Heat Transfer Coefficients Coils

Reference data and engineering information about heat transfer coefficients coils for thermodynamics applications.

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Overview

Engineering reference data for Heat Transfer Coefficients Coils in thermodynamics.

Key Formulas

First Law

$\Delta U = Q - W$

Energy is conserved — heat added minus work done.

Ideal Gas Law

$PV = nRT$

Relates pressure, volume, and temperature of an ideal gas.

Heat Transfer

$Q = mc\Delta T$

Sensible heat transfer.

Carnot Efficiency

$\eta = 1 - T_C/T_H$

Maximum efficiency between two temperatures.

Variables

Symbol	Description	Unit
$U$	Internal energy	J
$Q$	Heat	J
$W$	Work	J
$P$	Pressure	Pa
$V$	Volume	m³
$T$	Temperature	K

Heat Transfer Coefficients for Submerged Coils

This section provides typical overall heat transfer coefficients (U) for steam，hot water，and other fluid coils submerged in liquids.

13 rows

Overall heat transfer coefficients (U) for submerged coils (medium pressure steam, hot water, pipes)
Type of Coil	U(W/m²·°C)	U(Btu/hr·ft²·°F)
Steam to Aqueous Solutions, agitated	800 - 1200	140 - 210
Steam to Aqueous Solutions, natural convection	340 - 570	60 - 100
Steam to Light Oil, natural convection	170	30
Steam to Heavy Oil, natural convection	85 - 115	15 - 20
Steam to Heavy Oil, agitated	140 - 310	25 - 55
Steam to Fat, natural convection	30 - 60	5 - 10
Steam to Organics, agitated	510 - 800	90 - 140
Hot Water to Oil, natural convection	34 - 140	6 - 25
Hot Water to Water, natural convection	200 - 370	35 - 65
Hot Water to Water, agitated	480 - 850	90 - 150
Heat transfer oil to Organics, agitated	140 - 280	25 - 50
Salt brine to Water, agitated	280 - 630	50 - 110
Cooling Water to Glycerine, agitated	280 - 430	50 - 75

Source: engineeringtoolbox.com

Example Calculation: Steam Coil in Oil

The heat transfer rate ( $Q$ ) from a submerged coil can be calculated using the formula: $Q = U \cdot A \cdot \Delta T$

where:

$U$ is the overall heat transfer coefficient (W/m²·°C)
$A$ is the heat transfer surface area (m²)
$\Delta T$ is the temperature difference between the coil surface and the bulk fluid (°C)

The surface area ( $A$ ) of a cylindrical coil is: $A = \pi \cdot d_o \cdot L$

where:

$d_o$ is the outside diameter of the coil (m)
$L$ is the length of the coil (m)

Problem: A 50 mm nominal pipe coil ( $d_o = 60.3\ \text{mm} = 0.0603\ \text{m}$ ) with length $L = 10\ \text{m}$ is submerged in oil. The coil carries steam at 120 °C, and the oil is at 50 °C.

Solution:

Calculate the surface area: $A = \pi \cdot 0.0603\ \text{m} \cdot 10\ \text{m} = 1.89\ \text{m}^2$
From the table, select $U = 170\ \text{W/m}^2\text{·°C}$ for "Steam to Light Oil, natural convection".
Calculate the heat transfer rate: $Q = (1.89\ \text{m}^2) \cdot (170\ \text{W/m}^2\text{·°C}) \cdot (120\ °C - 50\ °C) = 22,491\ \text{W}$