Boiling & Condensation Calculator

• •Use the Boiling & Condensation Calculator to check your hand calculations on homework or exam problems — comparing its result with your own working helps identify arithmetic errors before they propagate.
• •Use it during the early design phase to rapidly iterate on parameters and narrow down feasible configurations before committing time to detailed finite element simulations or full design packages.
• •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility — a quick sanity check can prevent costly downstream errors.
• •Use it to generate reference data for a technical report or presentation without manual computation, ensuring consistent, reproducible numbers throughout the document.
• •Use it in the field when a quick estimate is needed and a full engineering software package is not available.

The Boiling & Condensation Calculator is a precision engineering calculation tool designed for students, engineers, and technical professionals. Rohsenow nucleate pool boiling, Bromley film boiling on a horizontal cylinder, and Nusselt film condensation on a vertical plate: heat flux q" and heat transfer coefficient h, with CoolProp water and R-134a presets All calculations are performed using established engineering formulas from the relevant scientific literature and standards. Follow the units printed beside each field. Where a unit selector is provided, the selected unit is converted internally. Results are computed in your browser without sending data to a server, which keeps your inputs private. This calculator is intended as a supplementary tool for learning and design exploration; always verify results against authoritative references for safety-critical applications.

Boiling and condensation are two-phase heat transfer processes that involve a phase change at or near a surface. Boiling heat transfer coefficients are much higher than single-phase convection because of intense fluid motion from bubble formation and detachment. Nucleate boiling, the efficient regime with isolated bubbles forming at the surface, produces heat transfer coefficients of 10,000-100,000 W/(m²·K) for water. Beyond the critical heat flux (CHF), the surface becomes covered by a vapor film (film boiling) with dramatically reduced heat transfer — this is the 'boiling crisis' that limits heat flux in pool boiling. Film condensation on vertical surfaces produces a liquid film that flows down under gravity, with Nusselt's classical smooth-film analysis applying below a film Reynolds number of 30. Wavy-laminar (30–1800) and turbulent films (above 1800) require separate correlations; this calculator refuses ambiguous transitions. Condensation coefficients are typically 5,000-25,000 W/(m²·K) — lower than boiling but still much higher than gas-phase convection. These processes are central to steam power plants (condensers), refrigeration (evaporators and condensers), and process heat transfer equipment.

• •Steam power plant condenser design: film condensation heat transfer coefficients determine required surface area for a given condensing duty.
• •Refrigeration evaporator design: nucleate boiling in refrigerant evaporators achieves high heat transfer rates in compact equipment.
• •Heat pipe and thermosiphon analysis: two-phase heat transfer devices rely on evaporation-condensation cycles for heat transport.
• •Nuclear reactor cooling: pressurized water reactors must operate below critical heat flux to avoid boiling crisis that could damage fuel rods.
• •Process cooling and heating: industrial condensers, reboilers, and evaporators size based on boiling and condensation heat transfer predictions.