Well it appears that no one wants to engage in dialaog or knows everything there is to know about HVAC so I will post the little I know.
The first pic of course is a liquid line solenoid valve which is engerized open when the thermostat calls for cooling thus allowing freon to flow into the evaporator coil raising the pressure on the suction line which closes a low pressure switch within the outside condensing unit allowing the contactor for the compressor to engerize starting the compressor.
In the reverse mode when the thermostat satisifys the solenoid valve denergizes and closes the flow of freon to the A-coil the compressor continues to operate until the low pressure switch opens which in turn denergizes the contactor for the compressor and ends the cooling cycle.
This set up is called a pump down system.
The second pic is not a TXV valve no thermal bulb it is a AXV automatic expansion valve operates on pressure between the high side and the low side of the system. Very uncommon to find one of these AXV’s on a residential 3 ton system not to say that it is wrong but just uncommon.