Module: BrighterPlanet::BusTrip::CarbonModel

Defined in:
lib/bus_trip/carbon_model.rb

Class Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/bus_trip/carbon_model.rb', line 22

def self.included(base)
  base.decide :emission, :with => :characteristics do
    ### Emission calculation
    # Returns the `emission` estimate (*kg CO<sub>2</sub>e*)
    committee :emission do
      #### Emission from fuel, emission factors, and passengers
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # - Multiplies diesel consumed (*l*) by the diesel emission factor (*kg CO<sub>2</sub>e / l*) to give diesel emissions (*kg CO<sub>2</sub>e*)
      # - Multiplies alternaive fuel consumed (*l*) by the alternative fuels emission factor (*kg CO<sub>2</sub>e / l*) to give alternative fuels emissions (*kg CO<sub>2</sub>e*)
      # - Multiplies distance (*km*) by the air conditioning emission factor (*kg CO<sub>2</sub>e / km*) to give air conditioning emissions (*kg CO<sub>2</sub>e*)
      # - Sums the diesel, alternative fuels, and air conditioning emissions and divides by passengers to give emissions per passenger (*kg CO<sub>2</sub>e*)
      quorum 'from fuels, emission factors, and passengers', :needs => [:diesel_consumed, :diesel_emission_factor, :alternative_fuels_consumed, :alternative_fuels_emission_factor, :distance, :air_conditioning_emission_factor, :passengers] do |characteristics|
        (characteristics[:diesel_consumed] * characteristics[:diesel_emission_factor] + characteristics[:alternative_fuels_consumed] * characteristics[:alternative_fuels_emission_factor] + characteristics[:distance] * characteristics[:air_conditioning_emission_factor]) / characteristics[:passengers]
      end
    end
    
    ### Air conditioning emission factor calculation
    # Returns the `air conditioning emission factor` (*kg CO<sub>2</sub>e / km*).
    # This is used to account for fugitive emissions of air conditioning refrigerants.
    committee :air_conditioning_emission_factor do
      #### Air conditioning emission factor from bus class
      # **Complies:** GHG Protocol, ISO 14046-1, Climate Registry Protocol
      #
      # Looks up the [bus class](http://data.brighterplanet.com/bus_classes) `air conditioning emission factor` (*kg CO<sub>2</sub>e / km*).
      quorum 'from bus class', :needs => :bus_class do |characteristics|
        characteristics[:bus_class].air_conditioning_emission_factor
      end
    end
    
    ### Diesel emission factor calculation
    # Returns the `diesel emission factor` (*kg CO<sub>2</sub>e / l*).
    committee :diesel_emission_factor do
      #### Default diesel emission factor
      # **Complies:** GHG Protocol, ISO 14046-1, Climate Registry Protocol
      #
      # Looks up [Distillate Fuel Oil 2](http://data.brighterplanet.com/fuel_types)'s `emission factor` (*kg CO<sub>2</sub>e / l*).
      quorum 'default' do
        diesel = FuelType.find_by_name "Distillate Fuel Oil 2"
        diesel.emission_factor
      end
    end
    
    ### Alternative fuels emission factor calculation
    # Returns the `alternative fuels emission factor` (*kg CO<sub>2</sub>e / l*).
    committee :alternative_fuels_emission_factor do
      #### Default alternative fuels emission factor
      # **Complies:** GHG Protocol, ISO 14046-1, Climate Registry Protocol
      #
      # Uses an `alternative fuels emission factor` of 1.17 *kg CO<sub>2</sub>e / l*.
      quorum 'default' do
        9.742.pounds_per_gallon.to(:kilograms_per_litre)
      end
    end
    
    ### Diesel consumed calculation
    # Returns the `diesel consumed` (*l*).
    committee :diesel_consumed do
      #### Diesel consumed from distance and diesel intensity
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Multiplies `distance` (*km*) by `diesel intensity` (*l / km*) to give *l*.
      quorum 'from distance and diesel intensity', :needs => [:distance, :diesel_intensity] do |characteristics|
        characteristics[:distance] * characteristics[:diesel_intensity]
      end
    end
    
