The best ideas are often the simplest
Minimising energy consumption with Fans and Pumps
These days, if you ask the management of almost any company about their immediate and medium-term operational priorities, the odds are high that minimising energy consumption will be at or near the top of the list. And when the list is broken down into where they can reduce that consumption, it should be sure to include fans and pumps.
In this article we focus on performance and energy improvements in Fan applications although many of the suggestions can be applied to other variable torque applications including many types of pumps and even hydraulic systems.
Not only is there an ethical and legal onus on organisations to cut their carbon footprint, but it makes economic sense too. Currently the UK emits 560 million tonnes of CO2 per year, with 40% of those emissions coming from industry. The emissions generally result from large scale energy use, which represents a major proportion of costs for many industries. This is dramatised by Cube Law, which means that energy used is cubed: so if one part is increased (or reduced) it has a cube increase or reduction. In other words, there does not have to be a major reduction in flow rates to result in a significant reduction in energy use.
The rising price of energy coupled with the increasing importance of cost-management combine to make energy-saving an important and pressing topic, which makes it worthwhile to focus on an area that utilises a vast amount of energy, often unnecessarily: fan and pump applications.
Simply reducing the speed of a 7.5kW fan motor by 20% typically equates to a saving of 6.5 tonnes of CO2 per annum and reduces energy consumption by around 40% – providing tangible savings.
However, the difficulty lies in knowing which fan or pump is best able to deliver cost savings, how great a reduction in speed is required to make a difference, whether that reduction is feasible without affecting the efficiency and performance of the fan or pump in its application, and whether or not the savings will make it worthwhile. Fans are used in numerous applications, but as a general rule savings can be made in the following applications:
- Air handling units
- Scrubbers
- Dust extraction
- Cooling towers
- Process and any other fan used in your production process
Identifying the correct steps to take to achieve savings can become even more difficult when you realise that there are in fact a number of ways you can choose to achieve the same end.
In a fan, for example, the simplest option is to change the ratio of the belt and pulleys. This is not only simple but also the cheapest and quickest method to reduce your costs. The necessary products are relatively inexpensive, readily available and easy to install, which means it is a high efficiency solution with a payback period measured in weeks rather than months. However, belts and pulleys have a finite life of approximately 25,000 hours which needs to be taken into account in any cost-saving calculations, and also space restrictions may mean that the change in ratios required to provide the savings simply cannot be achieved.
Alternatively, reducing the running speed of the fan by fitting an inverter and reducing the speed of the motor provides full speed control and flexibility. It is also an easy solution to install, providing extremely high efficiency, and ensures you use only the power you need. Again payback is quick – within a matter of months – and in this case with the added benefit of eligibility for funding from the Enhanced Capital Allowance (ECA) scheme, which provides businesses with enhanced tax relief for investments in equipment which meets published energy-saving criteria.
The third and final option provides the ultimate in efficiency and reliability. This involves reducing the running speed of the fan by fitting inverters, pulleys and belts and – where required – the new Revo air filter from Vokes. This option – which is easy to install – offers maximum speed control, flexibility and efficiency. Payback periods are again measured in mere months, and the installation is eligible for ECA funding.
You can find out more about funding, and the government’s ‘carrot and stick’ approach to carbon reduction and energy-saving, in the “Does saving energy cost money?”.
- Highly qualified engineers
- Analysis of current drive set-up, to evaluate savings to be made across all fan applications
- Solutions covering multiple core brand product selection, complete with carbon reduction figures, running cost savings and payback periods
- Optional panel and installation quotations
- Carbon trust loan calculation and assistance provided for SME companies