Legend Power Blog

The problem of force consumption in terms of energy conservation is that of line loss resistance.

Facilities near the beginning of the grid receive voltage at a higher level than needed and waste energy. Over $1 billion is wasted per year by commercial buildings due to forced grid consumption.

Voltage optimization reduces electrical energy consumption by up to 10%, which also reduces the facility’s energy cost and greenhouse gas emissions.

Here’s a technical explanation of how voltage optimization is used for power reduction and power savings.

If a 5Ω load resistor is connected to a 100V source it will draw 20A and consume 2kW. If we now put a transformer between the source and the load to reduce the load voltage by 5% to 95V, the load current will be reduced to 19A, with a power consumption of 1805W. This is also the power drawn from the source, which will now be supplying 18.05A. It can be seen that both the load and source currents are lower than they were without the transformer, but at the transformer the voltage has been stepped down (0.95:1) and the current up (1:0.95), so that the power into the transformer is the same as the power out.

As far as the load is concerned a similar reduction could be obtained by adding another resistor in series instead of the transformer.  We would have to pick a value of 0.263Ω to achieve the same result. Now both the load and source currents will be 19A. The load power has still been reduced to 1805W, but the source power has only been reduced to 1900W. This is because, unlike the transformer, the extra resistor is also consuming power (95W).

The Legend Power Harmonizer-AVR system is effectively a low loss transformer with a variable ratio. Both source and load powers are reduced at the same time and the power can be measured either at the source or the load. As in any real connection there will be some losses and in the above example this would be less than 10W. Although the system could be set up to reduce power consumption at any voltage, it is normally used where the line voltage is too high. This means that the consumer is using and paying for more electrical power than needed and the Harmonizer-AVR reduces this consumption to normal levels.

For resistive loads the percentage change in power consumption is approximately twice the percentage change in voltage, for small changes. If we take a per unit approach to the example above a 5% reduction in voltage means the new load voltage is 1 – 0.05. The new power is (1 – 0.05)², which is 1² – 2 x 1 x 0.05 + 0.05². This is approximately 1 – 0.10 = 0.9 per unit, a 10% reduction, or 1800W.

As facility managers and electrical engineers in commercial and industrial facilities, we are often asked to consider power conservation. We are used to thinking of this issue in terms of lights, air conditioning motors, industrial motors and other devices that consume electricity running at 120 volts (or a multiple of that). However, all of these devices are built to withstand a range of fluctuation in the public power grid that can lead to higher and lower voltages being delivered to the customer’s facility.

In reality, there is an optimal minimum voltage range below 120 volts where lights, motors, and other electrical equipment will operate with no perceptible effect on their practical performance. For example, at 114 volts the electrical loads mentioned above will generally operate with less waste, less heat, longer life, and a lower carbon footprint. Plus, since they are using 114 volts instead of 120 volts, they also consume less energy.

There are two key factors stopping us from delivering the minimum optimal voltage and consistently achieving maximum electrical energy efficiency in commercial and industrial facilities:

1. The physics of the power grid
A substation feeds electrical power to a number of facilities. Since there are inherent inefficiencies or “leaks” (line loss) along any length of cable run, the power company must deliver more voltage than is required to the buildings closest to the substation, so that facilities furthest from the substation will receive at least the minimum rated voltage. As a result, it is impossible for the power company to deliver the same, consistent and efficient voltage level to each facility.

2. The fluctuations in the power grid
Power supply is like DSL High speed internet – the more users on a line, and the more power each user wants, the greater the effect those users have on the actual power delivered to each individual. In other words, at peak use times the voltage to your facility drops, just like the speed of your internet drops during peak times. Since the power company must always deliver enough electricity to allow for “peak demand,” the voltage being delivered at non-peak times to your facility can rise well beyond what is efficiently required.

If a commercial or industrial facility measured their incoming voltage and found that it was quite high, they could install a transformer that would step down the incoming voltage by a certain percentage. This “fixed tap” transformer solution has been available for decades.

However, if the grid power fluctuated down, as detailed in point two above, the percentage reduction is “fixed” and the voltage can drop too low, causing a brown out, which has a visible impact to lighting and which can damage motors and other electrical devices. For this reason, in most cases in North America, fixed tap voltage reduction cannot achieve the best efficiencies while maintaining operational integrity.

The factor that most building owners and facility managers do not realize is that these inherent weaknesses in the general power grid mean that the power company must force feed some of its clients electricity they neither need nor want … but then you, the client, must still pay for that unnecessary power. In short, even though the electrical items in our buildings do not need the higher voltage, and, in fact, that higher voltage reduces the service life of electrical items and creates wasted energy through excess heat, the facility is STILL BILLED FOR THE EXTRA ENERGY.

Legend Power Systems Corp. provides a simple and effective solution that allows qualified commercial and industrial facilities to reduce their voltage to the optimal minimum level, without any worry about going too low when the power grid fluctuated down at peak times.

About Legend Power’s Electrical Harmonizer-AVR for Commercial-Sized Buildings

Legend Power’s Electrical Harmonizer-AVR is a patented and approved commercial/industrial power conservation unit that:

• Saves 6-10% on your facility power bill
• Lowers maintenance costs
• Reduces your facility’s carbon foot print
• Delivers an ROI in 3 years with available incentive funding
• And, can be up and running within a week with no interruption to the building or workers, and absolutely no changes to their work process or environment.

Ask us about ensuring that your facility is no longer receiving, or paying for, voltage that you just do not require.

David Orton
sales@legendpower.com
604.420.1500

Legend Power will complete a detailed audit, at no charge, ahead of the proposal to give you a clear savings figure.

Other Resources
* Have a look at our corporate video to hear what IKEA, Science World, and BC Hydro say firsthand about how effective the Legend Power system is for them.

Welcome to Legend Power’s new blog. Legend Power is an energy conservation company. Through a process called voltage optimization, we help commercial and light industrial facilities save electrical energy, both reducing their utility bills and carbon footprint by 6-10%.

For more information on what we are all about, check out the video below:

There are thousands of products available and countless articles published daily dealing with energy conservation and reducing green house gas emissions; our vision for this blog is to provide regular commentary on the energy conservation industry in as much of an unbiased approach as possible. Check back soon for updates.

Cheers,

Erik