    ### Alternative fuels consumed calculation
    # Returns the `alternative fuels consumed` (*l*).
    committee :alternative_fuels_consumed do
      #### Alternative fuels consumed from distance and alternative fuels intensity
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Multiplies `distance` (*km*) by `alternative fuels intensity` (*l / km*) to give *l*.
      quorum 'from distance and alternative fuels intensity', :needs => [:distance, :alternative_fuels_intensity] do |characteristics|
        characteristics[:distance] * characteristics[:alternative_fuels_intensity]
      end
    end
    
    ### Distance calculation
    # Returns the `distance` travelled (*km*).
    committee :distance do
      #### Distance from client input
      # **Complies:** All
      #
      # Uses the client-input `distance` (*km*).
      
      #### Distance from duration and speed
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Divides `duration` (*minutes*) by 60 and multiplies by `speed` (*km / hour*) to give *km*.
      quorum 'from duration and speed', :needs => [:duration, :speed] do |characteristics|
        characteristics[:duration] / 60 * characteristics[:speed]
      end
      
      #### Distance from bus class
      # **Complies:**
      #
      # Looks up the [bus class](http://data.brighterplanet.com/bus_classes) `distance` (*km*).
      quorum 'from bus class', :needs => :bus_class do |characteristics|
        characteristics[:bus_class].distance
      end
    end
    
    ### Speed calculation
    # Returns the average `speed` (*km / hour*).
    committee :speed do
      #### Speed from bus class
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [bus class](http://data.brighterplanet.com/bus_classes)' average `speed` (*km / hour*).
      quorum 'from bus class', :needs => :bus_class do |characteristics|
        characteristics[:bus_class].speed
      end
    end
    
    ### Duration calculation
    # Returns the trip's `duration` (*minutes*).
      #### Duration from client input
      # **Complies:** All
      #
      # Uses the client-input `duration` (*minutes*).
    
    ### Diesel intensity calculation
    # Returns the `diesel intensity` (*l / km*).
    committee :diesel_intensity do
      #### Diesel intensity from bus class
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [bus class](http://data.brighterplanet.com/bus_classes) `diesel intensity` (*l / km*).
      quorum 'from bus class', :needs => :bus_class do |characteristics|
        characteristics[:bus_class].diesel_intensity
      end
    end
    
    ### Alternative fuels intensity calculation
    # Returns the `alternative fuels intensity` (*l / km*).
    committee :alternative_fuels_intensity do
      #### Alternative fuels intensity from bus class
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [bus class](http://data.brighterplanet.com/bus_classes) `alternative fuels intensity` (*l / km*).
      quorum 'from bus class', :needs => :bus_class do |characteristics|
        characteristics[:bus_class].alternative_fuels_intensity
      end
    end
    
    ### Passengers calculation
    # Returns the number of `passengers` on the bus.
    committee :passengers do
      #### Passengers from bus class
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Looks up the [bus class](http://data.brighterplanet.com/bus_classes)' average number of `passengers`.
      quorum 'from bus class', :needs => :bus_class do |characteristics|
        characteristics[:bus_class].passengers
      end
    end
    
    ### Bus class calculation
    # Returns the `bus class`.
    # This is the type of bus used.
    committee :bus_class do
      #### From client input
      # **Complies:** All
      #
      # Uses the client-input [bus class](http://data.brighterplanet.com/bus_classes).
      
      #### Default bus class
      # **Complies:** GHG Protocol, ISO 14064-1, Climate Registry Protocol
      #
      # Uses an artificial [bus class](http://data.brighterplanet.com/bus_classes) that represents the U.S. average.
      quorum 'default' do
        BusClass.fallback
      end
    end
  end
end