The Justification Website is the first part of the Passive Solar Design Project. You can download the scoring sheet for the website and see an example that I've posted below.
justification_website_scoring.pdf | |
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Why would we want to design a home without electricity?
There are a few major problems with the use of electricity in a home.
PROBLEM:
ECONOMICS
Electricity costs money. According to the US Energy Information Administration, the average household in the US paid a monthly electrical bill of $110.55 while consuming 955 kilowatt hours per month. This was based on an average rate of 11.8 cents per kilowatt hour. Here in Novato, our energy is provided by PG&E which charges a higher average rate of around 16 cents per kilowatt hour, however, since we also don't have as great of a need for heating and air conditioning as much of the country, let's accept the $110.55 per month as average. Multiplied out over a year, this leads to a total cost of $1326.60 per year. That's a lot of money to spend on electricity and anything that could reduce the amount of energy used could save the homeowner a lot of money.
ENVIRONMENTAL IMPACT
When we use electricity, we have to generate that electricity in some way. The primary way that we generate electricity in the US is through burning coal which is a fossil fuel. We also burn natural gas and petroleum for energy generation. All of these ways of generating electricity account for 68.3 % of our total electricity generation. There are benefits to generating electricity in this way (it's relatively cheap, we have the infrastructure to do so, we know how to do so), but one of the big downsides to generating electricity by burning fossil fuels is that it puts out carbon emissions. Carbon emissions are gases such as carbon dioxide and methane that are created when we burn fossil fuels such as coal, natural gas, and oil.
CARBON CYCLE
The amount of carbon put into the atmosphere and the amount of carbon taken out of the atmosphere is naturally equal. Carbon is naturally released into the atmosphere by respiration and decomposition, but an equal amount is taken out of the atmosphere by the process of photosynthesis. When humans burn fossil fuels, they add 9 extra gigatons of carbon to the atmosphere and while photosynthesis is able to take in 5 of these extra gigatons, it still results in 4 gigatons of carbon added to the atmosphere every year.
This diagram of the carbon cycle from NASA's Earth Observatory can help explain how the carbon cycle works. All numbers are gigatons of carbon, but white numbers are stored carbon, yellow numbers are natural amounts released and taken in, and red numbers are human releases due to burning fossil fuels:
PROBLEM:
ECONOMICS
Electricity costs money. According to the US Energy Information Administration, the average household in the US paid a monthly electrical bill of $110.55 while consuming 955 kilowatt hours per month. This was based on an average rate of 11.8 cents per kilowatt hour. Here in Novato, our energy is provided by PG&E which charges a higher average rate of around 16 cents per kilowatt hour, however, since we also don't have as great of a need for heating and air conditioning as much of the country, let's accept the $110.55 per month as average. Multiplied out over a year, this leads to a total cost of $1326.60 per year. That's a lot of money to spend on electricity and anything that could reduce the amount of energy used could save the homeowner a lot of money.
ENVIRONMENTAL IMPACT
When we use electricity, we have to generate that electricity in some way. The primary way that we generate electricity in the US is through burning coal which is a fossil fuel. We also burn natural gas and petroleum for energy generation. All of these ways of generating electricity account for 68.3 % of our total electricity generation. There are benefits to generating electricity in this way (it's relatively cheap, we have the infrastructure to do so, we know how to do so), but one of the big downsides to generating electricity by burning fossil fuels is that it puts out carbon emissions. Carbon emissions are gases such as carbon dioxide and methane that are created when we burn fossil fuels such as coal, natural gas, and oil.
CARBON CYCLE
The amount of carbon put into the atmosphere and the amount of carbon taken out of the atmosphere is naturally equal. Carbon is naturally released into the atmosphere by respiration and decomposition, but an equal amount is taken out of the atmosphere by the process of photosynthesis. When humans burn fossil fuels, they add 9 extra gigatons of carbon to the atmosphere and while photosynthesis is able to take in 5 of these extra gigatons, it still results in 4 gigatons of carbon added to the atmosphere every year.
This diagram of the carbon cycle from NASA's Earth Observatory can help explain how the carbon cycle works. All numbers are gigatons of carbon, but white numbers are stored carbon, yellow numbers are natural amounts released and taken in, and red numbers are human releases due to burning fossil fuels:
SUN'S ENERGY
When energy comes from the sun to the Earth, not all of it reaches the surface of the Earth. Around 30% of the energy is reflected by clouds, the surface of the Earth, and the gases of the atmosphere. Another 20% is absorbed by the atmosphere and clouds. This leaves only about 50% of the total energy from the sun that hits and is absorbed by the Earth's surface. That 50% of the energy gets turned into heat energy (called infrared radiation) and overnight, will try to leave the Earth.
