Source code for honeybee_energy.hvac.idealair

# coding=utf-8
"""Simple ideal air system object used to condition zones."""
from __future__ import division

from honeybee._lockable import lockable
from honeybee.typing import valid_string, float_positive, float_in_range
from honeybee.altnumber import autosize, no_limit

from ._base import _HVACSystem
from ..reader import parse_idf_string
from ..writer import generate_idf_string
from ..properties.extension import IdealAirSystemProperties


[docs] @lockable class IdealAirSystem(_HVACSystem): """Simple ideal air system object used to condition zones. Args: identifier: Text string for ideal air system identifier. Must be < 100 characters and not contain any EnergyPlus special characters. This will be used to identify the object across a model and in the exported IDF. economizer_type: Text to indicate the type of air-side economizer used on the ideal air system. Economizers will mix in a greater amount of outdoor air to cool the zone (rather than running the cooling system) when the zone needs cooling and the outdoor air is cooler than the zone. Choose from the options below. (Default: DifferentialDryBulb). * NoEconomizer * DifferentialDryBulb * DifferentialEnthalpy demand_controlled_ventilation: Boolean to note whether demand controlled ventilation should be used on the system, which will vary the amount of ventilation air according to the occupancy schedule of the Room. (Default: False). sensible_heat_recovery: A number between 0 and 1 for the effectiveness of sensible heat recovery within the system. (Default: 0). latent_heat_recovery: A number between 0 and 1 for the effectiveness of latent heat recovery within the system. (Default: 0). heating_air_temperature: A number for the maximum heating supply air temperature [C]. (Default: 50, which is typical for many air-based HVAC systems). cooling_air_temperature: A number for the minimum cooling supply air temperature [C]. (Default: 13, which is typical for many air-based HVAC systems). heating_limit: A number for the maximum heating capacity in Watts. This can also be an Autosize object to indicate that the capacity should be determined during the EnergyPlus sizing calculation. This can also be a NoLimit object to indicate no upper limit to the heating capacity. (Default: autosize). cooling_limit: A number for the maximum cooling capacity in Watts. This can also be an Autosize object to indicate that the capacity should be determined during the EnergyPlus sizing calculation. This can also be a NoLimit object to indicate no upper limit to the cooling capacity. (Default: autosize). heating_availability: An optional on/off schedule to set the availability of heating over the course of the simulation. (Default: None). cooling_availability: An optional on/off schedule to set the availability of cooling over the course of the simulation. (Default: None). Properties: * identifier * display_name * economizer_type * demand_controlled_ventilation * sensible_heat_recovery * latent_heat_recovery * heating_air_temperature * cooling_air_temperature * heating_limit * cooling_limit * heating_availability * cooling_availability * schedules * properties """ __slots__ = ('_economizer_type', '_demand_controlled_ventilation', '_sensible_heat_recovery', '_latent_heat_recovery', '_heating_air_temperature', '_cooling_air_temperature', '_heating_limit', '_cooling_limit', '_heating_availability', '_cooling_availability', '_properties') ECONOMIZER_TYPES = ('NoEconomizer', 'DifferentialDryBulb', 'DifferentialEnthalpy') def __init__(self, identifier, economizer_type='DifferentialDryBulb', demand_controlled_ventilation=False, sensible_heat_recovery=0, latent_heat_recovery=0, heating_air_temperature=50, cooling_air_temperature=13, heating_limit=autosize, cooling_limit=autosize, heating_availability=None, cooling_availability=None): """Initialize IdealAirSystem.""" # initialize base HVAC system properties _HVACSystem.