ENERGY, Sun Today, Sun Tomorrow; Sun Yesterday?

By Cooper-Hewitt National Design Museum, April 5, 2010

Grade Level

  • Middle School

Category

  • Green Design

Subject Area

  • Mathematics
  • Science
  • Social Studies
  • Technology

Lesson Time

1-2 days

Introduction

The sun is one of the most precious natural resources we depend upon each day. Sunlight has been used throughout history to tell time, grow food and determine the design, arrangement and architecture of buildings from the ancient pyramids to modern skyscrapers. Without the sun our planet would not be habitable. Recently, designers have paid closer attention to passive and active strategies in harnessing the sun for light, electricity and heat for buildings. This has changed how many architects, engineers and designers approach or solve a problem.
In this lesson students will consider how the sun has played a part in influencing the design of our homes and the systems we use everyday. Students will learn how to track and measure the sun’s radiance. Students will also learn valuable passive solar design methods that harness the sun’s energy to heat and light buildings. We will explore these issues through the lens of world history – looking at how past civilizations have used the sun and how we can continue to maximize its role in our lives in the future.

National Standards

Common Core Literacy for Other Subjects
Grades 6-8
Common Core Literacy for Other Subjects
Grades 6-8
Common Core English Language Arts
Grades 6-8
   
Common Core Mathematics 6-8
Grade 6
World History
Level III (Grade 7-8)
Geography
Level III (Grade 6-8)
Science
Level III (Grade 6-8)
Technology
Level III (Grade 6-8)

Common Core State Standards

English Language Arts Standards: Science & Technical Subjects 

Grade 6-8    

Key Ideas and Details:

  • CCSS.ELA-LITERACY.RST.6-8.1 Cite specific textual evidence to support analysis of science and technical texts.
  • CCSS.ELA-LITERACY.RST.6-8.2 Determine the central ideas or conclusions of a text; provide an accurate summary of the text distinct from prior knowledge or opinions.
  • CCSS.ELA-LITERACY.RST.6-8.3 Follow precisely a multistep procedure when carrying out experiments, taking measurements, or performing technical tasks.

Craft and Structure:

  • CCSS.ELA-LITERACY.RST.6-8.4 Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 6-8 texts and topics.

Integration of Knowledge and Ideas:

  • CCSS.ELA-LITERACY.RST.6-8.7 Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).
  • CCSS.ELA-LITERACY.RST.6-8.8 Distinguish among facts, reasoned judgment based on research findings, and speculation in a text.
  • CCSS.ELA-LITERACY.RST.6-8.9 Compare and contrast the information gained from experiments, simulations, video, or multimedia sources with that gained from reading a text on the same topic.
Range of Reading and Level of Text Complexity:
  • CCSS.ELA-LITERACY.RST.6-8.10 By the end of grade 8, read and comprehend science/technical texts in the grades 6-8 text complexity band independently and proficiently.

English Language Arts Standards: Reading Informational Text

Grade 6-8    

Key Ideas and Details:

  • CCSS.ELA-LITERACY.RI.6-8.1 Cite several pieces of textual evidence to support analysis of what the text says explicitly as well as inferences drawn from the text.
  • CCSS.ELA-LITERACY.RI.6-8.2 Determine two or more central ideas in a text and analyze their development over the course of the text; provide an objective summary of the text.
  • CCSS.ELA-LITERACY.RI.6-8.3 Analyze the interactions between individuals, events, and ideas in a text (e.g., how ideas influence individuals or events, or how individuals influence ideas or events).
  • CCSS.ELA-LITERACY.RI.6-8.5 Analyze the structure an author uses to organize a text, including how the major sections contribute to the whole and to the development of the ideas.
  • CCSS.ELA-LITERACY.RI.6-8.6 Determine an author's point of view or purpose in a text and analyze how the author distinguishes his or her position from that of others.

