Transactions on GIGAKU: Scope and Policy
Nagaoka University of Technology publishes an online, open access journal titled “Transactions on
GIGAKU”, which is focused on the science and technology related to GIGAKU*. The mission ofthis journal is to spread out the concept of GIGAKU and the fruits of GIGAKU to the global world
and to be a strong network for innovations in science and technology and for development of next
generations of high-level human resources. This journal, therefore, covers research and education
activities related to GIGAKU in broad areas.
*

See ‘What is GIGAKU?’ below.

‘What is GIGAKU?’GIGAKU is a term composed of two Japanese word-roots; GI and GAKU. The word GI〔技〕
literally stands for all kinds of arts and technology, and GAKU 〔学〕 stands for scientificdisciplines in general when used as a suffix.
The term was originally coined to describe the fundamental philosophy of education and research of
Nagaoka University of Technology (NUT) when it was established in 1976. Through this term thefounders of NUT intended to express their recognition that all technical challenges in the real world
require a scientific approach. And NUT has a relentlessly pursued GIGAKU since then.
Thirty-five years have passed and all surrounding conditions have changed dramatically during those
years. We are witnessing rapidly globalizing economics and huge scale changes in demographic,
industrial and employment structures. All those changes seem to necessitate the further evolution of
GIGAKU. In response to this, NUT recently announced its new “Growth Plan” and a reneweddefinition of the term is given;
GIGAKU is a science of technologies, which gives us an angle to analyze and reinterpret diverse
technical processes and objects and thus helps us to advance technologies forward. By employing abroad range of knowledge about science and engineering, management, safety, information
technology and life sciences, GIGAKU provides us with workable solution and induces future
innovations.

July 2012
Koichi Niihara, President of Nagaoka Univesrsity of Technology

1Editors (2016 to 2017):
Editor-in-chief:
Prof. Masao Fukuda
Head of Library, Nagaoka University of Technology, Nagaoka Japan
Co-Editors:
Prof. Nobuhiko Azuma
President of Nagaoka University of Technology, Nagaoka Japan
Prof. Yoshiki Mikami
Nagaoka University of Technology, Nagaoka Japan
Prof. Yasuo Utsumi
Sendai National College of Technology, Sendai Japan
Prof. K. Bhanu Sankara Rao
Mahatma Gandhi Institute of Technology, Gandipet, Hyderabad India
Prof. Paritud Bhandhubanyong
Panyapiwat Institute of Management (PIM), Nonthaburi, Thailand
Prof. Takumi Fujiwara
Tohoku University, Sendai, Japan
Submission and Publishing“Transactions on GIGAKU” publishes original papers focusing on education, science, and technology
related to GIGAKU. Proposals for special issues aligned with conferences are strongly encouraged*,
and guest editors are welcomed. Papers submitted are peer-reviewed before publication. Publication
charge is free for all submitted papers.
* Please contact to Editor-in chief, masao@vos.nagaokaut.ac.jp
Copyright
The copyright of the papers published in Transactions on GIGAKU is transferred to Nagaoka
University of Technology. (See our copyright transfer form for details.)
Contactjoho-kiban@jcom.nagaokaut.ac.jp(Revised December 2016)
2

Editorial board of special issue of The 4th International Symposium on
Engineering, Energy and Environment (ISEEE2015), Vol.3, No.3. ofTransactions on GIGAKU
EditorDr. Masato Aketagawa, Professor, Department of Mechanical,, Nagaoka University ofTechnology, Japan

Co-Editors
Dr. Phadungsak Rattanadecho, Professor, Thammasat University, Thailand
Dr. Ryuichi Egashira, Associate Professor, Tokyo Institute of Technology, Japan
Dr. Masato Saitoh, Professor, Saitama University, Japan
Dr. Takashi Yukawa, Professor, Department of Management and Information Systems
Engineering, Nagaoka University of Technology, Japan
Dr. Shigeru Nagasawa Professor, Department of Mechanical, Nagaoka University ofTechnology, Japan
Dr. Tomoichiro Okamoto, Associate Professor, Department of Electrical, Electronics
and Information Engineering, Nagaoka University of Technology, Japan
Dr. Yukio Miyashita Associate Professor, Department of Mechanical, Nagaoka
University of Technology, Japan
Dr. Yuichi Otsuka, Associate Professor, Department of System Safety, Nagaoka
University of Technology, Japan3

