Source: https://guthlabs.ai/docs/instruments/cooling-tower-approach-range-calculator/implementation/

instrument implementation / implementation-contract

# Cooling Tower Approach/Range Calculator implementation

A source-bound implementation contract for Cooling Tower Approach/Range Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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**: t4-096

**Effect**: Computation or source lookup only

## Input and validation requirements

The effectiveness denominator can be zero, producing an undefined result, and negative approach or range values can produce mathematically finite but physically invalid outputs. Additionally, the specification lists effectiveness as an output but does not explicitly provide its formula; the calculations above assume the conventional formula Range/(Range+Approach) × 100.

## 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": {
    "water_in_temperature": 35,
    "water_out_temperature": 29,
    "wet_bulb_temperature": 25,
    "temperature_unit": "°C"
  },
  "expected_outputs": {
    "range": 6,
    "approach": 4,
    "effectiveness_percent": 60
  },
  "working": "Range = 35 − 29 = 6 °C. Approach = 29 − 25 = 4 °C. Effectiveness = [6 ÷ (6 + 4)] × 100 = (6 ÷ 10) × 100 = 60%."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/cooling-tower-approach-range-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/cooling-tower-approach-range-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/cooling-tower-approach-range-calculator/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`