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CHAPTER 8
Experimental methods for thermal
performance of heat exchangers
a
b
Wilfried Roetzel , Xing Luo , Dezhen Chen c
a
Institute of Thermodynamics, Helmut Schmidt University/University of the Federal Armed Forces Hamburg,
Hamburg, Germany
b
Institute of Thermodynamics, Gottfried Wilhelm Leibniz University Hannover, Hannover, Germany
c
Institute of Thermal Energy and Environmental Engineering, Tongji University, Shanghai, China
The thermal performance of heat exchangers can be evaluated by the use of
variety of correlations available from the literature, of which most of them
were obtained from experimental measurements. The purpose of an exper-
iment can be (1) measurement of heat duty of heat exchangers, (2) measure-
ment of overall heat transfer coefficients of heat exchangers, and (3)
measurement of heat transfer coefficients of heat transfer surfaces. The mea-
surement of heat transfer coefficients has special meaning because it can offer
us the general heat transfer performance of a specified heat transfer surface
that can be applied to similar heat transfer surfaces according to the similarity
theory and Buckingham pi theorem.
8.1 Fundamental principles
8.1.1 Measurement of heat exchanger duty
The experiment principles for thermal performance of heat exchangers
depend on the purposes of the experiments. The purpose of the heat duty
measurement is to examine whether the heat exchanger can reach its design
specifications under the specified operation conditions (mainly the flow
rates, inlet temperatures, and pressures of the hot and cold fluids).
8.1.1.1 Single-phase heat exchangers
For a basic measurement of the heat duty of single-phase heat exchangers,
the heat duty can be determined by the measured mass flow rates and
inlet and outlet fluid temperatures. For the specified mass flow rates
and inlet temperatures of the hot and cold fluids, while the exchanger
Design and Operation of Heat Exchangers and their Networks © 2020 Elsevier Inc.
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