Preface of the special issue for the ISEEE2015
The 4th International Symposium on Engineering, Energy and Environment(ISEEE2015) was held at the Pattaya Campus of Thammasat University, Chonburi,
Thailand from November 8 to 10, 2015. This International Conference wasco-organized by Faculty of Engineering of Thammasat University, Tokyo Institute ofTechnology, Saitama University and Nagaoka University of Technology. This
International Conference was also supported by Hiroshima University, Toyohashi
University of Technology, Sirindhorn Instiute of Technology and Faculty of Scienceand Technology of Thammasat University.
In the Conference, there were 2 keynote speeches and more than 100
presentations in various sessions: Renewable energy and energy management,
Environmental technology and management, Chemical processing, Material engineering,
Manufacturing and design, Productivity improvement, Biomedical engineering andengineering in medicine, Diagnostic and monitoring system, Digital technology,
Agricultural and food engineering, Transportation and logistics, Resilient engineering,Engineering and education and others. Among a large number of the presented papers,
the selected and peer-reviewed 2 papers are included in this special issue. We hope you
enjoy these interesting papers.
Prapat Wangskarn
General Chair
Dean of Faculty of Engineering, Thammasat University

Masato AKETAGAWA
International Organizing Committee of ISEEE2015
Professor, Nagaoka University of Technology

4Transactions on GIGAKU
Volume 3, No. 3, December 2016
special issue for the ISEEE2015
The 4th International Symposium on Engineering, Energy and Environment(ISEEE2015) was held at the Pattaya Campus of Thammasat University, Chonburi,
Thailand from November 8 to 10, 2015.
Table of contents
1. Pages S03001/1-7
Experimental Optimization of Heat Load and Cooling Flow Rate of a Micro Heat Pipewith R134a as Working Fluid.
Jirapol Klinbun, Somsak Vongpradubchaib
2. Pages S03002/1-6
Energy-Saving Behavior in Households after the Great East Japan Earthquake
Ayami Otsuka, Daisuke Narumi

5Transactions on GIGAKU 3(3)(2016)S03001/1-7

Experimental Optimization of Heat Input and Coolant Flow Rate of a
Micro Heat Pipe with R134a as Working Fluid
Jirapol Klinbuna* and Somsak VongpradubchaibaDepartment of Mechanical Enginnering, Faculty of Engineering, Rajamankala University ofTechnology
Rattanakosin (Salaya Campus), Phutthamonthon, Nakorn Prathom, 73170, ThailandbCenter of Excellence in Electromagnetic Energy Utilization in Engineering (CEEE), Thammasat
University (Rangsit Campus), Khlong Luang, Prathum Thani, 12121, Thailand
This research presents experimental optimization of heat input and coolant
velocity based on the thermal performance of a micro heat pipe. The working
fluid used is R134a. The coolant is water of 30 ºC and an inclination angle is set
at zero. A micro heat pipe made from straight copper tube with an outer diameterof 6 mm and length of 200 mm. The heat pipe was divided into 3 parts, such as
the evaporator section of 65 mm, adiabatic section of 70 mm and condenser
section of 65 mm. The effect of operating temperature (40, 50 and 60 ºC) andflow rate of coolant (0.25, 0.50 and 1.00 L/min) on thermal performance of a heatpipe are studied. It was found that the heat input and the cooling air velocity havesignificant effect on the effective thermal conductivity. The results were
optimized with the objective of maximizing the effective thermal conductivity;
the highest thermal efficient is 54.18 % and maximum heat transfer rate is 34.83
W at the operating temperature of 40 ºC and flow rate of coolant as 1.00
L/min.
1. Introduction
The heat pipes have been widely applied to a variety of both simple and complex designs for space andterrestrial applications. Heat pipes are devices used for efficient transport of heat over large distances.
Under typical operation, a metal container such as aluminum or copper contains a small amount working
fluid pressurized to its saturation point. The heat transfer system is based on the continuous cycle ofevaporation and condensation process. When heat is applied to the outer area of the tube, the liquid inside
the tube boils and vaporizes into a gas that moves through the tube seeking a cooler location where it
condenses, giving off its latent heat. Using capillary action, the wick transports the condensed liquid backto the evaporation section [1]. For gravity-assisted heat pipes, the liquid is condensed back to theevaporator section by means of gravity [2]. The appropriate choice of working fluid along with theinclination angle is therefore a major factor in heat transfer obtainable from heat pipes [3]. Heat pipes areenergy-efficient passive devices and do not consume fossil fuels and other environmentally hazardous
resources for carrying out its operation, thereby making itself extremely suitable for use in naturalventilation air streams. There are various heat pipe systems currently available which are applicable tooperating temperatures associated with building energy applications [4].
Micro Heat Pipes (MHPs) are used in applications where small to medium heat transfer rates aredesirable. The rate of cooling achieved from the MHP is significantly lower compared to forced
convection systems. However, the capability to control temperatures in environments of varying heatloads along with its compact size allows it to be used in various applications [5]. Micro and miniature
heat pipes are electronic component coolers. The interest stems from the possibility of achieving theextremely high heat fluxes near 1000 W/cm2, needed for future generation electronics cooling application[6]. Effect of water-based Al2O3 nano-fluids as working fluid on the thermal performance of a flat microheat pipe with a rectangular grooved wick is investigated [7]. A novel design of micro heat pipe (MHP)
with implanted arterial paths and an evaluation heat spreader are investigated. MHP implanted with* Corresponding author. Tel.: +662 441 6000 ext. 2675
E-mail address: Jirapol.kli@rmutr.ac.th1Transactions on GIGAKU 3(3)(2016)S03001/1-7

