get_building_segment_SWH_bat.md

get_building_segment_SWH_bat

Description: This function determines the SWH BAT for the given building segment.

Inputs:

• RMD
• building_segment
• is_leap_year

Returns:

• building_segment_swh_bat: one of the ServiceWaterHeatingSpaceOptions2019ASHRAE901 options

Function Call:

• get_energy_required_to_heat_swh_use
• get_component_by_ID

Data Lookup: None

Logic:

• set the building_segment_swh_bat to nil: building_segment_swh_bat = "UNDETERMINED"

• get the service_water_heating_building_area_type value: building_segment_swh_bat = building_segment.get("service_water_heating_building_area_type", None)

• if building_segment_swh_bat doesn't have service_water_heating_building_area_type, we need to determine the building segment SWH area type by looking at individual SWH uses: if building_segment_swh_bat is None

  • create a dictionary that will hold the different types of swh_use_bat_types and the total service water used for the year: swh_use_dict = {}
  • look at each service water heating use id: for swh_use in find_all(f'$.buildings[*].building_segments[*][?(@.id {building_segment.id}")].zones[*].spaces[*].service_water_heating_uses[*]', rmd):
    • if any swh_use has use_units equal to "OTHER" or swh_use is not an empty dict, the total energy required to heat the use cannot be determined, and building_segment_swh_bat is "UNDETERMINED": if swh_use and swh_use.use_units == "OTHER": building_segment_swh_bat = "UNDETERMINED"
    • calculate the total energy required to heat the swh_use using the function get_energy_required_to_heat_swh_use: swh_use_energy_by_space = get_energy_required_to_heat_swh_use(swh_use, RMD, building_segment, is_leap_year)
    • check to see if the swh_use has service_water_heating_area_type: if swh_use.area_type:
      • add the SWH building area type to the swh_use_dict and set the default value to 0: swh_use_dict.setdefault(swh_use.area_type, ZERO.ENERGY)
      • add the energy used by this swh_use: swh_use_dict[swh_use.area_type] += sum(swh_use_energy_by_space.values())
    • otherwise: else:
      • go through each space served by the swh_use and see if it has a service_water_heating_bat: for space_id in swh_use_energy_by_space:
        • get the space: space = get_component_by_ID(RMD, space_id)
        • check if the space has a swh_use_bat: if space.service_water_heating_bat:
          • First add the BAT and set the default: swh_use_dict.setdefault("space.service_water_heating_bat", ZERO.ENERGY)
          • add the energy used to the dict: swh_use_dict["space.service_water_heating_bat"] += swh_use_energy_by_space[space_id]
        • otherwise, we'll add this use to UNDETERMINED.else:
          • First add UNDETERMINED and set the default: swh_use_dict.setdefault("UNDETERMINED", ZERO.ENERGY)
          • add the energy used to the dict: swh_use_dict["UNDETERMINED"] += swh_use_energy_by_space[space_id]
  • now we need to determine the building_segment SWH area type based on the following rules:
  • At least 50% of the SWH uses needs to be assigned a SWH area type
  • All SWH needs to be assigned to the same SWH area type
  • Select the building area type that has the greateest value: building_segment_swh_bat = max(swh_use_dict, key=swh_use_dict.get) if swh_use_dict else "UNDETERMINED"

• if the building_segment.service_water_heating_building_area_type exists set the swh_bat to the one given: if building_segment.service_water_heating_building_area_type:

  • set the building_segment_swh_bat to the building_segment.service_water_heating_building_area_type: building_segment_swh_bat = building_segment.service_water_heating_building_area_type

• return result: return: building_segment_swh_bat

Returns building_segment_swh_bat

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Notes:

1. relies on re-structuring of SWH as in: open229/ruleset-model-description-schema#264