Independent testing undertaken by Titanium Products Ltd. confirms that energy cost savings of at least 6% can be added to the known lifetime benefits of titanium sheathed water heating elements and that the use of titanium represents a reliable and cost effective solution for hard and aggressive water applications.
Domestic hot water systems in hard and/or aggressive water areas have typically used nickel alloy sheathed heating elements, instead of copper, to combat the effects of lime scale build-up and corrosion. Titanium elements have been available as an alternative to nickel alloy for some time and their long lifetime benefits have been proven. Well-documented examination of both types of heater after many years' service in domestic installations has demonstrated minimal scale build-up on titanium elements compared with heavy encrustation on nickel alloy.
The Titanium Products Ltd. test programme - carried out by WatStech, the Water Science & Technology Group from the University of Wolverhampton - was set up, therefore, to measure the energy cost benefits resulting from reduced scale and corrosion build-up.
The methodology involved a series of trials with two identical 70 litre cylinders of synthetic hard water, maintained at a constant
56° C temperature using standard 3kW heaters - one of nickel alloy Superloy 825 (a nickel, iron, chromium alloy with molybdenum, copper and titanium additions, designed to provide exceptional resistance to corrosion), the other a titanium element, produced in an unalloyed titanium to specification ASTM B338 Grade 2.
An initial three week period of constant running combined with hard water drain down and top up was allowed for conditions to stabilise, followed by a six week period where both heaters were monitored 24/7.
The results indicated a power saving of 6% in favour of the titanium element.
However, it is believed by Titanium Products that the 6% cost saving is significantly understated for two key reasons. First, during the six weeks period, there were only eight replenishments of five litres of synthetic hard water whereas domestic consumption levels would be expected to be much higher.
Secondly, the power saving in the tests was achieved over a relatively short running time. A continuous build-up of scale over time on the nickel alloy element would result in much greater savings.
Says Titanium Products' MD, John Turner,' So encouraging are these test results that we are pushing forward to quantify precisely the life cycle cost benefits to the consumer, including the payback period. Such further work will also allow us to look at potential design benefits of reducing energy costs even further by using thinner tube wall thicknesses and utilising the higher thermal conductivity properties of titanium.'
Titanium Products Ltd. is a supplier and manufacturer of titanium welded and seamless tube and strip, specialising in non-standard sizes. The company also supplies machined components, welded and fabricated assemblies.