arteries is supposed to effectively limit the propagation of the dry-out region. [8].Then, the effects ofgravity, through the angle of inclination, on the heat transport capacity, the optimal charge level of theworking fluid, the liquid volume fraction distribution, the circulation strength of working fluid and thesolid wall temperature distribution are analyzed, to provide a better insight for the design of inclined
micro heat pipes [9]. A theoretical analysis of transient fluid flow and heat transfer in a triangular micro
heat pipes has been conducted to study the thermal response characteristics. By introducing the system
identification theory, the quantitative evaluation of the MHP’s transient thermal performance is realized[10]. The coupled effects of working fluid and solid wall on thermal performance of micro heat pipes; By
incorporating the solid wall conduction, together with the continuity, momentum, and energy equations of
the liquid and vapor phases, a mathematical model is developed based on the conservation laws and issolved to yield the heat and fluid flow characteristics of micro heat pipes [11].
From the available literature review, it may observe that a limited number of working fluids had beenused and some of them are rarely used, such as R134a. In addition to that, since most of the working
engineering systems use micro heat pipe and the research work studying the optimization effect was also
found to be very fields. Therefore, in order to study their effects on the performance of the micro heatpipe with R134a still need more work.
The objective of this work is to present the optimization of heat input and coolant velocity on the
maximum thermal performance of micro heat pipe, with R134a as a working fluid.
2. Materials and methods
2.1 Experimental apparatus
Fig. 1 shows the experimental setup for testing heat pipes. Heat pipes made of copper pipe diameter 6
mm, length 200 mm with a porous structure sintered and refrigerant R-134a as the working. The heat pipe
is divided in to three parts. It consists of the evaporator and the condenser, length of 70 mm bolt and theadiabatic section length of 60 mm. The tested the insulation to prevent heat loss in the system. The test set
is connected to the water temperature and the condensation and evaporation. The experiment wascontrolled coolant temperature of 30 ºC were studied by changing the operating temperature was 40, 50
and 60 º C and the flow rates of the cooling water are 0.25, 0.50 and 1.00 L/min, respectively.
Thermocouples K type are measuring the surface temperature of the heat pipe, the cooling water wascirculated through the condenser jacket before the heat was supplied to the evaporator. In addition, theinlet and outlet temperatures of the cooling water were measured using two thermocouples. The adiabatic
section of the heat pipe was completely insulated with the aero flex. The amount of heat loss from theevaporator and condenser surface was negligible. The thermocouples is connected the data logger(Yokokawa MW 2000) for record data. In order to analyzes the performance of heat pipe heat exchanger.

1. Heat pipe.
2. Hot bath and cold bath
3. Temperature recorder2

Transactions on GIGAKU 3(3)(2016)S03001/1-7

1
2,3,4
5
6
7
8,9,10
11

Teo
Te
Tei
Ta
Tco
Tc
Tci

Outlet temperature at evaporator section
temperature at evaporator section
Inlet temperature at evaporator section
temperature at adiabatic section
Outlet temperature at condenser section
temperature at condenser section
Inlet temperature at condenser section
Fig. 1. Schematic diagram of experimental apparatus.

2.2 Experimental procedure
In this work, the effect of flow rates of the cooling water and working temperature were examined.
The experiment runs were carried out according to the following steps:
1) The micro heat pipe was set up. One of these was filled with R134a. The inclination of pipe wascontrolled at 0o.
2) The hot water was supplied to evaporator of the micro heat pipe until the desired working
temperature level.
3) At the steady state after a time period of about 15 min, the surface temperatures were measured
and recorded.
4) After finishing the above steps, cooling flow rates and working temperature are changed, themicro heat pipe and to make it ready for further experimental purpose.
5) The tested are repeated step 1-4 again.
2.3 Calculation procedure
The obtained temperature was used to calculate the heat rate and the total thermal resistance.
The output heat transfer rate from the condenser was computed by applying an energy balance to thecondenser flow. Thus, the heat transfer rate of heat pipe was calculated using the equation.

