Calculation of Mean Temperature Difference in Air-Cooled Cross-Flow Heat Exchangers

1979 ◽  
Vol 101 (3) ◽  
pp. 511-513 ◽  
Author(s):  
W. Roetzel ◽  
J. Neubert
Keyword(s):  
Temperature Difference ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Process Stream ◽  
Explicit Equation ◽  
Fast Calculation ◽  
Mean Temperature ◽  
Flow Heat ◽  
The Mean ◽  
Empirical Coefficients

An approximate explicit equation together with empirical coefficients is presented for the fast calculation of the mean temperature difference of eight cross-flow arrangements. The mean temperature difference is calculated from the effectiveness of the process stream and the number of transfer units on the air side.

Mean Temperature Difference for Heat Exchanger Design—A General Approximate Explicit Equation

1975 ◽  
Vol 97 (1) ◽  
pp. 5-8 ◽  
Author(s):  
W. Roetzel ◽  
F. J. L. Nicole
Keyword(s):  
Temperature Difference ◽  
Cross Flow ◽  
Approximate Equation ◽  
Explicit Equation ◽  
Fast Calculation ◽  
Heat Exchanger Design ◽  
Mean Temperature ◽  
Shell And Tube ◽  
The Mean ◽  
Empirical Coefficients

An approximate equation together with empirical coefficients is presented for the fast calculation of the mean temperature difference of nine countercurrent cross-flow arrangements, as applied in air-cooled heat exchangers. The same equation can be used for other flow systems, as demonstrated for one shell-and-tube arrangement.

Mean Temperature Difference in Multipass Crossflow

1983 ◽  
Vol 105 (3) ◽  
pp. 584-591 ◽  
Author(s):  
A. Pignotti ◽  
G. O. Cordero
Keyword(s):  
Temperature Difference ◽  
Heat Exchangers ◽  
Arbitrary Number ◽  
Mean Temperature ◽  
Air Mixing ◽  
The Mean ◽  
Number Of Passes ◽  
Analytical Expressions

A procedure is developed to obtain analytical expressions for the mean temperature difference in crossflow heat exchangers with arbitrary number of passes and rows per pass. The influence of air mixing, along with different flow arrangements for the tube fluid between passes, is analyzed, both in co- and counter-crossflow.

scholarly journals The Recuperative Heat Exchangers – The Mean Temperature Difference in the Special Cases of Heat Transfer

2020 ◽  
Vol 70 (1) ◽  
pp. 47-56
Author(s):  
Gužela Štefan ◽  
Dzianik František
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Operating Characteristic ◽  
Mean Temperature ◽  
Special Cases ◽  
Key Variables ◽  
The Mean

AbstractThe heat exchangers are used to heat or cool the material streams. To calculate the heat exchanger, it is important to know the type of heat exchanger and its operating characteristic. This characteristic determines one of the key variables (e.g., F, NTUmin, or θ). In some special cases, it is not necessary to know its operating characteristic to calculate the heat exchanger. This article deals with these special cases. The article also contains a general dependency that allows checking the key variables related to a given heat exchanger.

Heat Exchanger Efficiency

2006 ◽  
Vol 129 (9) ◽  
pp. 1268-1276 ◽  
Author(s):  
Ahmad Fakheri
Keyword(s):  
Heat Capacity ◽  
Heat Exchanger ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Second Law Of Thermodynamics ◽  
Arithmetic Mean ◽  
Inlet Temperature ◽  
Mean Temperature ◽  
Flow Heat ◽  
The Ideal

This paper provides the solution to the problem of defining thermal efficiency for heat exchangers based on the second law of thermodynamics. It is shown that corresponding to each actual heat exchanger, there is an ideal heat exchanger that is a balanced counter-flow heat exchanger. The ideal heat exchanger has the same UA, the same arithmetic mean temperature difference, and the same cold to hot fluid inlet temperature ratio. The ideal heat exchanger’s heat capacity rates are equal to the minimum heat capacity rate of the actual heat exchanger. The ideal heat exchanger transfers the maximum amount of heat, equal to the product of UA and arithmetic mean temperature difference, and generates the minimum amount of entropy, making it the most efficient and least irreversible heat exchanger. The heat exchanger efficiency is defined as the ratio of the heat transferred in the actual heat exchanger to the heat that would be transferred in the ideal heat exchanger. The concept of heat exchanger efficiency provides a new way for the design and analysis of heat exchangers and heat exchanger networks.

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