor full-load actual volume flow rate, given in terms of cubic feet per minute ("cfm") and determined in accordance with the test procedure in § 431.344 .85 FR 1591, Jan. 10, 2020 82 FR 1102, 2/3/2017; 85 FR 1591, 3/10/2020