Module: PrototypeFan

Included in:
Standard
Defined in:
lib/openstudio-standards/prototypes/common/objects/Prototype.Fan.rb

Overview

Prototype fan calculation methods that are the same regardless of fan type. These methods are available to FanConstantVolume, FanOnOff, FanVariableVolume, and FanZoneExhaust

Fan collapse

Class Method Details

.apply_base_fan_variables(fan, fan_name: nil, fan_efficiency: nil, pressure_rise: nil, end_use_subcategory: nil) ⇒ OpenStudio::Model::StraightComponent

fan class method to apply fan variables

Parameters:

  • fan (OpenStudio::Model::StraightComponent) —

    fan object of type: FanConstantVolume, FanOnOff, FanVariableVolume, and FanZoneExhaust

  • fan_name (String) (defaults to: nil) —

    fan name

  • fan_efficiency (Double) (defaults to: nil) —

    fan efficiency

  • pressure_rise (Double) (defaults to: nil) —

    fan pressure rise in Pa

  • end_use_subcategory (String) (defaults to: nil) —

    end use subcategory name

Returns:

  • (OpenStudio::Model::StraightComponent) —

    fan object



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# File 'lib/openstudio-standards/prototypes/common/objects/Prototype.Fan.rb', line 83

def self.apply_base_fan_variables(fan,
                                  fan_name: nil,
                                  fan_efficiency: nil,
                                  pressure_rise: nil,
                                  end_use_subcategory: nil)
  fan.setName(fan_name) unless fan_name.nil?
  fan.setFanEfficiency(fan_efficiency) unless fan_efficiency.nil?
  fan.setPressureRise(pressure_rise) unless pressure_rise.nil?
  fan.setEndUseSubcategory(end_use_subcategory) unless end_use_subcategory.nil?
  return fan
end

Instance Method Details

#create_fan_by_name(model, standards_name, fan_name: nil, fan_efficiency: nil, pressure_rise: nil, motor_efficiency: nil, motor_in_airstream_fraction: nil, fan_power_minimum_flow_rate_input_method: nil, fan_power_minimum_flow_rate_fraction: nil, fan_power_coefficient_1: nil, fan_power_coefficient_2: nil, fan_power_coefficient_3: nil, fan_power_coefficient_4: nil, fan_power_coefficient_5: nil, system_availability_manager_coupling_mode: nil, end_use_subcategory: nil) ⇒ OpenStudio::Model::StraightComponent

create a fan with properties for a fan name in the standards data

Parameters:

  • fan_name (String) (defaults to: nil) —

    fan name

  • fan_efficiency (Double) (defaults to: nil) —

    fan efficiency

  • pressure_rise (Double) (defaults to: nil) —

    fan pressure rise in Pa

  • end_use_subcategory (String) (defaults to: nil) —

    end use subcategory name

Returns:

  • (OpenStudio::Model::StraightComponent) —

    fan object



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# File 'lib/openstudio-standards/prototypes/common/objects/Prototype.Fan.rb', line 137

def create_fan_by_name(model,
                       standards_name,
                       fan_name: nil,
                       fan_efficiency: nil,
                       pressure_rise: nil,
                       motor_efficiency: nil,
                       motor_in_airstream_fraction: nil,
                       fan_power_minimum_flow_rate_input_method: nil,
                       fan_power_minimum_flow_rate_fraction: nil,
                       fan_power_coefficient_1: nil,
                       fan_power_coefficient_2: nil,
                       fan_power_coefficient_3: nil,
                       fan_power_coefficient_4: nil,
                       fan_power_coefficient_5: nil,
                       system_availability_manager_coupling_mode: nil,
                       end_use_subcategory: nil)

  fan_json = get_fan_from_standards(standards_name: standards_name)

