Final answer:
The TXV bulb is generally liquid-charged as it contains the same refrigerant used in the system, which remains liquid under all operating conditions.
Step-by-step explanation:
The correct answer to the question is Liquid-charged. A TXV (Thermal Expansion Valve) bulb is charged with the same refrigerant used in the system, and some of it remains liquid under all operating conditions. This liquid refrigerant helps regulate the flow rate of refrigerant through the valve for optimal cooling efficiency.
For example, when the temperature inside a room is higher than the temperature of the refrigerant, heat transfer occurs, causing the refrigerant to condense from a gas to a liquid. The liquid refrigerant then flows back to the outdoor evaporator coils, where it is cooled and resumes the cooling cycle.