audit your energy usage...
A practical guide to energy management and electricity auditing
Activities for energy audits for home and school Energy conservation ideas
Demand Side Management written by Avril Wilkinson, WESSA
design & layout by Michelle Preen,
CONTENTS Introduction: Background reading material on energy related issues ........................................2 DSM [Demand Side Management] ..........................3 Sub-organiser for this module ..............................4 How to plan an electricity project [Teacher’s notes for the project] ..............................................5 Electricity audit [The preliminary audit] .................8 Electricity audit Part 1.....................................15 Electricity audit [Introducing kWh] ......................22 Electricity audit [The electricity meter] ................24 Electricity audit Part 2.....................................27 Electricity audit [Let’s take action—1] ..................30 Electricity audit [Let’s take action—2] ..................33 Energy conservation ideas [Working with natural processes] ....................................................37 Energy conservation ideas [Landscaping for energy efficiency] ...................................................40 Energy conservation ideas [Everyday energy-saving ideas] 44 Extended teaching strategies ............................ 46
This publication was made possible with funding from the DSM section of ESKOM
Introduction The objective of this education resource is for learners to develop an awareness of how electricity is used at home
and at school.
We use electricity every day of our lives, but rarely do we stop to consider how much we use. To decide if we are using our electricity wisely or not, we must understand where we use it and how much we actually use. Electricity is measured and sold just like any other product. You pay for what you use. Once the learners have reached an understanding of electrical auditing, the booklet then focuses on providing learners with an understanding on the greenhouse effect. Global warming is a term which many learners have heard, but most likely do not understand. This is not surprising, given that there is a great deal of uncertainty among scientists about global warming. Some scientists are very worried by a recent increase in average annual temperatures around the world. They are afraid that this warming trend will severely alter climates here on the planet Earth. These scientists believe that this warming trend is largely the result of human activities. Other scientists believe that the evidence is weak for a variety of reasons. The temperature on Earth has greatly fluctuated for millions of years. The observed increase in temperature may just be part of this natural fluctuation and have little tie to human activities. This would mean there would be very little, if anything, that could be done to stop the temperature changes. This uncertainty among the scientific community forces each person to make their own judgments about what may be happening to our environment. Learners need to ask themselves: Is it better to continue emitting large amounts of CO 2 and other harmful gases into the environment, hoping that global warming will not really occur, or, would it be safer to take steps to reduce the production of harmful gases, hoping that the temperature changes can be curbed? Lastly, the booklet addresses some ways of reducing our consumption of electricity by becoming good environmental stewards. It looks at energy management from a perspective of using the natural climatic processes to our best advantage. Using the auditing process in the first chapters of the book, will enable learners to make informed decisions about how they will react to the global warming crisis.
DSM [DEMAND SIDE MANAGEMENT] Electricity demand is the amount of electricity required by all electric equipment operating at one time in a building, an area, or a city. It is more expensive, and difficult, for an electricity service provider, to provide a large amount of electricity for a short time. Providing constant, smaller amounts of electricity at off-peak times is called demand side management. One way to obtain this is to manage electricity use so that all equipment is never operating at the same time and at the peak demand times. If we manage our electrical consumption in this way, we make the demand more consistent, and consequently, electricity suppliers are more able to meet the requirements of all its consumers. At the same time, we benefit because our use of electricity is managed, resulting from significant savings in electricity together with the associated cost.
Prescribed Learning Outcomes It is expected that learners will: relate energy systems to corresponding natural resources in their home and school environment. identify the environmental and societal impacts of a specific source of energy. describe the interactions between society, technology, and use of electricity. identify strategies for saving electricity as a result of society's concern for dwindling non-renewable energy resources. identify the organizations (and their roles) for supplying electricity in South Africa. identify alternative energy sources in South Africa and the potential impact of their use.
Suggested Assessment Strategies Assess learner’s electricity audit charts for accuracy, and thoroughness. Assess learner’s strategies for electricity reduction for realistic goals, planning details, means of tracking success, and outcomes. Assess learner’s activities for technological detail (accuracy, materials, function, creative design, durability). Assess learner’s audits using a predetermined rating scale (grammar, organization, citations, accuracy, number of details, etc.).
HOW TO PLAN AN ELECTRICITY PROJECT [TEACHER’S NOTES FOR THE PROJECT] Doing a good project with your learners will involve many elements to your teaching, and the following information will assist you in preparing the project in order to include all the necessary elements.
Step Step Step Step Step Step
I— State the Problem 2 - Research, and Hypothesize or Predict 3 - Plan Exercise and Gather Data 4 - Analyze the Data and Make a Conclusion 5 - Take Action 6 - Assessment
More information about Step 1 Begin by stating the project problem: How does human energy consumption affect the environment, and how can we cut down the amount of energy we use? Ask learners what they think the answers to these questions are before they begin research. You may want to record and post their answers in the classroom so that they can see how their knowledge base changes by the end of the project.
Develop a survey Since this project involves either the local school area or their homes, learners should begin by finding out how much the people within this community know already. This information will be useful to consider when learners design their energy-saving tips in step 5. Learner groups should begin by conducting an energy opinion survey of their peers, school staff, and parents or guardians. The following questions are perhaps some that might be asked: Do learners/school staff/parents/guardians think they use a lot of energy? Do they feel that using energy hurts the environment? What environmentally-friendly energy resources do they know of? Would they change their behavior to conserve energy? As an alternative, learners can develop their own survey questions using the following process: determine what, exactly, learners want to find out; design questions that will
get appropriate results; administer a test survey to a small sampling of people; analyze the results to see if the questions were on target; revise the questions if necessary; then conduct the survey on a wider scale.
More information about Step
Research Now learners should begin to find the answers to the following questions by asking questions, or by going to the library to look up information. You may want to divide groups up so that they investigate these questions for a different kind of energy. Talk to representatives from the local electrical service provider (usually a municipality or Eskom) to find out as many ways as you can to save energy in your home and/or school.
Energy type research questions What are the different kinds of energy used in South Africa? How are they used? What impact do the various kinds of energy have on the environment when used?
Energy usage and environmental impact research questions How much pollution is caused by South African energy use? Why do we consume so much energy? What is the history of energy consumption in South Africa — how has it grown, and why? How much energy do typical households and schools use? How can you find out how much energy you use? How can you reduce the amount of energy that you use? What are the costs involved with reducing energy use? Why hasn’t it been reduced in the past? What are the economic or political factors that may impact energy conservation? In the end the class can share their findings, and compile their data into an energy usage matrix on a chart for the classroom.
