A NOVEL INTEGRATED ENERGY SYSTEM OF SOLAR POWER, HEAT PUMPS AND AI-EV (AIR-CONDITIONER ELECTRIC VEHICLE)

Transcription

1 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics HEFAT6 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics July 6 Malaga, Spain A NOVEL INTEGRATED ENERGY SYSTEM OF SOLAR POWER, HEAT PUMPS AND AI-EV (AIR-CONDITIONER ELECTRIC VEHICLE) Tsuguiko N.* *Autor for correspondence Department of System Engineering, Graduate scool of Okayama Prefectural University, Kuboki, Soja, Okayama Japan, nakagawa@cse.oka-pu.ac.jp ABSTRACT In order to reduce CO emissions economically, it is important to construct a Smart Community wic is expected to be one of te solutions. In a Smart Community, energy supply and demand will be managed by some matematical models to consume energy efficiently and increase te introducing of renewable energy. In one of te systems, "Potovoltaic power generator (ereinafter referred to as PV) combined Electric Veicle (ereinafter referred to as EV) Smart System" as been developed.[] In te PV combined EV Smart System, PV power is carged directly to te EV battery, and ten te carged PV power is consumed by running and air-conditioning energy of a car and te surplus electricity is supplied to a ome. Tis system is able to reduce CO emissions economically. In order to expand te system, it is necessary to spread EV and clarify te effects. At first, it sould solve te issues of sort cruising distance, te ig cost of storage battery and te risk of dead battery. Terefore, te autors ave proposed an advanced EV suc as AI-EV (Air-conditioner Integrated Electric Veicle).[] AI-EV as a novel ybrid system wic drives te airconditioning system and generates electric power in te case of a low air-conditioning load troug te use of a small-engine. If PV power can not only reduce car fuels but also replace wit gas and liquid fuels wic are consumed at a ome, uge effect of CO reduction is obtained as te wole of te system. In tis paper, a novel energy system wic is combined and integrated wit solar power, AI-EV and ome eat pumps as been proposed. Heat pumps are car air-conditioner and CO eat pump water eater for ome use. A matematical simulation model wic is integrated wit AI-EV model, CO eat pump model and HEX model based on some experiments as been developed to evaluate a smart community wic is constructed at an office and a ome. And ten, CO emissions and economic efficiency are calculated and compared wit tose of te conventional system. As te result, te novel energy system is able to reduce more tan % of CO emissions in comparison wit te conventional system as te wole system, and te system can reduce more tan 6% of CO emissions in comparison wit te conventional ome. Te economic efficiency is evaluated by more tan.% of Internal Rate of Return witout some subsidies wen te legal service life of te depreciation equipment is assumed years. Terefore, te novel energy system can be widely spread in te future. Additionally, it is clarified tat te integrated smart system can reduce te fluctuations wic are caused by te PV power generation. NOMENCLATURE A [m ] Cross section area of air-conditioner blowing port A [m ] Surface area of te veicle cabin A [m ] Surface area of te veicle cabin materials A [m ] Exaust gap area A CU [m ] Solar radiation area of veicle A c,a [m ] Heat transfer area of air-conditioner condenser A c [m ] Heat transfer project area of air-conditioner condenser A e,a [m ] Heat transfer area of air-conditioner evaporator A c,wi [m ] Heat transfer area of water eater condenser A e,wi [m ] Heat transfer area of water eater evaporator c pa [kj.kg -.K - ] Specific eat of te air c pl [kj.kg -.K - ] Specific eat of te veicle cabin materials C m [-] Energy conversion factors from eac fuel to oter energy sources COP C [-] Coefficient of Performance of cooling COP H [-] Coefficient of Performance of eating E [kw] Te total amount of energy variation EF [kw] Energy variation of HEX wit Outflow, Inflow energy ES [kw] Energy variation of HEX wit generating energy, consumption and storage [kj/kg] Refrigerant entalpy of compressor inlet [kj/kg] Refrigerant entalpy of condenser inlet [kj/kg] Refrigerant entalpy of condenser outlet [kj/kg] Refrigerant entalpy of evaporator inlet 8

