Feature

In the manufacturing industry, energy costs are said to account for around 20% of a business’s overheads*. This is a considerable expenditure and one that could limit their growth potential. It’s easy to understand how a business can spend so much on energy costs when, in my experience, our engineers have routinely identified that boilerhouse managers tend to believe that they are operating at an efficiency level 15% higher than they actually are. This is likely due to them not having complete visibility of their boilerhouse components.

With economic uncertainty dampening the abilities of businesses to compete in a domestic and global market, companies are under increasing pressure to reduce operational costs. With this uncertain atmosphere in mind, energy managers can often find themselves tasked with identifying the efficiency of the boilerhouse in order to remedy this situation.

In my experience, the means of monitoring energy in most boilerhouses can quite often be limited. This can therefore translate into a limited knowledge of overall boilerhouse performance, with facilities often unaware of where energy losses could be identified. Indeed, it is frequently the case that boiler operators will be making use of the burner efficiency to indicate the overall efficiency of the boilerhouse. What they may be unaware of is that this method does not highlight all of the potential energy losses that can occur due to factors such as dirty heat transfer surfaces, carryover, radiation losses and excessive boiler blowdown rates.

By making use of burner efficiency for overall boilerhouse efficiency, boiler operators may be overestimating the performance of the system. They would gain a better understanding of their boilerhouse by metering all of the energy entering the boiler – both fuel and feedwater and compare this with the useful energy exiting the boiler in the steam.

This type of monitoring was once only possible by investing heavily in Building Management Systems (BMS) or Supervisory Control and Data Acquisition (SCADA) software systems. Monitoring in this way was a costly means of measuring energy use and could be prohibitive for smaller businesses. The upfront investment in such systems was not a cost-effective means of measurement as they only log non-compliant operations as opposed to providing the ‘why’ that exists behind that data. This is critical for those who operate the boiler as without it they could find themselves failing to observe where energy costs could be reduced and efficiency improved.

As has already been identified, boilerhouse operators tend to overestimate the performance of their energy systems. As such, it could transpire that energy losses are greater than first anticipated, resulting in increased fuel costs to account for creeping losses via the flue, radiation, distribution, flash, blowdown or condensate.

Take manual blowdown, for example – if it is insufficient it can cause scaling, which may result in rising energy costs. On the other hand, excessive manual blowdown can increase water usage – another undesirable outcome.

Using historical trending plant data, it is possible to better understand the fuel consumption, feedwater usage, steam production, condensate return and blowdown volumes of the boilerhouse. Logging the amount of condensate being returned to the boiler’s feedwater system for instance, enables boiler operators to accurately manage the water treatment plant output and better identify potential opportunities to increase fuel efficiency and reduce associated fuel, water and effluent costs.

Yet data analysis is only a first step – while management teams may be accustomed to some level of distribution loss, the true numbers can only be discerned with a monitoring system that provides a complete overview of the system that they may have otherwise lacked.

Spirax Sarco’s B850 boilerhouse energy monitor for instance, offers a cost-effective means of measuring the overall boilerhouse efficiency. The monitor accurately calculates the efficiency of the boilerhouse based on measured inputs from the fuel, feedwater, steam output, condensate return and blowdown. Cost-conscious boiler operators can utilise this data to make improvements in the efficiency of their steam system – yielding energy savings and reductions in the financial expenditure of the business.

With the right data in-hand, operators and management teams can systematically improve the steam system to limit the energy losses at multiple points. Take for instance water treatment and boiler water conditioning. This has significant potential for improving overall energy efficiency and lowering the total cost of ownership (TCO) of plant.

Treatment can help to prevent the build-up of alkaline deposits on heat transfer surfaces. Without treatment these deposits could form layers that act as a barrier against effective heat transfer, reducing the energy efficiency of the boiler dramatically. For example, a deposit layer just one millimetre thick could lower system efficiency by around 10%.

There are several other areas around the full boilerhouse system where losses can be found such as the economisers, flue-gas shut-off dampers and blowdown heat recovery. Equally, where there are losses, there is scope for efficiency savings. To achieve this boilerhouse operators can help themselves and their businesses by making use of intelligent monitoring systems.

In conclusion, UK businesses may continue to suffer from weakened competitiveness due to rising energy costs and an increasingly uncertain economic environment. Yet these businesses could reduce their operational costs by monitoring the energy performance of their boilerhouse. By cutting the costs of this energy, businesses could find that they are able to save money on their fuel bills.

The rigorous monitoring of the energy performance of the boilerhouse provides the foundations for cost-saving and reductions in fuel consumption. The future is uncertain enough, the finer detail of the operator’s steam system doesn’t have to be – with an energy monitoring system, losses can be quickly identified and rectified to put a stop to excess waste.