Forming the hypothesis Using the research findings, have the class predict which elements are the biggest energy wasters in the school/home, suggest what changes should be made within the school/home, and predict how much energy and money these changes would save within the school/home itself. Finally, ask learners to hypothesize how much this would impact their local environment. Have learners record their predictions, on another chart labeled "Predictions". At the end of the project, after learners have conducted their energy audits and encouraged their school community to make energy-saving measures, they will record their results in a column labeled "Results" in the same chart.
More information about Step 3 Conduct an energy audit following the directions from this booklet on pages 8 - 29. As you conduct your audit, different groups of learners can be responsible for looking into energy usage in various areas. Observations should be made daily and recorded in a lab book in order to keep the data organized. You should review how each group should record the different kinds of data before the audit begins.
More information about Step 4 Analyze the results of your energy audit. What were the most common areas of energy waste? Do your results show trends that might be important for other schools and homes in your area? If all the schools and homes in your area reduced their energy waste, how might this impact your local environment? Have each group of students write a report explaining the causes they found for energy waste, and what can be done to solve the problems. Learners need to consider the financial and behavioral aspects in coming up with solutions. You may want to ask an expert from the electrical service provider/Eskom for feedback on your findings.
More information on Step 5 When you finish your energy audit, put as many of your energy efficiency ideas into practice as you can. Many of these ideas are suggested from page 30 of this booklet. Keep a record of how much energy you save! Work as a class to write a tip sheet with your top 15 tips for easy and low-cost ways to save energy at home. Make sure learners use the information they gathered in the survey in step 1 about how much their intended audience knows about the topic, and what their attitudes are. They should gear their tip writing accordingly. Publish the tip sheet in your school magazine, and invite community members to visit the school for an open day by creating and passing out flyers to your community. Once action has been taken, have learner groups monitor how much energy was saved as a result of their actions. Record their findings in the "Results" column of their charts created in step 2.
More information on Step 6 Have learners write an article documenting the steps they took in this project. They should add a section reflecting on why energy saving strategies they devised were effective or ineffective. They should note what strategies worked, or where they went wrong, and how they would correct these ineffective strategies if they repeated the exercise. The article should include information from the chart and log books, and any feedback they got from experts in the field. Also, learners should include their reflections on what it was like to undertake this project. Once completed and edited, notify your local newspaper to raise awareness about the project in your community by sending them your reports.
ELECTRICITY AUDIT [THE PRELIMINARY AUDIT] Learning outcomes How did your learners benefit from this exercise? Knowledge: Skills: Attitudes:
Information We spend most of our time in buildings — homes, schools, offices and stores. But most people seldom notice details about the buildings, such as how they are designed, how they are built, and how well they are maintained. These details are important because they contribute to our comfort and well being and affect the cost of operating them. An "energy efficient" building is more comfortable than an energy wasteful building. It needs less fuel or electricity for heating or cooling. A building that is badly designed and poorly maintained wastes money. Why? Because it is trying to heat or air-condition the outdoors as well as the indoors. The following activity allows one to become an instant energy auditor.
Activity Photocopy the following questionnaire and ask your learners to fill it in at home together with their parents. Place a tick next to the correct answer under HOME. Leave the CLASS boxes blank for you to do with your learners after they have completed the home survey.
IS MY HOME AND SCHOOL ENERGY EFFICIENT? Name of person doing audit: Address:
Number of occupants in the house:__________________________________ List rooms in house:
Bedrooms_____ Passage_____ Lounges_____ Porch/verandah_____ Dining_____ Kitchen_____ Bathrooms_____ Pantry_____ Garage_____ Other_____
Number of rooms where there is electricity:___________________________
Which of the following would best describe the outside area immediately surrounding your home?
( _ ) protected by buildings on sides
( _ ) protected by buildings on sides
( _ ) protected from wind
( _ ) protected from wind
( _ ) faces north
( _ ) faces north
Which of the following would best describe the type of insulation in the ceiling or attic in your home? My Home (
) type of insulation
( _ ) none
My School (
) type of insulation
( _ ) none
What type of floor covering is in your home?
Carpets ___ Tiles ___
Carpets ___ Tiles ___
Wood ___ Other ___
Wood ___ Other ___
Does your home have cover at the doors and windows against cold (nor large gaps under doors or broken windows etc.), and/or curtains at windows against heat?
My Home Against cold?
What is the average temperature in your home?
degrees Centigrade) day - summer
degrees Centigrade) day - summer
degrees Centigrade) day - winter
degrees Centigrade) day - winter
Does your home have fluorescent lighting or CFLs?
( _ ) yes _____%
( _ ) yes _____%
If yes, where?
If yes, where?
( _ ) no
( _ ) no
Does your home have windows facing north and south? Count all the windows, and then work out your percentage. Remember to take the size of the windows in relation to the wall into account. My Home
Count your windows:
Count your windows:
N (___) S (___) E (___) W (___)
N (___) S (___) E (___) W (___)
Does your home have ceiling fans? If you do, how many?
( _ ) yes, how many?
( _ ) yes, how many?
( _ ) no
( _ ) no
Do you turn the lights off when you leave your room?
( _ ) yes
( _ ) yes
( _ ) no
( _ ) no
( _ ) sometimes
( _ ) sometimes
What is the temperature setting on the hot water tank? To estimate this, ask yourself if the water from your geyser is scalding hot, or whether it requires an even mix of hot and cold water to take a bath, or whether you need only a little cold water for your bath. My Home ( _ ) 55 – 60 °C low
( _ ) 55 – 60 °C low
( _ ) 60 - 65°C med
( _ ) 60 - 65°C med
( _ ) 65 - 70°C high
( _ ) 65 - 70°C high
Once the audit is complete, return the audit form to your teacher so that the class may compare results. You may want to draw up a graph showing your results. Discuss the findings and make recommendations for each question. The audit should be returned to your parents, and you should explain recommendations. Together with your teacher and the whole class, now do the audit at your school. Prepare a talk to your principal and governing body on your recommendations for better energy management.
To be completed only by the teacher or group leader when all the results of the survey have been completed. The following matrix is designed to assist you to evaluate your survey and to highlight troublesome areas in your group of homes as well as to make recommendations for each participating home.
Home 5, 6, 7, etc. (As many columns as there are homes)
Occupants in house? No. of rooms in house? 1. Outside area 2. Insulation 3. Floor covering 4. Protection from heat 4. Protection from cold 5. Ave temp summer 5. Ave temp winter 6. Fluorescent lights 7. % N facing windows 7. % S facing windows 8. Ceiling fans 9. turn off lights? 10. hot water setting
Circle all the high results with red. What have you discovered? Are our homes and school energy efficient?
