Products to save energy ... or maybe not?

Announced on the Internet and in the famous 'teletiendas', energy savers flooded the market offering potential buyers the possibility of lowering the electric bill from 10% to 30%. With the climbs that we are suffering, and those that are about to arrive, it is a very attractive advertising claim, but the question that comes out is: Do they fulfill what these devices promise? How do they work?
The R & D department of my company has tested one of these devices. We have disassembled and analyzed its components, and just open it we called attention to the simplicity of its elements. But let's first see the characteristics that, according to its vendors, have the Electricity-Saving Box, from now on, ESB.

Energy Saver Box disassembled It's everywhere: Web pages and online stores created for the sole purpose of marketing it, on YouTube channels and in the famous 'teletiendas', among others, and its price ranges between € 17.50 and € 50 Among the most relevant benefits offered by this device are:
Save energy
Improves the power factor
Protects appliances against voltage spikes
Stabilizes consumption
Save money

How does the Electricity Saving Box work?

Its surprising simplicity makes its operation instantly clear:

Inside of the Energy Saver Box The main component is neither more nor less than a motor capacitor mounted in parallel, used as surge suppressor to start motors. It is not the only component that is usually used in these cases; for example, star-delta connection switches are also used in the electrical panel, and the capacitor is sized according to the motor that we are going to maneuver. The capacitor is manufactured by the CHIRX brand.
The components that are in the printed circuit do not have much more utility than to make that the 2 green LEDs that there are in the housing shine, indispensable to give the impression of a complex operation and that the ESB does something in fact. An electrolytic capacitor, a rectifier bridge of full-wave diodes, polyethylene capacitors, resistors ... are just typical components used to supply constant current to an LED.

Components of the Energy Saving Box In the following video we will experiment with different types of loads and we will check if the ESB has all the qualities that it announces:

1. Save energy. FALSE.

In no case does the ESB achieve a decrease in kW / h. In fact, it increases it with its own consumption.

Improve the power factor. FALSE.

The power factor (hereinafter PF) is the relationship between the active power P and the apparent power S, also known in some circles as Cos. The result of the geometric sum between P and S is known as 'Reactive power Q'. It is here that the ESB assures to act, altering the value of the power factor, assures to obtain a Cos closer to 1, reducing the value of Q.

'Q' can originate in an inductive or capacitive load, or simplified, it can be negative or positive. The most common inductive loads such as motors, coils, arc furnaces and ballasts, usually generate electrical quality problems when they cause a very high lag between the voltage and the supply current. To solve this problem, the industry uses capacitor banks, which are nothing more than capacitive charges that oppose the inductive ones, compensating them, thus reducing the value of the reactive energy, making the angle φ much more acute, and its cosine Approach 1. The capacitor banks can be very complex, with reading, diagnostic and maneuvering instruments to control that the capacity of the battery is always correct and thus be able to keep the charges correctly compensated. In no case is it a simple condenser, since the charges always vary according to the activity that develops at that moment.

The working method of the ESB, simply, is to put a capacity of 6.0uF at all times without any other consideration. If it turns out that coincidentally our power factor is 0.65, putting the ESB the PF will become ideal, but such a condition will vary as soon as we turn off a device or light another. If our charges are appropriate and we connect the ESB to the network, the opposite effect will occur, that the PF will worsen as we saw in the video with the LED tube or the resistive halogen load. In short, the ESB does not work because it puts a capacitive load fixed to the fixed gear without considering the inductive load that we have.

Protects appliances against spikes. FALSE.

Except for the limited capacity that the condenser can have to absorb peaks, the ESB does not have any element of protection, filter or interruption. There is no fuse, varistors, filters, suppressors, and it does not even have a ground connection.

Stabilizes consumption. FALSE.

Apart from the ambiguity of the statement, as we have already said, the ESB does not have enough elements to carry out any of the aforementioned functions. The most common consumption stabilizers on the market are UPS Uninterruptible Power Systems, which among many other components, need batteries to function properly.

Save money. FALSE.

The ESB does not comply with any of the functions for which it is sold, and even if it complies, we must take into account certain particularities of the electricity business in Spain. Reactive power meters are only profitable in industry, where the volume of consumption and the type of loads used (engines, arc furnaces, large surfaces with fluorescence) demand a system to control that companies regulate their electrical quality downstream from your accountant.

It is a very simple fact to verify that in the residential area no penalty is charged for reactive consumption, you only have to read your last electricity bill and verify how no reference is made to the reactive. It is evident that no company can charge us for a variable concept (as is the reactive consumption) without quantifying it and specifying it in our invoice. For industry according to the necessary rate and the type of charges may be necessary, but as we have said above, more complex and more expensive systems are needed than a device sold on websites at € 50 and others at US $ 3.
More in depth: Harmonic distortion (THD)

One criterion that very few people take into account, but that certainly does not lack importance, is the harmonic distortion.

According to IEC 61000-2-2, a class C electrical element, such as an LED tube, must have a third-order harmonic percentage not higher than the product resulting from its power factor and 30.

The electrical quality reading of our LED tube with reference TUT820SKS150, yields the following result:

After connecting the ESB, the results change drastically, positioning as follows.

In conclusion: when connecting the saver, in reality the electrical quality of our installation is deteriorating.