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Über dieses Buch

A number of significant changes have occurred in Advances in Solar Energy since Volume 1 appeared in 1982. The delays in publication of the second volume are the result of reorganization of the American Solar Energy Society, and the negotiation of a new publishing arrangement. Beginning with this volume, Advances is now published jointly by the Society and Plenum Press. The Editorial Board has been enlarged to be more representative of the different fields of solar energy conversion. Production of Advances is being expedited through the use of modern word processing equipment and the 'lEX typesetting-editing program. We have gone to a single-column format to ease the problems of presenting long equations, and we expect that the user of the volume will find it easy to read. The use of 'lEX will make last minute updates possible. The external appearance of the volume matches that of Volume 1. We expect that future volumes of this annual will be proceeding on schedule. We invite comments from users and correspondence from prospective authors of critical reviews. Karl W. Boer John A. Duffie CONTENTS CHAPTER 1 The Measurement of Solar Radiation Ronald Stewart, Daniel W. Spencer and Richard Perez 1.1 Abstract 1 1.2 Characteristics of Pyranometers ....................................... . 2 1.3 General Features of a Pyranometer ................................... . 3 1.3.1 Instrument Sensitivity 4 1.3.2 Response with Time 4 1.3.3 Sensitivity 4 1.3.4 Responsivity ................................................. .



Chapter 1. The Measurement of Solar Radiation

The measurement of solar radiation has run the gamut from casual interest recordings to intensive scientific/technological experiments on satellites. In these situations, the interest has always been to obtain reliable, usable date. The choice of measurement technique has often depended upon availability of instrumentation and funding to design a proper data acquisition system and analysis program. The following monograph attempts to deal with some of the problems associated with the choice of instruments for such a program and with some of the questions of the techniques for the analysis of the data acquired.
The first section, adapted from the International Energy Agency Conference on Pyranometer Measurements,1 provides an analysis of various characteristics of pyranometers. We acknowledge the advice of Michael R. Riches, Office of Energy Research, U.S. DOE, on the use of this material.
The next section outlines some of the commonly noted problems with the measurement of solar radiation, as well as possible causes and solutions. Much of this information is based upon the recent experience of the U. S. DOE-sponsored Solar Energy Meteorological Research and Training Sites.
The last section is adapted from Sunworld (Solar Radiation Instruments by Kinsell L. Coulson and Yvonne Howell) and is reprinted with the kind permission of the publishers, Pergamon Press, Ltd. Additional information has been added from recent publications.
Appendix 1.1, Historical Perspective, is simply a compilation of dates and events in the history of solar radiation measurement. It provides the time perspective which has led us to today’s solar-oriented society. Much of the information is adapted from Coulson2 and Drummond,3 with input from EPLAB, Inc., Hollis Geosystems Corp., Casella London Ltd., LI-COR, Inc., and Kipp & Zonen.
Ronald Stewart, Daniel W. Spencer, Richard Perez

Chapter 2. Environmental Requirements for Anaerobic Digestion of Biomass

The anaerobic digestion process is experiencing renewed interest worldwide. Findings indicate that methanogenic bacteria have catalyzed a revolution in our understanding of procaryote diversity. A host of publications has emerged on this topic. Pure culture techniques have improved, allowing further elucidation of reactions and pathways. Agricultural and environmental engineers have demonstrated renewed interest in the anaerobic digestion process in attempts to address waste treatment management needs and provide supplemental energy supplies, or both. Energy corporations are evaluating anaerobic digestion as a possible source of alternative energy supplies from biomass and other renewable sources. Research in each aspect and overall interest in anaerobic digestion has never been greater.
This review summarizes the literature through 1982 on the microbiology of methanogens, their reactions, characteristics, and pathways. Historical information on nutrient requirements of both the methanogens and fermentation bacteria is compiled.
Particular emphasis is made on the recent discovery of nickel as an essential trace metal requirement for methanogens. Other trace metals such as selenium and tungsten have been discovered. Iron appears to be required in rather high concentrations.
Sulfur requirements for anaerobic digestion are not widely documented, but sulfur appears to be required in concentrations much higher than previously thought. The complex chemistry in anaerobic digestion makes it difficult to clearly identify the requirement for sulfur and trace metals.
Recent investigations of the toxicity response of methanogens has demonstrated they are much less sensitive than previously considered. Acclimation to a wide variety of toxicants has been demonstrated. In addition, toxicity is commonly reversible at the toxicant concentrations commonly observed in the environment.
The economic burden of alkalinity supplementation costs for anaerobic digestion of some types of biomass and industrial wastewaters is so great that a separate section is devoted to this matter. Sources, requirements, and conservation of alkalinity are addressed.
Efforts to model the anaerobic digestion process are reviewed. A number of general and specific models are available. Some models assume volatile acids utilization is rate limiting, while others assume lipids or cellulose degradation to be rate limiting.
The review also considers various design prerequisites. Process configuration, temperature, and type of feedstock are discussed. Some of the industrial wastewaters successfully treated by anaerobic digestion are summarized. Finally, treatability screening procedures and scale-up factors affecting performance are summarized.
R. E. Speece

