a survey of energy and water consumption of university ... · water consumption of these behaviors...

A Survey of Energy and Water Consumption of University Students H. Takata [email protected] Graduate school of Education, Hiroshima University, Japan Abstract In recent years, energy-saving has been an important issue in Japan where natural resources are limited. After the Great East Japan Earthquake, the Japanese government has enhanced energy-saving measures and has intensified its effort for the development and promotion of renewable energy. Many home appliance makers have also been developing energy-efficient appliances. Thus, the whole nation has been promoting measures for energy conservation. On the other hand, energy consumption in the residential sector is on the increase, which requires energy-saving measures. People in general are conscious of energy-saving, but it is not so clear if they have the accurate knowledge and recognition about the energy they use. If they don’t have the accurate information, any energy-saving measures could be worthless. And, instead of being eco-friendly, they may end up as mere gratification of the ego. The purpose of this study is to clarify people’s attitudes and actual situations on energy and water consumption. As many university students start to live by themselves and to pay fuel, lighting, and water expenses, they become more conscious of energy and water consumption. The author carried out an experiment on them regarding energy and water consumption in daily activities. Subjects were university students living alone, they were asked to use a computer, to boil water, to vacuum a carpet and to wash dishes. They were also asked to predict the amount of electricity, gas and water they would consume by doing these tasks. After comparing the predicted amount and the actual usage, it was turned out that they were not able to predict correctly except for the task of boiling water, and there were gaps between their predictions and the actual usage. Keywords Water Consumption, Electric Consumption, Gas consumption, Experiment, University Students

CIBW062 Symposium 2013

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1 Introduction As for energy consumption in Japan, the energy consumption in the residential sector has increased in the past few decades. People in general are conscious of energy-saving, but it is not so clear if they have the accurate knowledge and recognition about the energy they use. The purpose of this study is to clarify people’s attitudes and actual situations on energy and water consumption. As many university students start to live by themselves and to pay fuel, lighting, and water expenses, they become more conscious of energy and water consumption. The author carried out an experiment on them regarding energy and water consumption in daily activities. 2 Outline of the investigations The author carried out an experiment and two investigations for energy and water consumption in daily activities. Subjects were university students living alone. In the experiment which was called "Equipment use experiment", student subjects were asked to use a computer, to boil water, to vacuum a carpet and to wash dishes. The energy and water consumption of these behaviors were measured by some meters and a data logger. After the experiment, student subjects received a questionnaire to predict the amount of electricity, gas and water they would consume by doing these behaviors. This questionnaire investigation was called "Energy consciousness investigation". Finally, as for the monthly electricity, gas and water consumption in each dwelling, students answered the predicting values of those consumption in July, September and November 2012. Furthermore, they brought back the investigation sheet and filled it with the actual values of those consumption at a later date. The last questionnaire investigation was called "Energy consumption investigation". 2.1 Subjects Subjects were university students living alone in Higashi-hiroshima city. The author carried out an above experiment and two investigations for the same students. Table 1 shows outline of the student subjects. Male and Female were each 27 persons, and the total number of subject was 54 persons.

Table 1 - Outline of the student subjects 2.2 Investigation period The equipment use experiment and energy consciousness investigation were conducted from November 24 to December 6th of 2012. After these investigations, the energy consumption investigation was carried out from late November to late December.

Freshman Sophomore Junior Senior TotalMale [person] 6 6 6 9 27Female [person] 6 6 6 9 27Total [person] 12 12 12 18 54


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2.3 Outline of equipment use experiment 2.3.1 Equipments Equipment use experiment which used the electric and gas equipment were carried out to clarify the energy and water consumption in each behavior. The equipments were a notebook computer, an induction heating cooker, an electric vacuum cleaner and an instantaneous gas water heater. Table 2 shows the specification of equipments.

Table 2 - The specification of equipments 2.3.2 Measurement instruments Figure 1 shows the system diagram of the electric power, gas and water supply to the equipments and the measurement instruments in laboratory. The measurements of the volumes of electric, gas and water consumption, air temperature, cold and hot water temperature were carried out as follows. The electric consumption was measured by the electrical transducer. The gas and water consumption were measured by setting up a gas flow meter and a water flow sensor to the supply pipelines. These measurement data were recorded in a data logger by one second interval. Furthermore, room air, cold and hot water temperature were recorded into temperature data loggers by one second interval. 2.3.3 Experiment description In the equipment use experiment, student subjects were asked to use a computer, to boil water, to vacuum a carpet and to wash dishes. After the experiment, students predicted the amount of electricity, gas and water they would consume by doing these behaviors. Table 3 shows the contents of behaviors during the experiment. On the behavior of wash dishes, the hot water temperature was set at 40 degrees Celsius in advance. Students only operated on-off switch to discharge hot water. Figure 2 shows the layout of laboratory. The room air temperature was controlled by the air conditioning equipment and the gas heater to set up a comfortable environment during the experiment and investigation. The room air temperature were maintained between 18.7 and 23.0 degrees Celsius.

