# open the class to add methods to return sizing values
class OpenStudio::Model::FanOnOff

  # Sets the fan pressure rise based on the Prototype buildings inputs
  # which are governed by the flow rate coming through the fan
  # and whether the fan lives inside a unit heater, PTAC, etc.
  def setPrototypeFanPressureRise(building_type, building_vintage, climate_zone)
    
    # Get the max flow rate from the fan.
    maximum_flow_rate_m3_per_s = nil
    if self.maximumFlowRate.is_initialized
      maximum_flow_rate_m3_per_s = self.maximumFlowRate.get
    elsif self.autosizedMaximumFlowRate.is_initialized
      maximum_flow_rate_m3_per_s = self.autosizedMaximumFlowRate.get
    else
      OpenStudio::logFree(OpenStudio::Warn, "openstudio.prototype.FanOnOff", "For #{self.name} max flow rate is not available, cannot apply prototype assumptions.")
      return false
    end
    
    # Convert max flow rate to cfm
    maximum_flow_rate_cfm = OpenStudio.convert(maximum_flow_rate_m3_per_s, "m^3/s", "cfm").get
    
    # Pressure rise will be determined based on the 
    # following logic.
    pressure_rise_in_h2o = 0.0
    
    # If the fan lives inside of a zone hvac equipment
    if self.containingZoneHVACComponent.is_initialized
      zone_hvac = self.containingZoneHVACComponent.get
      if zone_hvac.to_ZoneHVACPackagedTerminalAirConditioner.is_initialized
        pressure_rise_in_h2o = 1.33
      elsif zone_hvac.to_ZoneHVACFourPipeFanCoil.is_initialized
        pressure_rise_in_h2o = 1.087563267
      elsif zone_hvac.to_ZoneHVACUnitHeater.is_initialized
        pressure_rise_in_h2o = 0.2
      else # This type of fan should not exist in the prototype models
        return false
      end
    end
    
    # If the fan lives on an airloop
    if self.airLoopHVAC.is_initialized
      case building_vintage
      when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004'
        if maximum_flow_rate_cfm < 7437
          pressure_rise_in_h2o = 2.5
        elsif maximum_flow_rate_cfm >= 7437 && maximum_flow_rate_cfm < 20000
          pressure_rise_in_h2o = 4.46
        else # Over 20,000 cfm
          pressure_rise_in_h2o = 4.09
        end
      when '90.1-2007', '90.1-2010', '90.1-2013'
        if maximum_flow_rate_cfm < 7437
          pressure_rise_in_h2o = 2.5
        else # Over 7,437 cfm
          pressure_rise_in_h2o = 4.09
        end
      end
    end

    # If the fan lives inside a unitary system
    if self.airLoopHVAC.empty? && self.containingZoneHVACComponent.empty?
      case building_vintage
      when 'DOE Ref Pre-1980', 'DOE Ref 1980-2004', '90.1-2004'
        if maximum_flow_rate_cfm < 7437
          pressure_rise_in_h2o = 2.5
        elsif maximum_flow_rate_cfm >= 7437 && maximum_flow_rate_cfm < 20000
          pressure_rise_in_h2o = 4.46
        else # Over 20,000 cfm
          pressure_rise_in_h2o = 4.09
        end
      when '90.1-2007', '90.1-2010', '90.1-2013'
        if maximum_flow_rate_cfm < 7437
          pressure_rise_in_h2o = 2.5
        else # Over 7,437 cfm
          pressure_rise_in_h2o = 4.09
        end
      end
    end
    
    # Set the fan pressure rise
    pressure_rise_pa = OpenStudio.convert(pressure_rise_in_h2o, "inH_{2}O","Pa").get
    self.setPressureRise(pressure_rise_pa)  
    
    OpenStudio::logFree(OpenStudio::Info, "openstudio.prototype.FanOnOff", "For Prototype: #{self.name}: #{maximum_flow_rate_cfm.round}cfm; Pressure Rise = #{pressure_rise_in_h2o}in w.c.")
    
    return true
    
  end

end