Section 3 presents the technical background of the pertinent elements of thermodynamics and the legislative background of Federal energy conservation programs. The analyses and conclusions of the study are the topics of Sections 4 and 5. This section addresses the methodology employed in assessing the relevance of The of the Federal Government that are related to energy conservation. study methodology involved examining actual examples of the use of Second Law analysis and hypothetical applications of its use in Federal energy conservation programs. Its relevance was assessed using a simple evaluation scheme. In principle, analyses based on the Laws of Thermodynamics are relevant to all systems in which energy is an important factor. But this does not mean that those analyses always will be useful. Relevance must be defined in a more limited sense for the purpose of this study. Typically, the criterion used to establish the relevance of an analytical tool to application in a particular area is that its benefit-cost ratio is favorable relative to other available tools. This may mean providing the same information that other tools do but more quickly, with less effort or at a lower cost; or, it may mean the tool in question provides new or additional information, the value of which is greater than the costs associated with its use. Energy analyses based on the Second Law of Thermodynamics clearly must fall within the latter of these categories if they are to be practical. will become clearer on review of the next section of this report.) (This assertion Therefore, the criterion used in this study for assessing the relevance of Second Law analyses to energy conservation programs is the following: Will Second Law analysis provide data, information, or insights of sufficient value or benefit beyond those obtained using "conventional" energy analysis techniques in relation to its for various energy conservation programs and generic classes of potential use is presented. In each case, one of three alternative levels of relevancy is given; i.e., Second Law analysis is useful, or is of limited applicability, or is not beneficial when considered in light of the above question. 1 As part of this study, an advisory team of in-house thermodynamicists was formed of which the authors of this report were a part. A literature survey was conducted to obtain a cross-section of the various applications of these analytical techniques. Close liaison was maintained with the staff of General Energy Associates who conducted the study presented in Volume 2 of the DoE report. NBS staff members also discussed the subject with several authorities on the application of the Second Law and with representatives of various sectors of industry including an ad hoc technical committee of the Chemical Manufacturers Association. During the period this study was conducted, two professional meetings specifically oriented toward Second Law analytical techniques were held. In December 1978, one of the team members organized and chaired a panel of experts from industry and the university sector to discuss the practical value of using Second Law techniques. This discussion was conducted at the Winter Annual Meeting of the American Society of Mechanical Engineers. In August 1979, several team members attended a Workshop on the Second Law of Thermodynamics held at George Washington University in Washington, D.C. Over twenty-five experts from the United States and Europe presented technical papers of various systems analyses based on Second Law techniques2. Dr. Frederick Costello, a private consultant who had previously conducted a study using Second Law 1. Dr. Max Klein, Senior Scientist of the Thermophysics Division, Dr. Kenneth Kreider, Chief of the Thermal Processes Division, 2. Dr. Preston McNall, Chief of the Building Thermal Performance Division, and the authors. The proceedings of that meeting may be obtained from Dr. Ali Cambel, of this study. Professor Richard A. Gaggioli, Marquette University made a detailed review of a draft of this report and offered many useful suggestions. In this section several terms used throughout the report are described. The first few are technology terms: sources of energy and feedstocks. energy conservation, energy consumption, These apply to conventional materials used in industrial systems. Then, the thermodynamic basis for quantifying the use of energy sources is explained in terms of internal energy, useful work (availability) and entropy. Next, measures of efficiency are described. Finally, the scope, application and limitations of energy analysis are treated in the context of what is practical and the broader analysis that includes cost, limitations imposed by materials and social factors. A.1 Energy Sources Energy conservation, as the term is commonly used and as it is used in this report, has as its goal the more efficient use of sources of energy. This means (a) using less of a source of energy to do a particular job, (b) doing several tasks (concurrently or sequentially) with the same portion of the source, or, (c) using a different source, one more closely matched to the task. An example of (a) is savings resulting from the use of better insulation. Use of process steam both for the generation of electricity or work and then for heating illustrates (b). Use of a low temperature heat source for space heating is an example of (c). Energy consumption means using the energy stored in a source. More correctly, it means converting the stored energy (chemical, gravitational, magnetic, etc.) to some other, desired form (often heat or work). Neither of these definitions of conservation or consumption should be confused with thermodynamic statements about the conservation of energy, discussed below. |