2 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics J [-] Colburn's j-factor M [kg] Weigt of te veicle cabin materials mf r [kg/s] Refrigerant mass flow rate mf c,a [kg/s] Air mass flow rate of condenser mf e,a [kg/s] Air mass flow rate of evaporator Pr [-] Prandtl number q [kj] Entalpy of outside air q [kj] Entalpy of air-conditioner blow off air q [kj] Heat transfer quantity from outside q [kj] Entalpy of cabin materials q [kj] Entalpy of cabin air, q [kj] Entalpy of discarged air to outside q n [kj] Required capacity of air-conditioner Q Sγ [W/m ] Solar radiation based on an annual weater at time T t Q P [W/(person)] Calorific value from person t [s] Elapsed time T [K] Air-conditioner blow off air temperature T [K] Outside air temperature T [K] Temperature of cabin materials T [K] Cabin air temperature T [K] Discarged air temperature to outside ΔT LMTD [K] Logaritmic mean temperature difference T a [K] Outside air temperature T cr,ave [K] Refrigerant average temperature at condenser T er,ave [K] Refrigerant average temperature at evaporator T cw,ave [K] Heated water average temperature u [m.s - ] Air blowing velocity from air-conditioner blowing port u [m.s - ] Velocity of discarged air to outside V [m ] Volume of te veicle cabin α [W/(m K)] Overall eat transfer coefficient between cabin and outside air α [W/(m K)] Overall eat transfer coefficient of te veicle cabin materials α c,a [W/(m K)] Heat transfer coefficient of air-conditioner condenser α e,a [W/(m K)] Heat transfer coefficient of air-conditioner evaporator α ct [W/(m K)] Overall eat transfer coefficient of water eater condenser α et [W/(m K)] Overall eat transfer coefficient of water eater evaporator β [-] Correction coefficient of solar radiation δ [-] Te cannel cange coefficient ρ a Air density η α [-] Te efficiency of mecanical η β [-] Te efficiency of adiabatic compression of te gas Subscripts Area [-] Te area tat is expressed in HEX i [-] Position of study area in a x-axis direction j [-] Position of study area in a y-axis direction k [-] Boundaries of HEXs m [-] Kind of energy source n [person] Te number of riding persons n [-] Te number of HEXs in a x-axis direction n [-] Te number of HEXs in a y-axis direction n [-] Te number of kinds of energy source r [-] Refrigerant INTRODUCTION In order to reduce CO emissions economically, it is important to construct a Smart Community wic is expected to be one of te solutions. In a Smart Community, energy supply and demand system will be managed by some matematical models to consume energy efficiently and increase te introducing of renewable energy. In one of te systems, PV combined EV Smart System" as been developed.[] In te PV combined EV Smart System, PV power is carged directly to te EV battery, and ten te carged PV power is consumed by running and air-conditioning energy of a car and te surplus electricity is supplied to a ome. Tis system is able to reduce CO emissions economically. In order to expand te system, it is necessary to spread EV and clarify te effects. At first, it sould solve te issues of sort cruising distance, te ig cost of storage battery and te risk of dead battery. Terefore, te autors ave proposed an advanced EV suc as AI-EV (Air-conditioner Integrated Electric Veicle).[] AI-EV as a novel ybrid system wic drives te airconditioning system and generates electric power in te case of a low air-conditioning load troug te use of a small-engine. If PV power can not only reduce car fuels but also replace wit gas and liquid fuels wic are consumed at a ome, uge effect of CO reduction is obtained as te wole of te system. In tis paper, a novel energy system wic is combined and integrated wit solar power, AI-EV and ome eat pumps as been proposed. Heat pumps are car air-conditioner and CO eat pump water eater for ome use. A matematical simulation model wic is integrated wit AI-EV model, CO eat pump model and HEX model based on some experiments as been developed to evaluate a smart community wic is constructed at an office and a ome. And ten, CO emissions and economic efficiency are calculated and compared wit tose of te conventional system.. INNOVATIVE CHANGES OF THE ENERGY SYSTEM -. INTEGRATED TWO-WAY ENERGY SYSTEM In te conventional system, energy flow is one direction from supplier to consumer. In te future energy system, anyone can build PV and wind power generation apparatus anywere. Terefore, many energy flows are two-way. For example, consumer can supply energy suc as PV combined EV smart system. -. ADVANCED PV COMBINED EV SMART SYSTEM Te advanced PV combined EV smart system wic is considered one of te future systems is sown in Figure. In te system, PV power is carged directly to te EV battery as DC. In te new system, it is considered to combine wit a commuter EV and a second EV. University Home EV PCS Power system DC AC AC/DC PV DC/DC EV Figure Advanced PV combined EV smart system PV Water Heater 86

