Significado de los principales símbolos energéticos de Odum, aplicados en Ejemplo de diagrama de flujos para una explotación maderera de pino ambiental em emergia, utilizando o Diagrama Emergético Ternário. . Odum ( ) para contabilizar os fluxos de massa e energia que ingressam e saem. um apanhado do desenvolvimento dos conceitos de forma de planta e .. períodos de seca, chamados de desertos e semidesertos frios (Odum ), e na região .. Figura 4 – Diagrama bioclimático de Dansereau (), em que as letras.
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Emergy is the amount of energy that was consumed in direct and indirect transformations to make a product or service. Emergy is an expression of all the energy used in the work processes that generate a product or service in units of one type of energy. Emergy is measured in units of emjoule s, a unit referring to the available energy consumed in transformations.
Emergy accounts for different forms of energy and resources e. Each form is generated by transformation processes in nature and each has a different ability to support work in natural and in human systems. The recognition of these quality differences is a key concept. The theoretical and conceptual basis for the emergy methodology is grounded in thermodynamics [ citation needed ]diagramz system theory  and systems ecology. Odum over the first thirty years is reviewed in Environmental Accounting  and in the volume edited by C.
Hall titled Maximum Power. Beginning in the s, Odmu analyzed energy flow in ecosystems e. Silver Springs, Florida ;  Enewetak atoll in the south Pacific;  Galveston BayTexas  and Puerto Rican rainforests,  amongst others where energies in various forms at various scales were observed.
His analysis of energy diagrsma in ecosystems, and the differences in the potential energy of sunlight, fresh water currents, wind and ocean currents led him to make the suggestion that when two or more different energy sources drive a system, they cannot be added without first converting them to a common measure that accounts for their differences in energy quality. This led him to introduce the concept of “energy of one kind” as a common denominator with the name “energy cost”.
Energy is measured diargama calories, btu ‘s, kilowatthours, and other intraconvertable units, but energy has a scale of quality which is not indicated by these measures.
The ability to do work for man depends on the energy quality and quantity and this is measurable by the amount of energy of a lower quality grade required to develop the higher grade. The scale of energy goes from dilute sunlight up to plant matter, to coal, from coal to oil, to electricity and up to the high quality efforts of computer and human information processing.
Inhe introduced a table of “Energy Quality Factors”, kilocalories of sunlight energy required to make a kilocalorie of a higher quality energy,  the first mention of the energy hierarchy principle which states that “energy quality is measured by the energy used in oudm transformations” from one type of energy to the next.
These energy quality factors, were placed on a fossil-fuel basis and called “Fossil Fuel Work Equivalents” FFWEand the quality of energies were measured based on a fossil fuel standard with rough equivalents of 1 kilocalorie of fossil fuel equal to kilocalories of sunlight. FFWE’s were replaced with coal equivalents CE and bythe system of evaluating osum was placed on a solar basis and termed solar equivalents SE. The term ” embodied energy ” was used for a time in the early s to refer to energy quality differences in terms of their costs of generation, and a ratio called a “quality osum for the calories or joules of one kind of energy required to make daigrama of another.
Use of the term “embodied energy” for this concept was modified in when David Sciencemana visiting scholar at the University of Florida from Australia, suggested the term “emergy” and “emjoule” or “emcalorie” as the unit of measure to distinguish emergy units from units of available energy.
It is important to note that throughout this xe years the baseline or the basis for diagraama forms of energy and resources shifted from organic matter, to diageama fuels and finally to solar energy.
Afterthe emergy methodology continued to develop as the community of scientists expanded and as new applied research dixgrama combined systems of humans and nature presented new conceptual and theoretical questions. The maturing of the emergy methodology resulted in more rigorous definitions of terms and nomenclature and refinement of the methods of calculating transformities.
Emergy — amount of energy of one form that is used in transformations directly and indirectly to make a product or ovum. The unit of emergy is the emjoule or emergy joule. Using emergy, sunlight, fuel, electricity, and human service can be put on a common dd by expressing each of them in the emjoules of solar energy that is required to produce them. If solar emergy is the baseline, then the results are solar emjoules abbreviated seJ.
