Engineering

Log-mean temperature difference API

Computes the LMTD = (ΔT1 − ΔT2)/ln(ΔT1/ΔT2) for a counter- or co-current heat exchanger from the four terminal temperatures, plus the heat duty Q = U·A·LMTD when conductance is supplied, with the equal-ΔT limit handled. Answers 'What is the LMTD of a heat exchanger?', 'What heat duty does this exchanger transfer?'.

Price$0.04per request

MethodPOST

Route/v1/engineering/lmtd

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

engineeringthermofluidslmtdheat-exchangerlog-meantemperature-differencecounter-flowheat-duty

API URLhttps://x402.hexl.dev/v1/engineering/lmtd

Integration docs

Example request

{
  "hotInletC": 150,
  "hotOutletC": 90,
  "coldInletC": 30,
  "coldOutletC": 70,
  "arrangement": "counter",
  "overallUWm2K": 340,
  "areaM2": 6
}

Example response

{
  "arrangement": "counter",
  "deltaT1K": 80,
  "deltaT2K": 60,
  "lmtdK": 69.52119,
  "formula": "LMTD = (ΔT1 - ΔT2) / ln(ΔT1/ΔT2)",
  "interpretation": "Counter-flow yields a larger LMTD (more effective) than parallel for the same terminal temperatures.",
  "overallUWm2K": 340,
  "areaM2": 6,
  "heatDutyW": 141823.227469
}

Input schema

{
  "type": "object",
  "required": [
    "hotInletC",
    "hotOutletC",
    "coldInletC",
    "coldOutletC"
  ],
  "properties": {
    "hotInletC": {
      "type": "number",
      "description": "hot stream inlet (°C)",
      "examples": [
        150
      ]
    },
    "hotOutletC": {
      "type": "number",
      "description": "hot stream outlet (°C)"
    },
    "coldInletC": {
      "type": "number",
      "description": "cold stream inlet (°C)"
    },
    "coldOutletC": {
      "type": "number",
      "description": "cold stream outlet (°C)"
    },
    "arrangement": {
      "type": "string",
      "enum": [
        "counter",
        "parallel"
      ],
      "examples": [
        "counter"
      ]
    },
    "overallUWm2K": {
      "type": "number",
      "description": "overall U (W/m^2·K) for heat duty"
    },
    "areaM2": {
      "type": "number",
      "description": "heat-transfer area (m^2)"
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}