Table 4.

A comparison of different methods and sensors used for a determination of acoustic power (u(P) means a relative uncertainty of the acoustic power measurement).

Detection method / sensor	u(P), %	Advantages	Disadvantages	Ref.
calorimetry	3 ÷ 5	simple measurement procedure	long measurement (~200 s); heat capacity and liquid mass have to be known or determined	[2], [3]
disequilibrium calorimetry	16	improved reproducibility compared with classic calorimetry	long measurement time (~600 s); heat capacity and liquid mass must be known	[4]
PVDF pyroelectric sensor	6	good repeatability	requires voltage signal filtering and amplification	[6], [7]
fiber optic probe hydrophone	5	small probe size (0.1 mm)	the need of measured signal amplification; sophisticated measurement setup	[12]
electrical impedance measurements	0.7 ÷ 7.1	low cost	requires extensive knowledge of transducer parameters, requires amplifier application	[16]
PZT piezoelectric hydrophone		small sensor dimensions	complex fabrication process of the sensor; complicated calculations; requires an amplifier; high sensor noise	[17]
anechoic tank with hydrophone			problems determining the equivalent diameter of the ultrasounds source (sonotrode tip with bubble cloud)	[51]
SbSeI piezoelectric nanogenerator	3.1	measurement simplicity; no amplifier requirement; small sensor size; facile sensor fabrication	calibration of the sensor required	this paper