ELECTRICITY AUDIT PART 1
Learning outcomes How did your learners benefit from this exercise? Knowledge: Skills: Attitudes:
Information We use electricity every day, and an energy audit will tell us how much we use. This activity will also help identify what items in your learner’s homes use electricity, how often they are used, and how much electricity they consume. Part 1 is designed to be used in three sections, or mini assignments, and learners are requested to take charts to fill out at home. Based on the information that is returned, your learners will be able to begin to very accurately audit their electrical consumption.
Activity Section 1. On the first chart, make a list of electric appliances found in your home. Place a tick in the rooms where you use the items (items may be found in more than one room).
HOME OF: ADDRESS:
Do you have it? Appliance
Where is the appliance situated? Kit. Bed. Bath. Lounge Dining Other If no, what do you use instead?
Stove Kettle Fridge Freezer Geyser Microwave Hifi Radio TV Video Foodwarmer Heater Iron Other________ Other________ Other________ Other________ Other________ Other________
kitchen beds baths lounges dining outside passage garage store other Lightbulbs – how many light fittings and lamps?
Once the chart has been completed, prepare a time of group discussion based on the information that your learners have collected.
You may want to ask the following questions: In the home, what area uses the most electricity? Why?
Answer: Kitchen. The kitchen contains many large electric appliances - fridge (on all the time) and stove (not on all the time but generates heat which results in high consumption). The kitchen also contains many other electric appliances - toaster, microwave, blender, food processor, electric fry pan, etc. In the home, what areas use the least electricity? Why?
Answer: Home entertainment equipment does not need a lot of electricity to operate. Also, these appliances are not on all the time.
Section 2. The following chart can be completed by your learners as a second homework assignment. We have already found out that the kitchen uses the most electricity, but we now will discover how much time we use an electrical appliance for. To do this, you will have to decide on a special ―audit day‖. This will give your group a very accurate assessment of electrical consumption in their homes. In order to get maximum benefit from the exercise, you may want to involve parents as well.
Audit Preparation for your audit day The following section is the most important part of all the audits that you will be doing and will need much preparation. This will greatly assist in the smooth running of your audit day, and will also make your results very accurate. 1. Refer to your list that you completed in section 1. You will have to make a small chart for EVERY electrical appliance, and EVERY light fitting that you have in your home, and you will have to stick each chart next to each appliance. It is also a good idea to get a number of pencils and cut them up into smaller pieces so that you have enough for each chart. Alternatively, you could suggest that each family member wear a ―pen necklace‖ around their necks for the entire day. This way, there will always be a pen handy when they use an electrical appliance. 2. Some of the appliances will need advance preparation to make your audit day easier, and more accurate.
Kettle: before audit day, boil a half-full kettle and time how long it takes. If it takes 2 minutes and 50 seconds, then we can work in units instead of time. The chart for the kettle will therefore look like this:
KETTLE: (half full = 2min 50 sec) Quarter-full: Half-full: Three-quarter full: Full: Total time used:
Each time that the kettle is used, tick the appropriate line, and at the end of the day you will easily work out how much time the kettle was used. Lights: Go through all the light bulbs in the house and find out what their watt rating is. You will need this information later, and it is best to get it now. On each chart for the lights write this watt rating down, and stick your light charts next to the light switch. Remember to place a chart next to the table lamps as well. Your light/lamp chart will therefore look like this:
Light bulbs (60watt/ 100 watt/ fluorescent bulb/ fluorescent light 1 bar/ fluorescent light 2 bar/ other). Circle which one it is. Time Time Time Time Time Time
on: off: on: off: on: off: Total time for this light:
Your charts for the video, foodwarmer, heater, iron and fans can also look like this, but omit the watt rating section.
The Stove chart will look like this: Stove: Small back plate: time taken: Large back plate: time taken Small front plate: time taken: Large front plate: time taken: Oven: time taken: Warming drawer: time taken:
Lastly, some of your charts like the microwave, washing machine, and any appliance which has its own timer will look like this: Microwave/ Washing machine/ other On: (write how long you have set it for) On: On: On: Total time taken:
Geyser: record at the end of the day how many baths and showers were taken, and how many times the sink was filled for dishwashing. Fridge and freezer: Consult your owner’s manual to find out what the on/off cycle is, and the watt rating is for your model. Often a phone call to the manufacturer will give you this information. Lastly, place a general chart in a visible spot for all the appliances that you would use only for a brief time, and then store away, such as a vacuum cleaner. 3. Very important: KEEP ALL YOUR CHARTS. You will need them later. 4. Good luck on audit day – try to keep the exercise fun!!! even though it can be very involved. And remember to discuss the audit requirements with the whole family so that all members of your household understand what is required.
- Audit Day
Over the weekend (Saturday or the Sunday) record the length of time that electrical appliances are used in your home during a 24-hour period, using the method that was explained in the preceeding pages. After audit day, tally up your times and complete the following table. Staple all your small charts to the back of this form for safe keeping.
Stove Kettle Fridge Freezer Geyser Microwave Hifi Radio TV Video Foodwarmer Heater Iron Other________ Other________ Other________ Other________ Other________ Other________ Light bulbs 60W each Light bulbs 100W each Light bulbs 120W Light bulbs 40W
Time used in 1 day (24 hours). This amount will be worked out from all the paper slips collected from audit day.
Some questions that could be asked now are: According to your chart, which appliances are used the least amount of time? Why?
Answer: Learner’s answers will vary, but some of the answers will be the toaster, the kettle, the iron. We use these appliances only for part of the time
Which appliances do you think use the most electricity? Why?
Answer: Fridge. Freezer and oven. The fridge and freezer are appliances that stay on all the time. The oven is an appliance that uses lots of electricity because it must generate heat.
Activity Section 3. Processing the information into graph form. Let us see if these answers show in a graph. With the information that your learners have collected, we can now draw up a graph that shows us the percentage of electricity each day (horizontal axis) is used in each area of our homes (vertical axis). In order to compile this graph, you will need to do some mathematical work to get the percentages.
TIME 50—60% 40—50% 30—40% 20—30% 10—20% 0—10% APPLIANCE
Home enter- Laundry Bedroom and Heating and Lighting Kitchen tainment Bathrooms Cooling Appliances
You are well on the way to becoming excellent Enegy Auditors! Let us learn further about kilowatt hours so that we can do an even more accurate audit!
ELECTRICITY AUDIT [INTRODUCING kWh]
Learning outcomes How did your learners benefit from this exercise? Knowledge: Skills: Attitudes:
Information In the previous energy audit, your learners were able to get some basic idea of the electrical consumption in their homes, and in which areas of the home the electricity was most used. It introduced the concept that each electrical appliance used varying amounts of electricity, and in the next audit, your learners will be able to very accurately determine the electrical consumption in their homes by the introduction of the watt rating of each appliance, and using this in their calculations in order to obtain the kilowatthour (kWh) consumption of each appliance. We have already collected half of the information required to do this in the previous exercise — that is, the time that each appliance is used. By now adding the watt rating, your learners will be able to calculate their electrical consumption very accurately. Let us discover how!
