Modern industrial systems and processes pay attention to sustainability strategies. A popular and effective method for building sustainable operations is maximizing the energy efficiency of various industrial systems and processes. It reduces the environmental impacts of a process, equipment or company and translates to better cost-savings.

It is easy to assume that energy savings related to solenoid valves have little or no effect on the sustainability of fluid control applications. After all, these flow control devices draw small amounts of power during operation. The energy consumption may be small compared to systems like boilers and pumps, but it is still something that definitely needs to be considered.

Optimizing the design, operation and installation of solenoid valves can minimize energy waste. Consider an industrial process relying on dozens or hundreds of solenoid valves to control and regulate fluids. Optimizing energy usage on each solenoid valve saves several watt hours of electricity daily. The company significantly lowers its energy costs and reduces its environmental impacts. We should explore the following things to understand the energy consumption of industrial solenoid valves:

• How solenoid valves operate
• The factors impacting the energy consumption of each solenoid valve

Let us explore all factors affecting the energy consumption of industrial solenoid valves and appropriate ways to minimize energy waste without lowering the efficiency of fluid systems and the performance of solenoid valves.

How Solenoid Valves Work

Solenoid valves are automated flow control devices that are versatile and vital for different applications. They provide efficient means to automate fluid, improving the safety and reliability of various industrial processes. These types of valves contain two elements:

• An electromagnet (solenoid)
• A valve - has two or more orifices for fluid control

The electromagnetic draws power from an external supply. The electric power energizes the electromagnetic coil and causes the orifices to open or close. Energizing the electromagnet builds up a magnetic field and generates a force to push or pull a plunger and manipulate the position of a valve.

Some solenoids use a pivoted armature instead of a plunger. Cutting the power supply de-energizes the electromagnetic coil. This causes the plunger to return to its original position due to spring action.

Solenoid valves are available in different designs and constructions. These valves are either:

• Normally open or normally closed solenoid valves
• Directly or indirectly operated valves

Elements Influencing Energy Efficiency Of Solenoid Valves

Solenoid valves require external power sources to operate. Some valves consume less energy than others, while others are energy-intensive and can significantly affect process operating costs. The following factors affect the energy consumption of solenoid valves and influence their performances in different fluid control systems.

Size Of Solenoid Valve

The dimension of a solenoid valve determines how much energy it draws from the source for it to operate. A large solenoid valve has a big solenoid. Such a system requires more current to generate a magnetic field and develop sufficient force to push the plunger and open or close the valve.

Large solenoid valves may permit higher flow rates beyond the designed capacities. The increased flow rates can increase power demand to compensate for increased flow rates. Engineers may over-dimension solenoid valves during the design stage. Oversized valves may achieve the intended flow control requirements but draw excess, unnecessary energy from the main supply.

Peak Current Requirements

Solenoid valves require a brief current surge to magnetize the electromagnetic system. The momentary surge is called the peak current requirement. The peak current is usually higher than the holding current (energy needed to hold the valve in the desired position).

Peak current requirements influence the total energy consumption of solenoid valves. The design and size of solenoid valves determine the peak power requirements of a valve. That means larger valves draw more power than small solenoid valves. The electrical system supplying power to the solenoid valves should function well and deliver the required peak power. Valves will not operate well if the supply system cannot provide adequate peak current. It also leads to unnecessary energy waste and system malfunctions.

Peak current requirements vary for AC and DC-powered solenoid valves. Solenoid valves can consume more energy if their peak current requirements exceed the current supplied by the electrical system. The supply system struggles to draw more power from the main supply to compensate for the energy deficit.

Solenoid Valve Design

Various solenoid valve designs and types exist in the market to meet the flow control requirements of different systems and processes. Solenoid valve designs influence energy consumption in several ways:

• Complex valve designs containing additional components like a pilot or servo valve consume more energy. These components draw more power from the electrical systems to support the operation of the valve.
• An indirectly-operated solenoid valve consumes less energy than a directly operated one. An indirectly operated solenoid valve relies heavily on fluid pressure to function. The solenoid draws little power to create a small valve opening before the pressure of the service medium controls valve positions.
• Using a normally-closed valve in a process where valves remain open most of the time will lead to unnecessary energy waste.

Choose the design of a solenoid valve based on the specific requirements of a process or flow control application. Evaluate factors such as flow rate, pressure, and required precision to optimize the energy consumption of solenoid valves.

Solenoid Valve Cycle Patterns

Cycle patterns refer to the frequency and the duration the valve stays in open and closed states during operation. The cycle patterns significantly impact energy consumption by the automated flow control devices. Solenoid valves have different cycle patterns depending on the prevailing system requirements.

A solenoid valve can have a normally open or normally closed configuration. The normally open solenoid valve remains open whenever there is no power supply. The valve will only close upon energizing the solenoid. The normally closed solenoid valve only opens upon energizing the valve. 

The cycle pattern of a solenoid valve defines how long the valve stays in an open or closed state. Energy consumption spikes if the valve is required to open and close more frequently. Solenoid valves consume more energy if they stay in open or closed states long. The valve requires additional holding power to keep it in the desired operating position.

For example, frequently cycled solenoid valves consume more energy than those that remain in open or closed states longer. Solenoid valves that remain in open or closed positions for longer consume more power than those with shorter open or closed durations.

How To Reduce SV Energy Utilization

Reducing the energy consumption of solenoid valves yields substantial cost savings in the long run. There are several ways to achieve energy efficiency when dealing with solenoid valves without compromising the efficiency of the fluid application or industrial process. Here are practical ways to reduce energy utilization.

