Module: BrighterPlanet::Meeting::CarbonModel

Defined in:
lib/meeting/carbon_model.rb

Class Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/meeting/carbon_model.rb', line 27

def self.included(base)
  base.decide :emission, :with => :characteristics do
    ### Emission calculation
    # Returns the `emission` estimate (*kg CO<sub>2</sub>e*).
    # This is the total emission produced by the meeting venue.
    committee :emission do
      #### Emission from duration, area, and emission factor
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Multiplies `area` (*square m*) by `duration` (*hours*) and the `emission factor` (*kg CO<sub>2</sub>e / square m hour*) to give *kg CO<sub>2</sub>e*.
      quorum 'from duration, area, and emission factor', :needs => [:duration, :area, :emission_factor] do |characteristics|
        characteristics[:duration] * characteristics[:area] * characteristics[:emission_factor]
      end
      
      #### Default emission
      # **Complies:**
      #
      # Displays an error if the previous method fails.
      quorum 'default' do
        raise "The emission committee's default quorum should never be called"
      end
    end
    
    ### Emission factor calculation
    # Returns the `emission factor` (*lbs CO<sub>2</sub>e / square m hour).
    committee :emission_factor do
      #### Emission factor from fuel intensities and eGRID subregion
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # - Looks up the [natural gas](http://data.brighterplanet.com/fuels) emission factor (*kg CO<sub>2</sub>e / cubic m*)
      # - Looks up the [fuel oil](http://data.brighterplanet.com/fuels) emission factor (*kg CO<sub>2</sub>e / l*)
      # - Looks up the [eGRID subregion](http://data.brighterplanet.com/egrid_subregions) electricity emission factor
      # - Divides the natural gas emission factor (*kg CO<sub>2</sub>e / cubic m*) by the natural gas energy content (38,339,000 *J / cubic m*) to give an energy-based natural gas emission factor (*kg CO<sub>2</sub>e / J*)
      # - Divides the fuel oil emission factor (*kg CO<sub>2</sub>e / l*) by the fuel oil energy content (38,655,000 *J / l*) to give an energy-based fuel oil emission factor (*kg CO<sub>2</sub>e / J*)
      # - Divides the energy-based natural gas emission factor by 0.817 and the energy-based fuel oil emission factor by 0.846, adds these together and divides by 2, and divides by 0.95. This gives a district heat emission factor (*kg CO<sub>2</sub>e / J*) based on the assumption that district heat is produced by 50% natural gas and 50% fuel oil, natural gas boilers are 81.7% efficient, fuel oil boilers are 84.6% efficient, and transmission losses are 5%.
      # - Multiplies `natural gas intensity` by the natural gas emission factor, `fuel oil intensity` by the fuel oil emission factor, `electricity intensity` by the electricity emission factor, and `district heat intensity` by the district heat emission factor
      # - Adds these together
      quorum 'from eGRID subregion and fuel intensities', :needs => [:egrid_subregion, :natural_gas_intensity, :fuel_oil_intensity, :electricity_intensity, :district_heat_intensity] do |characteristics|
        natural_gas = FuelType.find_by_name "Commercial Natural Gas"
        fuel_oil = FuelType.find_by_name "Distillate Fuel Oil 2"
        natural_gas_energy_ef = natural_gas.emission_factor / 38_339_000
        fuel_oil_energy_ef = fuel_oil.emission_factor / 38_655_000
        district_heat_emission_factor = (((natural_gas_energy_ef / 0.817) / 2) + ((fuel_oil_energy_ef / 0.846) / 2)) / 0.95
        
        (characteristics[:natural_gas_intensity] * natural_gas.emission_factor) +
          (characteristics[:fuel_oil_intensity] * fuel_oil.emission_factor) +
          (characteristics[:electricity_intensity] * characteristics[:egrid_subregion].electricity_emission_factor) +
          (characteristics[:district_heat_intensity] * district_heat_emission_factor)
      end
    end
    
    ### Natural gas intensity calculation
    # Returns the meeting venue's `natural gas intensity` (*cubic m / square m hour*).
    committee :natural_gas_intensity do # returns cubic metres per square metre hour
      #### From census division
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [census division](http://data.brighterplanet.com/census_divisions) meeting building `natural gas intensity` (*cubic m / square m hour*).
      quorum 'from census division', :needs => :census_division do |characteristics|
        characteristics[:census_division].meeting_building_natural_gas_intensity
      end
      
      #### Default natural gas intensity
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Uses the U.S. average `natural gas intensity` (*cubic m / square m hour*).
      quorum 'default' do
        CensusDivision.fallback.meeting_building_natural_gas_intensity
      end
    end
    
    ### Fuel oil intensity calculation
    # Returns the meeting venue's `fuel oil intensity` (*l / square m hour*).
    committee :fuel_oil_intensity do
      #### Fuel oil intensity from census division
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [census division](http://data.brighterplanet.com/census_divisions) meeting building `fuel oil intensity` (*l / square m hour*).
      quorum 'from census division', :needs => :census_division do |characteristics|
        characteristics[:census_division].meeting_building_fuel_oil_intensity
      end
      