  case fan_json['type']
  when 'ConstantVolume'
    create_fan_constant_volume_from_json(model,
                                         fan_json,
                                         fan_name: fan_name,
                                         fan_efficiency: fan_efficiency,
                                         pressure_rise: pressure_rise,
                                         motor_efficiency: motor_efficiency,
                                         motor_in_airstream_fraction: motor_in_airstream_fraction,
                                         end_use_subcategory: end_use_subcategory)
  when 'OnOff'
    create_fan_on_off_from_json(model,
                                fan_json,
                                fan_name: fan_name,
                                fan_efficiency: fan_efficiency,
                                pressure_rise: pressure_rise,
                                motor_efficiency: motor_efficiency,
                                motor_in_airstream_fraction: motor_in_airstream_fraction,
                                end_use_subcategory: end_use_subcategory)
  when 'VariableVolume'
    fan_power_coefficient_1, fan_power_coefficient_2, fan_power_coefficient_3, fan_power_coefficient_4, fan_power_coefficient_5 = lookup_fan_curve_coefficients_from_json(fan_json['fan_curve']) if fan_json['fan_curve']
    create_fan_variable_volume_from_json(model,
                                         fan_json,
                                         fan_name: fan_name,
                                         fan_efficiency: fan_efficiency,
                                         pressure_rise: pressure_rise,
                                         motor_efficiency: motor_efficiency,
                                         motor_in_airstream_fraction: motor_in_airstream_fraction,
                                         fan_power_minimum_flow_rate_input_method: fan_power_minimum_flow_rate_input_method,
                                         fan_power_minimum_flow_rate_fraction: fan_power_minimum_flow_rate_fraction,
                                         fan_power_coefficient_1: fan_power_coefficient_1,
                                         fan_power_coefficient_2: fan_power_coefficient_2,
                                         fan_power_coefficient_3: fan_power_coefficient_3,
                                         fan_power_coefficient_4: fan_power_coefficient_4,
                                         fan_power_coefficient_5: fan_power_coefficient_5,
                                         end_use_subcategory: end_use_subcategory)
  when 'ZoneExhaust'
    create_fan_zone_exhaust_from_json(model,
                                      fan_json,
                                      fan_name: fan_name,
                                      fan_efficiency: fan_efficiency,
                                      pressure_rise: pressure_rise,
                                      system_availability_manager_coupling_mode: system_availability_manager_coupling_mode,
                                      end_use_subcategory: end_use_subcategory)
  end
end

#get_fan_from_standards(standards_name: nil, type: nil, fan_efficiency: nil, pressure_rise: nil, motor_efficiency: nil, motor_in_airstream_fraction: nil, fan_power_minimum_flow_rate_input_method: nil, fan_power_coefficient_1: nil, fan_power_coefficient_2: nil, fan_power_coefficient_3: nil, fan_power_coefficient_4: nil, fan_power_coefficient_5: nil, system_availability_manager_coupling_mode: nil, end_use_subcategory: nil) ⇒ Object

Parameters:

  • fan_efficiency (Double) (defaults to: nil) —

    fan efficiency

  • pressure_rise (Double) (defaults to: nil) —

    fan pressure rise in Pa



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# File 'lib/openstudio-standards/prototypes/common/objects/Prototype.Fan.rb', line 97

def get_fan_from_standards(standards_name: nil,
                           type: nil,
                           fan_efficiency: nil,
                           pressure_rise: nil,
                           motor_efficiency: nil,
                           motor_in_airstream_fraction: nil,
                           fan_power_minimum_flow_rate_input_method: nil,
                           fan_power_coefficient_1: nil,
                           fan_power_coefficient_2: nil,
                           fan_power_coefficient_3: nil,
                           fan_power_coefficient_4: nil,
                           fan_power_coefficient_5: nil,
                           system_availability_manager_coupling_mode: nil,
                           end_use_subcategory: nil)
  search_criteria = {}
  standards_name ? search_criteria['name'] = standards_name : search_criteria['name'] = 'default'
  if type then search_criteria['type'] = type end
  if fan_efficiency then search_criteria['fan_efficiency'] = fan_efficiency end
  if pressure_rise then search_criteria['pressure_rise'] = pressure_rise end
  if motor_efficiency then search_criteria['motor_efficiency'] = motor_efficiency end
  if motor_in_airstream_fraction then search_criteria['motor_in_airstream_fraction'] = motor_in_airstream_fraction end
  if fan_power_minimum_flow_rate_input_method then search_criteria['fan_power_minimum_flow_rate_input_method'] = fan_power_minimum_flow_rate_input_method end
  if fan_power_coefficient_1 then search_criteria['fan_power_coefficient_1'] = fan_power_coefficient_1 end
  if fan_power_coefficient_2 then search_criteria['fan_power_coefficient_2'] = fan_power_coefficient_2 end
  if fan_power_coefficient_3 then search_criteria['fan_power_coefficient_3'] = fan_power_coefficient_3 end
  if fan_power_coefficient_4 then search_criteria['fan_power_coefficient_4'] = fan_power_coefficient_4 end
  if fan_power_coefficient_5 then search_criteria['fan_power_coefficient_5'] = fan_power_coefficient_5 end
  if system_availability_manager_coupling_mode then search_criteria['system_availability_manager_coupling_mode'] = system_availability_manager_coupling_mode end
  if end_use_subcategory then search_criteria['end_use_subcategory'] = end_use_subcategory end

  model_find_object(@standards_data['fans'], search_criteria)
end

#lookup_fan_curve_coefficients_from_json(fan_curve) ⇒ Array

Lookup fan curve coefficients

Parameters:

