Vol.3 No.3 2010
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Research paper : An optimum design method utilizing a strategic system design concept (J. Fukuda et al.)−193−Synthesiology - English edition Vol.3 No.3 (2010) shown below (Fig. 7).P2P1 EC2+TC2IC (1)Moreover, when the amount of reduced cost EC2 + TC2 is higher than the sum of environment measure investment IC and environment tax TC, the profit after measure P2 will be higher than the profit before environment tax P0, and the company will engage more actively in environment measure investment (Fig. 7).P2P0 EC2+TC2TC+IC (2)However, in practice, it is extremely difficult to fulfill the conditions of (1) and (2) by the effort of the datacenter company alone due to technological limitations.4.2.2 Two conditions for multiple companiesNext, value design is done for the case where the datacenter company X recovers waste heat energy and the greenhouse farmer Y reuses it.In this case, the environment measure investment will be conducted to improve the facility, if the total of the cost reduction by both parties EC2x + TC2x + EC2y + TC2y surpasses the total environment measure investment ICx + Icy.EC2x+TC2x+EC2y+TC2yICx+ICy (3)X and Y are different businesses, and they attain the advantage of significant cost reduction by Y reusing the waste heat from X. To reallocate the advantage between X and Y, it is necessary to conduct some monetary adjustment (AD). Here, the model considered is that in which the greenhouse farmer pays the adjustment cost AD to the datacenter company as the cost of used waste heat.EC2x+TC2x+ADICxEC2y+TC2y-ADICy (4)When condition (4) is fulfilled, X and Y can reduce the profit decrease due to the addition of external measures through investments ICx and ICy, and the two businesses can join hands to take measures (Fig. 8).Moreover, in the case of condition (5) shown below, the sum of the reduced costs of the two businesses EC2x + TC2x + EC2y + TC2y will be greater than the total of the environment tax and environment measure investment TCx + TCy + ICx + ICy, and both businesses can increase profit ability compared to before the imposition of the environment tax (Fig. 8).EC2x+TC2x+ADTCx+ICxEC2y+TC2y-ADTCy+ICy (5)To realize the composite system in which greenhouse farming uses the waste heat energy from the datacenter, it is necessary to introduce the facility cost ICy that fulfills the conditions of (4) or (5), the facility of ICx, as well as the adjustment cost AD.4.2.3 Value evaluation of the composite datacenter in case environment tax is imposedAssuming the case when environmental taxes are introduced by the social system that attempts to control emissions, calculations are done for the single datacenter and the composite datacenter in which the waste heat is used for greenhouse farming, using the model of environment tax rate 2,400 yen/t-CO2 (electricity 0.25 yen/kWh, kerosene 0.82 yen/L) assumed by the Ministry of Environment in October 2005Note 6). Assuming a single datacenter with 1,000 racks and 6 kW/rack located in Tokyo, the annual power consumption is 57,817 MWh. Other than the annual electricity cost EC = 693,807 thousand yen, the annual environment tax TC = 14,454 thousand yen will be required.When capping, the most effective measure, is done, the annual power consumption will be 54,697 MWh, and this will be a power cost reduction (EC2) of 37,437 thousand yen per year and an environment tax reduction (TC2) of 780 thousand yen per year. However, the acceptable upper limit of the facility investment IC for CO2 reduction must be less than 38,217 thousand yen per year. The investment per rack Fig. 7 Earnings from a single datacenterAfter imposition of environment taxFirst condition of environment measure investmentSecond condition of environment measure investmentSSales¥ECEnergycostECEnergycostEC2EnergycostEC2EnergycostP0ProfitP1ProfitP2ProfitP2ProfitTCEnvironmenttaxTC2EnvironmenttaxTC2EnvironmenttaxICEnvironmentmeasureinvestmentICEnvironment measureinvestment-ΔTC2-ΔEC2SSales1,000yenBefore impositionof environment taxAfter impositionof environment taxReuse of waste heatADAdjustmentcost-173,000DatacenterGreenhousefarmingAdjustmentcostECyEnergycost189,734=0689,009Px1Profit14,35480,000189,734Py1Py2ECxEnergycostADAdjustmentcost173,000Px2689,009189,734689,009ICy8,100ICy8,10014,354Px0ProfitPy0ProfitTCy1,402ECxEnergycostECyEnergycostPyProfitPy0+8,634Px0+78,646ECxEnergycostECyEnergycostECxEnergycost14,35480,000ECエネルギーコストDatacenterGreenhousefarmingDatacenterGreenhousefarmingGreenhousefarmingDatacenterEnvironmenttaxTCxEnvironmenttaxTCxEnvironmenttaxTCxEnvironmentmeasureinvestmentICxEnvironmentmeasure costICxFig. 8 Earnings from a composite datacenter

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