In a refrigeration system, what is the purpose of a TXV sensor bulb?

The purpose of a TXV (Thermal Expansion Valve) sensor bulb is to measure superheat in a refrigeration system. When refrigerant flows through the evaporator coil, it absorbs heat and changes from a liquid to a vapor. The superheat is the additional heat that the refrigerant vapor has gained above the temperature at which it would begin to condense back into a liquid.

The TXV sensor bulb is filled with a gas that expands and contracts in response to the temperature of the refrigerant vapor leaving the evaporator. This change in pressure within the bulb allows the TXV to adjust the flow of refrigerant into the evaporator based on the measured superheat. By controlling the refrigerant flow to maintain the proper superheat level, the TXV ensures efficient system operation, preventing issues such as liquid refrigerant returning to the compressor which could cause damage.

The other options focus on different functions within a refrigeration system: controlling refrigerant flow is a result of the sensor bulb's measurement; monitoring system pressure involves components like pressure switches or gauges, and detecting refrigerant leaks typically requires specialized detection equipment, rather than the TXV sensor bulb.