Q mc p Tco

Tci

(1)

The thermal resistance (R) was defined as

Te

R

Tc

(2)

Q

Thermal efficacy
th

Q act
Q th

(3)

where Te , Tc averaged values of temperatures at the evaporator and condenser were sections
respectively and Q is the heat supplied to the system. Qact, Qth are actual or measurement temperatureand theory temperature, respectively.
3. Results and discussion
This experimental investigation and optimization of working temperature and cooling flow rates atcondenser section on heat transfer rates of micro heat pipe, the results presented by the relationship ofworking temperature and cooling flow rates with other parameters.
Fig. 2. shows the relationship between the lengths of the heat pipe, the pipe surface temperature of heatpipe that used R134a as the working temperature was 40 °C under steady state operation. Temperature in
the evaporator was 40.5, 40.5 and 40.7 °C and the temperature in the condensation of 36.6, 35.7 and35.0 °C in is evident that the distribution of temperature along the length of the heat pipe, the same trend

3

Transactions on GIGAKU 3(3)(2016)S03001/1-7

in all cooling flow rates. The operating temperature is 50 °C and 60 °C, the evaporation and condensation
has soared. The difference in temperature between the evaporator and the condenser will be higher. Whensupplied heat to evaporator section, the working fluid boils become to vapor and transfers heat from theevaporator to the condenser. After that the working fluid is condensed become to liquid and absorb to theporous material then flows back to the evaporator by capillary pump force. When supply heat increased toevaporator section. The working fluid boiled and evaporates rapidly, but cannot flow back to theevaporator and some area of the evaporator was dry. It can see that at operating temperature 60 ºC. The
temperature of the evaporator fist point is higher than the others in the same section. This phenomenon iscalled capillary limit causes the limit based on the size of the capillary porosity and properties ofsubstances. When the temperature raises the viscosity and surface tension decrease capillary pressure that
occurs in porous materials porosity decreased.

4

Transactions on GIGAKU 3(3)(2016)S03001/1-7

(a)

(b)

Fig. 2. Relationship between the lengths and the surface temperature of heat pipe (a) Flow rate 0.25 L/min; (b) Flow rate 0.50
L/min; (c) Flow rate 1.00 L/min

Fig. 3 shows the relationship between the working temperatures (Tv) and the heat transfer rate of heatpipe that uses R134a as the working fluid found at working temperature 40 °C the heat transfer rate isequal to 12.19. W, 24.38 W and 34.83 W at a flow rate of cooling water 0.25, 0.50 and 1.00 L/min,
respectively; at working temperature 50 °C the heat transfer rates are equal to 24.38 W, 38.81 W and 41.8
W respectively; working temperature 60 °C the rate of heat transfer is equal to 33.09 W, 45.28 W and48.77 W at a flow rate of cooling water 0.25, 0.50 and 1.00 L/min, respectively. It seen these trend foundthat when the working temperature increases affect the heat transfer rate increases too. Due to the higher
temperature working fluid absorbs heat to change state to a vapor transfer from the evaporator to thecondenser more than low temperatures.

Fig. 3. Relationship between the working temperatures and heat transfer rate of heat pipe

Fig. 4 shows the relationship between the flow rate of cooling and the heat transfer rate of the heat
pipe. It was found at when cooling flow rate increase from 0.25 to 10.25 L/min, the heat transfer rateincrease from 12.19 W to 34.83 W at working temperature 40ºC.These trends are the same with working
temperature 50 ºC and 60 ºC. This is because when the flow rate increases the cooling water can transfer
heat from the surface of the heat pipe is higher than low flow rate. But at high flow rate and working
temperature the heat transfers heat is very small, these because the heat pipe is nearly to heat transfer
limit.

5

Transactions on GIGAKU 3(3)(2016)S03001/1-7

Fig. 4. Relationship between the flow rate of cooling and the heat transfer rate of the heat pipe

Fig. 5 shows the relationship between the working temperature and the thermal efficiency of heat
pipe. At the cooling flow rate 0.25 L/min, when working temperature increases from 40 ºC to 50 ºC, thethermal efficiency increases from 27.16% to 33.1% but when working temperature increases to 60 ºC thethermal efficiency decrease to 21.79%. These because when the working temperature increases from 40ºC to 50 ºC the heat pipe is still normal operated the thermal efficiency is increases. But when theoperation of the heat pipe at working temperature 60 ºC , the point where it is unstable to work, due to theworking fluid cannot flow back enough to received heat load from the evaporator section thus thermal
efficiency decreases. At a flow rate of cooling water 0.50 L/min and 1.00 L/min when working
temperature increases from 40 ºC to 60 ºC the thermal efficiency reduced from 45.27% to 18.97% and54.18% to 16.77% respectively. These because at working temperature 50 ºC and 60 ºC the heat pipe isoperated nearly heat transfer limited, thus the thermal efficiency continues reduced. At the same time,
property of working fluid is changed especially viscosity that affect to reduced capillary force to returnliquid condenses from condenser section evaporator section.

