PV Gap

Emily Said:

How are solar homes constructed?

We Answered:

Solar homes are generally oriented so they have a lot of window with a high U value and a large area facing south, Sarah. They typically have fewer, smaller windows on the east and west sides, and still fewer on the north side. This orientation ensures the house will pick up as much heat as possible in the winter months - think of a greenhouse trapping the heat of the sun. The summer sun is much higher in the sky, and the house's design prevents excessive heat gain in the summer by using awnings or by using the overhang of the roof to shade the windows. Alternately, living shade could be provided by deciduous trees near the house, since those trees would drop their leaves in the winter to allow the sun's heat to enter the house..

The house may also include 'active' solar components, such as solar panels, which gather additional heat for hot water or heating the house, or which convert sunlight to electrical power.

In addition, solar homes are typified by energy efficient construction, from the insulation in their walls and attic, to appliances which wring energy from every dollar spent at the utility company. These would include the furnace, air conditioner, hot water tank, washer, dryer, etc.

Anne Said:

Solar Energy???/???...............?

We Answered:

There are 2 normal ways... you either get the sun to heat some panels that have water pipes in them and this means that the sun heats the pipes, the pipes heat the water and when you circulate the water through your hot water tank, the water in you house gets warmer.

OOr you have a panel with cells which convert the sun's energy into electricity

Why is it important - because if you use solar energy you use less of other forms and hence we pollute less and the global warming problem gets less. If just you do it, it is negligible, if we all do it, it could make a huge difference.

Why can't we use it - we can. the correct question, I would suggest, is why don't we use it... and the answer is the upfront cost. It is expensive and we all care about our own short term cash problems, without thinking of long term game for mankind ie we are mean

Bertha Said:

solar energy question?

We Answered:

Because sun is the most abundant source of energy in the world, and by developing energy resources such as sun energy we would not only help our environment but ensure energy security and energy independence.

Gerald Said:

I need ur help here guyz! Why is it important that the surface of the soular panel has a large area?

We Answered:

Because the surface area is what collects the sunlight. The more surface area you have, the more sunlight you get at once.

Jimmie Said:

why is the middle east so important?

We Answered:

because that's where the terrorist come from

Benjamin Said:

Why is it important that fossil fuels not run out?

We Answered:

If they run out, it will take millions of years to get more.

And I know you're saying, "So? When we run out we can start using other energy sources!" Well, it's not that easy. When we run out, people will start scrambling and running to go get solar panels for their houses. There will be greater demand then there is supply, and some people won't even get some solar panels. If people start using and buying them now, there won't be such a scramble to get them if the future and it could save many people a lot of trouble.

Howard Said:

solar energy homework help! please?

We Answered:

Here is some of the information for you. Read and answer your questions... Main articles: Insolation and Solar radiation

About half the incoming solar energy reaches the earth's surface.The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere.[1] Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land masses. The spectrum of solar light at the Earth's surface is mostly spread across the visible and near-infrared ranges with a small part in the near-ultraviolet.[2]

The absorbed solar light heats the land surface, oceans and atmosphere. The warm air containing evaporated water from the oceans rises, driving atmospheric circulation or convection. When this air reaches a high altitude, where the temperature is low, water vapor condenses into clouds, which rain onto the earth's surface, completing the water cycle. The latent heat of water condensation amplifies convection, producing atmospheric phenomena such as cyclones and anti-cyclones. Wind is a manifestation of the atmospheric circulation driven by solar energy.[3] Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C.[4] The conversion of solar energy into chemical energy via photosynthesis produces food, wood and the biomass from which fossil fuels are derived.[5]

Yearly Solar fluxes & Human Energy Consumption
Solar 3,850,000 EJ [6]
Wind 2,250 EJ [7]
Biomass 3,000 EJ [8]
Primary energy use (2005) 487 EJ [9]
Electricity (2005) 56.7 EJ [10]
The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year.[11] In 2002, this was more energy in one hour than the world used in one year.[12][13] Photosynthesis captures approximately 3,000 EJ per year in biomass.[14] The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined.[15]

From the table of resources it would appear that solar, wind or biomass would be sufficient to supply all of our energy needs, however, the increased use of biomass has had a negative effect on global warming and dramatically increased food prices by diverting forests and crops into biofuel production.[16] As intermittent resources, solar and wind raise other issues.


Applications of solar technology

Average insolation showing land area (small black dots) required to replace the total world energy supply with solar electricity. Insolation for most people is from 150 to 300 W/m^2 or 3.5 to 7.0 kWh/m^2/day.Solar energy refers primarily to the use of solar radiation for practical ends. All other renewable energies other than geothermal derive their energy from the sun.

Solar technologies are broadly characterized as either passive or active depending on the way they capture, convert and distribute sunlight. Active solar techniques use photovoltaic panels, pumps, and fans to convert sunlight into useful outputs. Passive solar techniques include selecting materials with favorable thermal properties, designing spaces that naturally circulate air, and referencing the position of a building to the Sun. Active solar technologies increase the supply of energy and are considered supply side technologies, while passive solar technologies reduce the need for alternate resources and are generally considered demand side technologies.[17]


Architecture and urban planning
Main articles: Passive solar building design and Urban heat island

Darmstadt University of Technology won the 2007 Solar Decathlon in Washington, D.C. with this passive house designed specifically for the humid and hot subtropical climate[18]Sunlight has influenced building design since the beginning of architectural history.[19] Advanced solar architecture and urban planning methods were first employed by the Greeks and Chinese, who oriented their buildings toward the south to provide light and warmth.[20]

The common features of passive solar architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and thermal mass.[19] When these features are tailored to the local climate and environment they can produce well-lit spaces that stay in a comfortable temperature range. Socrates' Megaron House is a classic example of passive solar design.[19] The most recent approaches to solar design use computer modeling tying together solar lighting, heating and ventilation systems in an integrated solar design package.[21] Active solar equipment such as pumps, fans and switchable windows can complement passive design and improve system performance.

Urban heat islands (UHI) are metropolitan areas with higher temperatures t