Instantaneous heat transfer rate Formula

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Heat Rate is the amount of energy required by an electrical generator or a power plant to produce a one-kilowatt hour of electricity. Check FAQs
Qrate=hA(To-tf)(exp(-hAtρVTCo))
Qrate - Heat Rate?h - Convection Heat Transfer Coefficient?A - Surface Area?To - Initial Temperature?tf - Fluid Temperature?t - Time Elapsed?ρ - Density?VT - Total Volume?Co - Specific Heat Capacity?

Instantaneous heat transfer rate Example

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With units
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Here is how the Instantaneous heat transfer rate equation looks like with Values.

Here is how the Instantaneous heat transfer rate equation looks like with Units.

Here is how the Instantaneous heat transfer rate equation looks like.

7.1553Edit=0.04Edit18Edit(20Edit-10Edit)(exp(-0.04Edit18Edit12Edit5.51Edit63Edit4Edit))
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Instantaneous heat transfer rate Solution

Follow our step by step solution on how to calculate Instantaneous heat transfer rate?

FIRST Step Consider the formula
Qrate=hA(To-tf)(exp(-hAtρVTCo))
Next Step Substitute values of Variables
Qrate=0.04W/m²*K18(20K-10K)(exp(-0.04W/m²*K1812s5.51kg/m³634J/(kg*K)))
Next Step Prepare to Evaluate
Qrate=0.0418(20-10)(exp(-0.0418125.51634))
Next Step Evaluate
Qrate=7.15533744011914W
LAST Step Rounding Answer
Qrate=7.1553W

Instantaneous heat transfer rate Formula Elements

Variables
Functions
Heat Rate
Heat Rate is the amount of energy required by an electrical generator or a power plant to produce a one-kilowatt hour of electricity.
Symbol: Qrate
Measurement: PowerUnit: W
Note: Value can be positive or negative.
Convection Heat Transfer Coefficient
Convection Heat Transfer Coefficient is the rate of heat transfer between a solid surface and a fluid per unit surface area per unit temperature.
Symbol: h
Measurement: Heat Transfer CoefficientUnit: W/m²*K
Note: Value should be greater than 0.
Surface Area
The Surface Area of a three-dimensional shape is the sum of all of the surface areas of each of the sides.
Symbol: A
Measurement: AreaUnit:
Note: Value should be greater than 0.
Initial Temperature
The Initial Temperature is defined as the measure of heat under initial state or conditions.
Symbol: To
Measurement: TemperatureUnit: K
Note: Value can be positive or negative.
Fluid Temperature
Fluid Temperature is the temperature of the fluid surrounding the object.
Symbol: tf
Measurement: TemperatureUnit: K
Note: Value can be positive or negative.
Time Elapsed
Time Elapsed after a particular task is started.
Symbol: t
Measurement: TimeUnit: s
Note: Value should be greater than 0.
Density
The Density of a material shows the denseness of that material in a specific given area. This is taken as mass per unit volume of a given object.
Symbol: ρ
Measurement: DensityUnit: kg/m³
Note: Value should be greater than 0.
Total Volume
Total Volume is the overall amount of space that a substance or object occupies or that is enclosed within a container.
Symbol: VT
Measurement: VolumeUnit:
Note: Value should be greater than 0.
Specific Heat Capacity
Specific Heat Capacity is the heat required to raise the temperature of the unit mass of a given substance by a given amount.
Symbol: Co
Measurement: Specific Heat CapacityUnit: J/(kg*K)
Note: Value can be positive or negative.
exp
n an exponential function, the value of the function changes by a constant factor for every unit change in the independent variable.
Syntax: exp(Number)

Other formulas in Transient Heat Conduction category

​Go Total Heat Transfer during Time Interval
Q=ρcVT(To-tf)(1-(exp(-(BiFo))))
​Go Time Constant in unsteady state heat transfer
Tc=ρCoVThA

How to Evaluate Instantaneous heat transfer rate?

Instantaneous heat transfer rate evaluator uses Heat Rate = Convection Heat Transfer Coefficient*Surface Area*(Initial Temperature-Fluid Temperature)*(exp(-(Convection Heat Transfer Coefficient*Surface Area*Time Elapsed)/(Density*Total Volume*Specific Heat Capacity))) to evaluate the Heat Rate, The instantaneous heat transfer rate formula calculates the rate of heat transfer at the given instant when a lumped body is going for unsteady-state heat conduction. Heat Rate is denoted by Qrate symbol.

How to evaluate Instantaneous heat transfer rate using this online evaluator? To use this online evaluator for Instantaneous heat transfer rate, enter Convection Heat Transfer Coefficient (h), Surface Area (A), Initial Temperature (To), Fluid Temperature (tf), Time Elapsed (t), Density (ρ), Total Volume (VT) & Specific Heat Capacity (Co) and hit the calculate button.

FAQs on Instantaneous heat transfer rate

What is the formula to find Instantaneous heat transfer rate?
The formula of Instantaneous heat transfer rate is expressed as Heat Rate = Convection Heat Transfer Coefficient*Surface Area*(Initial Temperature-Fluid Temperature)*(exp(-(Convection Heat Transfer Coefficient*Surface Area*Time Elapsed)/(Density*Total Volume*Specific Heat Capacity))). Here is an example- 7.155337 = 0.04*18*(20-10)*(exp(-(0.04*18*12)/(5.51*63*4))).
How to calculate Instantaneous heat transfer rate?
With Convection Heat Transfer Coefficient (h), Surface Area (A), Initial Temperature (To), Fluid Temperature (tf), Time Elapsed (t), Density (ρ), Total Volume (VT) & Specific Heat Capacity (Co) we can find Instantaneous heat transfer rate using the formula - Heat Rate = Convection Heat Transfer Coefficient*Surface Area*(Initial Temperature-Fluid Temperature)*(exp(-(Convection Heat Transfer Coefficient*Surface Area*Time Elapsed)/(Density*Total Volume*Specific Heat Capacity))). This formula also uses Exponential Growth (exp) function(s).
Can the Instantaneous heat transfer rate be negative?
Yes, the Instantaneous heat transfer rate, measured in Power can be negative.
Which unit is used to measure Instantaneous heat transfer rate?
Instantaneous heat transfer rate is usually measured using the Watt[W] for Power. Kilowatt[W], Milliwatt[W], Microwatt[W] are the few other units in which Instantaneous heat transfer rate can be measured.
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