(Hf) is considered as the convective heat exchange between the foliage and the nearby air which is sensible heat flux, and (Lf) is considered as the heat exchange due to evaporation at the foliage level. The energy balance equation at the soil level is presented in equation 3:
Based on previous equations and figure 6, properties of soil and vegetation layers influence on the thermal behavior of different green roofs.
Having the equivalent outside temperatures (Θe,eq) and the heat flux (ɸ), and equivalent periodic thermal transmittance of a green roof can be calculated through equation below:
Taking into account of thermal inertia of green roof components, density and specific heat of the soil and outdoor temperature have more impact on thermal
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• Leaf reflectivity: Leaf reflectivity is the ratio of incident solar radiations that are reflected. It ranges from 0 to 1.
• Leas emissivity: Leas emissivity is the ratio of thermal radiations that are emitted from leaf surface compared to black body at the same temperature. It ranges from 0 to 1.
• Stomatal resistance: Stomatal resistance is the resistance of plant to transport moisture in unit of s/m. It normally ranges from 50.0 to 300.0 s/m.
• Roughness: It is related to the roughness of a particular material layer. The possible options for this character are “VeryRough”, “Rough”, “MediumRough”, “MediumSmooth”, “Smooth” and “VerySmooth”.
• Thickness: It is related to the depth of the growing media layer in meters.
• Conductivity: Thermal conductivity of the growing media which is related to the wet or dry environment (W/(m-K).
• Density: It is related to the density of the dry growing media
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Green roof can protect the roofing membrane against ultra-violet (UV) radiation and prevent physical damage due to degeneration of insulation and roofing materials. It can block solar radiations and decrease daily temperature fluctuations during summer and winter. All of these benefits make the roof lifetime longer [19].
The heat gain and heat loss through green roof are mainly defined by solar radiations coming from the sun. Green roof useful for reflecting solar radiations and reducing heat absorption by evapotranspiration. In addition, it can minimize the amount of heat transmitted through the roof membrane due to extra insulation. Determination of the green roof materials, foliage characteristic, and soil features which affect thermal performance of roof is necessary for designers [20].
1.2.3.2 Climate/Seasons consideration:
Solar radiation can change seasonally and in different locations, and can impact thermal performance of vegetated roofs and
Solar energy and climate were major contributing factors in the building plans of Anasazi architecture. The climate can be harsh in the Four Corners region of the country, with extremely hot days and very cool nights, unbearably hot summers, and frigid winters. In order to protect the inhabitants from their environment, the Anasazi architects incorporated their knowledge of the effect of solar energy on building materials, as well as location of the sun in determining how the structures may most efficiently either absorb or reflect heat. “A southern exposure would have taken advantage of the low, southern winter sun angle, helping keep rooms wa...
These leaves will also have no threat of excessive transpiration because the temperature in the shaded area will be lower and the humidity probably higher. Transpiration is the removal (evaporation) of water from a plant through the stomata in the leaves; this water is removed in a cycle due to the active uptake from the roots. Transpiration involves osmosis; which is the diffusion of water from a high concentration to a lower concentration through a partially permeable membrane, until both the concentrations are equally saturated. All these factors i.e. transpiration and photosynthesis, come together to confirm my hypothesis. To support my hypothesis further, I did a pilot study in a meadow in which I studied the population of certain plant species in areas of
The Solyndra Company, founded in 2005 by Christian Gronet, designed, manufactured, and sold a unique type of solar panels. They were termed “solar photovoltaic (PV) systems” and were designed for large, flat to low sloped commercial building roofs. The panels were designed to have the best performance when mounted horizontally and to be installed very close together so that they covered a much higher percentage of the roof top thus producing more electricity than the typical flat panel solar panels by comparison. This was created through the production by absorbing light from all directions including indirect and reflected light as well as direct sunlight when combined with a white roof. This was due to the design of having rolled its copper indium gallium selenite or CIGS into a cylindrical shape. Each tube had 40 of them in each 1-meter-by-2-meter panel (Solyndra, 2008).
Copper roofing is typically a good option to consider if you want a very strong roof that may also be able to help you out a bit when it comes to conserving energy. Listed below are just two of the many reasons to consider copper roofing.