3 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics Te commuter EV runs in morning and evening. In addition, it is parked by an office or a factory during te daytime on weekdays. So, PV is installed in te office or te factory because PV power is generated in daytime. On te oter and, te second EV is parked at a ome at almost time witout using. So, ot water eater is installed in te ome because surplus PV power is consumed efficiently. Te generated PV power carges te bot of EV batteries directly by DC. Wen eac EV battery level is full, generated PV power is supplied into te power source for te workplace or te ome after being converted from DC to AC. And, if te carging level of eac EV battery as some surplus power wic is not included te necessary power for te next driving, te surplus power can be supplied directly to te ome. So, tis system is possible to be minimized te number of conversions between DC and AC involving energy losses. In te novel energy system suc as te advanced PV combined EV smart system, it is important to spread and utilize EV effectively. In order to spread and expand EV, it sould solve te issues tat of sort cruising distance, ig cost of storage battery and te risk of dead battery. For solving tese issues, te new concept veicle suc as AI-EV is necessary.[]. AIR-CONDITIONER INTEGRATED ELECTRIC VEHICLE (AI-EV) -.BASIC DESIGN OF AI-EV AI-EV is utilized as not only an apparatus for locomotion, but also electricity transportation and a storage medium of electricity. AI-EV is integrated wit car driving power system, power storage system, power generation system and airconditioning power system. A simplified image of AI-EV is sown in Figure. An example of operating image is sown Figure.[] As sown in Figure and Figure, a small-engine is driven by a constant rotation tat is added up a air-conditioner compressor load and generator load wic is canged by airconditioning load. Te operation of constant rotation can be obtained a ig efficiency because it can be decreased te energy losses of acceleration and deceleration. Terefore, AI- EV can decrease te power consumption compared wit a conventional system. In addition, AI-EV is able to gain cruising distance by generated electricity wic is carged to te AI-EV battery. So, AI-EV can solve tree issues of conventional EV. -. MATHEMATICAL MODEL OF AI-EV --. HEAT BALANCE OF THE CAR A car air-conditioner capacity is determined based on te eat balance model between te inside and outside of te car. As sown in Figure, te inside of te car is eated or cooled depending on te weater conditions outside. Tis is sown by te eat balance equation from Eq. () to Eq. (7).[] Heat transfer quantity from outside Figure Heat balance model for air-conditioning q k k q q, q q AC q Discarged air entalpy Blow off air entalpy q : Entalpy of cabin materials q n q -q q : Entalpy of cabin air Air-conditioning capacity q () q t u T A ρ a c pa q t α A T T () () Figure Te Simplified image of AI-EV Figure Operation image of AI-EV q t q t T M c pl t q α A t q T V ρ a cpa t t u T A ρ a cpa () T T β QS γ ACU nqp () (6) (7) In order to calculate te eat transfer rate due to te temperature difference between te inside and te outside, Eq. () can be used. For tat, it is necessary to know te total eat transfer coefficient α wic is obtained troug te experiment. 87

