A thermostatic expansion valve (TXV) is a crucial component in refrigeration and air conditioning systems. It regulates the flow of refrigerant into the evaporator coil based on the temperature of the refrigerant. By adjusting the flow, the TXV helps maintain optimal cooling efficiency and prevents the evaporator from freezing. The TXV operates using a sensing bulb filled with refrigerant that expands and contracts with temperature changes. When the temperature rises, the bulb expands, opening the valve to allow more refrigerant to flow. Conversely, when the temperature drops, the valve closes to reduce the flow, ensuring the system operates effectively.