Fig. 5. Relationship between the working temperature and thermal efficiency of heat pipe6Transactions on GIGAKU 3(3)(2016)S03001/1-7

4. Conclusion
Experimental study of the thermal performance of a micro heat pipe with R134a as a working fluid ispresented. This study is concerned to optimize the effect of heat input and coolant flow rate. The main
results can be summarized as follows:-

The micro heat pipe wall temperature, the operating temperature, the temperature difference
between the evaporator and condenser, and the overall heat transfer coefficient are increased
corresponding to increasing heat input on over range of this work.
The optimum heat input and coolant flow rate are found to be 40 C and 1.0 L/min, respectively.
The highest thermal efficiency of 54.18% and maximum heat transfer rate is 34.83 W.
The obtained condition may be considered a helpful database tool.

-

Acknowledgements
The authors thank, Rajamangala University of Technology Rattanagosin and Limited Company
Fujikura has supported the work of this research as well.
References[1][2]

Faghri A. (1986). Vapor flow analysis in a double walled concentric heat pipe, Numer. Heat Transfer 10, 583–595
Hagens H, Ganzevles FLA, van der Geld CWM and Grooten MHM. (2007). Air heat exchangers with long heat pipes:
experiments and predictions, Applied Thermal Engineering 27: 14-15[3] Song F, Ewing D and Ching CY. (2008). Heat transfer in the evaporator section of moderate-speed rotating heat pipes,
International Journal of Heat and Mass Transfer 51, 1542-1550[4] Hassam Nasarullah Chaudhry. (2013). The Integration of Heat Pipe Technology into Natural Ventilation Systems, thesis
for the degree of Doctor of Philosophy, The University of Leeds, School of Civil Engineering 2013
[5] Reay D and Kew P. (2006). Heat Pipes-Theory, Design and Applications, Fifth Edition, Butterworth-Heinemann, Oxford
OX2 8DP, USA[6] Jian Qu, Huiying Wu, Ping Cheng (2008). Effects of functional surface on performance of a micro heat pipe, Heat andMass Transfer, vol. 35, February 2008, pp 523–528.
[7] Kyu Hyung Doa,, Sung Jin Kim, Suresh V. Garimella (2008). A mathematical model for analyzing the thermal
characteristics of a flat micro heat pipe with a grooved wick, Heat and Mass Transfer, vol. 51, April 2008, pp 4637–
4650.
[8] Vasiliev LL. (2008). Micro and miniature heat pipes – Electronic component coolers, Applied Thermal Engineering, vol.
28, April 2008, pp 266–273.
[9] Kyu Hyung Do, Seok Pil Jang (2010). Effect of nanofluids on the thermal performance of a flat micro heat pipe with arectangular grooved wick, Heat and Mass Transfer, vol. 53, January 2010, pp 2183–2192.
[10] Weiting Liu, Jian Kang, Xin Fu, Cesare Stefanini, Paolo Dario (2011). Analysis on heat resistance of the micro heat pipewith arteries, Microelectronic Engineering, vol. 88, February 2011, pp 2255–2258.
[11] Yew Mun Hung , Kek-Kiong Tio (2012). Thermal analysis of optimally designed inclined micro heat pipes with axial
solid wall conduction, Heat and Mass Transfer, vol. 39, July 2012, pp 1146–1153.
[12] Xiangdong Liu, Yongping Chen (2013). Transient thermal performance analysis of micro heat pipes, Heat and Mass
Transfer, vol. 58, April2013, pp 585–593.
[13] Fun Liang Chang, Yew Mun Hung (2014). The coupled effects of working fluid and solid wall on thermal performanceof micro heat pipes, Heat and Mass Transfer, vol. 73, February 2014, pp 76–87.