4 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics --. CAR AIR-CONDITIONER MODEL P- cart of a car air-conditioner refrigerating cycle is sown Figure. Pressure [MPa] Cooling Heating Ⅲ Expansion Valve Ⅳ, Condenser Evaporator Compressor Specific Entalpy [kj/kg] Figure P- cart of a car air-conditioner refrigerating cycle A condenser and an evaporator are multi-layer structure and complicated sape. Tose eat transfer quantities are expressed by te following formula.[] Equations of te condenser are sown Eq. (8) and Eq. (9). Equations of te evaporator are sown Eq. () and Eq. (). mf r ( ) δ c, a Ac, a (8) Te performance of an air-conditioner is evaluated by te coefficient of performance (ereinafter referred to as COP). Te cooling COP C is sown in Eq. (), eating COP H is sown in Eq. () COP C = COP H = η η m m η η p p T LMTD mfc, a α, Pr c a J C pa (9) Ac g ( we, ave we, s ) mfr ( ) e, a Ae, a TLMTD, e / () Le C p mfe, a α, Pr e a J C pa () Ae () (). HOME HEAT PUMPS In te conventional system, ot water is supplied wit gas ot water eater. Te advanced PV combined EV smart system can be used te generated PV power more efficiently troug te use of EV battery because CO eat pump water eater is driven by electricity. -. CO HEAT PUMP WATER HEATER MODEL P- cart of a CO eat pump water eater cycle is sown Figure 6. And, T-S cart is sown in Figure 7. A condenser and an evaporator are multi-layer structure and complicated sape. Tose eat transfer quantities are expressed by te following formula. Equations of te condenser Ⅰ Ⅱ are sown Eq. () and Eq. (), Equations of te evaporator are sown Eq. (6) and Eq. (7). [6] Pressure [MPa] Temperature [ ] Ⅲ Ⅳ C C C 8 C C 6 Specific Entalpy [kj/kg] Figure 6 P- cart of a CO eat pump water eater cycle mfr ( ) ct Ac, wi ( Tcr, ave Tcw, ave) () A,, c wi d ln o Ac wi ct (), c r Ln di c, w Ac, wo mfr ( ) et Ae, wi ( Ta Ter, ave et er a Ⅲ Ⅳ Ⅲ Expansion Valve Ⅳ Hot water temperature (6) (7) Condenser (Gas cooler) Evaporator Entropy [kj/kg K] Figure 7 T-S cart of a CO eat pump water eater cycle ) Ⅱ Ⅰ Compressor Ⅰ Ⅰ Ⅱ Ⅱ 88

5 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics Te performance of a CO eat pump water eater is evaluated by te COP H. Te eating COP H is sown in Eq. () wic is evaluated as te same as an air-conditioner.. EXPERIMENTS -. HEAT BALANCE OF THE CAR α can be obtained by Eq. () to Eq. (7). In tis metod, Q sγ solar radiation is disturbance factor to calculate te overall eat transfer coefficient α. For tis reason, te experiments were conducted in te nigt witout solar radiation. Furtermore, Q p is a fixed value wic is using literature data. [7] Te required compressor power of a car air-conditioner is able to be calculated based on te obtained air-conditioning load. Cabin materials average temperature:t and cabin air temperature:t are obtained, if Eq.() to (7) are given α. Terefore, residual sum of squares (RSS) was calculated from eac predicted values and eac experimental values. Te result is sown in Figure 8. In Figure 8, all results of te average running speed are km/. Residual sum of squares [ ] 8 6 Overall eat transfer coefficient [W/m K] Figure 8 Measured overall eat transfer coefficient α From Figure 8, it is obtained tat α is 8 W/(m K). Terefore, te required air-conditioning temperature is able to calculate using from Eq. () to Eq. (7). Terefore, te required air-conditioning load for cooling is calculated based on te capacity to cool outside air to a target condition of car inside troug te use of te air-conditioner model from Eq. (8) to Eq. (). As te results, necessary compressor power can be calculated by te required air-conditioning load wic canges wit time to use it. -. CAR AIR CONDITIONER An experimental device is sown potograp using an air-conditioner wic was equipped wit Daiatsu MIRA in. Using tis experimental device, te matematical model was verified by te experiments. --. EXPERIMENTAL CONDITION Heat excanger size of MIRA is sown in Table. Fres air flow quantity of condenser side is. Nm /s and tat of evaporator side is. Nm /s. Te refrigerant flow quantity is canged it by compressor rotation speed. Poto. Experimental device of Air-conditioner Condenser Evaporator Table Size of eat excanger [mm] [mm] Lengt widt dept EXPERIMENT RESULT Example of te experimental results is sown in Figure 9. Te results of te cooling experiment accorded wit te calculation result of te model well. Cooling performance [kw] Fres air Fres air radiator condenser compressor compressor engine Calculated Experimental result Cold air Hot air 6 Refrigerant flow quantity [g/s] Figure 9 Comparison of calculated values and experimental values. EVALUATION OF THE NOVEL ENERGY SYSTEM -. THEORETICAL ENERGY BALANCE MODEL FOR REGIONAL AREA (HEX MODEL) It is difficult to evaluate te energy system using various kinds of energy source suc as te system tat fossil fuels, electricity and PV power are mixed in te small area. In te future energy system, PV generates electricity in arbitrary places and electricity is transported and stored by EV. Terefore, it is necessary to consider interconversion of te Evaporator 89