Notebook computer Induction heating cooker

Electric vacuum cleaner

Instantaneousgas water heater

Maximum electricpower consumption 65 W 1400 W 950 W

Gas consumptionper hour 0.8 kg/h

OS : Windows 7 Heating power adjuster 63 kJ/hMicrosoft Office 2010 : 7 Levels

Appliance

Remarks column


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Figure 1 - The system diagram and measurement instruments

Table 3 - Contents of behaviors during the experiment

Electricpower

Watersupply

Gas supply

Room air temperature:Temperature data logger Hot water

supply

Notebookcomputer

Cold and hot water temperature:

Temperature data logger

Electric transducer

Data logger

Gas flowmeter

Water flow sensor

InductionHeatingcooker

ElectricVacuumcleaner

Instantaneousgas waterheater

Electricpower

Watersupply

Gas supply

Room air temperature:Temperature data logger Hot water

supply

Notebookcomputer

Cold and hot water temperature:

Temperature data logger

Electric transducer

Data logger

Gas flowmeter

Water flow sensor

InductionHeatingcooker

ElectricVacuumcleaner

Instantaneousgas waterheater

Behavior Appliance Details of the procedure1. Plug the power cable into socket2. Push the power button of computer3. Launch Microsoft Office Word4. Write a designeted sentence (about 200 letters)5. Save the file to a drive6. Shut down the computer7. Unplug the power cable from socket1. Plug the power cable into socket2. Put water (300ml) into the pot3. Heat water until boiling4. Turn off the heat after boiling5. Unplug the power cable from socket1. Plug the power cable into socket2. Push the power button of cleaner3. Vacuum a carpet (1860mm x 1860mm)4. Turn off the vacuum after cleaning5. Unplug the power cable from socket1. Put some dishwashing liquid on a sponge2. Wash dishes (a rice bowl, a bowl for soup, two middle plates, a cup, a pair of chopsticks) by hand in hot water3. Rinse the dishes

Vacuum a carpet Electric vacuum cleaner

Instantaneous gas water heaterWash dishes

Use a computer Notebook computer

Boil water Induction heating cooker


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Figure 2 - Layout of laboratory 2.4 Outline of questionnaire investigation 2.4.1 Energy consciousness investigation The author asked students about their characteristics, the predicting values of energy and water consumption of behaviors, the consciousness of energy-environmental issues, the kind of heat source of their home, and hours of staying at home, etc. by energy consciousness investigation. 2.4.2 Energy consumption investigation In this investigation, the author asked students to predict the values of energy and water consumption at their home in July, September and November 2012 and to record the actual these values by checking the energy and water bills. 3 Results of the measurement and investigation 3.1 Results of the energy consciousness investigation Results of the measurement and the energy consciousness investigation of 54 persons were validated by confirmation of these values and answers. As for the results of the energy consciousness investigation, Figure 3 shows the ratio of student's grade. The senior students were 18 persons (33.3%), and the other grades were 12 persons (22.2%) in each. The ratios of grade were composed in men and women at equal rate. Figure 4 shows the ratio of the heat source of student's home. As the heat source, the ratios of gas had a high percentage in each situation. 7 persons lived in all-electric home. Figure 5 shows the ratio of the hours of staying at home per day. The number of subject and the ratio of "9-12 hours" were the most common. Figure 6 shows the ratio of the consciousness of energy-environmental issues. The most common was "Somewhat interested" which 19 persons answered. Interested group which was total ratio of "Very interested" and "Somewhat interested" accounted for over half, about 63%.

Gas heater


Measurement equipment

Sink

Window blind

Induction heating cooker

Notebook computer

Electric vacuumcleanerCarpetDesk

Chair

Air-conditioningequipment

Gas heater


Measurement equipment

Sink

Window blind

Induction heating cooker

Notebook computer

Electric vacuumcleanerCarpetDesk

Chair

Air-conditioningequipment


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Figure 3 - Student's grade Figure 4 - Heat source Figure 5 - Hours of staying at home per day Figure 6 - consciousness of energy- environmental issues 3.2 Predicted energy and water consumption on the equipment use experiment Figure 7 shows the results of predicted electric consumption. As for the total value, the average of predicted values on "Use a computer" was 41.3Wh. And, the minimum and maximum values were 2.5 and 140Wh respectively. The average of predicted values on "Boil water" was 51.4Wh. The minimum and maximum values were 5 and 200Wh, respectively. The average of predicted values on "Vacuum a carpet" was 45.6Wh. The minimum and maximum values were 5 and 150Wh, respectively. In each behavior, female's distributions of predicted value were smaller than male's distributions of that.