What is a watt (W)?
Answer: A watt is a unit of power and each appliance is marked with its watt rating. For instance, if you look carefully at a light bulb you will see 60W or 100W printed on the bulb. This is its watt rating. Look at other appliances to find the watt rating. What is a Kilowatt (kW)?
Answer: A kilowatt is a thousand watts . To calculate kW from W, divide the W rating by 1000 : kW = W ÷ 1000. What is a KilowattHour (kWh)?
Answer: kWh is the term used to calculate electrical use. One kWh is one unit of electricity. Electric companies charge for the number of units that each household uses. How do I calculate kWh?
Answer: Multiply the number of kilowatts by the time that the appliance was used.
For example: If a 100 watt light bulb is left on for 10 hours, one kilowatt hour (kWh) of electricity is used (100 ÷ 1000 x 10) Suppose a 100-watt bulb, serving as an outside night light, is left on for eight hours a night, 365 days a year. This bulb consumes 292 kWh of electricity a year ((365 x 8 x 100) ÷ 1,000 = 292 kWh).
Activity The formula for calculating kWh is therefore the watt rating divided by 1000 (to get the kW), then multiplied by the time. Can your learners complete the following table?
Watt rating Hours per day Hours per month
2 bar heater
No. of kWh in one month 120kWh (2000÷1000 x 60)
ELECTRICITY AUDIT [THE ELECTRICITY METER] Learning outcomes How did your learners benefit from this exercise? Knowledge: Skills: Attitudes:
Information Every home is equipped with an electricity meter. The meter measures the amount of electricity consumed in a house in units called kilowatthours (kWh). We are then charged according to the amount of electricity we have used. Reading our own meter keeps us informed of how much electricity we are using. If we are trying to reduce energy consumption and costs, we want to keep track of those kilowatthours!
Activity Ask your learners to find their electricity box at home. The electricity meter box may look different in many South African homes, depending on the age of the house. Some boxes are locked, and can usually be opened with a special allan key, or even a pair of long-nosed pliars. If the box cannot be opened in this way, then they should not force it open, and must not complete the activities in this chapter.
What have you discovered about your electricity meter?
Answer: Generally, the meter will have a 6-digit number—5 numbers in black, with a red number after as a decimal of the number. For instance, 54100,6 (6 is in red). Under the digital reading, they will see a horizontally spinning disc which is recording the electricity consumption.
Activity Reading our meter for a week. Your learners will need five days at home to complete this activity. They will be taking the actual reading of their own electricity meter. It may be best to use a full, Monday to Friday week for the activity. It is important for the learners to get into the habit of reading their meters. When all the electrical audits have been completed, and electrical measures have been taken, then this is the way that learners can check up on themselves to see if the sav ing measures are working. Remind the learners that they need to take the reading at the same time each day.
Day of the week
Reading for the day
Sunday’s reading is
Do not fill in here
Monday’s reading is
Monday’s reading minus Sunday’s reading =
Tuesday’s reading is
Tuesday’s reading minus Monday’s reading =
Wednesday’s reading is
Wednesday’s reading minus Tuesday’s reading =
Thursday’s reading is
Thursday’s reading minus Wednesday’s reading =
Friday’s reading is
Fridays reading minus Thursday’s reading =
From the results of your readings: Work out your average daily kWh. (Add 5 readings and divide by 5) Record the amount here Work out your average monthly kWh. (Daily average multiplied by 30) Record the amount here
Activity Activities for the school’s electricity meter. Ask the caretaker if the learners can read the school’s electricity meter for five days in a row. After you have completed the activity for the consumption of electricity at school, the learners can compare the amount of electricity the school uses to the amount they use at home. Have the learners read the school’s electricity meter at the end of each month and make a graph for each month. Which months does the school use the most electricity? The least? Why? Have the learners collect old electricity accounts for their homes. They can compare their monthly estimate to the actual amount on the account. Is their amount about the same as what is listed on the account? In which months do they use the most electricity? The least? Why?
ELECTRICITY AUDIT PART 2 Learning outcomes How did your learners benefit from this exercise? Knowledge: Skills: Attitudes:
Information Your learners have now reached the stage where they are able to conduct a full electricity audit. They have learned much over the past lessons and activities. The full audit will show your learners the energy consumption in exact amounts, as well as when, and where, the electricity is used. They have recorded the appliances in their homes, and the time that the appliances are used, and they have also learned how to calculate the kWh consumption for each appliance. All that now remains to be done is to complete the full audit table to ascertain how much electricity each of the appliances uses. Once this is done, they are asked to refer to the electricity meter reading activity to compare that reading with the reading that they have determined from the table in this activity. The two readings should be very similar.
Activity It is time to conduct the full electrical audit. In the following table, the first column was completed in part 1 of the electricity audit. The other columns were also exercises and activities in the previous chapters. Some of the watt ratings have been added to the list, and some you will have to find out by looking it up on the appliance or in the appliance handbook. You can also make inquiry at your local Eskom office or at the appliance service center. Also, for convenience, we have added some in the table at the end of this activity.
1. Electrical Appliance
2. Time (in minutes) used in 1 day (24 hours) Use the information from activity 2 of audit – part 1
3. Time (in hours, expressed as a decimal). To do this, divide the time (in minutes) in column 2 by 60
4. Time used in 1 month. Multiply the time in column 3 by 30.
5. Watt rating. This is to be found on the appliance, or in the appliance handbook.
Stove front large plate
Stove front small plate
Stove back large plate
Stove back small plate
Light bulbs 60W each
Light bulbs 100W each
Light bulbs 40W each
Light bulbs 120W
Another wattage 2000W
Radio TV Video
80W 300W 80W
Washing machine - unheated
Fans Sewing machine Other________ Other________ Other________
55W each 85W
6. Kilowatt rating. Divide the watt rating by 1000. kW = W ÷ 1000
7. kWh Multiply the kW rating in column 6 by the month time in column 4. kW rating x time
Now add up all the numbers in the last column (your kWh for 1 month) To verify your results, go back to the chapter on reading the electricity meter. Your monthly figure should be similar. Some other watt ratings that you might need are: Dishwasher – heater Dishwasher – motor only Frying pan Toaster Electric beater Tumble Dryer
2000W 700W 1500W 1100W 200W 300W
Washing machine - heated Heater (fan type) Heater (ceramic type) Vacuum cleaner Electric blanket
2800W 2000W 1500W 600W 100W
YOUR AUDIT IS COMPLETE! CONGRATULATIONS! The Ladysmith High School did the audit and some of their totals were as follows: Home Home Home Home
1 2 3 4
1195.07 (audit total) 636.70 (audit total) 1389.85 (audit total) 871.26 (audit total)
1164 (meter reading total) 609 (meter reading total) 998 (meter reading total) 876 (meter reading total)
Activity Converting the data into cost per unit. Remember, each unit of electricity is one kWh of electricity. Find out what the cost per unit is of the electricity in your area. To do so, you will have to phone your electricity service provider—either your municipality or Eskom. You can also get this information from your lights and water account. In order to get a basic figure, divide your ―charge‖ by your ―consumption‖, and this should be in the region of 30c per unit. Which are the most expensive appliances to run?
