G
Geothermal heat pumps (vertical or horizontal
evaporator)
Heat pumps use renewable energy drawn in from the outside air, ground water
or surface water in the ground. The technology of reversible heat pumps makes
it possible to heat and/or cool using the same equipment. The heat pumps ground
collection network may be horizontal (at a depth of 50/80 cm) or vertical depending
on the topography of the site. It may be installed in any type of ground. Geothermal
piles form one collection variant, and consist of piles in which a tube or a
network of tubes has been installed to circulate a heat conductor fluid and
to exchange heat with the subsoil. When connected to a heat pump, these piles
are capable of extracting heat from the subsoil to satisfy heating needs in
winter, and to reject heat generated from cooling in the summer. They can perform
two functions: to act as a foundation for the building and to exchange calories
with the ground. They can be used in tertiary and residential areas.
Glare
Luminance conditions producing visual discomfort or reduction in ability to
discern details of objects.
Global (or total) solar radiation
(kWh or kWh/m², MJ or MJ/m²)
The sum of the direct and diffuse
radiation incident on a surface.
Greenhouse effect
The greenhouse effect results from a three-stage process whereby shortwave solar
energy is collected through glazing in the building envelope, absorbed by the
opaque or solid elements in the building, and reemitted as long wave radiation
which is prevented by the glazing from leaving the building.
The efficiency of this collecting system is affected by its geometry, the characteristics of the glazing, (for example, the percentage of glazed area and the spectral transmission curve) and those of the solid elements struck by the solar radiation, such as solar absorptance and spectral thermal emission curve.
Green roof
Several technologies already exist on the market, the best performances being
achieved with extensive green roofs.
Green roofs appear attractive to provide thermal insulation external to the building and that can reduce energy consumption and improve summer comfort. They can also be considered as improving acoustic comfort. Furthermore, in urban areas, the "heat island" phenomenon can amplify ambient temperatures due to the large mineral areas that reflect, emit and store heat. Similarly, the impermeabilization of soils is the reason for large quantities of almost instantaneous runoff requiring the construction of oversized drainage works to handle violent storms.
By creating "breathing" surfaces, green roofs can contribute to improve thermal comfort in summer (reducing the heat island effect), and reduce the impermeability of the ground thus introducing a rain storage effect, delaying runoff and filter rain water.