6 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics energy by suc a system and cannot obtain te optimum solution using by a network type model because network type model sould decide te system structure before te analysis. For tis reason, HEX(exagons) model wic is able to evaluate te liquid fuel, gas, electricity, eat and renewable energy unitarily wit measurement data as developed. HEX model is sown in Figure. [8] Figure HEX model Te energy balance of eac HEX (exagons) evaluates a total of EF ijmt (te energy variation of HEX wit energy outflow and inflow suc as EV) and ES ijmt (Te energy variation of HEX wit generating energy, consumption and storage). Terefore, te total energy variation of HEX (i, j) at time Tt is sown in Eq. (8) and (9). In addition, C m as sown in Eq. (9) is te electrical conversion factors of eac fuel. In te future, wen te energy system will be designed witin HEX as all energy consumption is substituted by electricity witout using fuel, it is possible to calculate energy consumption by Eq. (9). E E C E n ijt m m ijmt (8) (9) A wide area is sown as aggregate of continued plurality of HEX. And, te amount of energy variation wit total of object area is sown in Eq. (). E ijmt EF ijmt ES n n Area t E ij t i j (i,j+) 6 (i+,j+) 6 ijmt (i+,j) (i+,j+) (i+,j) (i+,j+) (i+,j+) () Te basic restriction conditions of E ijt and E Areat are sown in Eq. (). It is necessary to satisfy te balance of energy supply and demand witin te object area at all times. E ijt >, E Area t > () -. CALCULATED CONDITION In tis case study, four different types of veicle were simulated, a gasoline engine veicle and AI-EV. Te commuter veicles as been used for a commuting between a ome and Okayama Prefectural University (ereinafter referred to as OPU) once a day. Te second veicle wic is used for leisure or going sopping as been moved for an actual data of ousewife wo as lived in kurasiki city in Japan. Te PV data is sown in Table. Te amount of generated PV power is calculated by using an annual weater database wic as ourly solar radiation data and reflected PV power fluctuations caused by te weater, te season and te time. [9] AI-EV data is sown in Table. In tis study, all cases are simulated on a condition tat all inverse current to a conventional power system is zero. Table PV date Table AI-EV data Electricity consumption (witout air-conditioner) 9. km/kw Available capacity of battery -8 % Te capacity of te battery. kw Commuting distance Commute day Displacementof engine 8. km/day. days/year. CC As oter data, AI-EV uses LPG to drive a small-engine and te average running speed: km/. Additionally, CO emission coefficient of gasoline:.6 kg-co /l, CO emission coefficient of electricity:.79 kg-co /kw (Average of te Japanese power companies in ), CO emission coefficient of LPG (liquefied petroleum gas):.8 kg-co /kg [] -. RESULTS --. CO EMISSIONS Figure sows te simulated results of annual CO emissions tat compare wit te conventional system wic is used a gasoline and PV combined AI-EV Smart System. CO Emissions [t-co /year] Maximum power. W Output per unit area 9. W/m Installed area for commuter AI-EV Installed area for second AI-EV Total power. m. m. kw LPG LPG. Gasoline. Home Electricity.9. Gasoline. Home Electricity.9 University Electricity.6 67%..9 Wole community %..9. Home Conventional PV combined EV system smart system Figure Comparison of annual CO emission 8

7 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics From Figure, PV combined AI-EV Smart System is able to reduce 68% of CO emissions in comparison wit te conventional system as te ome energy system because gasoline and gas fuel were replaced wit PV power and system electricity was reduced by PV power. Terefore, PV combined AI-EV Smart System is able to reduce % of CO emissions in comparison wit te conventional system as te wole community. In te new system, te fuel consumption of te veicle tat AI-EV uses is about % of te conventional gasoline veicle. Terefore, if tis fuel replaces bio-etanol, AI-EV can drive all by a natural energy, tat will be te first veicle in te world. In tis case, CO emissions can reduce above 7%. --. IMPROVEMENT PERFORMANCE OF AI-EV Te performance of AI-EV can be improved by te airconditioner performance. For example, te effect of increasing