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Rule22-9.md

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CHW&CW - Rule 22-9

Schema Version: 0.0.10
Mandatory Rule: True
Rule ID: 22-9
Rule Description: For Baseline chilled water system with cooling capacity of 300 tons or more, the secondary loop shall be modeled with a minimum flow of 25% of the design flow rate.
Rule Assertion: B-RMR = expected value
Appendix G Section: Section 22 CHW&CW Loop
90.1 Section Reference: Section G3.1.3.10 Chilled-water pumps (System 7, 8, 11, 12 and 13)
Data Lookup: None
Evaluation Context: Building
Applicability Checks:

  1. B-RMR is modeled with at least one air-side system that is Type-7, 8, 11, 12, 13, 7b, 8b, 11.1b, 12b.
  2. B-RMR is modeled with primary-secondary configuration.
  3. B-RMR chilled water system cooling capacity is 300 tons or more.

Function Calls:

  1. get_baseline_system_types()
  2. get_primary_secondary_loops_dict()
  3. get_component_by_id()

Applicability Checks:

  • Check 1: Get B-RMR system types: baseline_hvac_system_dict = get_baseline_system_types(B-RMR)

    • Check if B-RMR is modeled with at least one air-side system that is Type-7, 8, 11.1, 11.2, 12, 13, 7b, 8b, 11.1b, 12b, i.e. with air-side system served by chiller(s), continue to the next applicability check: if any(sys_type in baseline_hvac_system_dict.keys() for sys_type in ["SYS-7", "SYS-8", "SYS-11.1", "SYS-11.2", "SYS-12", "SYS-13", "SYS-7B", "SYS-8B", "SYS-11.1B", "SYS-12B"]): NEXT_APPLICABILITY_CHECK

    • Else, rule is not applicable to B-RMR: else: RULE_NOT_APPLICABLE

  • Check 2: Get primary and secondary loops for B-RMR: primary_secondary_loop_dictionary = get_primary_secondary_loops_dict(B_RMR)

    • Check if B-RMR is modeled with primary-secondary configuration, continue to rule logic: if LEN(primary_secondary_loop_dictionary) != 0: CHECK_RULE_LOGIC

    • Else, rule is not applicable to B-RMR: else: RULE_NOT_APPLICABLE

Rule Logic:

  • For each chiller in B_RMR: for chiller_b in B_RMR.RulesetModelInstance.chillers:

    • Get cooling loop that chiller serves: chw_loop_b_id = chiller_b.cooling_loop

      • Add chiller rated capacity to primary CHW loop total capacity: chw_loop_capacity_dict[chw_loop_b_id] += chiller_b.rated_capacity

  • For each primary CHW loop: for loop_b_id in primary_secondary_loop_dictionary["PRIMARY"]:

    • Check if CHW primary loop total cooling capacity is 300 tons or more: if chw_loop_capacity_dict[loop_b_id] >= 300 * CONVERSION(TON_TO_BTUH):

      • Get primary loop: primary_loop_b = get_component_by_id(loop_b_id)

        • For each secondary loop served by primary CHW loop: for secondary_loop_id_b in primary_loop_b.child_loops:

          Rule Assertion - Component:

          • Case 1: If secondary loop is modeled with a minimum flow of 25% of the design flow rate: if secondary_loop_id_b.cooling_or_condensing_design_and_control.minimum_flow_fraction == 0.25: PASS

          • Case 2: Else: else: FAIL

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