Date - December 2009
Over the last few years, the demand for electric heating products has increased - and in line with this, new, innovative and more sophisticated products have been developed. One of the main advancements in the electric heating sector has been the electric wet central heating flow boiler. Here Robin Wood, head of Heatrae Sadia's electrical division, explains how the company's Amptec electric boiler was designed to offer long life, reliability, end user comfort and energy efficiency.
The need for electric heating products for all-electric dwellings has certainly been rising. With one and two person households making up a significant percentage of the UK housing market*, housing developers have been encouraged to build a higher proportion of apartments, which are typically all-electric. In recent years the number of new build flats has increased - growing from 23,626 in 2000 to 56,823 in 2007 - changing the mix of housing in the UK quite dramatically.
In multi-storey dwellings, electric heating products are usually less problematic to install than mains gas appliances. There are generally few restrictions on the supply of electricity, and there are no flueing, condensate drainage or pluming issues to consider either. In addition, electric heating offers simple maintenance - which is particularly important in social housing properties, where gaining access for legally required annual gas boiler services can be problematic.
And, as electricity has become a more popular heating fuel, products have become more sophisticated. Fortunately, we have moved on from the inflexible, largely uncontrollable night storage heaters that electric heating was once associated with. Heaters which store energy overnight and release it during the day, whether or not it's needed, are not an appropriate solution for today's consumers - so electric heating manufacturers have responded with innovative products that provide heating and hot water when the householder wants it.
There are now many options to consider - some of which offer end users a level of controllability and flexibility that doesn't differ from mains gas.
For example, electric wet central heating flow boilers really revolutionised the electric heating sector. Their real strength is that they work in a similar way to gas fired boilers, which are of course very controllable. Electric flow boilers are used in conjunction with a conventional wet radiator or underfloor heating system. Providing central heating on demand, when it's actually needed, they are controlled and operated by a programmer and thermostat. They are usually compact and wall hung, and also very efficient - Heatrae Sadia's Amptec, for example, offers 99.8 per cent efficiency.
When designing Amptec, the main aim was to make the product as comparable to a gas boiler as possible in terms of user benefits and operating life. And, with the electric wet central heating boiler being a completely new concept, yet having huge potential, we wanted to bring something to market that was sophisticated, reliable and long-lasting.
So, we aimed to provide homeowners, developers and installers with a product that would stand the test of time. We ensured the product offered a long operating life, similar to traditional cast iron gas boilers, which can boast a lifespan of around 25 years.
While there are cheaper alternatives on the market, low-cost electric boilers will prove to be false economy, as after just a few years they will either need to be repaired or replaced. In comparison, products that last will save a homeowner money in the long run, and will offer peace of mind. Products that are designed to last for a long time can also be seen as more sustainable, as they reduce the amount of components and parts that need to be manufactured (hence also reducing energy usage and carbon emissions) and landfill.
To ensure a long operational life, several key benefits were designed into the product. For example, we use solid state technology, which is when circuits or devices are built entirely from solid materials, and the electrons, or other charge carriers, are confined entirely within the solid material. With solid state technology it is normal practice to exclude electro-mechanical devices with moving parts, such as relays and switches.
Whereas it is acceptable to use electro-mechanical switching on hot water cylinders, there are more switching operations required in an electric boiler, so a different approach is required if we are to ensure long life of the product. We believe that only solid state technology is suitable for the typical switching life required for a long-lasting electric boiler, and we avoided using mechanical relays to switch the heating elements on and off.
Using solid state technology also enabled us to use zero volt switching, which reduces thermal shock on the heating elements each time they are switched on and off - helping to prolong their life.
Another important consideration in the design of Amptec was Watt density. Having too high a Watt density can result in failure of the heater and damage to the material being heated or other components. The heating elements used in Amptec are designed to run at low Watts density, which is essential to prolong the boiler's life.
In addition, we also looked at materials closely, and chose copper sheathed elements. Tests have shown that in a typical central heating circuit using copper pipework, copper elements last longer than other materials.
The final thing to mention is Amptec's fully brazed heat exchanger. Heat exchangers made up of nuts, bolts and compression fittings can leak, but using a fully brazed component eliminates any risk.
Recent reports have actually confirmed that the number of electric heating installations taking place in the UK is on the increase, with some industry experts even predicting that in 10 years' time electricity could be the dominant heating fuel. In line with this view of the future, we have high hopes for the Amptec within the market, as it has been designed and developed particularly with long life in mind. Its design and innovation will provide reliable, energy efficient and comfortable heating for the customer for many years to come.
* Nearly 70 per cent, according to Office of National Statistics (April 2007)