Figure 7 - Predicted energy consumption on the equipment use experiment

0% 20% 40% 60% 80% 100%

Total (54)

Male (27)

Female (27)

Ratio

Freshman Sophomore Junior Senior

0% 20% 40% 60% 80% 100%

Hot water in the kitchen (54)

Hot water in the bath (54)

Heat source of the range (54)

Ratio

Electricity Gas Unknown

0% 20% 40% 60% 80% 100%

Total (54)

Male (27)

Female (27)

Ratio

Less than 6 hours 6-9 hours

9-12 hours 12-15 hours

More than 15 hours

0% 20% 40% 60% 80% 100%

Total (54)

Male (27)

Female (27)

Ratio

Very interested Somewhat interested

Not sure Not very interested

Not at all interested

41.3 49.333.2

51.470.5

32.345.6 53.9

37.2

0

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Use a computer Boil water Vacuum a carpet

Pred

icte

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ectri

c co

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ptio

n ［W

h］

Average

Maximum

Minimum


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Figure 8 shows the results of predicted gas and water consumption. As for the total value of gas and water consumption, the averages of predicted values were 5.4 and 5.1L,respectively. The male's average value was lower than the female's average value for gas consumption. On the other hand, as for the water consumption, the male's average value was higher than the female's average value.

Figure 8 - Predicted gas and water consumption on the "Wash dishes" Student subjects were asked to arrange the predicted values of four behaviors in descending order. Furthermore, subjects were asked the level of self-confidence to the order. Figure 9 shows the level of self-confidence to the order of predicted values for four behaviors. As for total and female, the ratios of "Not very confident" were high. However, most male's students answered "Somewhat confident".

Figure 9 - Level of self-confidence to the order of predicted values for four behaviors 3.3 Predicted energy and water consumption at home Figure 10 shows the predicted electric consumption at home in July, September and November 2012. There were large differences between the maximum values and the minimum values. As for the total, the average values in July, September and November were 475.1, 418.7 and 542.3 kWh. The electric consumption in July and November were predicted higher than that in September in both male and female. Figure 11 shows the predicted gas consumption at home. There were large differences between the maximum values and the minimum values. This tendency was most obvious on females than males. As for the total, the average values in July, September and November were 107.3, 109.6 and 142.6 m3. The gas consumption was increased during July and November in both male and female.

0% 20% 40% 60% 80% 100%

Total (54)

Male (27)

Female (27)

Ratio

Very confident Somewhat confident

Not very confident Not at all confident

5.4 5.2 5.5 5.1 5.3 4.9

0

5

10

15

20

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Total Male Female Total Male Female

Wash dishes (Gas) Wash dishes (Water)

Pred

icte

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s / w

ater

con

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L］

Average

Maximum

Minimum


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Figure 12 shows the predicted water consumption at home. As for the total, the average values in July, September and November were 198.1, 157.5 and 207.8 m3.

Figure 10 - Predicted electric consumption at home (Jul., Sep., Nov.)

Figure 11 - Predicted gas consumption at home (Jul., Sep., Nov.)

Figure 12 - Predicted water consumption at home (Jul., Sep., Nov.)

Figure 13 shows the level of self-confidence to the predicted energy and water consumption at home. On all item, electric, gas and water consumption, the ratio of "Not at all confident" were the most common. Therefore, most subjects have no confident about the predicted value for energy and water consumption in their home.

475 480 471 419 430 408 542 577 507

0

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2,000

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Electricity (Jul.) Electricity (Sep.) Electricity (Nov.)

Pred

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c co

nsum

ptio

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h］

Average

Maximum

Minimum

107 90 124 110 91 127 143 108175

0

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Gas (Jul.) Gas (Sep.) Gas (Nov.)

Pred

icte

d ga

s con

sum

ptio

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Average

Maximum

Minimum

198 207 189 158 199 116 208 200 215

0

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2,000

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3,000

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Water (Jul.) Water (Sep.) Water (Nov.)

Pred

icte

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ater

con

sum

ptio

n ［m

3 ］

Average

Maximum

Minimum


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Figure 13 - Level of self-confidence to the predicted energy and water consumption at home

4 Comparative analysis of consciousness and actual 4.1 Predicted and measured values of energy and water consumption on equipment use experiment Figure 14 shows the predicted and measured electric consumption on equipment use experiment. Except for "Boil water", there were large differences between predicted values and measured values. Students predicted the electric consumptions larger than the actual consumptions. As for "Boil water", predicted values were rarely different from measured values.

