Solar greenhouses, as their name suggests, utilize energy from the sun in order to meet their temperature needs. The solar radiation from the sun passes through their surfaces to heat the ground. The solar greenhouse design then traps this energy in order to maintain the higher temperature it needs.
The walls and ceiling of these useful structures also serve to prevent the warmer air within from mixing with the cooler air without. A more technical way of saying this is that they prevent convection (heat transfer through moving gas or liquid) and conduction (transmission of heat from particle to particle within solids) from equalizing inner and outer temperatures.
How do Solar Greenhouses Work
Solar greenhouses will also serve to control internal temperature by controlling the transparency to the solar and terrestrial thermal radiation bands. For a warmer temperature than the surrounding environment, more transparency is presented to the solar radiation band. At the same time, more resistance to the thermal radiation band serves to trap the heat in greenhouse.
A surface that is more reflective to solar energy while less restrictive to the thermal radiation band will of course have the opposite effect- a cooler environment than the sounding temperatures. Generally, solar greenhouses are utilized for the purpose of creating a warmer environment. For this, a material is chosen which absorb some of the infrared (IR) radiation which is leaving the space.
A portion of this will be radiated back into the greenhouse. As a result, there is less energy lost to the sky than would happen without such a structure. So it can be seen that both heatloss through conduction and IR can be discouraged with good insulation and glazing which absorbs infrared radiation. Another effective aspect to solar greenhouses is the optimized usage of the soil base.
A portion of the available heat during daytime will be absorbed by this mass. At night, this becomes a source of radiant heat. If the enhancement of this effect is desirable, it is possible to do so by installing tubing for subterranean air circulation.
In addition to this, while a subterranean design can provide heating at night, it can also encourage cooling during the daytime through this same method of absorption. Another method of encouraging this same effect of absorption include utilizing storage materials with a high capacity for heat.
Bins of sand and rock or containers of water are such examples. Greenhouse overheating during the daytime can be prevented while the temperature during the more cool periods, such as night, can be maintained simply and effectively.
It is not very surprising that as both human civilization and science progress, better and better design develops as well. Solar greenhouses benefit greatly from the newest and latest plastic surfaces and glazing options. With better material and design, a greenhouse owner is better able to control both the wavelengths of incoming solar radiation as well as those of outgoing thermal infrared radiation.
Better insulation for the reduction of the conductive loss through glazing is another area which sees ongoing achievement. Some owners will even use a “greenhouse-in-a-greenhouse” technique to provide extra warmth where it is needed in particular.
Constructed from either glass or plastics, solar greenhouses differ from standard greenhouse structures that absorb solar energy and keep in greenhouse structure. They store the solar energy when the Sun is not shining – specifically in the Northern hemisphere (NH) sunlight exposure may be limited, especially in colder season, and a solar pit greenhouse allows the most of what solar energy is provided.
This process of heating and cooling needs to be complete with a minimum of solar energy input from other resources other than the Sun. Passive solar is the cheapest and easiest way to maintain consistent heat in a greenhouse structure. And what one isn’t searching for cheap. The key elements for solar heat: sun, water, and insulation, are either very inexpensive.
The amount of solar energy trapped by solar greenhouse is crucial to regulate – this is presumable to overheat the vegetables, ornamentals, or herbs in the warmer season and in colder season precautions should be taken to sustain heat from escaping:
- Since passive solar energy heating depends on the sun, it is crucial to ensure the structure receives as much direct solar heating as possible.
- Brick, rocks or concrete on the dark ceramic flooring and northern exposure, will store solar energy that has been collected.
- If there are simply a small amount of vegetables, ornamentals, or herbs in the structures, water filled containers may boost the solar energy amount retained.
- The south side wall is typically covered in order to maximize solar energy retention – additionally, the north facing wall may be insulated to sustain heat from escaping. In addition, insulation could be placed over the greenhouse structure during nights and colder season to prevent further solar energy loss.
Solar greenhouses can be constructed as attached designs or free standing. Attached designs are lean-to greenhouse structures that form a space jutting out from a barn or house. These greenhouse structures provide room for herbs, transplants, or limited quantities of vegetables and plants. Freestanding solar pit greenhouse is large enough for the commercial purpose of vegetables, ornamentals, or herbs.