Answer: From your audit results, answers will differ, but they are the appliances with the highest kWh. For energy saving ideas, learners should concentrate on these appliances. From the results of the audit, each learner will now be able to make informed recommendations on electrical saving in their homes. The results of the audit should be taken home and discussed with parents. This audit can also be done for your school! Recently a school in East London, Stirling Primary, conducted an electricity audit at their school. To interpret their data, they compiled a speadsheet of electrical consumption showing how much money each appliance cost to run. They also used the data to draw a bar graph using the appliances on the horizontal axis and the amount in rands on the vertical axis. Their findings showed that ceiling fans and lights were the schools highest expenditure for electricity. Why is this different to an audit at home?
ELECTRICITY AUDIT [LET’S TAKE ACTION - 1]
Learning outcomes How did your learners benefit from this exercise? Knowledge: Skills: Attitudes:
Information Conducting an energy audit is a good method of showing your learners how electricity is used in their homes. However, the focus of the teaching strategy should ultimately be good environmental stewardship. If we can use less electricity, we will generate less carbon dioxide, and in doing so we will be contributing to a sustainable environment. In this activity, learners become familiar with the concept that one of the major sources of carbon dioxide is the production of electricity. They identify ways in which they might decrease their contribution to the carbon dioxide in our atmosphere by decreasing their use of electricity. Most people believe that air pollution is a problem caused by factories and cars. This is so, but our excess use of electricity is also a contributing factor. The largest contributor to excess carbon dioxide in the atmosphere is from the burning of fossil fuels. We burn fossil fuels directly in our cars, but the excess carbon dioxide in the atmosphere is also from electricity. The electricity we use here in South Africa is generated primarily by burning coal. Every time we use electricity, we are contributing to the greenhouse gases.
Activity How much CO2 do we put into the atmosphere each day by our use of electricity? Your learners have already made a very accurate assessment of the amount of electricity (in kWh) that they have used, by conducting the electricity audits in the previous chapters. Now they can calculate the approximate corresponding amount of carbon dioxide added to the atmosphere for the amount of electricity that was used in their home. For every 1 kWh of electricity that we use, approximately 1.1 kg of carbon dioxide is released to the atmosphere. We have already calculated our consumption of electricity for a month in kWh. All we need to do now is multiply this amount by 1.1 to calculate how much CO2 we put into the atmosphere. (kWh x 1.1 = amount in kilograms of CO2. )
Activity After our calculations in the previous activity, we may be in some shock! Let us go on an ―energy‖ diet! If you had to choose 3 appliances to "go without" for 2 weeks in order to help reduce CO2 emissions, which appliances would you choose? Explain why you choose these appliances. How much CO2 do you think that you will save over the 2 week period? Ask each student to draw up an Energy Diet Plan for their home. Get each member of your family to commit to making at least one change aimed at saving electricity. Be sure to let them decide what they would like to go without. 9 kilograms of CO2 are emitted into the atmosphere for approximately every 4 litres of gasoline burned in your family car. Calculate your CO2 contribution to the atmosphere from driving or being driven for a typical day. Can you find ways to also go on a ―petrol‖ diet? Perhaps share with a neighbour or walk to school…..
Energy experts say that the carbon dioxide released per family during the production of the things we buy and the services we use, is about equal to the amount of carbon dioxide produced by our direct use of energy. Can we also go on a ―spending‖ diet? Do we really need that extra T-shirt or that ice-cream….. If your family's car was more efficient, a large amount of carbon dioxide would be prevented from going into the atmosphere. Can we also go on an ―car efficiency‖ diet? Ask your learners to discuss this with their parents to find ways to get better fuel consumption (per km driven) from our cars. Make a list of other actions that your family could take to reduce carbon dioxide emissions. If your work on this project is to be written up and presented, it might be a good idea for you to verify your savings by taking your electrical consumption reading each month from the electricity meter, and/ or proving that your electrical saving ideas are working by the reduction of electricity from your monthly account. We are well on the way to becoming good environmental stewards. In this activity we explored ways to help reduce the carbon dioxide emissions to the atmosphere. In the following chapter, we look at ways in which we can actively take a role in making our environment a better place for us all.
ELECTRICITY AUDIT [LET’S TAKE ACTION - 2] Learning outcomes How did your learners benefit from this exercise? Knowledge: Skills: Attitudes:
Information Deciduous trees reduce cooling costs in the summer, but don't block out the sun's warming rays in the winter. They also absorb carbon dioxide and prevent it from going to the atmosphere. The process of absorbing CO2 and releasing oxygen is part of photosynthesis.
Activity Calculating how much CO2 is absorbed by trees during photosynthesis. Depending on its size, approximately 10 to 23 kilograms of CO2 per year is absorbed by a tree. With this information, we can begin to collect data which will give us the necessary information in order to take action. The 10 to 23 kilogram range stated for the amount of CO2 absorbed by a tree presents an interesting challenge for learners. Educators may choose simply to use the average of this range, in which case each tree is counted in the designated area, and the average of 15.5 kg per tree per year is used. (10 + 23 ÷ 2 = 15.5) However, it might be more beneficial for learners to set up their own criteria for how to use the numbers. For example, learners may want
to measure the circumference of the tree trunk one meter above the ground as their standard. They could take a trip around their home garden and/ or school ground to see the variation that exists and then set up a scale by which they assign a number from 10 to 23 for different circumferences. Learners may wish to estimate the height of the trees. For example, if the tree is one story or less in height, they might want to assign a number close to 10 for its CO2 absorbing ability. This makes for interesting discussion on the learners part, while requiring them to think about scale. It is important, however, that a class consensus be reached. If each learner uses a different scale, it will not be possible to compare and pool results. As learners are deciding on which areas to assess, you may want to list several small parks, the school grounds, and other key areas in your community. Most learners, however, will want to assess their own garden, as this makes the idea of carbon debt more personal. However, there will be some learners who do not have gardens, or are unable to assess their gardens. Ask these learners to volunteer to survey the other areas. This would insure a broad sampling of a variety of areas. The following table is a sample data table for the activity, if you choose to use your own set of criteria for calculating CO2 absorption of trees. If you are using the average of 15.5Kg, then the following table is unnecessary.
