What is the simplest type of expansion valve used in refrigeration systems?

The simplest type of expansion valve used in refrigeration systems is the hand expansion valve. This type of valve operates manually, allowing an operator to adjust the flow of refrigerant through the system by opening or closing the valve. This straightforward design does not require complex controls or sensors, thus facilitating easy installation and operation in basic refrigeration applications. Hand expansion valves are often used in small-scale or temporary refrigeration setups where precise control is less critical, making them a practical choice for systems requiring minimal complexity.

In contrast, options like the electronic expansion valve and the thermostatic expansion valve incorporate advanced technology to modulate refrigerant flow based on specific parameters, which adds complexity. The capillary tube expansion valve, while also simple in design, functions as a fixed restriction rather than a true expansion valve that allows for manual adjustments. While all these valves serve important roles in refrigeration systems, the hand expansion valve stands out for its simplicity and ease of use.