Rankine Cycle Efficiency Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t7-013

Effect

Computation or source lookup only

Input and validation requirements

The calculator can encounter a zero heat-input denominator, producing an undefined efficiency and requiring explicit rejection or an undefined result. The optional-reheat branch and the pump-work sign convention also require explicit handling to prevent materially different outputs.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "cycle": "simple Rankine",
    "boiler_pressure_kPa": 8000,
    "boiler_temperature_C": 480,
    "condenser_pressure_kPa": 10,
    "turbine_efficiency": 0.85,
    "pump_efficiency": 0.8,
    "h1_kJ_per_kg": 3349.5,
    "h2s_kJ_per_kg": 2145,
    "h3_kJ_per_kg": 191.81,
    "v3_m3_per_kg": 0.00101
  },
  "expected_outputs": {
    "eta": 0.322067,
    "net_work_kJ_per_kg": 1013.737625,
    "steam_rate_kg_per_kWh": 3.5512,
    "heat_rejected_kJ_per_kg": 2133.865
  },
  "reference_data": {
    "h1_kJ_per_kg": {
      "value": 3349.5,
      "source_convention": "widely tabulated standard value; superheated-steam tables consistent with IAPWS-IF97"
    },
    "h2s_kJ_per_kg": {
      "value": 2145,
      "source_convention": "widely tabulated standard value; pressure-entropy steam-table state"
    },
    "h3_kJ_per_kg": {
      "value": 191.81,
      "source_convention": "widely tabulated standard value; saturated-liquid water at 10 kPa"
    },
    "v3_m3_per_kg": {
      "value": 0.00101,
      "source_convention": "widely tabulated standard value; saturated-liquid water at 10 kPa"
    }
  },
  "working": "Isentropic turbine enthalpy drop = h1-h2s = 3349.5-2145.0 = 1204.5 kJ/kg. Actual turbine drop = 0.85*1204.5 = 1023.825 kJ/kg, so h2 = 3349.5-1023.825 = 2325.675 kJ/kg. Isentropic pump work = v3(P4-P3) = 0.00101*(8000-10) = 0.00101*7990 = 8.0699 kJ/kg. Actual pump work = 8.0699/0.8 = 10.087375 kJ/kg, so h4 = 191.81+10.087375 = 201.897375 kJ/kg. Wnet = (h1-h2)-(h4-h3) = 1023.825-10.087375 = 1013.737625 kJ/kg. Qin = h1-h4 = 3349.5-201.897375 = 3147.602625 kJ/kg. eta = 1013.737625/3147.602625 = 0.322067. qout = h2-h3 = 2325.675-191.81 = 2133.865 kJ/kg. Steam rate = 3600/1013.737625 = 3.5512 kg/kWh."
}

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-tranche7/tranche7-results.json