# Heat Flow Rate

Browse 4 online Heat Flow Rate tools for working with heat flow rate data in your browser. Text inputs are not stored, and uploaded files are deleted after 6 hours.

> Canonical page: https://elysiatools.com/en/tags/heat-flow-rate

## Overview

Explore 4 Heat Flow Rate tools for processing, converting, validating, and managing heat flow rate data through a browser-based interface without installing software.

## Frequently asked questions

### What can I do with Heat Flow Rate tools?

You can use the available tools to process, convert, validate, and manage heat flow rate data through your browser.

### Do I need to install software?

No software installation is required. You can operate the tools through the browser interface.

### How is my data handled?

Requests are submitted from the browser and processed on Elysia Tools servers. Text inputs are not stored, and uploaded files are automatically deleted after 6 hours.

## Tools

- [Cylinder Radial Heat Conduction (Q=2πkL·ΔT/ln(r₂/r₁))](https://elysiatools.com/en/tools/cylinder-radial-conduction): Compute radial steady-state heat conduction through a single-layer cylindrical wall (Fourier's law in cylindrical coordinates): radial heat flow rate Q = 2π·k·L·ΔT/ln(r₂/r₁) (W), inner-surface heat flux q_inner = Q/(2π·r₁·L) (W/m²), outer-surface heat flux q_outer = Q/(2π·r₂·L) (W/m²), and cylindrical thermal resistance R = ln(r₂/r₁)/(2π·k·L) (K/W). k is the thermal conductivity (W/(m·K)); L the cylinder length; r₁ the inner radius, r₂ the outer radius (must have r₂ > r₁ > 0); ΔT the temperature difference (K; a °C difference equals a K difference, a °F difference is converted by ×5/9). ΔT may be negative (indicating reverse heat flow), but k, L, r₁ and r₂ must be positive. Length and radius in m/cm/mm.
- [Heat Conduction Calculator (Fourier's Law, q=kΔT/d)](https://elysiatools.com/en/tools/heat-conduction-calculator): Compute 1-D steady-state heat conduction through a flat slab (Fourier's law): heat flux q = k·ΔT/d (W/m²), heat flow rate Q = k·A·ΔT/d (W), and thermal resistance R = d/(k·A) (K/W). k is the thermal conductivity (W/(m·K)); ΔT is the temperature difference (K; a °C difference equals a K difference, a °F difference is converted by ×5/9); d the slab thickness; A the cross-section area. ΔT may be negative (indicating reverse heat flow), but k, d and A must be positive. Thickness in m/cm/mm, area in m²/cm².
- [Heat Convection Calculator (Newton's Law, q=hΔT)](https://elysiatools.com/en/tools/heat-convection-calculator): Compute convective heat transfer (Newton's law of cooling): heat flux q = h·ΔT (W/m²), heat flow rate Q = h·A·ΔT (W), and convective thermal resistance R_conv = 1/(h·A) (K/W). h is the convective heat-transfer coefficient (W/(m²·K)); ΔT is the temperature difference between the surface and the fluid (K; a °C difference equals a K difference, a °F difference is converted by ×5/9); A the heat-transfer area. ΔT may be negative (indicating reverse heat flow), but h and A must be positive. Area in m²/cm².
- [Overall Heat Transfer Coefficient (1/U=ΣR)](https://elysiatools.com/en/tools/overall-heat-transfer-coefficient): Compute the overall heat transfer coefficient for series thermal resistances (flat-wall model): total resistance R_total = Σ R_i (K/W), thermal conductance G = 1/R_total (W/K), area-based coefficient U = 1/(R_total·A) (W/(m²·K)), and if a temperature difference is given the heat flow rate Q = ΔT/R_total (W). Each R_i is a layer resistance already containing the area factor (e.g. convection R_conv=1/(h·A), conduction R_cond=d/(k·A), fouling R_foul=R_f''/A). Enter one resistance (K/W) per line, at least one, all positive. ΔT may be negative (reverse heat flow); a °C difference equals a K difference, a °F difference is converted by ×5/9.

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