Check the school's energy use

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 Background material

 Curriculum goals

Objectives

• Measure the school's energy use
• Compare the energy consumption with nearby schools and schools in other countries
• Propose measures for reducing the use of energy

Potential partners

Maintenance staff (janitor) at the school, local energy supply company, environmental protection organizations.

Background

Students at Myklebust School in Norway have together with the janitors measured energy consumption and sought ways of saving energy since 2001. Energy use has gone down by more than 20% over the past four years. This is largely due to a change in attitude as a result of their studies.

The burning of fossil fuels such as oil, coal and gas leads to the emission of the greenhouse gas carbon dioxide (CO₂) as well as sulphur and nitrogen compounds. Cutting down on the use of fuel oil in schools is therefore an important step in reducing emissions of such pollutants. Nor are there any excuses for wasting electricity generated by hydropower, even if this energy source causes no direct pollution. The saved hydro energy could probably reduce the need for fossil energy other places.

Implementation

You will collect and register the following data in the online database:

• Weekly energy consumption (total and specific)
• The schools activity level
• Temperature (weekly average)
• Comment any incidence that may have affected the energy consumption

You need:

1. At least one group who have the main responsibility for the project.
2. Access to energy metres or weekly consumption totals from operational staff.
3. Access to weekly temperature logs or outdoor temperature averages or, alternatively, the temperature can be measured with a thermometer.
4. Internet connection for registering the results in the www.sustain.no online database. When the data is submitted to the database, it is possible to view the results by means of automatic graphic display, compare the results with those from other schools and get feedback from professionals.

Follow-up:

1. Establish routines that enable the students to gain access to consumption figures and temperature data.
2. Ensure registration of the measurements in the database and on the poster for energy readings.
3. Identify and focus on behaviour that can influence energy use at the school.
4. Make the entire school aware of the project.

Duration

The energy usage may vary a lot during a year. We therefore recommend the project to be carried out at least over 12 weeks. Preferably the project should include 3-6 weeks from each season, or even better; every week the school is in use during one year.

Finding the energy use

The group(s) responsible must have access to energy use totals. If the school uses only electric energy for heating or cooling, it is easy to find out the consumption by reading the electricity meter. Bear in mind that the school may have several meters. Make sure the readings are taken at the same time every week, for example every Monday morning at 08:00. Record the meter reading on a form and calculate consumption for each week.

If the school uses other energy sources such as oil, district heating, bio- or solar energy or heat pumps, consumption must still be registered. Some sources can be converted and calculated as kWh. Professional partners can help with other sources. It is the total of all energy used, which must be registered each week.

Some general guidelines for the energy contents of various sources are given in the table below. Since some heat is lost in the exhaust, one should multiply with the energy efficiency constant to get the amount of utilizable energy.

In many schools, caretakers and grounds staff keep regular energy accounts summarizing both electricity consumption and total energy use. They can supply the students with the necessary data if needed.

Temperature data

Obviously the need for heating or cooling is related to the outdoor temperature. Many meteorological authorities register the average temperature on a weekly basis. If no such information is available for the district of your school, the temperature can easily be measured with a thermometer connected to a computer or an outdoor thermometer placed in a position shielded from the sun. Make as many diurnal readings as possible, and try to do the reading at fixed times of the day throughout the week (e.g. every fourth hour). Calculate the average temperature for each week.

Specific energy use

Energy use is probably much higher in large than a small school building. In order to compare measurements from different schools, the specific energy use must be found. The school's specific energy use is the total energy use divided by the heated or cooled area (kWh/m²). The heated area is defined as the total floor area in all rooms with temperatures exceeding 15°C, discounting rooms such as lofts, cellars and cold stores. The cooled area is defined as the total floor area in all rooms with air condition equipment installed. Measuring and calculating the school's area can be an excellent mathematics exercise in its own right, using floor plans or direct measurements of the building.

How to use the measurements

The measurements presented graphically on the data results page represent a good basis for teaching about energy in several subjects. The students can answer such questions as: How does the energy use change from week to week? Which energy sources did the school use and why did it choose these? Where does the energy come from? Is the school hurting the environment? Discuss some possible regions for the variations in energy use, and what can be done to reduce it.

The data result pages will presentation the energy consumption with different diagrams. An example of such a diagram is shown below.

The schools ET curve

The school's energy usage will be plotted as an ET-curve, where the "E" stands for energy consumption and the "T" for temperature. An ET curve is an experience curve in an axis cross where the x-axis represents the average temperature over a period of time while the y-axis shows the building's energy use during the same period. The curve is a useful tool for managing energy usage and discovering deviations that cannot be explained by temperature conditions. The ET curve is unique to each building and is calculated on the basis of long-term measurements - ideally over an entire year.

What is the energy used for?

By registering energy use on different meters and by different energy sources, it is also possible to find out how much of the energy is used for various purposes. As a rule, a school uses energy for these purposes:

• Heating: Energy is necessary for heating up the building, in the form of heated water in radiators and under floors or electric ovens or heated cables. Energy is also used to warm up air passing through a ventilation system.
• Cooling: Schools in certain climatic regions use energy for air conditioning (cooling).
• Ventilation, fans and pumps. The fans use energy to move air in and out of the rooms through ventilation ducts. The pumps use energy to pump water though the pipes.
• Hot water: Hot water is used in the building for showers, cleaning floors, washing up, etc.
• Lighting: Energy is used in light bulbs, fluorescent tubes and possibly lighted signs.
• Various equipment: There are many other energy-using devices in a school, e.g. copying machines, computers and lifts.

Save energy!

The burning of fossil fuels such as oil, coal and gas leads to the emission of the greenhouse gas carbon dioxide (CO₂) as well as sulphur and nitrogen compounds. Cutting down on the use of fuel oil in school is therefore an important step in reducing emissions of such pollutants. Nor is there any excuse for wasting electricity generated by hydropower, even if this energy source causes no direct pollution, as part of Norway's energy consumption is currently met by imported energy from coal-fired power stations.

Energy saving means using less energy, for example by using low-energy light bulbs and lowering the indoor temperature, utilizing energy more efficiently and using less environmentally burdensome forms of energy.

In many schools classroom temperatures are too high, or are kept high even if the school is not in use. Keeping a daytime temperature of ca. 20°C is a good energy-saving measure, which also helps to improve the indoor climate.

Think about whether high-energy use might be due to:

• Poor insulation
• Ventilation system without heat recycling
• Draughts from windows
• Excessive indoor temperatures
• Wrongly adjusted thermostats
• Wasting hot water
• Unnecessary use of lighting
• Open windows
• Extensive use of the building outside school hours.

Discuss initiatives you can take to reduce the school's energy use. Test energy-saving measures and see if they make an impact on registered energy use.

Measuring energy at home

Energy measurements can also be carried out in the students' homes. The procedures are the same as for school, but are usually simpler because most homes use only electricity and have one meter. If other energy sources are used, you must include these in the calculations.

Did you know that...

• The little red lights on our TVs, PCs and many other electric household items waste around 3500 millions € per year in Germany and 100 millions € per year in Norway.
• The average car drives 10 km in 10 minutes on a litre of petrol.
• 1 litre of petrol contains ca. 10.5 kWh.
• An average car therefore uses 63 kWh per hour, 60 km.
• What other fun things can you do with 63 kWh?
• Supply all the energy needs of one Bangladeshi for 63 days
• Supply all the energy needs of one Norwegian for 7.5 hours
• Burn a sack of wood in an old oven.

Form

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