Figure 14 - The predicted and measured electric consumption on equipment use experiment

Figure 15 shows the predicted and measured gas and water consumption on the "Wash dishes" experiment. Both gas and water consumption showed significant differences between predicted values and measured values. Therefore, it is difficult to predict the gas and water consumption accurately. Students predicted the gas and water consumptions less than the actual consumptions.

0% 20% 40% 60% 80% 100%

Electric consumption (54)

Gas consumption (47)

Water consumption (54)

Ratio

Very confident Somewhat confident

Not very confident Not at all confident

41.3

2.1

51.4 51.545.6

21.9

0

10

20

30

40

50

60

Predictedvalue

Measuredvalue

Predictedvalue

Measuredvalue

Predictedvalue

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Use a computer Boil water Vacuum a carpet

Elec

tric

cons

umpt

ion

[Wh] n : 54


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Figure 15 - The predicted and measured gas and water consumption on the "Wash dishes"

As for the relationship between predicted values and measured values, figure 16 and 17 show the scatter plot of electric consumption, gas and water consumption. According to figure 16, all student subjects predicted the electric consumptions larger than the actual consumptions. Although the predicted values of "Boil water" had wide distribution, the average predicted values were nearly equal to the measured value. According to figure 17, gas consumptions of "Wash dishes" were predicted less than the actual consumption. Also, water consumptions of "Wash dishes" were predicted less than the actual consumption and varied widely.

Figure 16 - Predicted and measured values of electric consumptions a) Wash dishes (Gas consumption) b) Wash dishes (Water consumption)

Figure 17 - Predicted and measured values of gas and water consumptions

5.4

13.0

5.1

7.9

0

2

4

6

8

10

12

14

Predictedvalue

Measuredvalue

Predictedvalue

Measuredvalue

Wash dishes (Gas) Wash dishes (Water)

Gas

/ W

ater

con

sum

ptio

n ［

L］ n : 54

y=x0

25

50

75

100

125

150

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Pred

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lue

[Wh]

Male(27)

Female(27)

a) Use a computer

y=x

0

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50

75

100

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150

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Male(27)

Female(27)c) Vacuum a carpet

y=x

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Measured value [Wh]

Male(27)

Female(27)

b) Boil water

y=x

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4.2 Predicted and recorded values of energy and water consumption at home Figure 18 shows the predicted and recorded electric, gas and water consumption at home in each month, July, September and November. As the results of t-test, the predicted and recorded average values showed a significant difference on gas consumption in November and water consumption in September. The others showed no significant differences. As for the electric and water consumption, recorded actual values were constant with month. However, the predicted values were differed widely by month. The predicted and recorded gas consumptions were increased throughout the months of July until November.

Figure 18 - Predicted and recorded values of energy and water consumption at home 5 Conclusions In this paper, the author carried out an experiment and two questionnaire investigations for energy and water consumption in daily activities to clarify people’s attitudes and actual situations on energy and water consumption. From the result, after comparing the predicted values and the actual usage, it was turned out that university students were not able to predict correctly except for the task of boiling water, and there were gaps between their predictions and the actual usage. On the equipment use experiment, students predicted the electric consumptions larger than the actual consumptions. On the other hand, students predicted the gas and water consumptions less than the actual consumptions. As for the Electric, gas and water consumption per month, students predicted all consumptions larger than the actual consumptions. 6 References 1. S. Matsubara and H. Goto, ‘The Consciousness and Actual Behaviour of Young

People in Their Twenties about "mottainai" Related to Daily Life, J. Human and Living Environment 19(2),pp.153-160

2. A.Takaaze et al.: Analysis on Cold and Hot Water Usage of Students in Each Dwelling, Proceedings of the CIB-W62 International Symposium on Water Supply and Drainage for Buildings (Hong Kong), pp.50-57, (2008)

269.1

178.5

433.4

126.1 122.8 127.6

0

100

200

300

400

500

Jul. Sep. Nov.

Elec

tric

cons

umpt

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[kW

h]

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a) Electricity

41.9

59.3

127.6

2.7 1.612.1

0

20

40

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80

100

120

140

Jul. Sep. Nov.

Gas

con

sum

ptio

n [m

3 ]


b) Gas 212.6

33.3

236.5

11.7 11.4 10.1

0

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Jul. Sep. Nov.

Wat

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onsu

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[m3 ]


c) Water


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7 Presentation of Author Hiroshi Takata is the Associate Professor at Graduate school of education, Hiroshima University. His special field is the planning of cold and hot water supply systems.


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a survey of energy and water consumption of university ... · water consumption of these behaviors...

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