The control valves could they are but regulators accessories? In the catalogs of control systems suppliers and GTB, the valves are sometimes relegated to accessories such as measuring sensors. However, the actuators are the components which condition the qualities of the regulations; these qualities are of prime importance for efficiently controlling energy systems.
What is the role of control valves in energy efficiency?
First, note that the quality of an action chain does not exceed that of its least performing component. The least efficient is the one that involves mechanical components. Valves are the only mechanical elements of regulation chains, essential. Using the globe valve also offers a great variety of supports now.
The qualities of digital processing and communications make it possible to achieve perfection with regard to the expected results. The qualities of sensors have progressed with integration and microelectronics technologies. But a mechanism cannot be free from friction, wear and inertia.
In addition, leaks when closing are to be feared. A leakage rate, even a very small one, causes a thermal power “leak” which can be substantial, throughout the duration of the closure. It is a cause of wasted energy which can be significant.
The manufacturers must master several technologies which make the qualities of the valves; the precision of the mechanics is an essential element.
Control valve body
So, to effectively regulate energy, attention must now be focused on the control valves. To act on energy transfers by water, it is necessary to modulate the surface of a restriction to the passage of water. There is no other solution to gradually regulate thermal energy. The mechanical energy to circulate the water in the distributions is therefore lost mainly in the valves.
- For the progressive adjustment, it is known that the valves must exhibit a high pressure drop on opening (approximately 50% of the load of the regulated circuit). This ratio is established for the total opening, at nominal values.
- But during operation, during a large part of the heating or cooling season, the fraction of the mechanical energy lost in the valve goes as far as 100%. Control valves therefore drop almost all of the mechanical energy (the load) spent to circulate the water that distributes thermal energy. It is however a necessary condition to modulate the thermal power.
- Along with the quality of regulation, the electrical energy for water circulation is an additional reason to pay attention to the choice of hydraulic circuits and valves to regulate thermal energy.
The preferred solution now consists in choosing circuits fitted with two-way valves which modulate the flow of circulators whose differential pressure is regulated: constant or proportional to the flow.
The efficiency of the regulation and the control of the consumption of auxiliaries gain there
Progressive valves are placed in all parts of the climatic engineering installations. They are used to control the generator circuits, to adjust the water temperatures at the head of the networks and the powers emitted by the terminals.
In addition, the distributions are usefully equipped with motorized shut-off valves, sealed when closing, to segment the distributions of zones or sub-zones. They allow energy supplies to be dynamically adapted to the needs of the areas.