Chapter 3. Principles and Technology of Biomass Gasification

After a dormant period following World War II, biomass gasification entered a period of rapid development. The major types of gasifiers and their various modes of operation are discussed. The role of thermodynamic equilibrium and kinetics in gasifier operation is presented. The mechanisms and kinetics of pyrolysis and char gasification are reviewed and the current state of gasifier modeling is surveyed.
Thomas B. Reed

Chapter 4. Biomass Pyrolysis: A Review of the Literature Part 2—Lignocellulose Pyrolysis

A normative review of the literature describing the products, mechanisms, and rates of lignin and whole biomass pyrolysis is presented. The role of a complex sequence of competing solid- and vapor-phase pyrolysis pathways is elucidated.
Michael Jerry Antal

Chapter 5. Thermal Comfort and Passive Design

Already Socrates and later Vitruvius had some thoughts on the climatic suitability of buildings, but these had never seriously influenced architects and builders. Up to the Industrial Revolution, thermal comfort was largely an academic question and, as such, rarely raised. When it was cold, a fire was lit to ameliorate the conditions. The potential of the available controls was the limiting factor, rather than the risk of overheating. When it was hot, the use of hand-operated fans was about the only possibility for relief. Only in exceptional situations was the heat storage capacity of caves used for cooling, or—in some other cultures—man-made tunnels and wind towers used for a similar purpose. In none of these cases was it necessary to specify the desirable environmental conditions.
S. V. Szokolay

Chapter 6. Earth Contact Buildings: Applications, Thermal Analysis and Energy Benefits

Earth contact buildings, also referred to as earth sheltered or underground structures, have been identified as one means of passive cooling that can contribute to reducing total energy requirements as well as peak load demands. Unlike most conservation and passive heating or cooling strategies which are singular in their purpose and effect, the use of earth contact represents a wide range of energy-related characteristics, as well as a number of diverse advantages not directly related to energy use. Earth contact is part of the thermal envelope in virtually all buildings, and presents opportunities for energy conservation in residential-scale and larger structures, in complexes of several structures, and in more innovative coupling of buildings to the ground.
To provide an overview of these various facets of earth contact design and research, this chapter is divided into three parts. The first provides general background material on earth contact structures and their application. The second section summarizes key issues and pertinent research related to thermal analysis of earth contact buildings. The final section includes preliminary results of energy performance analysis for components of small earth contact structures.
John C. Carmody, George D. Meixel, Kenneth B. Labs, Lester S. Shen

Chapter 7. Testing Solar Collectors

The state of the art in testing solar collectors to determine their thermal performance is reviewed here. A brief history of the significant work done to establish the procedures for testing is given, including the current proposed and adopted worldwide procedures. In the second section, the basic mathematical equations describing the thermal performance of solar collectors are given as the basis for showing what information can be obtained from such tests. In the third section, a detailed description is given of the testing techniques used to determine collector thermal performance under clear-sky, full-irradiance conditions, as typically called for in most of the currently adopted standards. This section will also include a discussion of typical instrumentation, its accuracies and limitations, the results of major round-robin programs conducted to date showing the comparability of data between laboratories when the tests are conducted outside under real-sun conditions, and special techniques required to test concentrating collectors. In the fourth section, a technique for obtaining collector efficiency indoors under zero-irradiance will be discussed. In the fifth section, special considerations when testing air collectors will be discussed. In the final section, concepts for using test data to calculate all-day collector performance will be presented.
James E. Hill, Byard D. Wood, Kent A. Reed

Chapter 8. Concentrating Solar Collectors

This chapter provides an introduction to concentrating solar collectors. The optical and thermal characteristics are described in relatively simple terms, and copious references to the more technical literature are given. A unified framework is used for analyzing the performance of all solar collector types; it involves optical efficiency, U-value, and heat transfer factor. Two measures of performance are of particular interest: the instantaneous efficiency under peak insolation (which is easy to measure), and the annual energy delivered by the collector (which is difficult to measure but is crucial for the economic evaluation). A simple but accurate graphical procedure is presented for obtaining the annual energy from the instantaneous efficiency curve. The chapter includes a discussion of practical aspects, covering choice of materials as well as problems of cleaning and tracking. Data for cost and performance of current collectors are provided.
A. Rabl


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