Integration of Knowledge and Ideas:

  • CCSS.ELA-LITERACY.RI.6-8.8 Trace and evaluate the argument and specific claims in a text, assessing whether the reasoning is sound and the evidence is relevant and sufficient to support the claims.
  • CCSS.ELA-LITERACY.RI.6-7.9 Analyze how two or more authors writing about the same topic shape their presentations of key information by emphasizing different evidence or advancing different interpretations of facts.
Range of Reading and Level of Text Complexity:

  • CCSS.ELA-LITERACY.RI.6-8.10 By the end of the year, read and comprehend literary nonfiction in the grades 6-8 text complexity band proficiently, with scaffolding as needed at the high end of the range.

English Language Arts Standards: Speaking and Listening

Grade 6-8

Comprehension and Collaboration:

  • CCSS.ELA-LITERACY.SL.6-8.1 Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade level topics, texts, and issues, building on others' ideas and expressing their own clearly.
  • CCSS.ELA-LITERACY.SL.6-8.1.A Come to discussions prepared, having read or researched material under study; explicitly draw on that preparation by referring to evidence on the topic, text, or issue to probe and reflect on ideas under discussion.
  • CCSS.ELA-LITERACY.SL.6-8.2 Analyze the purpose of information presented in diverse media and formats (e.g., visually, quantitatively, orally) and evaluate the motives (e.g., social, commercial, political) behind its presentation.
  • CCSS.ELA-LITERACY.SL.8.3 Delineate a speaker's argument and specific claims, evaluating the soundness of the reasoning and relevance and sufficiency of the evidence and identifying when irrelevant evidence is introduced.

Presentation of Knowledge and Ideas:

  • CCSS.ELA-LITERACY.SL.6-8.4 Present claims and findings, emphasizing salient points in a focused, coherent manner with relevant evidence, sound valid reasoning, and well-chosen details; use appropriate eye contact, adequate volume, and clear pronunciation.
  • CCSS.ELA-LITERACY.SL.6-8.5 Integrate multimedia and visual displays into presentations to clarify information, strengthen claims and evidence, and add interest.
  • CCSS.ELA-LITERACY.SL.6-8.6 Adapt speech to a variety of contexts and tasks, demonstrating command of formal English when indicated or appropriate. (See grade 8 Language standards 1 and 3 here for specific expectations.)

English Language Arts Standards Writing 

Grade 6-8

Production and Distribution of Writing:

  • CCSS.ELA-LITERACY.WHST.6-8.4 Produce clear and coherent writing in which the development, organization, and style are appropriate to task, purpose, and audience.
  • CCSS.ELA-LITERACY.WHST.6-8.5 With some guidance and support from peers and adults, develop and strengthen writing as needed by planning, revising, editing, rewriting, or trying a new approach, focusing on how well purpose and audience have been addressed.
  • CCSS.ELA-LITERACY.WHST.6-8.6 Use technology, including the Internet, to produce and publish writing and present the relationships between information and ideas clearly and efficiently.

Research to Build and Present Knowledge:

  • CCSS.ELA-LITERACY.WHST.6-8.7 Conduct short research projects to answer a question (including a self-generated question), drawing on several sources and generating additional related, focused questions that allow for multiple avenues of exploration.
  • CCSS.ELA-LITERACY.WHST.6-8.8 Gather relevant information from multiple print and digital sources, using search terms effectively; assess the credibility and accuracy of each source; and quote or paraphrase the data and conclusions of others while avoiding plagiarism and following a standard format for citation.
  • CCSS.ELA-LITERACY.WHST.6-8.9 Draw evidence from informational texts to support analysis, reflection, and research.

Objectives

  •  Students will learn about historical and contemporary uses of the sun for food production, passive solar design, daylighting and energy harvesting.
  •  Students will create a timeline of past, present and future uses of the sun in their region.
  •  Students will use design-thinking skills to consider functional uses that maximize or use the sun in some way.
  •  Students will better understand some of the environmental benefits of using the sun to produce energy, light or heat for a building or design.

Resources

Look at Cooper-Hewitt’s Design for the Other 90% archive of energy related design projects including StarSight and the Sierra Portable Light Project.

Materials

Paper, pencil, modeling materials like cardboard, glue, tape, string, etc.

