Nat. Bur. Stand. (U.S.), Tech. Note 1115, 51 pages (Aug. 1980)
CODEN: NBTNAE

U.S. GOVERNMENT PRINTING OFFICE
WASHINGTON: 1980

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This is a study of the relevance to Federal energy conservation programs of the use of the concept of energy efficiency as being the ratio of the minimum available work necessary for accomplishing a given task to the available work in the actual fuel used to accomplish this task. Included within the study is a review of selected elements of thermodynamics and efficiency concepts, and identification of the technology pertinent to energy conservation programs. The study examines the potential benefits, if any, that would accrue from the application of Second Law of Thermodynamics principles to these technologies. Results indicate the positive value of the Second Law analytical techniques in the planning and design stages of system development, and the rather limited value of its use during the performance monitoring stage. Needs for advancing the acceptance and use of the Second Law analytical techniques are identified.

Key words:

Availability analysis; energy conservation; energy; process efficiency, Second Law of Thermodynamics; system efficiency

Section 683 of the National Energy Conservation Policy Act (NECPA), Pub. L. 95-619, directed the Secretary of Energy to conduct a study of the "relevance to energy conservation programs of the use of the concept of energy efficiency as being the ratio of the minimum available work necessary for accomplishing a given task to the available work in the actual fuel used to accomplish that task" (hereinafter referred to as the "study" or the "Second Law Study"). This concept of energy efficiency is based on the First and Second Laws of Thermodynamics.

The National Bureau of Standards (NBS) conducted this study for the Department of Energy (DOE). Staff members at NBS carried out a qualitative assessment of the benefits of applying the Second Law of Thermodynamics concepts to the various energy technologies which comprise the energy conservation programs that are specified in Section 683 of NECPA. The discussion and results of this effort are covered in Volume 1 of the the DoE report to Congress (DoE/CS/40178.000-01) of January 1980. NBS also contracted with a private firm specializing in Second Law analyses to conduct detailed technical analyses. The contractor's report consisting of a quantitative analyses of selected technology systems and generalized conclusions are presented in Volume 2 of the same DoE report. This NBS report is a rewrite of Volume 1. It contains a modest elaboration of the thermodynamics background and is oriented towards a slightly more Although the conclusions are generally identical to

technical audience.

those in the DOE report, it is hoped that the technical discussion is more precise and explicit. (A format identical to Volume 1 has been maintained for ease of comparison.)

The energy conservation programs addressed in this study include (1) those authorized in the Energy Policy and Conservation Act (EPCA), Pub. L. 94-163; the Energy Conservation and Production Act (ECPA), Pub. L. 94-385; and NECPA;

stration.

The process of establishing the relevance of the Second Law of Thermodynamics to these energy conservation programs includes reviewing the elements of thermodynamics and efficiency concepts, identifying the technologies pertinent to energy conservation programs* and finally establishing what particular benefits, if any, would accrue from application of Second Law principles to these technologies.

In particular, consideration has been given as to how the analytical techniques based on the Second Law of Thermodynamics might be useful in:

(1) planning and setting of research priorities (i.e. the assessment of technologies for investment, management, regulatory, or policy purposes) (2) design, analysis and testing of components or systems

(3) monitoring or rating of operating systems

With reference to each of these questions, sample energy systems from the

following five major energy technology groups were considered:

(1) industrial processes which involve the generation of process steam as

applied to the manufacture of chemical products, paper, and allied
products, food products, transportation equipment, machinery and
textiles;

(2) industrial systems which involve direct heating as applied to the
processing of primary metals, fabricated metals, stone, glass and
clay products, petroleum and coal products;

(3) transportation;

(4) generation of electrical power; and

(5) building, heating, ventilating and air conditioning systems.

* Only those aspects of energy conservation programs that deal with "more efficient use" have been considered. The curtailment aspects of the programs were not considered relevant to this study.