Does anyone know what the microchannel heat exchanger for air conditioning is all about?

Micro-channel heat exchanger is a new type of heat exchanger, different from the traditional copper tube + aluminum foil structure form, it is all-aluminum material, the traditional copper tube + aluminum foil heat exchanger, the outer diameter of the copper tube is generally 5mm, 7mm and 9mm, through the expansion of the form of the tube interspersed with the aluminum foil, while the micro-channel heat exchanger refrigerant channel is a root of the flat tube in parallel, each flat tube inside the 10 or so channel, each channel of the The inner diameter of each channel is less than 1mm, so that the contact area of the refrigerant increases, the same volume of heat transfer effect is better, so it is called micro-channel heat exchanger. Micro-channel heat exchanger is now mostly used on the outside of the machine, because it has a big disadvantage, the refrigerant sound is larger, with the noise on the inside of the machine is not good.