Vocabulary

  •  Passive Solar - Passive Solar technologies are means of using sunlight for useful energy without use of active mechanical systems.
  •  Solar Radiation - The total radiant energy from the sun, including ultraviolet and infrared wave lengths as well as visible light.
  •  Heat Gain - An increase in the amount of heat contained in a space, resulting from direct solar radiation, heat flow through walls, windows, and other building surfaces and the heat given off by people, lights, equipment and other sources.
  •  Solar Tracker - A solar tracker is a device for orienting a daylighting reflector, solar photovoltaic panel or concentrating solar reflector or lens toward the sun.

Procedures

The History of the Sun (10 minutes – Review)
Begin your lesson with a discussion of how the sun influenced ancient civilizations around the world. First, discuss earliest human communities, our distant antecedents.  Move the discussion forward to consider examples of the sun's influence on the more recent cultures of the Middle East, Egypt and Mesopotamia. Ask students to explore what tools were developed and used to harness the sun as a resource. Talk about how ancient civilizations depended on the sun as a resource for survival and how architecture was influenced in accordance with this resource.  For example, according to Egyptologists, the true pyramid (i.e. the smooth-sided pyramid) was a solar symbol, its shape signifying the rays of the Sun falling to the earth.
The Sun Today (10 minutes – Investigate)
Relate your discussion to contemporary issues. How do we use the sun today?
  •  Solar tracking – The sun can be used as a navigation device; we can measure radiance and predict climate and weather patterns from the sun’s movement. It also dictates seasons.
  •  Passive solar design – Solar passive design is a strategy to harness the sun’s heat energy through unobtrusive architecture.
  •  Renewable Energy – Photovoltaics (solar panels) convert the sun’s light energy into electricity.
Investigate what kinds of solar resources you have in your region of the country. This is usually measured in a unit called solar radiance (measured in kW-h/m2). This is the amount of sunlight that hits a surface. This will change based on where you are and what time of the year. The National Renewable Energy Lab and sites like CoolerPlanet will help you calculate the solar radiance in your area.
As a great math activity, obtain a Solar Pathfinder, if time and resources allow. With the pathfinder you can calculate the solar potential for your school. The pathfinder helps you find information about:
  •  Time: The solar pathfinder tells you what time during the day the most sunlight hits the earth.
  •  Latitude/longitude: These coordinates tell you where you are on the earth.
  •  Percent of sun: This gives you a percentage of sunlight concentration on a certain area.
Your School, the Sun and Design (10 minutes - Frame/Reframe)
Now focus on your school and its design. How can a consideration of the sun impact your school’s design? How does a design methodology that considers the sun improve our relationship to the earth?
If we design with the sun in mind we can help buildings in terms of:
  •  Efficiency – lower electricity and heating costs
  •  Better indoor air quality and lighting
  •  Reducing climate change footprints
One application is passive solar design, the method of designing a building to use solar energy to provide lighting, heating and cooling.
Buildings consume 50% of all energy produced in the US and 75% of all electricity. Due to this, buildings are one of the nation’s largest consumers of fossil fuels, causing them to be the largest producers of pollution as well as greenhouse gases (which is a direct cause of global warming). By designing with passive solar techniques, a building can save on energy costs which helps to save money as well as cut back on the amount of pollution (and greenhouse gases) produced.