Location Thandi’s garden
No. of trees
Circumference of tree
Kg of CO2 assigned Kg of CO2 absorbed for circumference by trees
> 2 meters
23 x 3 = 69 kg
< 2 meters
15 x 2 = 30 kg
23 x 5 = 115 kg
< 1 meter
10 x 6 = 60 kg 175 kg CO2 per yr
Review this with your learners before they begin collecting data so that it is understood. Once all the data has been collected and the calculations completed, ask each person to display their findings on a class poster or on the blackboard. This will allow learners to determine total CO2 absorption by all the trees surveyed by their classmates. Once a grand total has been achieved, learners will really get the idea that the trees in their community do make a difference on helping reduce greenhouse gases.
Activity Balancing the carbon dioxide debt. In the previous activity, your learners were able to assess how much carbon dioxide is absorbed in a specific area. Most of the learners will have chosen their home gardens in which to do this assessment. This activity deals with planting trees to balance the carbon dioxide generated by our personal and/ or family use of electricity.
We have already established how much electricity we use in one month. We also know that for every I kWh of electricity that we use, approximately 1.1 kg of carbon dioxide is released to the atmosphere, therefore we have established how much carbon dioxide each of our homes places into the atmosphere by our use of electricity. Remember also to calculate the yearly amount by multiplying the monthly figure by 12. We also know that each tree absorbs an average of 15.5 kg per year of carbon dioxide. Can your learners work out how many trees they would have to plant to balance their carbon dioxide debt? At the end of this activity, it would be interesting to produce a table showing all the results of all your audits. At Ladysmith High school, the results were tabulated as follows: Name Audit of home result
Electrical meter reading
Ave of the 2 monthly readings
CO2 output month
No. of trees No. of No. of trees required for trees in needed to CO2 balance garden plant
Are you shocked! The group at Ladysmith were! Because the number of trees required to balance our carbon debt is so high it is important not to become discouraged. The following activity is designed to move your project from a very local focus, into the broader community in order to involve a greater number of people. In this way, we are becoming good environmental stewards by encouraging others about environmental responsibility, and at the same time, planting a greater number of trees than what our gardens can accommodate.
Activity Plant-a-Tree campaign. By now, your learners will have got the idea that planting trees will help our environment. They might even have made promises to plant trees in their gardens and/ or school grounds to balance their carbon dioxide debt. It is now time to take this even further! Challenge the class to draw a street plan of a specific area in their community where trees could be planted for the benefit of the whole community. On the map, mark the places where trees are currently growing, as well as other structural objects. Draw up a plan designed to increase the number of trees in the area. As part of the plan, include information on the CO2 absorbing ability of the proposed trees. Mark the locations of the new trees on your map. Be sure to consider the importance of shade on buildings in deciding where to place the trees. (Shade helps reduce the cooling costs of buildings.) Design an advertising campaign aimed at getting people to plant more trees. Present your campaign in the form of a poster, brochure, newspaper, or other creative form. Emphasize and communicate the CO2-absorbing abilities of trees. Design colorful graphs, charts, and other graphics to help illustrate the CO2 absorbing abilities of trees.
Be creative! You should also read through the chapter on ―Landscaping for energy efficiency‖ further on in this book. This will give you some ideas about how to do this activity.
[WORKING WITH NATURAL PROCESSES] Many energy conservation ideas can be put in place merely by understanding nature, the environment and climatic processes in South Africa. For instance, we know that hot air rises, and cool air sinks. By using this concept, and many other elements of the natural environment, we can reduce the temperature of our homes significantly in Summer, and raise the temperature in Winter. This is called passive heating and cooling. In Summer, open all you windows in the evening to allow free passage of cooling air during the night. In the morning, as soon as the temperature begins to rise, close up the windows and draw your curtains against the heat. This will keep the temperature of the house cooler for longer. As the temperature begins to rise later in the day, open the top windows to allow the hot air to escape. In the evening, open all your windows again as before. In Winter, reverse the process to keep the house warm. Listed below are some natural processes that you can use in passive heating and cooling. Radiation : This is the passage of energy through open space, like sunlight. In the winter, during the daytime a building absorbs solar radiation, but after the sun goes down, it starts to re-radiate heat to the cold outside air unless something is done to block the radiation. In the summer, efforts have to be made to block solar radiated heat from entering the house. Conduction : This is the passage of heat through a material. Some materials, like glass and metal, conduct heat (and lose it) easily. Insulation helps to block conduction of heat. If ceilings and walls are poorly insulated, they conduct heat from the house to the outside. Installing a ―blanket‖ of material (like pink aerolite) in your ceiling will keep your house cool in Summer and warm in Winter without the exorbitant electricity costs associated with air conditioners! Convection: This is the transfer of heat by movement of air. In the winter, as heated air contacts cold surfaces such as windows, it loses heat. The cooled air is denser than warm air, so it tends to settle, pushing warm air toward the ceiling. These temperature changes and air movements form a pattern. Warm, light air from the ceiling area is chilled along the windows, becomes heavier and drops to the floor. It moves across the floor, is reheated, moves up the opposite wall (away from the window), across the ceiling and down past the window again. During each cycle the air loses heat. Heat must be supplied from a sunny window, a furnace, stove, or other heater to maintain a comfortable temperature.
Air Infiltration: This is the air seepage due to wind. Air pressure pushes hot air (cold air in the winter) through tiny openings on the windy side and draws cooled air in on the opposite side of the house. Infiltration occurs through wall cracks, gaps around paneling (top, bottom, sides), cutouts for pipes and wiring, poor seals for window sashes, doors with poor weatherstripping, and loose moldings. Hot Water Waste : Most people waste hot water by following some of the these bad habits:(1) letting the hot water flow while shaving, (2) using excessive hot water in taking a bath or shower, (3) using hot water for all loads when washing clothes, (4) setting the hot water geyser too high, (5) not insulating all the hot water lines and hot water cylinder, and (6) letting the hot water run while rinsing dishes. Here are some ways that you can save hot water waste: 1) Turn the hot water control off when not in use, do not let it run for chores like rinsing dishes, shaving or washing your face. 2) Repair all water leaks. 3) Install a flow control valve on all shower heads. 4) Heat your hot water with gas if available. 5) Install a hot water timer on your water cylinder. 6) Insulate your hot water tank and pipes. 7) Turn water heater off if you leave for more than two days. 55°C - 60°C: The average family can save ten to twenty percent (10-20%) of their electricity account by setting the thermostat at 55°C in the summer and 60°C in the winter. Fluorescent Lights: Up to thirty percent (30%) of lighting costs (80% if CFLs are used) can be eliminated by using fluorescent instead of incandescent lights. It is now possible to replace most incandescent light bulbs with fluorescent bulbs. Windbreak: A dense row of trees, or a fence or other barrier that interrupts and changes the local path of the wind can also help to keep temperatures stable. Windbreaks located on the predominately windy side of a building can save heat by reducing wind chill and air infiltration. House Orientation: Most energy conservation practices will be made much easier if the home is properly oriented. A North orientation will make it possible to use natural light and natural heating and cooling. During Autumn and Spring, it may be possible to use only natural heating and cooling with windows and doors only on the long axis of the house (the South and North). It is possible to draw the South and North breezes for cooling purposes. The sun coming in from the North windows is beneficial for winter heating.