eat excanger area of te air conditioner is sown in Figure Condenser eat transfer area [m ] Driving distance [km] Figure Effect of improving air-conditioner performance In Figure., te limit driving distance of AI-EV wic is mounted conventional air-conditioner tat is operated a cc displacement engine is 7km in te case of driving in a city area (average speed km/, miles/) in summer season. For example, COP can improve from.8 to. by doubling te eat transfer area of te condenser. Terefore, te power consumption of te air-conditioner decreases and power generation increases. As te result, te driving distance of AI- EV extends by % in te same engine displacement. Te performance of AI-EV wic is mounted advanced airconditioner is sown in Figure. Driving distance [km] Advanced Conventional COP [-] Air temperature. Relative umidity 6. % Air temperature. Relative umidity 6. % Amount of solar radiation.8 kw/m Average running speed [km/] Figure Performance of te advanced AI-EV --. ECONOMY Economic efficiency is evaluated by IRR (Internal Rate of Return)=.% of te new system wen te legal service life of te depreciation equipment is assumed years. Terefore, te new system can be widely spread in te future. 6.CONCLUSIONS A novel energy system wic is combined and integrated wit solar power, AI-EV and ome eat pumps as been proposed. Heat pumps are car air-conditioner and CO eat pump water eater for ome use. A matematical simulation model wic is integrated wit AI-EV model, CO eat pump model and HEX model based on some experiments as been developed to evaluate a smart community wic is constructed at an office and a ome. And ten, CO emissions and economic efficiency are calculated and compared wit tose of te conventional system. Te results are as follows ; Te novel energy system is able to reduce more tan % of CO emissions in comparison wit te conventional system as te wole system, and te system can reduce more tan 6% of CO emissions in comparison wit te conventional ome. Te driving distance of AI-EV extends by % according to te COP improvement from.8 of conventional airconditioner to. of advanced air-conditioner. Additionally, it is clarified tat te battery can reduce te fluctuations wic are caused by te PV power generation. Also eat pumps can effectively utilize for absorbing electric power variations wic are caused by supply and demand balance of energy. Te economic efficiency is evaluated more tan.% of Internal Rate of Return witout some subsidies wen te legal service life of te depreciation equipment is assumed years. Terefore, te novel energy system can be spread widely in te future. REFERENCES [] Noriiro K., Tsuguiko N., Kouiti S., Design Metod of PV and EV Combined System Using a HEX Model, Journal of Cemical Engineering of Japan, Vol. 8, No. 6, November, pp.- [] Yu N., Tsuguiko N., A Novel Concept of AI-EV for te Advanced Smart Community, proceedings of t HEFAT International Conference on Heat Transfer, Fluid Mecanics and Termodynamics, Orlando, USA,, July, pp.89-8 [] Masasi S., Tsuguiko N., Evaluation of advanced AI-EV, Proceedings of International Conference on Power Engineering e ICOPE- Yokoama, Japan, ICOPE--67, December pp.-8 [] Kyouei S., Seisirou S., Tsuguiko N., Air-conditioner Integrated Electric Veicle, Proceedings of te Japan Society Of Mecanical Engineers Termal Engineering Conference, Hirosaki, Japan, Paper number F, October [] J.Dong, J.Cen, Z.Cen, W. Zang, Y. Zou, Heat transfer and pressure drop correlations for te multi-louvered fin compact eat excanger, Energy Conversion and Management, vol.8, No., May (7), pp.6- [6] Ryoei Y., Takesi S., Kazuisa T., Koici I., Performance Analysis of a Hot Water Supply System wit a CO Heat Pump by Numerical Simulation, Journal of Japan Society of Mecanical Engineering(B), Vol.7, No.77, July, pp

8 t International Conference on Heat Transfer, Fluid Mecanics and Termodynamics [7] Kenici F., Automotive Air Conditioner Society of Engineers, Automotive Air-Conditioner. (9) edition Tokyo Denki University Press [8] Noriiro K., Tsuguiko N., Effective Metod of Renewable Energy by Using Electric Veicles and Evaluation by te HEX Model, Journal of Japan Society of Energy and Resources, Vol., No., June, pp8-6 [9] Japan Meteorological Agency, Climate Statistics (). ttp:// [] Ministry of te Environment, Publication of electric power companies-specific emission factors at. () ttp:// 8