Ammonia Vessel Sizing Calculator
This free calculator sizes pumped-recirculator suction accumulators and low-pressure receivers for ammonia and halocarbon refrigeration systems. Enter system capacity, temperature, and vessel geometry; it returns vessel volume and level/charge results, relief-valve sizing, and connected line sizing — on screen, free, with no account required.
It runs as part of the Vessel Sizer, one of the four calculators in the ColdCalcs dashboard. Results are a preliminary sizing pass only, not a certified design.
Who it's for
Refrigeration engineers and ammonia system designers who need a fast preliminary vessel size, liquid charge, and relief-valve number before a full code-compliance 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 relief-sizing inlet-line pressure-drop check uses a flat 10%-of-set-pressure compliance screen as a documented conservative proxy, not the full per-valve blowdown criterion in the applicable code edition], and it does not perform nozzle reinforcement calculations or fabrication drawing review. 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 |
|---|---|---|---|
| System capacity | Input | TR | Tons of refrigeration served by the recirculator. |
| Suction / saturation temperature | Input | °F | System operating condition. |
| Vessel geometry | Input | in | Diameter, seam-to-seam length, orientation. |
| Circulation rate | Output | gpm | [ELI-REVIEW: liquid overfeed circulation basis.] |
| Vapor-space separation velocity | Output | fpm | [ELI-REVIEW: Souders-Brown vapor-disengagement velocity and related correlations.] |
| Liquid hold time / level bands | Output | min, in | [ELI-REVIEW: referenced to IIAR-2 §11 liquid-level guidance.] |
| Relief valve orifice area | Output | in² | [ELI-REVIEW: per ASME VIII UG-125(c)(2) and API 526 standard sizes.] |
| Suction / wet-return line size | Output | in | [ELI-REVIEW: per IIAR-2 §11.2.2 / §11.4 velocity guidance.] |
Frequently asked questions
What vessels does this calculator size?
It sizes pumped-recirculator (liquid-overfeed) suction accumulators and low-pressure receivers used in ammonia and other halocarbon refrigeration systems, plus their liquid level and volume, relief valve sizing, and connected line sizing.
What is a suction accumulator, in this context?
[ELI-REVIEW: A suction accumulator (also called a low-pressure receiver or recirculator vessel) separates liquid refrigerant from suction vapor and holds a working liquid charge, sized around vapor-space disengagement velocity and required liquid hold time.] It is not the same vessel as a high-pressure receiver.
Does it size the relief valve too?
[ELI-REVIEW: Yes — required relief capacity per ANSI/ASHRAE-15, orifice area per ASME VIII UG-125(c)(2) and API 526 standard sizes, plus an inlet-line pressure-drop compliance screen.] This is a preliminary sizing pass, not a certified relief-system design.
What line sizes does it cover?
[ELI-REVIEW: Pump suction and wet-return line sizing referenced to IIAR-2 §11.2.2 and §11.4 velocity/sizing guidance.] Confirm final line sizes against the full code edition applicable to your project.
Is it free to use?
Yes. Full on-screen results for every tab 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.