Ammonia Heat Recovery Coil Sizing Calculator
This free calculator sizes a submerged coil that recovers reject heat from a boiling ammonia pool into a secondary fluid (water or glycol). Enter coil geometry, vessel size, secondary-fluid flow rate, and inlet temperature; it returns recovered duty and outlet temperature — on screen, free, with no account required.
It runs as the Heat Recovery tab of the Coil Suite, one of the four calculators in the ColdCalcs dashboard, alongside Subcooler and Boil-out. Results are a preliminary sizing pass only, not a certified design.
Who it's for
Refrigeration engineers and facility designers evaluating a heat-recovery coil for reject-heat reuse, who need a fast preliminary duty and outlet-temperature number before a full design pass. It is not a substitute for a design package prepared by a qualified engineer.
Limits
This calculator performs a preliminary sizing pass only. [ELI-REVIEW: its shell-side pool-boiling coefficient uses a correlation calibrated to a small set of reference designs over a stated bath-temperature range, not a universal correlation], and it does not verify pipe pressure rating separately. Every result must be independently verified by a qualified engineer against the applicable code edition before it is used for design, fabrication, or construction.
Inputs and outputs
| Parameter | Type | Unit | Notes |
|---|---|---|---|
| Coil pipe size / schedule | Input | NPS | Tube size and wall schedule. |
| Winding count and length | Input | —, ft | Coil construction (single- through six-wound). |
| Secondary fluid and mix | Input | — | Water or a glycol/water mixture. |
| Secondary-fluid flow rate and inlet temperature | Input | gpm, °F | Fluid entering the coil. |
| Recovered duty | Output | Btu/hr | Heat picked up from the boiling ammonia pool. |
| Secondary-fluid outlet temperature | Output | °F | Fluid leaving the coil. |
| Pressure drop | Output | psi | Coil-side pressure drop, with a pass/marginal threshold. |
| Fouling factor | Output | hr·ft²·°F/Btu | [ELI-REVIEW: default assumption applied to the resistance stack (TEMA Clean, 0.0005), selectable.] |
Frequently asked questions
What does the heat recovery calculator compute?
[ELI-REVIEW: For a coil submerged in a boiling ammonia pool, it computes recovered duty and outlet temperature for a secondary fluid (water or glycol) that picks up reject heat from the pool, the reverse heat-flow direction from the Subcooler tab.] Results display on screen for free, with no account required.
What is ammonia heat recovery, in this context?
[ELI-REVIEW: A secondary fluid — typically water or a glycol/water mix — flows through a coil submerged in boiling ammonia, picking up reject heat that would otherwise go to the condenser, for reuse elsewhere in the facility.]
What secondary fluids does it support?
[ELI-REVIEW: Water and water/glycol mixtures, using ASHRAE Handbook 2017, Chapter 31 property correlations.]
Does it check pressure drop and fouling?
[ELI-REVIEW: Yes — coil-side pressure drop against a pass/marginal threshold, and a default fouling-factor assumption (TEMA Clean) applied on both sides of the tube wall.] These are on-screen checks, not code compliance certifications.
Is it free to use?
Yes. Full on-screen results are free for every user, with no account required. PDF export and saved projects are part of a paid plan; on-screen results never are.
Related
Preliminary sizing for engineering evaluation only. Not for construction. All results must be independently verified by a qualified engineer against the applicable code edition.