Resistivity is the oppose to conductivity. It's a measure of material's ability to oppose the flow of electric current. It is a property of the material, and it remains constant, not depending on the certain shape of the material, however it does depend on the mass and density of the particular material. The resistivity of a particular material can be found by multiplying the resistance of the material by its cross sectional area, and then divided by it's length, this is shown in the equation below:
In passive solar design, the vertical and horizontal surfaces control the heat transfer; in winters collect and distribute solar heat and dissipate heat in summer. Passive solar techniques utilize solar energy through direct or indirect solar gain to achieve environmental comfort in the building. The key factors in passive solar building design are: site planning and design; thermal mass; solar geometry; ventilation and vegetation.
= My aim of this investigation was to check the affect of environmental factors affecting stomatal opening. My experiment was designed to check the stomata opening in light. Plants move in ways that may not seem obvious.
Fiberglass reinforced concrete doesn’t crack easily where it can be cut without chipping because it is sprayed on, the surface has no bugholes or voids. GFRC used for creative prefabricated architectural cladding. GFRC is an perfect material to use on a variety of roofing structures. It is easy to fix lightweight but tough and unaffected by environmental conditions. It can imitate traditional roofing materials such as slate, natural stone or clay products but unlike these materials it is neither heavy nor brittle. GFRC can be moulded into complex shapes for roofing accessories such as finials, ridges and chimneys. It is non-combustible with a high impact strength and can be used on all types of roof. Next, GFRC use in renovation. Thin lightweight panels are easy to fix and minimise the weight imposed on the existing structure. In addition,GFRC can provide best solutions in the construction of foundations and floors where in-situ concrete floors it can give economic benefits together with excellent appearance. On ground floor concrete slabs, during cold climate insulated GFRC can help in minimising heat loss from the
Olgyay expresses the comfort zone in graphic form taking into consideration two climatic variables which are the dry bulb temperature (DBT) on the vertical axis and the relative humidity (RH) on the horizontal axis. The comfort zone lies in the area to the center of this chart. The upper lines above the comfort zone indicates the effect of air movement on extending the upper boundary of the comfort zone. The lower lines below the comfort zone indicate various levels of radiation that would compensate for the lower than comfortable temperatures (Auliciems, et al, 2007). Figure (12)
...ts the flower formation. These types of strategy used by many farmers have an important economic impact since most of the energy for maintaining green house is at night. There is a need of further research developments in this area to link the minimum exposure during day and magnitude at higher temperatures .in inhibiting the process of flowering. The flowering time is less at 230C, but the number of buds per plant and inflorescences is low at cool temperatures..
It has been proven that an effective, environmental landscape design can cool your home in summer and warm it in winter. Energy efficient landscaping can actually reduce your energy costs by up to 20%, according to the Plants for Clean Air Council” (Benefits of Gardening).
In theory, the concept of the Green Deal seems perfect. The homes in Britain are considered ‘draughty’ and by implementing energy-saving techniques such as insulation, draught proofing, double-glazing these homes can become more energy effici...
Passive solar design and architecture may seem like a distant dream in our fast paced modern world, but in reality it’s more of a modern revival of a style of energy efficient building that has been around for millennia. What once seemed to be common sense ideas for designing a house that could both keep you cool in the summer and warm in the winter has somehow been forgotten since we started to overuse the planet’s resources on our own comforts. When heating a house took lots of effort it was the wise choice to design a building that could use the energy provided by the sun in the most advantageous ways. Unfortunately, in my opinion, since all we have to do now to heat our house is a turn a dial and pay the bills, many of the simplest ways to cut down on our rising energy consumption have been completely disregarded. Fossil fuels allowed people to provide artificial light and temperatures. This meant that houses could be built without paying attention to the natural world. However, as more and more people agree that fossil fuels will almost certainly run out sometime in the next century, there has been a growing revival in passive solar design. Here, I hope to show you some of the basic principles of passive solar design and how they helped people thousands of years ago in an effort to make people understand how these ancient techniques can be improved on today to help with our growing energy problem.
Bamboo is a building material that is mostly used in rural communities for houses, but even Architects and Engineers are beginning to use Bamboo for it strength as a structural component and a styling agent by means of bamboo window blinds and many more. Bamboo is also commonly used as a type of construction for schools, farms and bridges. Bamboo is also used as scaffolding, shutters, a reinforcing agent for concrete and water piping, the demand for bamboo has recently increased as a new development of variety of bamboo based panels (Dunkelberg, 1992) has been constructed and incorporated into many buildings. Small buildings both non-structural and structural in nature both can be made entirely out of bamboo with the obvious exception of chimneys and fireplaces due to bamboo being a fuelling agent for fires, but it is not used alone it...
insulation from the roof on winter days so that the roof would get hot, and