Summary The most effective low cost energy savers include: 1) Plant trees, grass and shrubs in the desired location. 2) Adjust your thermostat to 55°C in the summer and 60°C in the winter. 3) Change all bulbs to fluorescent or CFLs. 4) Turn all lights off when you leave a room. 5) Install ceiling fans. 6) Lower the thermostat to 120°F on your water heater.
[LANDSCAPING FOR ENERGY EFFICIENCY] This chapter will give you some landscaping tips that will help you save energy and money year-round, and includes climate and site considerations, design and planning, and tree and shrub selection. Are you looking for cost-effective yet eye-pleasing ways to lower your electricity costs? Planting trees, shrubs, vines, grasses, and hedges could be the answer. In fact, landscaping may be your best long-term investment for reducing heating and cooling costs, while also bringing other improvements to your community. A well-designed landscape will: Cut your summer and winter electricity costs dramatically. Protect your home/school from winter wind and summer sun. Reduce consumption of water, pesticides, and fuel for landscaping and lawn maintenance. Help control noise and air pollution.
Summer You may have noticed the coolness of parks and wooded areas compared to the temperature of nearby city streets. Shading and evapotranspiration (the process by which a plant actively moves and releases water vapor) from trees can reduce surrounding air temperatures as much as 9 degrees F (5 degrees C). Because cool air settles near the ground, air temperatures directly under trees can be as much as 25 degrees F (14 degrees C) cooler than air temperatures above nearby black rooftops.
Winter You may be familiar with wind chill. If the outside temperature is 10 degrees F (-12 degrees C) and the wind speed is 32 kilometers per hour, the wind chill is -24 degrees F (-31 degrees C). Trees, fences, or geographical features can be used as windbreaks to shield your house from the wind. Houses with windbreaks placed only on the windward side (the side from which the wind is coming) can significantly reduce their energy consumption compared to similar but unprotected homes. If you live in a windy climate, your well-planned landscape can reduce your winter heating costs.
Landscaping for a Cleaner Environment Widespread tree planting and indigenous planting offer substantial environmental benefits. Trees and vegetation control erosion, protect water supplies, provide food, create habitat for wildlife, and clean the air by absorbing carbon dioxide and releasing oxygen.
Certain grasses, such as buffalo grass and fescue, only grow to a certain height — roughly 15 centimeters — and are water thrifty. By using these species, you can eliminate the fuel, water, and time consumption associated with lawn mowing, watering, and trimming. Also, recent studies have found that gasoline-powered mowers and edge trimmers also contribute to air pollution.
Climate, Site, and Design Considerations Climate South Africa can be divided into four approximate climatic regions for easy understanding of this principal: temperate, hot-arid, hot-humid, and cool. The energy-conserving landscape strategies you use should depend on which region you live in. These landscaping strategies are listed by region and in order of importance below.
Temperate Maximize warming effects of the sun in the winter. Maximize shade during the summer. Deflect winter winds away from buildings. Funnel summer breezes toward the home.
Hot-Arid Provide shade to cool roofs, walls, and windows.
Hot-Humid Channel summer breezes toward the home. Maximize summer shade with trees that still allow penetration of low-angle winter sun. Avoid locating planting beds close to the home if they require frequent watering.
Cool Use dense windbreaks to protect the home from cold winter winds. Allow the winter sun to reach north-facing windows. Shade north and west windows and walls from the direct summer sun, if summer overheating is a problem.
Microclimate The climate immediately surrounding your home is called its microclimate. If your home is located on a sunny northern slope, it may have a warm microclimate, even if you live in a cool region. Or, even though you live in a hot-humid region, your home may be situated in a comfortable microclimate because of abundant shade and dry breezes. Nearby bodies of water may increase your site's humidity or decrease its air temperature. Your home's microclimate may be more sunny, shady, windy, calm, rainy, snowy, moist, or dry than average local conditions. These factors all help determine what plants may or may not grow in your microclimate.
Siting and Design A well-oriented and well-designed home admits low-angle winter sun, rejects overhead summer sun, and minimizes the cooling effect of winter winds. If you are building a
home, pay attention to its orientation. In the southern hemisphere, it is usually best to align the home's long axis in an eastwest direction. The home's longest wall with the most window area should face north or northeast. The home's south-facing and west-facing walls should have fewer windows because these walls generally face winter's prevailing winds. South-facing windows receive little direct sunlight. If your home is already built, inventory its comfort and energy problems, then use the following landscaping ideas to help minimize these problems.
Shading Solar heat passing through windows and being absorbed through the roof is the major reason for air-conditioner use. Shading is the most cost-effective way to reduce solar heat gain and cut air-conditioning costs. Using shade effectively requires you to know the size, shape, and location of the moving shadow that your shading device casts. Remember that homes in cool regions may never overheat and may not require shading. Trees can be selected with appropriate sizes, densities, and shapes for almost any shading application. To block solar heat in the summer but let much of it in during the winter, use deciduous trees. To provide continuous shade or to block heavy winds, use evergreen trees or shrubs. Deciduous trees with high, spreading crowns (i.e., leaves and branches) can be planted to the north of your home to provide maximum summertime roof shading. Trees with crowns lower to the ground are more appropriate to the west, where shade is needed from lower afternoon sun angles. Trees should not be planted on the northern sides of solar- heated homes in cold climates because the branches of these deciduous trees will block some winter sun. Trees, shrubs, and groundcover plants can also shade the ground and pavement around the home. This reduces heat radiation and cools the air before it reaches your home's walls and windows. Use a large bush or row of shrubs to shade a patio or driveway. Plant a hedge to shade a sidewalk. Build a trellis for climbing vines to shade a patio area. Vines can shade walls during their first growing season. A lattice or trellis with climbing vines, or a planter box with trailing vines, shades the home's perimeter while admitting cooling breezes to the shaded area. Shrubs planted close to the house will fill in rapidly and begin shading walls and windows within a few years. However, avoid allowing dense foliage to grow immediately next to a home where wetness or continual humidity are problems.
