Morphing Air Conditioner into Autocascade System

[mytekcontrols]

The new project is coming together, and now pressurized for leak check. Insulation of the HXC stack should occur possibly later today.

As can be seen in the photos, there are quite a few valves involved. Here is a breakdown of their use:

1. Sporlan A3F1 - Buffer Valve
2. Sporlan A3F1 - Defrost Valve
3. Sporlan A3F1 - HXC ByPass Valve
4. Danfoss BML10 - Comp Suction Valve (hiding under solenoid valves)

The "HXC ByPass Valve" is activated during the defrost cycle at the same time as the "Defrost Valve". It's purpose is to reroute the returning hot gases from the evaporator directly to the compressor suction. This prevents heating up the HXC Stack while defrosting (allows for faster cool-down when defrost is terminated, and the unit is once again put back into cooling mode).

The "Buffer Valve" is used to dump gases from the 1st phase separator directly into the combo Buffer/Expansion Tank whenever compressor discharge pressures exceed a preset amount. These gases are then metered back into the suction via a very small captube.

The "Comp Suction Valve" allows for doing pump downs to verify the integrity of the compressor, and also to suck in a charge from a pre-mix tank. It has an extended shaft routed out to where the front panel will eventually be, to allow access.

AC3 Modes of Operation:

1. Compressor ON = COOL MODE
2. Compressor ON w/Defrost Valve Open = DEFROST MODE
3. Compressor OFF when Defrost has completed = STANDBY MODE

There is no independent Cool Control Solenoid Valve. The ever so higher flow of the defrost circuit, effectively prevents any flow from the final evaporator captube, and thereby prevents cooling while defrosting. When defrost is done, as determined by a temperature switch monitoring the evaporator return, the compressor power is terminated. This puts the system effectively into "STANDBY MODE". Reactivating the compressor puts us back in "COOL MODE".

Eliminating the Cool Valve allows for standard refrigeration rated components to be used, and thereby keeps the cost reasonable.

Target Evaporator Temperature: -155C