News tagged with greenhouse
Greenhouse
A greenhouse (also called a glasshouse) is a building in which plants are grown. These structures range in size from small sheds to very large buildings. A miniature greenhouse is known as a cold frame.
A greenhouse is a structure with different types of covering materials, such as a glass or plastic roof and frequently glass or plastic walls; it heats up because incoming visible solar radiation (for which the glass is transparent) from the sun is absorbed by plants, soil, and other things inside the building. Air warmed by the heat from hot interior surfaces is retained in the building by the roof and wall. In addition, the warmed structures and plants inside the greenhouse re-radiate some of their thermal energy in the infra-red, to which glass is partly opaque, so some of this energy is also trapped inside the glasshouse. However, this latter process is a minor player compared with the former (convective) process. Thus, the primary heating mechanism of a greenhouse is convection. This can be demonstrated by opening a small window near the roof of a greenhouse: the temperature drops considerably. This principle is the basis of the autovent automatic cooling system. Thus, the glass used for a greenhouse works as a barrier to air flow, and its effect is to trap energy within the greenhouse. The air that is warmed near the ground is prevented from rising indefinitely and flowing away.
Although there is some heat loss due to thermal conduction through the glass and other building materials, there is a net increase in energy (and therefore temperature) inside the greenhouse.
Greenhouses can be divided into glass greenhouses and plastic greenhouses. Plastics mostly used are PEfilm and multiwall sheet in PC or PMMA. Commercial glass greenhouses are often high tech production facilities for vegetables or flowers. The glass greenhouses are filled with equipment like screening installations, heating, cooling, lighting and may be automatically controlled by a computer.
For more information about Greenhouse, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
Computer model used to pinpoint prime materials for efficient carbon capture
When power plants begin capturing their carbon emissions to reduce greenhouse gases – and to most in the electric power industry, it's a question of when, not if – it will be an expensive undertaking.
May 27, 2012 |
5 / 5 (1) |
2
|
A 'B12 shot' for marine algae? Scientists find key protein for algae growth in the ocean
Scientists have revealed a key cog in the biochemical machinery that allows marine algae at the base of the oceanic food chain to thrive. They have discovered a previously unknown protein in algae that grabs an essential ...
9 hours ago |
5 / 5 (2) |
3
|
Study takes novel 'back-casting' approach to transform cities for healthier lives
Researchers at four of the country's leading universities are embarking on a low carbon engineering project that could transform the way cities are built, as well as the way we live in them, by taking a novel 'back-casting' ...
May 29, 2012 |
5 / 5 (4) |
0
Recovering water from tailings ponds
(Phys.org) -- As Alberta faces increasing pressure to make the oil industry more sustainable, one University of Alberta researcher may have found a natural solution to a problem that has been plaguing oil companies for years.
May 29, 2012 |
5 / 5 (2) |
0
Research: Negative leakage could be key to reducing carbon emissions
(Phys.org) -- The unilateral efforts of a single country or region to reduce the emissions of greenhouse gases could reduce exports, increase imports and lead to higher emissions elsewhere – what economists call “leakage.” ...
May 25, 2012 |
5 / 5 (3) |
1
Development of nonvolatile white light-emitting liquid that is coatable on diverse range of materials
A Japanese research team headed by Dr. Takashi Nakanishi of the National Institute for Materials Science developed a nonvolatile liquid material which emits white light at room temperature.
May 30, 2012 |
5 / 5 (4) |
0
