Voltage optimisation in the domestic

[David]

I am starting to see companies now moving Voltage Optimisation into the domestic arena. What I understand is that the network is rated at 240V, but in practice this can be anywhere from 210V to 250V, yet domestic appliances can operate comfortably at 220V, so by cutting down the suppply from 240 to 220V you save 20V.

1. How does it actually work? What is the impact of the technology (ie Heat)?
2. Does it actually save money and carbon in the domestic billing environment?
3. Has anybody any experience with this? If so what are the potential pitfalls and when does it not work?

Any feedback, not from the sellers gratefully received.

Thanks
Dave Colbourne

[Matt Lucas]

Hi David
We are a "seller" as such, we are the national installer for a proven domestic. We aren't however the product manufacturer or distributor .
(I work for Carillion Energy Services formally Eaga). I'll give you my comments below if it helps.

You are right in that the national voltage average in the UK is around 240v-245v and most of today's appliances can operate at 210v - 220v
The technology we use steps this voltage down at source so only 220v is used eliminating the waste. (You can go down to 210v if you wish).
I'm unaware of any Heat implications but will check.

Yes it does save money and carbon depending on the set up in the home, monetary savings anywhere from £50 - £135 per annum can be achieved.
It's been estimated that the device will save over 4 tonnes of carbon over it's lifetime also.

The product we use has been tested and these savings were consistently demonstrated.

Some pitfalls to watch out for is that the device must be professionally installed by a qualified electrician both for health and safety reasons and to ensure the device is working correctly.
We wouldn't recommend installing the device if the property's voltage is already at 210-220v as little or no saving will be realised.
Where a property uses Electric Heating e.g. Closed loop (thermostatically controlled) no energy savings will be made through voltage optimisation.
Reducing the voltage applied to an ohmic heating element will reduce the heat output from that element and the power drawn by that element however the element will remain on longer to achieve the same heating effect (and therefore consume the same amount of energy).

It's a very exciting technology and one that we hope consumers will embrace to save money off their electricity bill.
Hope that helps

Matt

[Peter.Chisnall]

I'm still to be convinced over voltage optimisation in the domestic sector. I have looked into this for commercial applications and there the savings do stack up, particularly if there is a lot of lighting.

The way I understand the principle is it relates to Ohm's law, reducing the voltage albeit slightly, reduces the power consumption and for lights it means they operate slightly dimmer. However there is no such thing as a free lunch in connection with energy and other electrical equipment such as kettles and fridges need the same amount of electricity to do their work, so if the voltage is reduced they just operate for longer to convert that electricity into something useful like heat or cool, so no savings there.

[Matt Lucas]

Vo works well with refrigeration.

I've noticed no difference with lighting also.

[James]

Wikipedia (http://en.wikipedia.org/wiki/Voltage_optimisation) has the following to say on the subject:

However, there are criticisms of aspects of voltage optimisation, particularly its use in a home context. These centre around the issue that variation in voltage does not affect the cost of the power used in many contexts in the home. This is because consumers are charged through the power they use, rather than the voltage they use. For instance, for practical purposes, it costs the same to boil a kettle at 200v as at 240v, and uses same amount of power overall.[4]

In a similar way, devices fitted with a thermostat, such as a fridge, use very similar amounts of power at different voltages.[4] The "electrical" work needed to keep the fridge at a certain temperature is the same - (but it can be delivered more quickly at a higher voltage - the thermostat acts to keep the temperature and hence the power used the same over time however). Modern electronic devices such as PCs also have similar power management.

Therefore the main way that voltage optimisers are able to reduce power consumption and costs in the home seems to be to make lights become dimmer, the electric shower may become slightly less hot at a given setting etc. They may also save money by regulating spikes in the electricity supply that may reduce the life of electrical equipment.

There is suspicion amongst some members of electicians forums in the UK that the problem of "overvoltage" and "voltage optimisation" may be a marketing device in order to sell voltage transformers. See http://www.powerswitch.org.uk/forum/vie ... sc&start=0 and http://www.electriciansforums.co.uk/ele ... isers.html

Does anyone have any evidence to dispute this? Are there any subtle technical considerations that result in an energy saving with fridges/freezers?

[ClareRedfern]

I believe Stockport Homes (ALMO) are using these with their Solar PV scheme - perhaps try contacting them for an "in practice" opinion?

Personally I'm also not convinced, VPhase did a presentation at one of our recent CAN meetings and my initial thought is its too expensive, whose going to pay (privately) for something they cant see or more importantly check is working, then they were slated in Which magazine from what i remember for the fact that you have no way of knowing if the system is working or not, although I believe VPhase are disputing this.

[tony]

In my view expensive and akin to snake oil. Tony BSc with physics and domestic electrician