By specifically placing the windows, doors and the roof, carefully choosing the site, materials, and design features, a building can collect, store and distribute the sun’s heat in winter, block the sun’s heat during the summer, and provide natural daylight. Due to the movement of the earth around the sun and the angle of the tilt of the earth’s axis, in the northern hemisphere having south-facing windows allows for the most amount of solar energy to enter a building.
Another possible application is solar panels. Solar panels can be placed on the façade or roof of the school to collect the sun’s light energy and produce electricity. In most cases and with current technology, you should aim for a 25% offset from solar panel use. Solar will most likely not be able to replace all electricity usage in the school.
Math Connection
Energy is measured in a number of ways depending on what property is being represented.
  •  Total Energy - Joules and ergs - The total amount of energy in various forms (kinetic, potential, magnetic, thermal, gravitational)
  •  Power - Watts, Joules/second or ergs/second – the rate at which energy is produced or consumed in time. Power = Energy/Time
  •  Flux - Watts/meter^2, Joules/sec/meter^2 or ergs/sec/meter^2 – the rate with which energy flows through a given area in given amount of time: Flux=Power/Area
  •  1 Joule = 10 million ergs
  •  1 kilowatt = 1,000 watts
  •  1 Watt = 1 Joule/1 second
  •  1 megaJoule = 1,000,000 Joules
  •  1 hour = 3600 seconds
  •  3 feet = 1.0 meters
Example: A 5-watt flashlight is left on for 1 hour. Convert its energy consumption of 5 watt-hours to Joules.
                           1 Joule            3,600 sec
5 Watt-hours x ----------------- x --------------- = 18,000 Joules
                         1 sec 1 watt         1 hour
Problem: How many ergs of energy are collected from a solar panel on a roof, if the sunlight provides a flux of 300 Joules/sec/meter^2, the solar panels have an area of 27 square feet, and are operating for 8 hours during the day?
Problem: The common energy unit for electricity is the watt-hour (Wh), which can be written as 1 watt x 1 hour. How many megajoules equal 1 kilowatt-hour (1 kWh)?
Solar Design Lab (20 Minutes - Generate Solutions)
Using the following steps, assist students in the design of the ideal PV for the roof of your school building. The PV system’s goal should be to offset electricity usage by at least 25-50%.
Step 1: Estimate your electricity needs
To get started, it's good to have a sense of how much electricity your school building uses. You'll have a better point for comparison if you find out how many kilowatt-hours (kWh) the building uses per day, per month and per year. Your school’s utility bill should include this information and can most likely be accessed by contacting the manager of facilities or principal at your school.
The utility bill should also display your costs and many utilities include a graph that displays how your monthly energy use/cost varies throughout the year. That helps you estimate where your highest energy use is and at what time of year.
Step 2: Think about the future
In 2005, average residential electricity rates across the US ranged from 6 to nearly 16 cents per kilowatt-hour, depending on the geographic location of a home. Average retail and commercial electricity rates have increased by roughly 30% since 1999.  This upward trend will likely continue, especially as costs for the coal and hydropower used to generate electricity rise as well.

