A thermoacoustic machine including a device for measuring at least one parameter representative of a temperature of a first external source and/or of a second external source, and a control device configured to modulate the acoustic power generated by one or more acoustic sources such that the temperature of one said external source connected to one or more thermoacoustic cells of the machine reaches or remains substantially identical to a setpoint temperature is disclosed.

A cryocooling system includes a compressor, a refrigerator, and a controller, which is communicatively coupled to the compressor and the refrigerator. The compressor is configured to be driven at a drive frequency. The refrigerator is coupled to the compressor via a first fluid path and includes a cold heat exchanger, an output, a reservoir, and a flow resistor. The flow resistor controls fluid flow along a second fluid path between the output and the reservoir. The controller optimizes a rate of cooling of the cold heat exchanger by adjusting both a drive frequency of the compressor and a resistance of the flow resistor along the second fluid path.