Usuario:Czajko/Borrador 1

Un edificio energía cero (EEC) or edificio energía neta cero es un término aplicado a edificios con un consumo de energía neta cercana a cero en un año típico. En otras palabras, la energía proviene del propio edificio mediante fuentes de energías renovables que deberá ser igual a la energía demandada por el edificio.

Demanda energía = generación energía

Un edificio que se acerque a un uso de la energía próximo a cero se denomina cercano a edificio energía cero o edificio energía ultra-baja. Los que producen un exceso de energía se conocen como edificios energía plus.

Aunque los edificios energía cero siguen siendo infrecuentes en los países desarrollados, están ganando en importancia y popularidad. La proximidad de hacer masivos los edificios energía cero implica una solución potencial a una gama de problemas sociales y ambientales, incluyendo la reducción de las emisiones de CO2 (dióxido de carbono), la reducción de dependencia de la energía fósil para el funcionamiento de los sistemas de climatización, las importaciones de petróleo y derivados, y el uso racional de combustible fósil para otros usos mejorando los problemas de abastecimiento en un escenario de crísis energética, precios crecientes y agotamiento del recurso fósil.

El debate generación de energía vs conservación de energía

Una de las áreas claves del debate respecto a los edificios energía cero es sobre el balance entre conservación de energía y el uso de energías renovables.

La mayoría de los diseñadores de edificios energía cero, tiene la postura que no alcanza con consumir más es igual a generar más sino todo lo contrario. El edificio en su concepción, construcción y funcionamiento debe demandar la mínima cantidad de energía y esta demanda mínima debe ser cubierta por las energías renovables. Esto nos lleva a pensar en lo postulado por la casa pasiva junto a un edificio energéticamente eficiente. Esto por otra parte implica superar largamente los estándares propuestos por las normas y códigos de edificación de la mayoría de los países que cuentan con dichos instrumentos de regulación de la calidad energética de la construcción.

Sin embargo, mientras que reconoce que la conservación de energía es una pieza importante en el juego, otra buena parte de los diseñadores considera que esto es de una importancia más baja y valoriza en mayor grado las técnicas “activas” (energía solar fotovoltaica, energía eólica, etc.) para compensar la energía / el déficit de calor.

Generación de energía

In the case of individual houses, various microgeneration technologies may be used to provide heat and electricity to the building, perhaps using solar cells or wind turbines for electricity, and biofuels, or solar collectors linked to seasonal thermal stores, for space heating. To cope with fluctuations in demand, zero energy buildings are frequently connected to the electricity grid, and may export electricity to it when there is a surplus. Others may be fully autonomous (off-grid) buildings.

Zero-energy neighbourhoods, such as the BedZED development in the United Kingdom, may use distributed generation schemes combined with district heating. There are currently plans to use similar technologies to build entire zero-energy cities, such as Dongtan near Shanghai.

Diseño y construcción

To achieve minimal energy use, the design and construction of zero energy buildings departs significantly from conventional building practise. In conventional building design the emphasis is normally on minimizing construction costs. Designers rarely do any energy analysis or lifecycle operating cost calculations beyond those necessary to comply with local building codes.

In the ZEB approach every decision about major sub-system selection is evaluated in terms of its future consequences on energy demand using life cycle energy analysis. ZEB designers are usually prepared to increase construction costs if doing so will reduce energy demand and operating costs by an equal or greater amount. The ZEB approach might be described as "energy first" building design.

In addition to using renewable sources, zero energy buildings are also designed to make use of energy gained from other sources including white goods, lighting, and even body heat. They are normally optimised to use passive solar heat gain, use thermal mass to even out temperature variations throughout the day, and in most climates are superinsulated. All the technologies needed to create zero energy buildings are available off the shelf today.

Designers typically use sophisticated computer simulation tools to take into account a wide range of design variables such as building orientation (relative to the sun), window type and placement, overhang depth, insulation values of the building elements, air tightness, the efficiency of heating, lighting and other equipment, as well as local climate. These simulations help the designers to know how the building will perform before it is built, and enable them to model the financial implications on building cost.

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Ventajas potenciales de EEC

• it appears to isolate the buildings' occupant(s) from energy price increases
• buildings built using ZEB concepts tend to be more comfortable due to more uniform interior temperatures (this can be demonstrated with comparative isotherm maps)
• it is substantially less expensive to improve energy efficiency during initial design and construction than it is to do so through a retrofit
• higher resale value
• the value of a ZEB building relative to similar conventional building increases as energy costs increase

Desventajas potenciales de EEC

• initial costs can be expected to be higher in the near term
• possible significant declines in future energy costs could strand capital invested in energy efficiency
• new solar cells technology could strand capital invested in a solar electric generating system
• challenge to recover higher initial costs on resale of building
• passive design may limit future ability to respond to rising ambient temperatures

Ver además

• Passive house
• Superinsulation
• Solar cell
• Insulation
• Weatherization
• Active solar
• Thermal conductivity (for an explanation of thermal conductivity, thermal conductance, and thermal resistance)
• Thermal mass
• Earth sheltering
• Earthship
• Energy-efficient landscaping
• Environmental design
• Life cycle energy analysis
• Natural Building
• Renewable energy
• Autonomous building
• Straw-bale construction
• Peak oil
• Sim Van der Ryn
• Steve Baer
• Ecopolis (city)
• Low-energy house
• Green building
• EnerGuide for Houses
• Environmental economics

Referencias

• Common Fire Foundation Comprehensive Overview of Green Building, plus info on the net-zero energy "Greenest Building in the Eastern US" (non-profit)
• Oak Ridge National Lab (ORNL)
• Download 2000 ZEB meeting report
• Zero Energy House - NAHB Research Center
• "Self-Sufficient Solar House " Fraunhofer Institute's (ZEB), Freiburg, Germany
• ecoLogical Home Ideas Magazine for green home building/remodeling

Lectura adicional

Nisson, J. D. Ned; and Gautam Dutt, "The Superinsulated Home Book", John Wiley & Sons, 1985, ISBN 0-471-88734-X, ISBN 0-471-81343-5. Markvart, Thomas; Editor, "Solar Electricity" John Wiley & Sons; 2nd edition, 2000, ISBN 0-471-98853-7.

Clarke, Joseph; "Energy Simulation in Building Design", Second Edition Butterworth-Heinemann; 2nd edition, 2001, ISBN 0-7506-5082-6.