Acoustic resonance in plate heat exchangers

A 'whistling' sound, which develops under transient conditions in some automobile air conditioning systems equipped with plate type evaporators, was identified as acoustic resonance. The 'whistle' was reproduced in the laboratory under steady-state conditions. Testing of these heat exchangers was done first with R134a and then with nitrogen. Nitrogen testing proved to be much faster and easier and provided results comparable to the results obtained using R134a. The evidence presented in this work suggests that the acoustic resonance in this type of heat exchanger is similar in nature to the acoustic resonance problems reported for tube array in duct type heat exchangers. This is to the authors' knowledge the first time that acoustic resonance problems have been reported in the literature for plate heat exchangers.