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The abbreviation for a self-acting temperature control valve is temperature control valve; it represents a typical application of control valves in temperature regulation. When the load changes, such valves have the important function of adjusting the degree to which the valve is open in order to regulate flow rate. This allows them to eliminate any unnecessary effects caused by fluctuations in the load and help restore the temperature to its set value. Let’s explain how the heating system in thermostatic valves achieves effective energy savings: The heating system is calculated based on the maximum heat load required by the outdoor minimum temperature. However, the design temperature of a thermostatic valve is only relevant for a few days during the extremely cold seasons; this means that the heating system operates at full capacity only during those few days of the heating season. Generally speaking, the heat load required to maintain a comfortable room temperature is much lower than the designated value, and moreover, this heat load keeps changing. The heat load varies from day to day throughout the heating season. A thermostatic valve can automatically maintain the desired room temperature as specified, regardless of weather conditions. By installing a thermostatic valve in each room, it is possible to make full use of the “free” heat generated by sunlight, lighting fixtures, machinery, and human bodies, thereby achieving energy savings. Self-acting temperature control valves can automatically adjust temperature without the need for external energy, which saves labor and improves the efficiency of work in various companies and manufacturers. They are suitable for use in various heat exchange applications involving media such as steam, hot water, and hot oil. They are widely used for automatic temperature control in heating systems, air conditioning, and domestic hot water supply, as well as in special applications such as those in the chemical, textile, and pharmaceutical industries. With so many applications, how do they function? Let’s take a look together. A self-acting temperature control valve achieves automatic regulation by utilizing the principles of thermal expansion of liquids and the incompressibility of liquids. The expansion of the liquid inside the temperature sensor is uniform, resulting in proportional control. When the temperature of the medium being controlled changes, the volume of the temperature-sensitive liquid inside the sensor expands or contracts accordingly. When the temperature of the medium is higher than the set value, the temperature-sensitive liquid expands, pushing the valve core downward to close the valve and reduce the flow rate of the heat medium; when the temperature of the medium is lower than the set value, the temperature-sensitive liquid contracts, and the return spring pushes the valve core open to increase the flow rate of the heat medium. Self-acting temperature control valves are chosen with a diameter that remains as constant as possible during pipeline use; therefore, when using such valves, the issue of selecting the appropriate diameter arises. Valves of different diameters have different flow rate ranges under their control. When selecting a valve, it is advisable to set the design flow rate for the pipeline system connected to the valve within the upper part of its optimal operating range. If the valve diameter is too small, the valve will operate at the higher end of its flow rate range, which can easily lead to noise generation. If the valve diameter is too large, the valve will operate at the lower end of its flow rate range, resulting in large fluctuations in system flow rates. This can cause hydraulic imbalances in the pipelines outside the valve, as well as economic waste. Generally, it is better for the valve diameter to be equal to or one size smaller than the diameter of the interface pipes in the pipeline system.