Although other baselines have been used, such as coal emjoules or electrical emjoules, in most cases emergy data are given in solar emjoules. Emergy accounting converts the thermodynamic basis of odim forms of energy, resources and human services into equivalents diaggrama a single form of energy, usually solar.
To evaluate a system, a system diagram organizes the evaluation and account for energy inputs and outflows. A table of the flows of resources, labor and energy is constructed from the diagram and all flows are evaluated. The final step involves interpreting the results.
In some cases, an evaluation is done to determine the fit of a development proposal within its environment. It also allows comparison of alternatives. Another purpose is to seek the best use of resources to maximize economic vitality. System diagrams show the inputs that are evaluated and summed to obtain the emergy of a flow.
A diagram of a city and its regional support area is shown in Figure 1. A table see example below of resource flows, labor and energy is constructed from the diagram.
Raw data on inflows that cross the boundary are converted into emergy units, and then summed to obtain total emergy supporting the system. Energy flows per unit time usually per year are presented in the table as separate line items. The table allows a unit emergy value to be calculated. Then the input emergy is summed and the unit emergy value is calculated by dividing the emergy by the units of the output.
Figure 2 shows non-renewable environmental contributions N as an emergy storage of materials, renewable environmental inputs Rand inputs from the economy as purchased F goods and services. Purchased inputs are needed for the process to take place and include human service and purchased non-renewable energy and material brought in from elsewhere fuels, minerals, electricity, machinery, fertilizer, etc.
Several ratios, or indices are given in Figure 2 that assess the global performance of a process. The recognition of the relevance of energy to the growth and dynamics of complex systems has resulted in increased emphasis on environmental evaluation methods that can account for and interpret the effects of matter and energy flows at all scales in systems of humanity and nature.
The following table lists some general areas in which the emergy methodology has been employed. References for each of the citations in this table are given in a separate list at the end of this article. The concept of emergy has been controversial within academe including ecology, thermodynamics and economy.
Thus it does not purport to replace economic values but to provide additional information, from a different point of view. The idea that a calorie of sunlight is not equivalent to a calorie of fossil fuel or electricity strikes many as absurd, based on the 1st Law definition of energy units as measures of heat i.
Joule’s mechanical equivalent of heat. In combining systems of humanity and nature and evaluating environmental input to economies, mainstream economists criticize the emergy methodology for disregarding market values. From Wikipedia, the free encyclopedia. Business and economics portal Ecology portal Environment portal Sociology portal. Anthropogenic metabolism Ecological economics Ecological energetics Energetics Energy accounting Environmental accounting Industrial metabolism Material flow analysis Maximum power principle Social metabolism Systems ecology Urban metabolism.
Emergy and Environmental Decision Making. New York p. Self organization and maximum power.
Hall, University Press of Colorado, Niwot. Trophic structure and productivity of Silver Springs, Florida.
Howard T. Odum
Trophic structure and productivity of a windward coral reef at Eniwetok Atoll, Marshall Odun. Comparative studies of the metabolism of Texas Bays. A Tropical Rain Forest. Division of Technical Information, U. Energetics of food production. House of Representatives,U. Printing Office, Wash, DC. Energy Basis for Man and Nature. Energy, ecology and economics. Royal Swedish Academy of Science. Tropical Ecology 16 l: Energy analysis, energy quality and environment. Energy systems and environmental education.
Emergy – Wikipedia
Plenum Press, New York. Murota edsEnvironmental Economics: The Analysis of a Major Interface, R. Environment, Power and Society. Energy Analysis Overview of Nations. Handbook of Emergy Evaluation: Folio 1 — Introduction and Global Budget. Available on line at: Archived from the original on Archived copy as title link.
Confusing Production and Consumption. Aggregation and the role of energy in the economy. Promise and problems of emergy analysis. Ecology, odhm and H. The theory of power and efficiency in ecology. Praeger Publishers, New York, pp. On the Second-Law inconsistency of Emergy Analysis. Retrieved from ” https: Emergy Energy Systems theory. Archived copy as title Webarchive template wayback links All articles with unsourced statements Articles with unsourced statements from November Articles with unsourced statements from January Articles with unsourced statements from May Views Read Edit View history.