Size Solenoid Valves Properly

How do you size solenoid valves to meet the desired flow control requirements? Evaluate flow rates through the piping system when selecting or designing solenoid valves. One can easily over-dimension solenoid valves. However, there is a trade-off — prepare to spend more money on power bills. 

Under-sizing solenoid valves compromise the quality of fluid control applications. The valve might not achieve the desired flow rates. It can also be a source of leakages and fugitive emissions due to non-compatible connections or loose tolerances. To ensure effective and efficient flow control:

• Determine the flow rates through the piping system. Define the maximum and minimum flow rates. The flow rates are affected by the size of process pipes or tubes and the net pressure drop across valves.
• Evaluate the flow coefficient (Cv) value of the valve. The flow coefficient measures the flow capacity of the solenoid valve. The valve should have a Cv value equal to or higher than the designed flow rates of the piping system.
• Consider pressure and temperature variations of the fluid application. Each solenoid valve is designed to operate within specific pressure and temperature ranges (ex. High temperature steam valves vs Low pressure/gas solenoid valves). The valve should satisfy the system conditions aside from meeting the system flow rates.
• Ensure the solenoid valve is compatible with other system components. Check if valve connection points are compatible with adjacent pipes. Confirm if the solenoid valve fittings and control equipment conform with the existing pipelines and process and control equipment.

Optimize Valve Designs

Understand how different valve designs influence energy consumption. The first choice is between normally open or normally closed valves. They also weigh between directly or indirectly operated solenoid valves. The flow rate through a directly operated solenoid valve depends on the size of the orifices on the valve. These valves are critical for pipelines with low flow rates. These valves can work irrespective of the pressure differences between the orifices and do not require a minimum pressure to operate. The indirectly-operated valves are suitable for systems with high flow rates. These valves rely on system pressure to regulate and control fluid flow.

One should optimize valve designs depending on the intended application. Install a directly operated solenoid valve in a small, frequently-cycled fluid application. Use indirectly-operated solenoid valves when dealing with large systems like commercial irrigation pipelines. One can achieve higher flow rates, predictable energy consumption and consistent system responsiveness.

Use a normally open valve if the cycling requirements of the system require the valves to remain in an open position for most of the time. Energy consumption by these valves spikes when solenoid valves are energized. Where possible, reduce the number of additional parts that will increase energy consumption by valves. Utilize energy-efficient manufacturing materials to lower energy losses by solenoid valves due to fluid friction or wear due to the physical characteristics of the service media.

Evaluate Cycling Requirements Of Fluid Applications

As mentioned, cycling patterns dictate how frequently solenoid valves open or close. They also determine how long the valve remains in a particular position — say open or closed state. Solenoid valves chosen for fluid applications should sustain the cycle requirements of the application. 

When evaluating the cycling requirements of an application, engineers should consider the response times of the selected solenoid valves. Valves with faster response times can be energy efficient. But, can they sustain frequent on/off operations? It may be necessary to adjust valve control settings if the selected valves are out of sync with the control system.

Continuously monitor the cycle patterns of the fluid application and record energy consumption throughout the day. Track things like:

• How long does it take for the valve to open or close?
• How long does the valve stay in a closed or open position?
• How much energy do valves consume at each instance?

Use Auxiliary Circuits and Latch Solenoid Valves

Solenoid valves may contain additional electrical circuits to reduce energy requirements for operating solenoid valves. Such a system is beneficial when using DC-powered solenoid valves. Auxiliary electrical circuits provide temporary peak currents to energize solenoids and reduce power consumption.

After opening or closing the solenoid valve, they should remain in a specific position to achieve desired flow control. Energizing the solenoid manipulates the location of the plunger. Solenoid valves have a stop position at the top of the electromagnetic coil. It means the valve continues drawing power for the electrical supply system. Latching the solenoid valve offers an energy-efficient option for keeping the valve in the desired position. The valve is fitted with a small permanent magnet atop the electromagnetic coil.

The small permanent magnet is strong enough to hold the plunger in place. However, it cannot lift the plunger without the assistance of the magnetic force from the solenoid. The plunger can return to its original position by reversing the polarity of the power required to energize the solenoid valve. Latched solenoid valves consume less energy compared to those without such assistive systems.

Solenoid Valves Vs Actuated Ball Valves

Actuated ball valves can provide dependable fluid control as solenoid valves. Ball valves are highly-responsive to changes in flow conditions and control fluids by manipulating the positions of the flow control mechanism (hollow bore/ball). It can be necessary to energize certain solenoid valves throughout their operating cycles. Can ball valves replace unlatched solenoid valves?

Let's take an example of a solenoid valve and an actuated ball valve having the same flow coefficient (Cv) values. The energy consumption required to move a ball valve from its static position is higher than that required to energize the electromagnetic coil and actuate a solenoid valve. How does the daily energy consumption for these two units compare?

The ball valve consumes more energy to move from its original position to its intended position. The valve does not consume more energy once it achieves the desired flow control position. The actuator relay draws a small amount of power from the electrical supply system.

The unlatched solenoid valve might consume more energy than the actuated ball valve, even though they have similar cycle patterns. It is because the valve may remain energized for an extended period. This implies certain processes can utilize ball valves as alternatives to solenoid valves. If this is the case for you, and you are considering switching to ball valves, make sure you first evaluate the safety requirements of the fluid system, confirm the capability of the ball valve to meet the necessary chemical compatibility.

Conclusion

Solenoid valves are indispensable flow control devices that reduce human interventions in fluid applications. These valves are available in different sizes and designs to meet the performance requirements of various industrial applications and processes.

Improving the energy efficiency of solenoid valves demands proactive approaches to valve sizing and design. Reducing energy utilization and waste when operating solenoid valves yields substantial financial savings for large industrial facilities leveraging multiple valves to control fluid flow.