from the co fluid the ultrasonic transducers 44 can have any suitable shape or design for example the ultrasonic transducers 44 may have a long and narrow shape a flat disc shape etc and can be flexible or rigid in configurations in which the ultrasonic transducers 44 are mounted to the exterior surface 46 of the desorber 20 it may be beneficial for the desorber 20 to have a minimal wall thickness at the location at which the ultrasonic transducers 44 are mounted in order to minimize attenuation of the ultrasonic vibration furthermore it may be beneficial to apply the ultrasonic vibration to the mixture of the refrigerant and co fluid at a location at which the mixture of the refrigerant and co fluid is static or at a location of reduced or minimal flow rate of the mixture of the refrigerant and co fluid because fluids flowing at high rates can be more difficult to excite with ultrasonic energy a control module or controller 48 may be in communication e g wired or wireless communication with the ultrasonic transducers 44 and may control operation of the ultrasonic transducers 44 the control module 48 can control the frequency and amplitude of electrical current supplied to the ultrasonic transducers 44 e g electrical current supplied to the ultrasonic transducers 44 by a battery and or other electrical power source to control the frequency and amplitude of the vibration that the ultrasonic transducers 44 produce the control module 48 may also be in communication with and control operation.