State

(Cents/kWh)

(Cents/kWh)

2005 Average Electricity Rate

2005 Yearly Cost ($)

2025 Average Electricity Rate

2025 Yearly Cost ($)

Arizona

8.9 cents

$1,170

28.4 cents

$3,751

California

12.5 cents

$1,652

40.1 cents

$5,296

Colorado

9.0 cents

$1,996

29.1 cents

$3,835

Massachusetts

13.4 cents

$1,769

43.0 cents

$5,673

Maryland

8.5 cents

$1,122

27.3 cents

$3,598

New Jersey

11.7 cents

$1,544

37.5 cents

$4,953

New York

15.7 cents

$2,072

50.4 cents

$6,646

Texas

10.9 cents

$1,439

35.0 cents

$4,614

Math Connection
Using the chart above, ask students to determine the rate of increase for the expected price of electricity in 2025. If your state isn’t listed in the chart, ask students to research projected and real data for your region. How much of an increase will your region see? If this rate of increase continues on a similar path, what is an estimate of the cost of electricity in 2050?
Step 3: How much sun do you get?
A photovoltaic (PV) system's performance is related to the amount of sun available during your region's peak daylight hours.  It is also dependent on the efficiency of something called an inverter, which is used to convert solar derived energy from direct current (DC) to alternating current (AC). Most appliances and buildings use AC power sources because they are easier to manage and are less dangerous.
The above image depicts a typical solar panel.
Solar photovoltaic systems work just about anywhere in the US. Even in the Northeast or in "rainy Seattle," a PV system can produce electricity if designed and installed properly. In New York or New Jersey, a one kilowatt system should produce about 1270 kilowatt hours of electricity per year, in Seattle, a one kilowatt system should produce about 1200 kilowatt hours per year. In the Southwest, of course, those ratios will be much greater. You can use something called a solar pathfinder to your regions solar irradiance. Solar irradiance is the amount of solar energy received on a given surface area in a given time. This measurement varies based on weather and latitude. Solar irradiance is a constant value, to find your SR value visit: http://solarelectricityhandbook.com/solar-irradiance.html.
Step 4: Size your system
In general, solar photovoltaic systems sized between 1 to 5 kilowatts (kW) are sufficient to meet the electricity needs of a small home. For a large building or school system, you will need a system that is quite a bit bigger to offset 25-50% of your electricity consumption ranging from 10-20 kW. Most PV systems are grid-tied systems, which means they are connected to the energy grid. This allows you to use solar PV to supplement or offset some of your electricity needs while enabling you to add to the system later if needed.
A general rule of thumb in sizing your system is that one square foot yields 10 watts. So in bright sunlight, a square foot of a conventional photovoltaic panel will produce 10 watts of power. A 1000 watt system, for example, may need 100 – 200 square feet of area, depending on the type of PV module used.
To size your system you will need to do two calculations, which help to determine your system and roof size.
System Size: This is determined by taking your average daily electrical usage, and dividing that by your solar radiance at 71%. The 71% factor is necessary in order to approximate for the inherit inefficiencies in solar power systems.
1. Determine System Size
a. System Size: (kW) = Daily electrical usage/((Solar Irradiance) x (71%))
Roof Size: Approximate roof size needed to accommodate your solar power system (9-10 watts/sq ft).
2. Determine the size of your roof (that is able to receive sunlight)
a. Roof Size (square feet) = Roof Size/10
After conducting these two calculations you will be able to determine the size of the PV system needed for your school’s energy needs.
Step 5. Determine Cost
To determine your estimated cost, use a $9/watt value and multiply this by your system size. Also consider rebates and the costs of insurance, installation and other permitting costs.
Estimated Cost ($) = ($9/watt) x (System Size)
To find solar contractors and get estimates about your system size visit: http://solar.coolerplanet.com/Articles/solar-calculator.aspx
After conducting this study and collecting information, challenge students to redesign their schools using their new knowledge about solar applications and the sun. Some possible re-designs may include:
  •  Solar Array on the Roof – using the sun for electricity.
  •  Rooftop learning lab or garden – use the sun as a way to grow food.
  •  Solar Passive Design – more windows and better designed façade allows sunlight to come into the school.
Each student should brainstorm, sketch and begin finalizing a design to work with.
After preliminary design and brainstorming, students or design teams will then make models that illustrate their newly designed schools. (Edit and develop ideas)
Design Fair and Presentation 
If possible host a mini-school design fair inviting students and teachers to come see the new designs. To celebrate make a big model of the sun as a piñata and fill it with treats! (Share and Evaluate)
Display your new “solar designs” around the school.(Finalize)

Assessment

Reflection Questions
  • Why do you feel the sun has been such an important recurring symbol in cultures across history and vast geographies?
  • Why do you think the vocabulary system pertaining to energy use and consumption is so complex?
  • When do you think you use the most energy?  While at school or at home?  Think about the different ways you use energy throughout the day and the times of the day that you use them.
  • Which type of building do you estimate uses the least energy per person?  A single family home or a large office building?

Enrichment Extension Activities

Differentiation for Elementary School:
  • Younger students can skip the complex math problems. Instead, show historical and contemporary examples of buildings that use passive solar design and solar panels to get your students thinking creatively about their school's energy-friendly redesign.
  • Take a walk around your school with the class. Ask students to point out potential areas where passive solar design and solar panels can be incorporated. Let them sketch their ideas on paper as they tour the school's grounds.
Differentiation for High School:
  • Bring a solar energy expert or engineer to the class and allow students to interview him or her. What challenges might they face in trying to build solar panels on school ground? This interview can help set parameters during their redesign process.
  • As an additional challenge, students can do similar calculations for installing solar panels at their homes. How much will installation cost? How much money will the household save per year on energy use? How long before the savings in energy use offset the cost of installation? How many pounds of carbon will the household save? They can share this information with their parents/guardians.

Leave a reply

You must be logged in to post a comment.