Room Air Changes Rearing

Compute effective fresh-air changes and source-free mixed tracer decay from fan duty, recirculation and mixing calibration; unlike mining steady contaminant dilution, no generation-limit airflow or disease-control guarantee.

Description

Fresh-air exchange differs from total fan flow when air recirculates.

Fresh-air exchange differs from total fan flow when air recirculates. A source-free tracer decays exponentially under an effective mixed-room model.

When to use Room Air Changes Rearing

Use this tool to compute effective fresh-air changes and source-free mixed tracer decay from fan duty, recirculation and mixing calibration; unlike mining steady contaminant dilution, no generation-limit airflow or disease-control guarantee.

Prepare cocoon, larval, leaf or reeling measurements on a consistent batch and moisture basis. Use the declared mass, length and time units.

How to use Room Air Changes Rearing and understand its results

Prepare cocoon, larval, leaf or reeling measurements on a consistent batch and moisture basis. Use the declared mass, length and time units.
Enter roomVolumeM3, fanFlowsM3PerHour, fanDutyFractions, freshAirFractions, mixingEfficiencyFraction, targetRemainingTracerFraction using the field table and calculation rules, then run the tool.
Read effectiveFreshAirM3PerHour, effectiveAirChangesPerHour, modelTracerDecayMinutes. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
roomVolumeM3	Room volume m3	number	Required
fanFlowsM3PerHour	Fan flows m3 per hour	list of number	Required
fanDutyFractions	Fan duty fractions	list of number	Required
freshAirFractions	Fresh air fractions	list of number	Required
mixingEfficiencyFraction	Mixing efficiency fraction	number	Required
targetRemainingTracerFraction	Target remaining tracer fraction	number	Required

Align nonnegative fan flows with duty and fresh-air fractions in [0,1], and apply mixing efficiency in [0,1]. Require positive room volume and effective fresh flow, and target remaining fraction in (0,1].^[1]

Paired lists must be nonempty and have equal lengths.

ACH = effective fresh m³/h/room volume; decay minutes = −60 ln(remaining fraction)/ACH

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
effectiveFreshAirM3PerHour	Effective fresh air m3 per hour	number
effectiveAirChangesPerHour	Effective air changes per hour	number
modelTracerDecayMinutes	Model tracer decay minutes	number

json

{
  "input": {
    "roomVolumeM3": 100,
    "fanFlowsM3PerHour": [
      300,
      200
    ],
    "fanDutyFractions": [
      1,
      0.5
    ],
    "freshAirFractions": [
      0.5,
      1
    ],
    "mixingEfficiencyFraction": 0.8,
    "targetRemainingTracerFraction": 0.1
  },
  "output": {
    "effectiveFreshAirM3PerHour": 200,
    "effectiveAirChangesPerHour": 2,
    "modelTracerDecayMinutes": 69.07755278982137
  }
}

Limitations and assumptions

No ongoing contaminant generation, spatial airflow or disease-control guarantee is modeled.

Numbers and computed results must be finite; overflow produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Tray Stack Gap Height: Calculate equal clear intertray gap after tray thickness and room edge clearances and compare caller minimum; airflow, rack strength and ergonomics are not certified. For a complementary task, use Muscardine Humidity Risk Checker: Integrate linearly interpolated RH exposure above a caller muscardine monitoring threshold and longest continuous spell; does not diagnose infection or predict disease probability.

References

Room Air Changes Rearing — tool.io

Similar or alternative tools

Tray Stack Gap Height
Calculate equal clear intertray gap after tray thickness and room edge clearances and compare caller minimum; airflow, rack strength and ergonomics are not certified.
Muscardine Humidity Risk Checker
Integrate linearly interpolated RH exposure above a caller muscardine monitoring threshold and longest continuous spell; does not diagnose infection or predict disease probability.