Energetically positive districts
Introduction
A zero energy building (EEC) or zero net energy building is a term applied to buildings with near-zero net energy consumption in a typical year. In other words, the energy comes from the building itself through renewable energy sources that must be equal to the energy demanded by the building.
Energy demand = energy generation.
A building that approaches near-zero energy use is called a nearly zero energy building (EECN, in English: nZEB) or an ultra-low energy building. Those that produce excess energy are known as energy plus buildings.
Background and general characteristics
Near-zero energy demand buildings are not contemporary. Although the first experiments were carried out in the middle of the century by the pioneers of Solar Architecture, it was not until 1977 that Esbensen and Korsgaard built a house in Denmark and coined the expression Zero Energy House.[1].
Although zero energy buildings remain uncommon in developed countries, they are gaining in importance and popularity. The proximity of making zero energy buildings massive implies a potential solution to a range of social and environmental problems, including the reduction of CO emissions, the reduction of dependence on fossil energy for the operation of air conditioning systems, imports of oil and derivatives, and the rational use of fossil fuel for other uses, improving supply problems in a scenario of energy crisis, rising prices and depletion of the fossil resource.
Power generation
In the case of individual houses, various microgeneration technologies can be used to provide heat and electricity to the building.
• - Electricity: through solar cells (photovoltaic), wind turbines (wind energy) and fuel cells (hydrogen).
• - Heat: through biofuels, biomass "Biomass (energy)"), thermal solar collectors (hot water, hot air, low pressure steam), accumulation in the thermal mass of the building, water walls and Trombe-Michel walls, among other thermal strategies of the bioclimatic arsenal, synthesized in the passive house. With these techniques, heating, cooling and even refrigeration can be provided to the environments of the house or building. Among the most recent developments is geothermal heating or the accumulation of phreatic heat by which wells are made at depths between 40 and 70 m of approximately 30 cm in diameter through which the water from the fan coil or radiant floor type air conditioning systems is recirculated. Thus summer heat accumulates to be used in winter and vice versa. The most notable example is the German Parliament building in Berlin by architect Norman Foster.