      #### Default fuel oil intensity
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Uses the U.S. average `fuel oil intensity` (*l / square m hour*).
      quorum 'default' do
        CensusDivision.fallback.meeting_building_fuel_oil_intensity
      end
    end
    
    ### Electricity intensity calculation
    # Returns the meeting venue's `electricity intensity` (*kWh / square m hour*).
    committee :electricity_intensity do
      #### Electricity intensity from census division and eGRID region
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # - Looks up the [census division](http://data.brighterplanet.com/census_divisions) meeting building `electricity intensity` (*kWh / square m hour*)
      # - Looks up the [eGRID region](http://data.brighterplanet.com/egrid_regions) loss factor
      # - Divides the `electricity intensity` by 1 - the loss factor to account for electricity transmission and distribution losses
      quorum 'from eGRID region and census division', :needs => [:egrid_region, :census_division] do |characteristics|
        characteristics[:census_division].meeting_building_electricity_intensity / (1 - characteristics[:egrid_region].loss_factor)
      end
      
      #### Electricity intensity from eGRID region
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # - Uses the U.S. average meeting building `electricity intensity` (*kWh / square m hour*)
      # - Looks up the [eGRID region](http://data.brighterplanet.com/egrid_regions) loss factor
      # - Divides the `electricity intensity` by (1 - the loss factor) to account for electricity transmission and distribution losses
      quorum 'from eGRID region', :needs => :egrid_region do |characteristics|
        CensusDivision.fallback.meeting_building_electricity_intensity / (1 - characteristics[:egrid_region].loss_factor)
      end
    end
    
    ### District heat intensity calculation
    # Returns the meeting venue's `district heat intensity` (*J / square m hour*)
    committee :district_heat_intensity do
      #### District heat intensity from census division
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [census division](http://data.brighterplanet.com/census_divisions) meeting building `district heat intensity`.
      quorum 'from census division', :needs => :census_division do |characteristics|
        characteristics[:census_division].meeting_building_district_heat_intensity
      end
      
      #### Default district heat intensity
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Uses the U.S. average.
      quorum 'default' do
        CensusDivision.fallback.meeting_building_district_heat_intensity
      end
    end
    
    ### eGRID region calculation
    # Returns the meeting venue's [eGRID region](http://data.brighterplanet.com/egrid_regions).
    committee :egrid_region do
      #### eGRID region from eGRID subregion
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [eGRID subregion](http://data.brighterplanet.com/egrid_subregions) `eGRID region`.
      quorum 'from eGRID subregion', :needs => :egrid_subregion do |characteristics|
        characteristics[:egrid_subregion].egrid_region
      end
    end
    
    ### eGRID subregion calculation
    # Returns the meeting venue's [eGRID subregion](http://data.brighterplanet.com/egrid_subregions).
    committee :egrid_subregion do
      #### eGRID subregion from zip code
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [zip code](http://data.brighterplanet.com/zip_codes) `eGRID subregion`.
      quorum 'from zip code', :needs => :zip_code do |characteristics|
        characteristics[:zip_code].egrid_subregion
      end
      
      #### Default eGRID subregion
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Uses an artificial eGRID subregion that represents the U.S. average.
      quorum 'default' do
        EgridSubregion.find_by_abbreviation 'US'
      end
    end
    
    ### Census division calculation
    # Returns the meeting venue's [census division](http://data.brighterplanet.com/census_divisions).
    committee :census_division do
      #### Census division from state
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [state](http://data.brighterplanet.com/states) `census division`.
      quorum 'from state', :needs => :state do |characteristics|
        characteristics[:state].census_division
      end
    end
    
    ### State calculation
    # Returns the meeting venue's [state](http://data.brighterplanet.com/states).
    committee :state do
      #### State from zip code
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [zip code](http://data.brighterplanet.com/zip_codes) `state`.
      quorum 'from zip code', :needs => :zip_code do |characteristics|
        characteristics[:zip_code].state
      end
    end
    
    ### Zip code calculation
    # Returns the meeting venue's [zip code](http://data.brighterplanet.com/zip_codes).
      #### Zip code from client input
      # **Complies:** All
      #
      # Uses the client-input [zip code](http://data.brighterplanet.com/zip_codes).
    
    ### Area calculation
    # Returns the meeting venue's `area` (*square m*).
    committee :area do
      #### Area from client input
      # **Complies:** All
      #
      # Uses the client-input `area` (*square m*).
      
      #### Default area
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Uses a default `area` of 1,184.5 *square m*.
      # This is the median size of buildings in the [EIA Commercial Building Energy Consumption Survey](http://www.eia.doe.gov/emeu/cbecs/).
      quorum 'default' do
        base.fallback.area
      end
    end
    
    ### Duration calculation
    # Returns the meeting's `duration` (hours).
    committee :duration do
      #### Duration from client input
      # **Complies:** All
      #
      # Uses the client-input `duration` (*hours*).
      
      #### Default duration
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Uses a default `duration` of 8 *hours*.
      quorum 'default' do
        8
      end
    end
  end
end