[jeff5may]

dc€x,

The Gree unit you referenced is a perfect example of the type of units the OEM's are producing now. Obviously, the manufacturers have done the research and know how to control these units. Electronic valves, variable frequency or DC brushless motors, and digital controls with temperature sensors everywhere inside the unit.

EDIT: I was not aware of the massive progress in this realm.

On the industrial side, the big mfr's have "universal superheat" controllers that can be rigged to basically any vapor compression system. Emerson, Sporlan, and Danfoss all have kits you can buy to convert whatever you have to electronic, seat-of-your-pants-efficiency. Basically, the older and more complicated the system is, the better the new control scheme and valve will improve it. The controls go together like erector sets, and are self-learning.

On the consumer/residential side, the OEM's use programmable controller chips much like found in TV sets and microwaves to make the units behave however they want them to. From one basic chassis, many unique models are produced. The OEM simply mixes and matches from a menu of approved components, then flash the controller with firmware to enable whatever unique features that unit possesses. The unit is loaded with sensors, which feed back to the self-learning controller. Once the unit runs for a few minutes, it optimizes its own efficiency.