__init__(self, identifier) # set the main features of the HVAC system self.economizer_type = economizer_type self.demand_controlled_ventilation = demand_controlled_ventilation self.sensible_heat_recovery = sensible_heat_recovery self.latent_heat_recovery = latent_heat_recovery # set the options affecting heating and cooling # set heating_air_temperature without the setter to ensure > cooling check works self._heating_air_temperature = \ float_positive(heating_air_temperature, 'ideal air heating air temperature') self.cooling_air_temperature = cooling_air_temperature self.heating_limit = heating_limit self.cooling_limit = cooling_limit self.heating_availability = heating_availability self.cooling_availability = cooling_availability # initialize properties for extensions self._properties = IdealAirSystemProperties(self) @property def economizer_type(self): """Get or set text to indicate the type of air-side economizer. Choose from the following options: * NoEconomizer * DifferentialDryBulb * DifferentialEnthalpy """ return self._economizer_type @economizer_type.setter def economizer_type(self, value): clean_input = valid_string(value).lower() for key in self.ECONOMIZER_TYPES: if key.lower() == clean_input: value = key break else: raise ValueError( 'economizer_type {} is not recognized.\nChoose from the ' 'following:\n{}'.format(value, self.ECONOMIZER_TYPES)) self._economizer_type = value @property def demand_controlled_ventilation(self): """Get or set a boolean for whether demand controlled ventilation is present.""" return self._demand_controlled_ventilation @demand_controlled_ventilation.setter def demand_controlled_ventilation(self, value): self._demand_controlled_ventilation = bool(value) @property def sensible_heat_recovery(self): """Get or set a number for the effectiveness of sensible heat recovery.""" return self._sensible_heat_recovery @sensible_heat_recovery.setter def sensible_heat_recovery(self, value): self._sensible_heat_recovery = float_in_range( value, 0.0, 1.0, 'ideal air sensible heat recovery') @property def latent_heat_recovery(self): """Get or set a number for the effectiveness of latent heat recovery.""" return self._latent_heat_recovery @latent_heat_recovery.setter def latent_heat_recovery(self, value): self._latent_heat_recovery = float_in_range( value, 0.0, 1.0, 'ideal air latent heat recovery') @property def heating_air_temperature(self): """Get or set a number for the maximum heating supply air temperature.""" return self._heating_air_temperature @heating_air_temperature.setter def heating_air_temperature(self, value): self._heating_air_temperature = float_in_range( value, 0, 100, 'ideal air heating air temperature') self._air_temperature_check() @property def cooling_air_temperature(self): """Get or set a number for the minimum cooling supply air temperature.""" return self._cooling_air_temperature @cooling_air_temperature.setter def cooling_air_temperature(self, value): self._cooling_air_temperature = float_in_range( value, -100, 50, 'ideal air cooling air temperature') self._air_temperature_check() @property def heating_limit(self): """Get or set a number for the maximum heating capacity in Watts.""" return self._heating_limit @heating_limit.setter def heating_limit(self, value): if value == autosize or value is None: self._heating_limit = autosize elif value == no_limit: self._heating_limit = no_limit else: self._heating_limit = float_positive(value, 'ideal air heating limit') @property def cooling_limit(self): """Get or set a number for the maximum cooling capacity in Watts.""" return self._cooling_limit @cooling_limit.setter def cooling_limit(self, value): if value == autosize or value is None: self._cooling_limit = autosize elif value == no_limit: assert self.economizer_type == 'NoEconomizer', 'Ideal air system ' \ 'economizer_type must be "NoEconomizer" to have no cooling limit.' self._cooling_limit = no_limit else: self._cooling_limit = float_positive(value, 'ideal air cooling limit') @property def heating_availability(self): """Get or set a ScheduleRuleset/ScheduleFixedInterval for heating availability. """ return self._heating_availability @heating_availability.setter def heating_availability(self, value): if value is not None: self._check_schedule(value, 'heating_availability') value.lock() # lock editing in case schedule has multiple references self._heating_availability = value @property def cooling_availability(self): """Get or set a ScheduleRuleset/ScheduleFixedInterval for cooling availability. """ return self._cooling_availability @cooling_availability.setter def cooling_availability(self, value): if value is not None: self._check_schedule(value, 'cooling_availability') value.lock() # lock editing in case schedule has multiple references self._cooling_availability = value @property def schedules(self): """Get an array of all the schedules associated with the HVAC system.""" schedules = [] if self._heating_availability is not None: schedules.append(self._heating_availability) if self._cooling_availability is not None: schedules.append(self._cooling_availability) return schedules
