Enter the actual heat transfer rate and the maximum possible heat transfer rate into the calculator to determine the heat exchanger effectiveness.
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Heat Exchanger Effectiveness Formula
The following formula is used to calculate heat exchanger effectiveness.
E = \frac{AHT}{MHT}\times 100- Where E is the heat exchanger effectiveness (%)
- AHT is the actual heat transfer rate
- MHT is the maximum possible heat transfer rate
To calculate heat exchanger effectiveness, divide the actual heat transfer rate by the maximum possible heat transfer rate, then multiply by 100.
In many applications, the maximum possible heat transfer rate is based on the inlet temperature difference and the smaller heat capacity rate: \(q_{\max}=C_{\min}(T_{h,in}-T_{c,in})\), where \(C=\dot m\,c_p\).
What is Heat Exchanger Effectiveness?
Definition:
A heat exchanger effectiveness is a measure of the percentage of heat transfer a heat exchanger performs relative to a maximum theoretical heat transfer limit.
The maximum possible heat transfer rate depends on the inlet temperature difference and the heat capacity rates (flow rate times specific heat) of the two streams. This is not the same as Carnot efficiency (which applies to heat engines).
How to calculate Heat Exchanger Effectiveness?
Example Problem:
The following example outlines how to calculate a Heat Exchanger Effectiveness.
First, determine the actual heat transfer rate of the system. In this example, the actual heat transfer rate is 100 J/s.
Next, determine the maximum possible heat transfer rate. In this case, the maximum possible heat transfer rate is 150 J/s.
Finally, calculate the heat exchanger effectiveness using the formula above:
E = (AHT / MHT) * 100
E = (100 / 150) * 100
E = 66.67%