7

Transactions on GIGAKU 3(3)(2016)S03002/1-6

Electricity-Saving Behavior in Households after the Great East Japan
Earthquake

1)

Ayami Otsuka1*, Daisuke Narumi1
Graduate School of Environmental and Information Science, Yokohama National University,
79-7 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa, 240-8501, Japan*E-mail: otsuka-ayami-kx@ynu.jp

The paper presents the result of an internet-based questionnaire survey
conducted on electricity-saving behavior in households in the summer after
the Great East Japan Earthquake in March 2011. A total of 60 households
residing in metropolitan Kanto region where electricity is provided by Tokyo
Electric Power Company was surveyed based on the 3 groups, A, B, and C,
depending on their level of electricity-saving behavior declared by each
respondent. Electricity consumption data was obtained from the electricity
bills. A comparison of electricity data showed that the total electricity
consumed from April to November in 2010, i.e. before the Earthquake,accounted for 2,113 kWh for Group A whereas it added up to over 3,000kWh
for Group B and C, reflecting active electricity-saving behaviors taken bypeople in Group A.
In addition, Group B showed the greatest
electricity-saving rate in June and July of 2011, as declared to have engaged
in electricity-saving behavior triggered by the Earthquake. However, a great
deal of “rebound” was also confirmed in the months soon after the lift of theelectricity saving edict in group B, indicating the difficulty of sustaining theelectricity-saving behavior and its effect driven by a top-down approach.
The attributes identified via factor analysis could be interpreted as those
proposed in the widely used theory of planned behavior. Different weight ofthese factors in leading to electricity-saving behavior for each group implies
the importance of fostering sensibility for general environmental issues forsustained electricity-saving practices and its effects.

1. Introduction
Promotion of energy-saving, including electricity-saving, behavior in households is becoming
increasingly important from the viewpoint of climate change measures in the recent years. It is also
considered difficult, however, as it happens in private spheres where social norms tend to be weak [1].
In response to the serious energy crisis caused by the Great East Japan Earthquake (the Earthquake)and the subsequent disastrous accident at the Fukushima Daiichi Nuclear Power Plant (theFukushima Accident) of Tokyo Electric Power Company (TEPCO) in March 2011, the household
sector contributed to the nation-wide electricity-saving effort by achieving 11% reduction rate fromthe previous year based on a non-binding voluntary reduction target[2]. This paper explores
psychological mechanisms behind electricity-saving behavior among people by looking at the resultsof a questionnaire survey conducted after the Fukushima Accident in 2011, with the aim of finding
implications for promoting, and more importantly sustaining, energy-saving behaviors inhouseholds.

2. Research Method
An internet-based questionnaire survey was conducted in December 2011 targeting families (acouple with 1-2 children) residing in metropolitan Kanto region where electricity is served by
TEPCO. A total of 60 households participated in the survey, after a pre-screening process whereconditions such as having access to the electricity bills for the period relevant to the study and not

1

Transactions on GIGAKU 3(3)(2016)S03002/1-6

undergoing any renovation work or moving since April 2010 were confirmed. Households wereseparated into three groups, A, B, and C, with 20 households in each group, depending on the levelof electricity-saving behavior taken at home as declared by each respondent. People in Group A
claim to have been active electricity-savers even before the energy crisis; Group B consists of those
who began taking electricity-saving behaviors after the energy crisis, and people in Group C claimthat they have never engaged in electricity-saving behavior either before or after the energy crisis.
The survey consisted of five parts: 1) 14 questions constructed on the psychological determinantfactors of their electricity-saving behaviors on a 7-point scale; 2) actual electricity-saving behaviors
conducted on a 3-point scale; 3) electricity consumption data, in the form of total kWh written on theelectricity bills from April to November in 2010 and 2011; and 4) other questions related to the
Earthquake and the Fukushima Accident, such as experience of rolling blackout, feelings towards
these incidents, as well as sustainability of electricity-saving intention; and lastly 5) demographic
facts such as age, age of children, occupation, and household income. The survey answers wereanalyzed by statistical analyses, such as analysis of variance and factor analysis, to evaluate thedeterminant attributes of electricity-saving behavior for each group.
The demographic features of the respondents are summarized as follows. Age groups of the
respondents were: among in their 30s (30%), 40s (43%) and 50s (27%). The number of children
were divided into one (57%) and two (43%) as specified in the pre-screening condition. The age ofthe first child ranged “over 18” being the largest (42%), followed by “between 6 and 18 (33%)” and“under 6 (25%).” The household income ranged: 20% in the lower income (less than 4 million
yen) group; 43% in the middle range (income between 4 to 8 million yen); and 36% in the higher
income (8 million yen or more) group. All respondents were female, perhaps due to our requestthat the main person in charge of daily housework in each house to fill the survey; and 70% of themwere housewives with no paid jobs whereas only 15% are working on a full-time basis. A majority(63%) of the respondents did not undergo actual rolling blackouts, as the metropolitan Tokyo wards
where 42% of the respondents reside and areas where high-level of emergency functions, such as
hospitals and fire stations, were excluded from the rolling turns.
3. Results and Discussion
3.1 Electricity Consumption
A comparison of electricity consumption data, in the form of total kWh written on the electricity
bills from April to November in 2010 and 2011, is shown in Table 1. The total electricity
consumed from April to November in 2010, i.e. before the energy crisis, accounted for 2,113 kWhfor group A whereas it added up to over 3,000 kWh for group B and C. A more detailed
comparison of the monthly average consumption figures for 2010 and 2011 within each group(“t”-values under the “Electricity saved” heading in Table 1) reveals differences between these twoyears are of statistical significance for all months for Group A. By contrast, differences in April
and May for Group B and April for Group C were not statistically significant. This means that thepeople in Group A had even begun to take more electricity-saving measures on a voluntary basis
already in April, reflecting active electricity-saving behaviors as claimed by them. In addition, theanalysis of variance for electricity consumption across the groups in the same months, shown in“F”-values and corresponding “p”-values in Table 1, indicates significant statistical differences formost of the months, except September 2011. Similar trends are apparent in the amount ofelectricity saved, i.e. electricity-saving rates. In general, Group B showed the greatest saving ratein June and July of 2011, as declared to have engaged in electricity-saving behavior since the energy
crisis. However, a great deal of “rebound” was also confirmed in the months soon after the lift ofthe electricity saving edict in early September in Group B, implying a difficulty of sustaining theelectricity-saving behavior and its effect driven by a top-down approach. It should also be notedthat there is not much statistical differences between Group B and C in terms of electricity
consumption and saving data, although their perception of their own electricity-saving behavior,
whether they perceive themselves to be engaged in electricity-saving or otherwise, is different.
3.2. Psychological factors determining electricity-saving behavior
Fourteen questions rated by the degree of agreement on a 7-point scale (1: do not agree at all to2Transactions on GIGAKU 3(3)(2016)S03002/1-6