[docs] @classmethod def from_idf(cls, idf_string, schedule_dict): """Create an IdealAirSystem object from an EnergyPlus IDF text string. Args: idf_string: A text string fully describing an EnergyPlus HVACTemplate:Zone:IdealLoadsAirSystem definition. schedule_dict: A dictionary with schedule identifiers as keys and honeybee schedule objects as values (either ScheduleRuleset or ScheduleFixedInterval). These will be used to assign the schedules to the IdealAirSystem object. Returns: A tuple with two elements - ideal_air_system: An IdealAirSystem object loaded from the idf_string. - zone_identifier: The identifier of the zone to which the IdealAirSystem object should be assigned. """ # check the inputs ep_strs = parse_idf_string(idf_string, 'HVACTemplate:Zone:IdealLoadsAirSystem,') # set defaults for anything not included identifier = '{} Ideal Loads Air System'.format(ep_strs[0]) econ = 'DifferentialDryBulb' dcv = False sensible = 0 latent = 0 heat_temp = 50 cool_temp = 13 heat_limit = autosize cool_limit = autosize heat_sch = None cool_sch = None # extract the properties from the string try: heat_temp = ep_strs[3] if ep_strs[3] != '' else heat_temp cool_temp = ep_strs[4] if ep_strs[4] != '' else cool_temp if ep_strs[7].lower() == 'limitcapacity' or \ ep_strs[7].lower() == 'limitflowrateandcapacity': heat_limit = autosize if ep_strs[9] == '' or \ ep_strs[9].lower() == 'autosize' else ep_strs[9] else: heat_limit = no_limit if ep_strs[10].lower() == 'limitcapacity' or \ ep_strs[10].lower() == 'limitflowrateandcapacity': cool_limit = autosize if ep_strs[12] == '' or \ ep_strs[12].lower() == 'autosize' else ep_strs[12] else: cool_limit = no_limit if ep_strs[13] != '': heat_sch = schedule_dict[ep_strs[13]] if ep_strs[14] != '': cool_sch = schedule_dict[ep_strs[14]] if ep_strs[25].lower() == 'occupancyschedule': dcv = True if ep_strs[26].lower() != 'differentialdrybulb': econ = ep_strs[26] if ep_strs[27].lower() == 'sensible': sensible = ep_strs[28] if ep_strs[28] != '' else 0.7 elif ep_strs[27].lower() == 'enthalpy': sensible = ep_strs[28] if ep_strs[28] != '' else 0.7 latent = ep_strs[29] if ep_strs[29] != '' else 0.65 except IndexError: pass # shorter Ideal air loads definition # return the object and the zone identifier for the object ideal_air_system = cls( identifier, econ, dcv, sensible, latent, heat_temp, cool_temp, heat_limit, cool_limit, heat_sch, cool_sch) zone_identifier = ep_strs[0] return ideal_air_system, zone_identifier
[docs] @classmethod def from_dict(cls, data): """Create a IdealAirSystem object from a dictionary. Args: data: A IdealAirSystem dictionary in following the format below. .. code-block:: python { "type": "IdealAirSystem", "identifier": "Classroom1 Ideal Loads Air System", # identifier for the HVAC "display_name": "Standard IdealAir", # name for the HVAC "economizer_type": 'DifferentialDryBulb', # Economizer type "demand_controlled_ventilation": True, # Demand controlled ventilation "sensible_heat_recovery": 0.75, # Sensible heat recovery effectiveness "latent_heat_recovery": 0.7, # Latent heat recovery effectiveness "heating_air_temperature": 50, # Heating supply air temperature "cooling_air_temperature": 13, # Cooling supply air temperature "heating_limit": {'type': 'Autosize'}, # Max size of the heating system "cooling_limit": {'type': 'Autosize'}, # Max size of the cooling system "heating_availability": {}, # Schedule for availability of heat or None "cooling_availability": {} # Schedule for availability of cooling or None } """ assert data['type'] == 'IdealAirSystem', \ 'Expected IdealAirSystem dictionary. Got {}.'