SIMPLE EEC CALCULATION METHOD FOR BUILDINGS BASED ON INPUT-OUTPUT ANALYSISE Keizo YOKOYAMA, Tatsuo OKA, Noriyoshi YOKOO Kogakuin University, Utsunomiya University, Japan

Introduction When buildings change to ZEB/ZEH, the environmental loads related to construction account for a large part of the life cycle load. The reduction of EEC becomes important. Simple calculation method in order to evaluate EEC at design stage is proposed.

Outline of calculation procedure Calculate the mass / volume of each materials / equipments by measuring drawings or quotation. Quantity of materials x Use EEC coefficients stored in the database. Multiply quantity of materials by EEC coefficients. EE & EC coefficients(intensity) + Calculate using delivery distances for each material from manufacture gate to site. Transport + Site activity Based on contractors historical data. = EEC at construction stage Add the above embodied impacts

Why simple calculation needed? In order to reduce EEC, it is effective to estimate EEC at an early design stage. In that time, it is difficult to get the amount of materials or equipments totally. The EEC shall be calculated focusing on the amount of materials and equipment by pinpointing in the building where a great deal of energy consumption and CO2 emissions would occur.

Materials and equipment for simple calculation The equipment and materials are total 18 items as shown in Table Item Name of materials and equipment Unit Building Structure Concrete Volume (m3) Steel bar Weight (t) Outer wall finishing Tile Area (m2) or Price Metal window frame Insulation Fluorocarbon Weight (kg) Internal finishing Gross floor area (m2) Other work for building Price or Gross floor area Electric Equipment Capacity (kVA) or Price Lighting fixtures Quantity Other work for electric HVAC Chillers Capacity (kW) or Price Air conditioners Other work for HVAC Plumbing Plumbing work Lift Site work Temporary work, electricity bill

Simple calculation sheet (Initial) Item Name of materials and equipment Quan-tity Unit EE　coefficient EC coefficient Initial EE Initial EC MJ/Unit kg-CO2/unit GJ t-CO2 Building Structure Concrete A B C D=A*B E=A*C Steel bars Outer wall finishing Tiles Metal window frames Insulation Fluorocarbon gases 1,030 (R245fa) ： Lifts Site work Temporary work, electricity bill Total 18 items

Simple calculation sheet (Lifecycle) Item Name of materials and equipment Initial EE Initial EC Maintenance ratio No. of Times Replaced Demolition Lifecycle　EE Lifecycle EC GJ t-CO2 Building Struc-ture Concrete D E F G H I J Steel bars Outer wall finish-ing Tiles Metal window frames Insulation Fluorocarbon gases ： Lifts Site work Temporary work, electricity bill Total I=1+D*(F*years +G+H) 18 items J=1+E*(F*years +G+H)

EEC coefficients (Intensities) Database: 1)Process based method, 2)Input-output analysis, 3)Hybrid method. (Depending on the user) Fluorocarbon gas: content in the insulation material, chiller and air-conditioner. The coefficients of site work, interior finishing work and other works are obtained according to detail calculation results of some buildings.

Type of fluorocarbon gas Intensity of refrigerants Type of fluorocarbon gases and their content rates in Insulators Thermal conductivity W/(m·K) Density kg/m3 Type of fluorocarbon gas GWP (-) Content rate (%) Expanded polystyrene 0.034 29 R-134a 1,430 2.7 Urethane foam (board-shaped) 0.028 30 R-245fa 1,030 4.7 Urethane foam (foamed on-site) 7.3 Emissions factor and collection rate by refrigerator Name of Equipment Intensity of refrigerants [kg/kWth] CO2 emissions factor Recovery efficiency IPCC Guideline Japan Chillers 0.33 2%-15% 6%-7% 30% Residential and commercial A/C 1%-10% 2%-5%

Sample Calculation Outline of building Building life time : 60 years Intended use Library Location Japan Structure Reinforced-concrete No. of stories 3 stories Site Area 849.37m2 Gross floor aria 2412.99m2 Electrical equipment Receiving high voltage electricity: 125kVA, Lighting and consent, Broadcast and telephone equipment, Disaster prevention system Air-conditioning equipment Air cooled chiller, Gas heat-pump-unit, FCU on each floor Water supply and drainage sanitation System for direct connection to water supply, Sanitary facilities, City gas equipment Elevator facilities 750kg x 1 unit.

Result of simple calculation(Initial) Item Name of materials and equipment Quantity Unit EE coeffi cient EC coeffi Initial EE Initial EC MJ/unit kg-CO2/unit GJ t-CO2 Building   Structure Concrete 1,729 m3 1,295 267 2,239 462 Steel bars 220 t 14100 1360 3,102 299 Outer Wall finishing Tiles 4.426 106Yen 54,376 3,500 241 15 Metal window frames 13.256 35,353 2,878 469 38 Insulation 0.754 44,584 3,057 34 2 Fluorocarbon gases kg 1030 Internal finishing 2,413 m2GFA 733 59 1,769 142 Other work for building 37.437 26,500 2,100 992 79 Subtotal 8,845 1,038 Electric Transformers 0.341 21,509 1,727 7 1 Switching boards 3.433 22,878 1,780 6 Lighting 557 Nos. 85.6 6.2 48 3 Other work for electric 16.642 441 35 575 45 HVAC Chillers 8.440 23,502 1,808 198 Air conditioners 11.081 260 20 26 2,090 54 Other work for HVAC 24.800 657 52 1,116 Plumbing 10.965 291 23 Lifts 6.300 28,735 2,359 181 Site work Temporary work, electricity bill 431 33 1,040 80 Total 12,047 1,342 per GFA /m2 4.993 0.556

Result of simple calculation(60 years) Item Name of materials and equipment Initial EE Initial EC Mainte-nance Number of Times Replaced Demoli-tion Lifecycle　EE Lifecycle EC GJ t-CO2 Building   Structure Concrete 2,239 462 Steel bars 3,102 299 Outer wall finishing Tiles 241 15 Metal window frames 469 38 1 937 76 Insulation 34 2 67 5 Fluorocarbon gases Internal finishing 1,769 142 5,306 427 Other work for building 992 79 3 3,968 314 Subtotal 8,845 1,038 15,861 1,599 Electric Transformers 7 Switching boards 6 236 18 Lighting 48 286 21 Other work for electric 441 35 1,323 105 575 45 1,859 145 HVAC Chillers 198 595 46 Air conditioners 260 20 781 60 54 2% 70% 141 Other work for HVAC 657 52 1,972 156 1,116 3,348 403 Plumbing 291 23 872 69 Lifts 181 543 Site work Temporary work, electricity bill 1,040 80 Total 12,047 1,342 23,523 2,341 per GFA /m2 4.993 0.556 9.748 0.970

Result of calculation EE is 5GJ/m2 at initial stage, and 14 GJ/m2 at lifecycle. EC is 600 kg-CO2 /m2 at initial stage, and 1400 kg-CO2/m2 at lifecycle. Building work is account for large part of total emissions. Embodied Energy Embodied CO2 Initial Lifecycle Initial Lifecycle

Comparison with the simple and detailed calculation method Table shows comparison of the simple calculation method and the result of the detailed calculation. The difference between simple calculation and detail calculation is only 4%. The simple calculation method is good enough to evaluate EEC. Method Simple Calculation Detailed Calculation MJ kg-CO2  Total 12,047,000 1,342,000 12,568,761 1,367,120 96% 98% 100%

Conclusion This study proposes a simple calculation method. The selected equipment and materials are total 18 items only. It is calculate that the fluorocarbon gas include in insulation material and air conditioners. EEC calculation accuracy is relatively high.

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