Table 1 Comparison of electricity consumption in 2010 and 2011 by group

7: completely agree) were asked to measure psychological factors determining electricity-saving
behavior among people. Items specifically related to the Earthquake and Fukushima Accident werealso included. The wording of each question was made in the past tense, as this study looked backat the electricity-savings done in the past. The results are presented in Table 2. Degrees ofagreement on 8 measures on awareness of problems and sense of responsibility, economic factors,
perceived behavior control, and subjective norm, altruistic/egoism value are generally low,indicating the low level of awareness among the respondents. This is especially true for the issuesof general environmental problems such as global warming. The result of analysis of variance thenidentified 6 items with statistically significant differences among groups: two measures on social
responsibility, one perceived behavior control, one economic factor, and one egoism value.
A Principal Factor Analysis (PFA) with promax rotation was then conducted to find potential
determinant factors for electricity-saving behavior among people. The result of PFA revealed four
factors explaining 77.6% of the variance. The factor loadings of each variable and reliability of scale
are shown in Table 3. Of the fourteen questions, the measures on intention to buy energy-efficient
Table 2 Rating of psychological factors determining electricity-saving behavior

3

Transactions on GIGAKU 3(3)(2016)S03002/1-6

products and egoistic value were excluded from further analysis as they did not fit well into any of
the four factors. The fourth factor with eigenvalue of less than 1 was adopted based on thejudgement on the scree plot and the account of explained variance.
The first factor consists of all the questions specifically related to the Earthquake and Fukushima
Accident, whereas the second factor reflects more general pro-environmental attitude. The third
factor was identified as “perceived seriousness of the risk/problem” when it actually occurs arisingfrom the experiences of the Earthquake/Fukushima Accident, noted to be a different scale from thegeneral “perception of probability of the risk occurring[3]. Finally, the forth factor is reflecting
personal subjective norm. Three far-right columns in Table 3 indicate the contribution of eachfactor in percentage by Group, of which interpretation will follow in section 3.5. below.
3.3. Electricity-saving behavior
Specific electricity-saving behaviors engaged by the respondents were rated by a 3-point scale
extending from “I have been engaging in this behavior since before the Earthquake;” “I haveengaged in this behavior since the Earthquake;” and “I have never conducted this activity either
before or after the Earthquake.” The results are presented in Table 4. Performance rates are
generally high in Group A, followed by Group B then C, but a good proportion of people in Group B
and C also engaged in many of the activities even before the Earthquake, resulting in only 5
behaviors with statistically significant differences among the groups shown with asterisks in Table 4.
Table 3 Factor loadings of the determinants for electricity-saving

