Voltage Optimisers
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 Power Distribution Units

Energy Saving Voltage Optimisers

Voltage optimisers systematically reduce the voltage of the mains power supply entering a domestic, commercial or industrial building to reduce the level of energy uses and reactive power. Some voltage optimisers have a fixed voltage adjustment, whilst others can automatically and electronically regulate their supply voltages. Commercial building and industrial voltage optimisers tend to be based around auto-tap-changing transformers, with advanced electronic control circuitry, whilst smaller domestic voltage optimisers tend use a toroidal type transformer. Domestic voltage optimisers and Commercial units (up to 100A) can be purchased for home installation by a certified and qualified electrician.

For larger Commercial and Industrial Voltage Optimisers, we recommend a voltage optimisation desktop survey to quickly assess if a voltage optimiser is right for your application. Please complete our VO desk top assessment form and send us (post or scanned) a copy of your most recent electricity bills

Carbon Trust

The UK Government provides funding for voltage optimiser financing through the Carbon Trust. Loans are available with capital enhancement incentives for projects costing from £3,0000 to £100,000 and which are repayable within a project payback period of up to 4 years The loan size is based on the amount of carbon dioxide that can be saved by the project. EcoPowerSupplies.com works with Voltage Optimisation companies who are registered with the Carbon Trust and can assist in application and project planning for energy saving project loans.

For more information on voltage optimisers call the Eco Power Projects team for advice or to arrange a site survey or quotation on 0800 612 7388, email us or complete our enquiry form.

How Voltage Optimisation Units Work

Voltage optimisation is a voltage correction technology that reduces the AC voltage supplied to electrical equipment to reduce their electrical power usage and allow them to operate at their optimal efficiency. The following example helps to explain the concept in terms of Ohms Law.

Voltage = Amps x Resistance (V=IR)

Power = Volts x Amps (P=IV) Watts

In the table below we use a mains power supply wire with a constant resistance of 100 Ohms and can calculate the current being drawn at the two AC voltages. We can also calculate the power being drawn and show the saving.

SituationMains Power Supply VoltageCurrentPowerSaving
No Voltage Optimiser250Vac250 × 100 = 2.5A250 × 100 = 2.5kW
Voltage Optimiser Installed220Vac220 × 100 = 2.2A220 × 100 = 2.2kW0.3kW

This example shows a saving of 0.3kW or in terms of how we are billed electricity 0.3kWh. Over a 24 hour period the saving is 24×0.3kWh=7.2kWh or in a year 109.5kWh.

Using VO with Solar PV Installations

Installing a voltage optimisation unit to an installation already benefitting from a solar PV installation can provide the following further benefits:

  • An Overall reduction in energy consumption from voltage optimisation.
  • As building systems will use the Solar PV generated electricity first, less electricity has to be imported from the Grid, lowering operating bills.
  • Reduce wear and tear on electrical systems and appliances, especially if the AC voltage from the solar inverter is higher than the local mains power supply.

The ideal installation places a voltage optimiser between the consumer unit and its AC power sources: the mains power supply or a solar PV inverter. The voltage optimisers from EcoPowerSupplies.com can be retrofitted to existing solar PV installations by a suitable qualified electrical contractor.

Potential Savings

The following voltage optimisation examples of savings are based on a 7.5% voltage drop (242Vac to 224Vac)

Appliances with MotorsA-rated Freezer/Refridgerator 16%, 3-speed heat pump 15-18%
HeatingResistive heating 14%*
LightingCompact Fluorescent Lighting 11%, Sodium/Discharge 15% Halogen 12%, High Freq Fluorescent 0%
MotorsAir Compressors 12%, Circulation pumps 12%, Fans 12%, Vacuum cleaner low power 24%, Vacuum cleaner full power 16%
TVs/ComputersCRT 5%, Plasma/LCD 0%, PC 4%, Laptops average 6%, Radio 9%, Printer 7%, Scanner 12%
Consumer ElectronicsDAB Radio 5%, DECT phone base station 30%, ADSL modem and wireless router 5%, HiFi 13%

*thermostatic control will result in a much smaller saving.

Site Surveys and Project Process

Domestic and some commercial voltage optimisers can be sold as standard units that require connection by a suitably qualified electrical contractor who will select an appropriate setting on the unit to match it to the local mains power supply voltage. Larger units require a site survey and the manufacture of a suitably matched unit. This is more common for larger commercial systems above 100A and industrial-sized systems.

Spike and Transient Suppression

Voltage optimisers do not typically provide surge or transient protection. This can be achieved by connecting a surge protected power strip or power distribution unit (PDU) to an upstream socket or fused-spur, or the installation of Transient Voltage Surge Suppressors (TVSS) within LV switchgear and circuit-breaker boards.