Have been pondering up something lately, maybe someone will have something to contribute.

A system wherein a compressor and condenser system is used as normal, however post condenser a suction line heat exchanger is added inline between the compressor and evaporator, and of course after the filter/drier mechanism. Past this suction line heat exchanger the system feeds into a capillary tube heading to the evaporator. However before this metering device a T is added and as well as a low temperature rated solenoid. (Post suction line heat exchanger after all). This solenoid feeds to a second even lower restriction metering device, upon which feeds to the suction line heat exchanger, such that this is turned in a sense into a subcooler.
The solenoid is linked to a fan cycler, and is set at the upper range of the systems high pressure; such that should a very high system pressure be reached, say 300 or 325 psi given the upcoming refrigerant information, the solenoid is opened feeding additional liquid refrigerant out of the high side, into the low side (raising low side pressure), and providing additional subcooling to the refrigerant mix.

The purpose of all of this being so that a system could be run using a near autocascade style mix, possible R290A and a double digit percentage of R170 (ethane). Thus the system operates at a lower temperature without wasting flow to maintain a sufficient heat exchanger temperature, and instead creates additional saturation when required.

Most likely the solenoid would be operated in short bursts, not greatly effecting the overall evaporator load, or when the system finds a nice equilibrium for a given load after first cooling down, does not find a need to operate the solenoid.

Any thoughts?