Table 4 Comparison of electricity-saving measures conducted by each group4

Transactions on GIGAKU 3(3)(2016)S03002/1-6

The results of a PFA with promax rotation then identified three factors explaining 54% of thevariance (Table 5). Three variables (reducing standby power by unplugging, avoiding unnecessary
opening of refrigerator, and partial use/removal of lighting tubes) were excluded from further
analysis as they did not fit well into any of the three factors. Each factor is named “Change inhabit,” “setting change (small cost but with some endurance),” and “setting change (little endurance
but with some cost),” respectively. Three far-right columns in Table 5 indicate the performance
rates conducted for each factor by Group as declared by the respondents in the survey. The
differences in performance rates among groups give an interesting implication: especially of thatpeople in Group B, who claim that they actively engaged in electricity-saving since the Earthquake,changed in a number of habits, but activities requiring certain level of endurance, such as setting
air-conditioning at 28 degrees celcius, remained indifferent from Group C.
Table 5 Factor loadings of the electricity-saving behaviors actually taken

3.4. Other factors
Demographic variables, such as income, age of the respondents, and experience of rolling
blackouts, were considered for its interaction effects. Overall, interaction effects were minimal
both in psychological determinants of electricity-saving behavior and actual behaviors taken bypeople. This could presumably be due to the physical and mental proximity of the respondents tothe experience of the rolling blackouts actually happening in the nearby areas. The severity of theshock of the incidents also could have worked to foster a moral norm when considering the victims
and those affected by the Earthquake and Fukushima Accident.
3.5. Implication
A closer look at the factors identified in 3.2 and 3.3 gives some implications for how different
factors determined electricity-saving behaviors taken by people in each group. Although the small
sample size of the study, especially when analyzed by group, hindered an application of structural
equation modelling, retrofitting the psychological factors determining the electricity-saving behavior
identified in this study could be related to the factors proposed in the widely well accepted theory ofplanned behavior (TPB) by Ajzen[1] namely attitude, personal norm, perceived behavioral control
which lead to form the behavioral intention, which consequently reaches to actual behavior (Fig.1).
In particular, the most powerful factor by far, namely “Earthquake-driven attitude” identified in thisstudy could be equated with the “perceived behavioral control” of the TPB. If so, when perceived
behavioral control is so powerful and almost become a moral norm, behavioral intention and actual
behavior occurs almost simultaneously, leading to immediate action on electricity-saving as seen in
the case of Group A and B (Fig. 2 and 3). Without a more general “attitudinal drivers,” however,
the action does not sustain and showed a significant rebound as soon as the top-down
electricity-saving edict was lifted as in Group B. From the sustainability point of view, the role ofmore general pro-environmental attitude become critical as in the case of Group A, suggesting a5Transactions on GIGAKU 3(3)(2016)S03002/1-6

Fig. 1 Theory of planned behavior (TPB) by
Ajzen [1]Fig. 2 Notational image of psychological pathusing Theory of Planned Behavior for Group A

Fig. 3 Notational image of psychological pathusing Theory of Planned Behavior for Group B

Fig. 4 Notational image of psychological pathusing Theory of Planned Behavior for Group C

continued need for environmental and moral education. It is also interesting that people in Group C,
claimed as non-active electricity savers, share a more similar psychological traits with Group A thanthose in Group B, except that they were more influenced by external drivers, i.e. subjective norms,
than by their internal, i.e. attitudinal, drivers (Fig 4).

4. Conclusion
In evaluation of the factors determining electricity-saving behavior in households in the summer
after the Great East Japan Earthquake, it was suggested that four factors, closely related to the theoryof planned behavior, differently influenced the structure of electricity-saving behavior for each group.
The “Earthquake-driven,” perceived behavioral control had the greatest influence by far, but
fostering a sensibility and attitude for general environmental problems is more crucial for sustained
electricity-saving practices and its effects. It should be noted, however, that the small sample sizeof the study puts a certain limitation on generalizing the conclusion found in this study. In addition,rather than taking an approach where grouping by self-declared perception of engagement inelectricity-saving behavior and their psychological determinants as a central focus of the analysis, amore detailed consideration of grouping by demographic characteristics such household income andage of the children as well as by the actual electricity consumption/saving could add further
implications for promotion of energy-saving, including electricity-saving, behavior in households.
References[1] Ajzen, I. (1991), The theory of panned behavior. Organizational Behavior and Human Decision
Processes, 50, 179-211.
[2] Ministry of Economics, Trade and Industry, Follow-up on Elec-saving measures, Oct. 2011.
[3] Yagita, K., Iwafune Y. (2011), Visualization of energy-consumption and its effects by energysaving advice for househod, Jurnal of Energy and Resources, 32-4, (2011), 25-33.
5HFHLYHG1RYHPEHU$FFHSWHG-XO\

6