.format(data['type']) # extract the key features and properties of the HVAC econ, dcv, sensible, latent, heat_temp, cool_temp, heat_limit, cool_limit = \ cls._properties_from_dict(data) # extract the schedules heat_avail = cls._get_schedule_from_dict(data['heating_availability']) if \ 'heating_availability' in data and data['heating_availability'] is not None \ else None cool_avail = cls._get_schedule_from_dict(data['cooling_availability']) if \ 'cooling_availability' in data and data['cooling_availability'] is not None \ else None new_obj = cls(data['identifier'], econ, dcv, sensible, latent, heat_temp, cool_temp, heat_limit, cool_limit, heat_avail, cool_avail) if 'display_name' in data and data['display_name'] is not None: new_obj.display_name = data['display_name'] if 'user_data' in data and data['user_data'] is not None: new_obj.user_data = data['user_data'] if 'properties' in data and data['properties'] is not None: new_obj.properties._load_extension_attr_from_dict(data['properties']) return new_obj
[docs] @classmethod def from_dict_abridged(cls, data, schedule_dict): """Create a IdealAirSystem object from an abridged dictionary. Args: data: A IdealAirSystemAbridged dictionary in following the format below. schedule_dict: A dictionary with schedule identifiers as keys and honeybee schedule objects as values (either ScheduleRuleset or ScheduleFixedInterval). These will be used to assign the schedules to the Setpoint object. .. code-block:: python { "type": 'IdealAirSystemAbridged', "identifier": 'Warehouse1 Ideal Loads Air System', # identifier for the HVAC "economizer_type": 'DifferentialDryBulb', # Economizer type "demand_controlled_ventilation": True, # Demand controlled ventilation "sensible_heat_recovery": 0.75, # Sensible heat recovery effectiveness "latent_heat_recovery": 0.7, # Latent heat recovery effectiveness "heating_air_temperature": 40, # Heating supply air temperature "cooling_air_temperature": 15, # Cooling supply air temperature "heating_limit": 'autosize', # Max size of the heating system in Watts "cooling_limit": 'autosize', # Max size of the cooling system in Watts "heating_availability": "Warehouse Heating Control", # schedule identifier "cooling_availability": "Warehouse Cooling Control", # schedule identifier } """ assert data['type'] == 'IdealAirSystemAbridged', \ 'Expected IdealAirSystemAbridged dictionary. Got {}.'.format(data['type']) # extract the key features and properties of the HVAC econ, dcv, sensible, latent, heat_temp, cool_temp, heat_limit, cool_limit = \ cls._properties_from_dict(data) # extract the schedules heat_avail = None cool_avail = None if 'heating_availability' in data and data['heating_availability'] is not None: try: heat_avail = schedule_dict[data['heating_availability']] except KeyError as e: raise ValueError('Failed to find {} in the schedule_dict.'.format(e)) if 'cooling_availability' in data and data['cooling_availability'] is not None: try: cool_avail = schedule_dict[data['cooling_availability']] except KeyError as e: raise ValueError('Failed to find {} in the schedule_dict.'.format(e)) new_obj = cls(data['identifier'], econ, dcv, sensible, latent, heat_temp, cool_temp, heat_limit, cool_limit, heat_avail, cool_avail) if 'display_name' in data and data['display_name'] is not None: new_obj.display_name = data['display_name'] if 'user_data' in data and data['user_data'] is not None: new_obj.user_data = data['user_data'] if 'properties' in data and data['properties'] is not None: new_obj.properties._load_extension_attr_from_dict(data['properties']) return new_obj
[docs] def to_idf(self, room): """IDF string representation of IdealAirSystem object. Note that this method does not return full definitions of heating/cooling availability schedules and so this objects's schedules must also be translated into the final IDF file. Args: room: A Honeybee Room for which the specific IDF string will be generated. This Room must have a Setpoint object for this method to work correctly since all setpoints (and any ventilation requirements) are pulled from this Room. .. code-block:: shell HVACTemplate:Zone:IdealLoadsAirSystem, Zone 1, !- Zone Name All Zones, !- Thermostat Name FanAvailSched, !- System Availability Schedule Name 50, !- Maximum Heating Supply Air Temperature {C} 13, !- Minimum Cooling Supply Air Temperature {C} 0.0156, !- Maximum Heating Supply Air Humidity Ratio {kgWater/kgDryAir} 0.0077, !- Minimum Cooling Supply Air Humidity Ratio {kgWater/kgDryAir} NoLimit, !- Heating Limit , !- Maximum Heating Air Flow Rate {m3/s} , !- Maximum Sensible Heating Capacity {W} NoLimit, !