Wind Protection Properly selected and placed landscaping can provide excellent wind protection, which will reduce heating costs considerably. Furthermore, these benefits will increase as the trees and shrubs mature. The best windbreaks block wind close to the ground by using trees and shrubs that have low crowns. Evergreen trees and shrubs planted in the path of the prevailing winds in your area are the most common type of windbreak. Trees, bushes, and shrubs are often planted together to block or impede wind from ground level to the treetops. A windbreak will reduce wind speed for a distance of as much as 30 times the windbreak's
height. But for maximum protection, plant your windbreak at a distance from your home of two to five times the mature height of the trees. In addition to more distant windbreaks, planting shrubs, bushes, and vines next to your house creates dead air spaces that insulate your home in both winter and summer. Plant so there will be at least 30 centimeters of space between full-grown plants and your home's wall.
Planning Your Landscape Before you start landscaping, you must first develop a plan. The components of your plan could include deciduous trees and plants, coniferous trees and plants, earth berms, walls, fences, sheds, and garages. This section will help you create a landscape plan before you plant around your existing home or before you begin construction on a new house. Use paper and different-colored pencils to begin designing your landscape. First, sketch a simple, scaled drawing of your yard. Locate its buildings, walks, driveways, and services (e.g., sewer, electric, and telephone lines). Note the location of all paved surfaces — streets, driveways, patios, or sidewalks — near your home. Then identify potential uses for different areas of your yard: vegetable gardens, flower beds, patios, and play areas. Draw arrows to show sun angles and prevailing winds for both summer and winter. As you sketch, circle the areas of your yard needing shade or wind protection. Indicate with arrows how you want views to be preserved or screened. Mark routes of noise pollution you wish to block. Also, highlight areas where landscaping height or width may be restricted, such as under servitude lines or along sidewalks. Notice yard areas that suffer from poor drainage and standing water. Some trees and shrubs will not grow well in poorly drained areas; others will. Note existing trees and shrubs. Plan for their replacement if they are old or sick and if they provide valued shade or windbreak. Perhaps you live in an urban area where yards are small and neighbours close. Your neighbor's yard may be the best place for trees to shade your north-facing windows. Your yard may be the best location for their windbreak. Bringing your neighbours into your plans could benefit everyone involved. The more you identify your goals and familiarize yourself with your yard's features — current and proposed — the better your chances for success with your landscaping projects.
Selecting and Planting Trees and Shrubs Trees and shrubs come in all shapes and sizes. How you select your trees and shrubs and how you plant them will directly affect your home's comfort and energy efficiency. You can get information on regionally appropriate species from your local nursery and landscaping experts. Trees and shrubs have a life span of many years and can become more attractive and functional with age. But poor planning of landscape improvements often creates trouble. Ensure proper plant placement and minimal maintenance before you plant! Contact your county extension agents, public libraries, local nurseries, landscape architects, landscape contractors, and local energy offices for additional information on regionally appropriate plants and their maintenance requirements.
[EVERYDAY ENERGY-SAVING IDEAS] Energy Management at Home and at School Energy management means using electricity more wisely. There are two ways of saving energy: replacing old equipment with more energy efficient technologies or reducing the use of the appliance. A Grade 4 to 6 learner is not going to replace expensive equipment, other than relatively inexpensive items like incandescent light bulbs with compact fluorescent lights. However, there are many things that learners can do to use electricity wisely at home and at school.
At School All artificial light is produced from electricity. Fluorescent lighting requires less electricity to produce the same amount of light as incandescent lights (common light bulbs). Fluorescent lighting is very common in schools. Lower wattage fluorescent tubes have been developed to produce the same amount of light as the standard 40-watt tube. Many schools are converting to lower wattage tubes and reflectors to increase lighting efficiency. Of course, the simplest thing for the learners to do is to shut lights off in rooms that will be unoccupied even for a few minutes. A common misconception is that leaving fluorescent lights on is more energy efficient than turning them off because the lights require a lot of electricity to start up and burn out more quickly when turned on and off frequently. However, modern fluorescent lights require little electricity to start up. While being turned on and off does decrease the life of the tube, the value of the saved electricity is greater than the increased cost of replacing fluorescent tubes. All fluorescent lights should be shut off if the room will be unoccupied, even for a few minutes.
At Home The most important message that learners can take home to their families is to shut off electric appliances when they are not in use. Lights, TV’s, VCR, and other appliances are often left on accidentally. Almost one third of all home electricity use is in the kitchen. Learners can do a number of things to reduce electricity use in the kitchen. In our climate, dishes air dry very quickly, and a dishwasher may not be needed. Fridges and freezers should be defrosted regularly to remove ice buildup and door seals should be kept in good condition. Frostfree fridges do not require defrosting, but use more electricity. Fridge and freezer doors should be closed as quickly as possible. When the oven is used, several dishes should be cooked at the same time.
Learners can also be encouraged to have their families experiment with compact fluorescent lights. While the initial cost of these lights is much higher, they cost much less to operate and last much longer than incandescent bulbs. A 17-watt fluorescent light can replace a 100-watt incandescent light. Fluorescent lights usually last 10 times longer than incandescent bulbs. In some cases, using one appliance instead of another can save energy. For example, using the microwave, fry pan or slow cooker instead of the stove top and/ or oven saves electricity. Of course, choosing not to use equipment also saves electricity. For example, many families hang up wet clothes instead of using the clothes dryer.
EXTENDED TEACHING STRATEGIES Have the class brainstorm to list the natural resources available in South Africa. Create a chart and then have learners identify the energy systems involved in each resource and the pros and cons of using each system. Have several guest speakers present information about petrochemical and hydroelectric energy sources in South Africa. Have learners prepare questions about the benefits, costs, and negative impacts of using these energy sources. Have small groups of learners conduct research and create web diagrams showing the links among energy use, societal demand, resource use, and environmental effects. Have each group provide a creative and informative presentation to the class. It may be possible for learners to repeat their presentations to other classes or grades. Present a chart or other resource describing the cost and use of solar energy. Have small groups of learners develop strategies for reducing energy consumption in their communities. Have learners research technologies that have emerged in response to the problem of non-renewable energy resources and then develop a report on their findings. Have small groups of learners design projects based on renewable energy (e.g., a solar cooker or solar collector). Organize a field trip to a power facility. Have learners research and debate the pros and cons of nuclear technology, including the international issue of nuclear waste disposal. Have learners research various sources of power (e.g., coal-fired generating stations, nuclear power plants). Develop role-plays based on environmental situations such as the installation of a hydro line across a farmer's field. Have an environmental panel of learners listen to the arguments and render a decision on the project.