Degree-Day Energy Estimator mechanism

Model scope

The heating equation is dimensionally and conceptually valid as a rough sensible-load estimate under the stated assumptions. The specification needs an explicit cooling formula, a defined cooling performance input (preferably COP), degree-day base-temperature metadata, input validation, and clearly labeled units before implementation can be verified as complete.

• The heating formula is standard only when UA is a whole-building heat-loss coefficient in W/K or kW/K, degree-days use the same temperature scale, and system efficiency η is a dimensionless delivered-to-input efficiency greater than zero.
• The cooling formula is not actually specified: 'similar for CDD cooling' does not define whether the denominator is a dimensionless efficiency, a coefficient of performance (COP), or another rating. Cooling normally uses Energy = UA·CDD·24/COP, with additional treatment often needed for latent cooling.
• The degree-day balance temperature or base temperature is not specified. HDD/CDD values depend on that temperature and cannot be interpreted unambiguously without it.
• A single constant UA and degree-day multiplication omits weather variation, solar gains, internal loads, ventilation/infiltration changes, thermal storage, part-load behavior, and for cooling, latent loads.

Units and conventions

• For heating, UA is assumed to be W/K or kW/K, HDD is in degree-days on the matching temperature scale, 24 is hours per day, and η is dimensionless.
• With UA in W/K, the heating result is Wh; divide by 1000 for kWh. With UA in kW/K, the result is directly kWh.
• For cooling test calculations, the unspecified 'system efficiency' is interpreted as a dimensionless COP, so cooling energy equals UA·CDD·24/COP.
• Fahrenheit degree-days must be converted to Celsius/Kelvin degree-days by multiplying by 5/9 before combining with UA expressed per K.
• HDD/CDD are assumed to be nonnegative and based on a clearly stated balance/base temperature.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "mode": "heating",
    "UA_W_per_K": 250,
    "HDD_degree_days_C": 1800,
    "efficiency_eta": 0.9
  },
  "expected_outputs": {
    "seasonal_energy_Wh": 12000000,
    "seasonal_energy_kWh": 12000
  },
  "working": "UA·HDD·24/η = 250 W/K × 1800 K·day × 24 h/day ÷ 0.9 = 450000 W·day × 24 h/day ÷ 0.9 = 10800000 Wh ÷ 0.9 = 12000000 Wh = 12000 kWh."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

Zero efficiency produces an undefined division and must be rejected; additionally, an unspoken Fahrenheit-versus-kelvin degree-day convention can change the result from 166.6666667 kWh to 300 kWh for the same numeric input.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json