- Cooling Limit , !- Maximum Cooling Air Flow Rate {m3/s} , !- Maximum Total Cooling Capacity {W} , !- Heating Availability Schedule Name , !- Cooling Availability Schedule Name ConstantSensibleHeatRatio, !- Dehumidification Control Type 0.7, !- Cooling Sensible Heat Ratio 60, !- Dehumidification Setpoint {percent} None, !- Humidification Control Type 30, !- Humidification Setpoint {percent} flow/person, !- Outdoor Air Method 0.00944, !- Outdoor Air Flow Rate per Person {m3/s} 0.0, !- Outdoor Air Flow Rate per Zone Floor Area {m3/s-m2} 0.0, !- Outdoor Air Flow Rate per Zone {m3/s} , !- Design Specification Outdoor Air Object Name None, !- Demand Controlled Ventilation Type NoEconomizer, !- Outdoor Air Economizer Type None, !- Heat Recovery Type 0.70, !- Sensible Heat Recovery Effectiveness 0.65; !- Latent Heat Recovery Effectiveness """ # check that a setpoint object is assigned r_set_p = room.properties.energy.setpoint assert r_set_p is not None, 'IdealAirSystem must be assigned to a Room ' \ 'with a setpoint object to use IdealAirSystem.to_idf.' # extract all of the fields from this object and its room # heating limit if self.heating_limit != no_limit: h_lim_type = 'LimitCapacity' heat_limit = str(self.heating_limit) # stringify Autosize else: h_lim_type = 'NoLimit' heat_limit = '' # cooling limit if self.cooling_limit != no_limit: c_lim_type = 'LimitFlowRateAndCapacity' air_limit = 'Autosize' cool_limit = str(self.cooling_limit) # stringify Autosize else: c_lim_type = 'NoLimit' air_limit = cool_limit = '' # availability schedules heat_avail = self.heating_availability.identifier if \ self.heating_availability is not None else '' cool_avail = self.cooling_availability.identifier if \ self.cooling_availability is not None else '' # humidifying setpoint if r_set_p.humidifying_setpoint is not None: humid_type = 'Humidistat' humid_setpt = r_set_p.humidifying_setpoint else: humid_type = 'None' humid_setpt = '' # dehumidifying setpoint if r_set_p.dehumidifying_setpoint is not None: dehumid_type = 'Humidistat' dehumid_setpt = r_set_p.dehumidifying_setpoint else: dehumid_type = 'None' dehumid_setpt = '' # ventilation requirements if room.properties.energy.ventilation is not None: oa_method = 'DetailedSpecification' oa_id = '{}..{}'.format(room.properties.energy.ventilation.identifier, room.identifier) else: oa_method = 'None' oa_id = '' # demand controlled ventilation dcv = 'OccupancySchedule' if self.demand_controlled_ventilation else 'None' # heat recovery if self.sensible_heat_recovery == 0 and self.latent_heat_recovery == 0: heat_recovery = 'None' elif self.latent_heat_recovery != 0: heat_recovery = 'Enthalpy' else: heat_recovery = 'Sensible' # return a full IDF string thermostat = '{}..{}'.format(r_set_p.identifier, room.identifier) \ if r_set_p.setpoint_cutout_difference == 0 else '' values = (room.identifier, thermostat, '', self.heating_air_temperature, self.cooling_air_temperature, '', '', h_lim_type, '', heat_limit, c_lim_type, air_limit, cool_limit, heat_avail, cool_avail, dehumid_type, '', dehumid_setpt, humid_type, humid_setpt, oa_method, '', '', '', oa_id, dcv, self.economizer_type, heat_recovery, self.sensible_heat_recovery, self.latent_heat_recovery) comments = ( 'zone name', 'template thermostat name', 'availability schedule', 'heating supply air temp {C}', 'cooling supply air temp {C}', 'max heating supply air hr {kg-H2O/kg-air}', 'min cooling supply air hr {kg-H2O/kg-air}', 'heating limit', 'max heating fow rate {m3/s}', 'max sensible heat capacity', 'cooling limit', 'max cooling fow rate {m3/s}', 'max total cooling capacity', 'heating availability schedule', 'cooling availability schedule', 'dehumidification type', 'cooling shr', 'dehumidification setpoint', 'humidification type', 'humidification setpoint', 'outdoor air method', 'oa per person', 'oa per area', 'oa per zone', 'outdoor air object name', 'demand controlled vent type', 'economizer type', 'heat recovery type', 'sensible heat recovery effectiveness', 'latent heat recovery effectiveness') return generate_idf_string( 'HVACTemplate:Zone:IdealLoadsAirSystem', values, comments)