In the diagram below, we can see how this works
When energy comes from the sun to the Earth, not all of it reaches the surface of the Earth. Around 30% of the energy is reflected by clouds, the surface of the Earth, and the gases of the atmosphere. Another 20% is absorbed by the atmosphere and clouds. This leaves only about 50% of the total energy from the sun that hits and is absorbed by the Earth's surface. That 50% of the energy gets turned into heat energy (called infrared radiation) and overnight, will try to leave the Earth.
In the diagram below, we can see how this works
GREENHOUSE EFFECT
There are certain gases that trap this infrared heat close to the surface of the Earth. These gases are called Greenhouse Gases and the trapping of the heat close to the Earth is called the Greenhouse Effect. The Greenhouse Effect is a good thing because it keeps the Earth at a temperature that we can survive and live in. Some of these Greenhouse Gases are Carbon Dioxide, Methane, Water Vapor, and Nitrous Oxide. These Greenhouse Gases occur naturally but more of them are released when we burn fossil fuels to create electricity.
This diagram from Australia's Climate Commission shows the trapping of heat in the Greenhouse Effect:
There are certain gases that trap this infrared heat close to the surface of the Earth. These gases are called Greenhouse Gases and the trapping of the heat close to the Earth is called the Greenhouse Effect. The Greenhouse Effect is a good thing because it keeps the Earth at a temperature that we can survive and live in. Some of these Greenhouse Gases are Carbon Dioxide, Methane, Water Vapor, and Nitrous Oxide. These Greenhouse Gases occur naturally but more of them are released when we burn fossil fuels to create electricity.
This diagram from Australia's Climate Commission shows the trapping of heat in the Greenhouse Effect:
CLIMATE CHANGE
While the natural greenhouse effect is a good thing, adding too many extra greenhouse gases to the atmosphere by burning fossil fuels for electricity can have some very bad consequences. The result of these extra greenhouse gases is more heat being trapped close to the surface of the Earth and higher temperatures. We've seen an increase in the global average temperature of 1 degree Celcius in the past 150 years and that is expected to increase in the future. The years from 2001 to 2011 are all in the top 12 hottest years that we have temperatures recorded for (data is not available for 2012 yet, but it looks to be among the hottest ever). These higher temperatures can result in a few negative consequences:
This graph from NASA shows the increase in temperature since 1880
While the natural greenhouse effect is a good thing, adding too many extra greenhouse gases to the atmosphere by burning fossil fuels for electricity can have some very bad consequences. The result of these extra greenhouse gases is more heat being trapped close to the surface of the Earth and higher temperatures. We've seen an increase in the global average temperature of 1 degree Celcius in the past 150 years and that is expected to increase in the future. The years from 2001 to 2011 are all in the top 12 hottest years that we have temperatures recorded for (data is not available for 2012 yet, but it looks to be among the hottest ever). These higher temperatures can result in a few negative consequences:
- Higher Sea Levels - When temperatures are higher, more ice is going to melt in Antarctica and Greenland and flow into the oceans, raising sea levels. Additionally, warmer water expands which will further raise water levels. These higher sea levels will destroy coastal communities and lead to more flooding.
- Change of Habitat - As the temperature gets warmer in the Arctic, ice and permafrost melts which makes it difficult for animals and plants that live in the Arctic to continue to survive. The warming of the ocean waters will also greatly change where certain species of fish and sea life can survive.
- Intense Storms - Storms such as hurricanes get their energy from the heat of the water that they form over. If ocean temperatures are warmer, the hurricanes can pick up more of that energy and do more damage as they hit land.
- Drought and Rainfall - As temperatures change, so does the amount of rainfall in different areas. Areas that are used to more rainfall experience drought while other areas less prepared for the rain will receive more.
This graph from NASA shows the increase in temperature since 1880
SOLUTION:
There are ways to generate electricity without carbon emissions such as nuclear, hydroelectric, wind, and solar power. Solar power and wind power can even be adapted to fit on your property and provide for your electricity needs. However, the initial start-up costs for both solar panels and a windmill are very expensive. While the cost of solar panels is falling, it still costs $10,000-$20,000 to outfit your home not including installation and support. This is a bit outside of our budget for a class project.
PASSIVE SOLAR
Instead of generating electricity, we've decided to build our structure without electricity. We're going to do this using passive solar design. Passive solar design uses the heat and light from the sun to directly heat and light the building. It does this by angling the building so that it faces the sun (South for those of us in the Northern hemisphere), placing windows strategically for light, angling the roof to maximize winter sun and minimize summer sun, and insulating well to hold the heat inside. Obviously, because it uses the sun directly, it would have no light at night when the sun isn't out, however since our structure will be on a school campus where most activities take place during the day, this shouldn't be too great of a problem. Many passive solar homes have electricity as well for the night time and use the passive solar design to reduce electricity use as much as possible, but ours will get all of its heat and light from the sun via its passive solar design.
The image below shows how passive solar design works to heat a home.