  • fan_curve (String) —

    name of the fan curve

Returns:

  • (Array) —

    an array of fan curve coefficients



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# File 'lib/openstudio-standards/prototypes/common/objects/Prototype.Fan.rb', line 207

def lookup_fan_curve_coefficients_from_json(fan_curve)
  search_criteria = {}
  search_criteria['name'] = fan_curve
  fan_curve = model_find_object(@standards_data['curves'], search_criteria)
  return [fan_curve['coeff_1'], fan_curve['coeff_2'], fan_curve['coeff_3'], fan_curve['coeff_4'], fan_curve['coeff_5']]
end

#prototype_fan_apply_prototype_fan_efficiency(fan) ⇒ Boolean

Sets the fan motor efficiency using the Prototype model assumptions for fan impeller efficiency, motor type, and a 10% safety factor on brake horsepower.

Parameters:

  • fan (OpenStudio::Model::StraightComponent) —

    fan object of type: FanConstantVolume, FanOnOff, FanVariableVolume, and FanZoneExhaust

Returns:

  • (Boolean) —

    returns true if successful, false if not



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# File 'lib/openstudio-standards/prototypes/common/objects/Prototype.Fan.rb', line 13

def prototype_fan_apply_prototype_fan_efficiency(fan)
  # Do not modify dummy exhaust fans
  return true if fan.name.to_s.downcase.include? 'dummy'

  # Get the max flow rate from the fan.
  maximum_flow_rate_m3_per_s = nil
  if fan.maximumFlowRate.is_initialized
    maximum_flow_rate_m3_per_s = fan.maximumFlowRate.get
  elsif fan.autosizedMaximumFlowRate.is_initialized
    maximum_flow_rate_m3_per_s = fan.autosizedMaximumFlowRate.get
  else
    OpenStudio.logFree(OpenStudio::Warn, 'openstudio.standards.Fan', "For #{fan.name} max flow rate is not hard sized, cannot apply efficiency standard.")
    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

  # Get the pressure rise from the fan
  pressure_rise_pa = fan.pressureRise
  pressure_rise_in_h2o = OpenStudio.convert(pressure_rise_pa, 'Pa', 'inH_{2}O').get

  # Get the default impeller efficiency
  fan_impeller_eff = fan_baseline_impeller_efficiency(fan)

  # Calculate the Brake Horsepower
  brake_hp = (pressure_rise_in_h2o * maximum_flow_rate_cfm) / (fan_impeller_eff * 6356)
  allowed_hp = brake_hp * 1.1 # Per PNNL document
  # @todo add reference
  if allowed_hp > 0.1
    allowed_hp = allowed_hp.round(2) + 0.0001
  elsif allowed_hp < 0.01
    allowed_hp = 0.01
  end

  # Minimum motor size for efficiency lookup
  # is 1 HP unless the motor serves an exhaust fan,
  # a powered VAV terminal, or a fan coil unit.
  if !fan_small_fan?(fan) && allowed_hp < 1.0
    allowed_hp = 1.01
  end

  # Find the motor efficiency
  motor_eff, nominal_hp = fan_standard_minimum_motor_efficiency_and_size(fan, allowed_hp)

  # Calculate the total fan efficiency
  total_fan_eff = fan_impeller_eff * motor_eff

  # Set the total fan efficiency and the motor efficiency
  if fan.to_FanZoneExhaust.is_initialized
    fan.setFanEfficiency(total_fan_eff)
  else
    fan.setFanEfficiency(total_fan_eff)
    fan.setMotorEfficiency(motor_eff)
  end

  OpenStudio.logFree(OpenStudio::Info, 'openstudio.standards.Fan', "For #{fan.name}: allowed_hp = #{allowed_hp.round(2)}HP; motor eff = #{(motor_eff * 100).round(2)}%; total fan eff = #{(total_fan_eff * 100).round}% based on #{maximum_flow_rate_cfm.round} cfm.")

  return true
end