[docs] def to_dict(self, abridged=False): """IdealAirSystem dictionary representation. Args: abridged: Boolean to note whether the full dictionary describing the object should be returned (False) or just an abridged version (True), which only specifies the identifiers of schedules. Default: False. """ base = {'type': 'IdealAirSystem'} if not \ abridged else {'type': 'IdealAirSystemAbridged'} base['identifier'] = self.identifier base['economizer_type'] = self.economizer_type base['demand_controlled_ventilation'] = self.demand_controlled_ventilation base['sensible_heat_recovery'] = self.sensible_heat_recovery base['latent_heat_recovery'] = self.latent_heat_recovery base['heating_air_temperature'] = self.heating_air_temperature base['cooling_air_temperature'] = self.cooling_air_temperature base['heating_limit'] = self.heating_limit if \ isinstance(self.heating_limit, float) else self.heating_limit.to_dict() base['cooling_limit'] = self.cooling_limit if \ isinstance(self.cooling_limit, float) else self.cooling_limit.to_dict() if self.heating_availability is not None: base['heating_availability'] = self.heating_availability.identifier if \ abridged else self.heating_availability.to_dict() if self.cooling_availability is not None: base['cooling_availability'] = self.cooling_availability.identifier if \ abridged else self.cooling_availability.to_dict() if self._display_name is not None: base['display_name'] = self.display_name if self._user_data is not None: base['user_data'] = self.user_data prop_dict = self.properties.to_dict() if prop_dict is not None: base['properties'] = prop_dict return base
def _air_temperature_check(self): """Check that heating_air_temperature is greater than cooling_air_temperature.""" assert self._heating_air_temperature > self._cooling_air_temperature, \ 'Ideal air heating_air_temperature must be greater than ' \ 'cooling_air_temperature.' @staticmethod def _properties_from_dict(data): """Extract basic properties from a dictionary and assign defaults.""" # extract the key features of the HVAC econ = data['economizer_type'] if 'economizer_type' in data and \ data['economizer_type'] is not None else 'DifferentialDryBulb' dcv = data['demand_controlled_ventilation'] if \ 'demand_controlled_ventilation' in data else False sensible = data['sensible_heat_recovery'] if \ 'sensible_heat_recovery' in data else 0 latent = data['latent_heat_recovery'] if \ 'latent_heat_recovery' in data else 0 # extract the heating and cooling temperature heat_temp = data['heating_air_temperature'] if \ 'heating_air_temperature' in data else 50 cool_temp = data['cooling_air_temperature'] if \ 'cooling_air_temperature' in data else 13 # extract the heating and cooling limits if 'heating_limit' not in data or data['heating_limit'] == autosize.to_dict(): heat_limit = autosize else: heat_limit = no_limit if data['heating_limit'] == no_limit.to_dict() \ else data['heating_limit'] if 'cooling_limit' not in data or data['cooling_limit'] == autosize.to_dict(): cool_limit = autosize else: cool_limit = no_limit if data['cooling_limit'] == no_limit.to_dict() \ else data['cooling_limit'] return econ, dcv, sensible, latent, heat_temp, cool_temp, heat_limit, cool_limit @property def properties(self): """Get properties for extensions.""" return self._properties def __copy__(self): new_obj = IdealAirSystem( self._identifier, self._economizer_type, self._demand_controlled_ventilation, self._sensible_heat_recovery, self._latent_heat_recovery, self._heating_air_temperature, self._cooling_air_temperature, self._heating_limit, self._cooling_limit, self._heating_availability, self._cooling_availability) new_obj._display_name = self._display_name new_obj._user_data = None if self._user_data is None else self._user_data.copy() new_obj._properties._duplicate_extension_attr(self._properties) return new_obj def __key(self): """A tuple based on the object properties, useful for hashing.""" return ( self._identifier, self._economizer_type, self._demand_controlled_ventilation, self._sensible_heat_recovery, self._latent_heat_recovery, self._heating_air_temperature, self._cooling_air_temperature, str(self._heating_limit), str(self._cooling_limit), hash(self._heating_availability), hash(self._cooling_availability)) def __hash__(self): return hash(self.__key()) def __eq__(self, other): return isinstance(other, IdealAirSystem) and self.__key() == other.__key() def __ne__(self, other): return not self.__eq__(other) def __repr__(self): return 'IdealAirSystem: {}'.format(self.display_name)