Modern factories are investing in technology to reduce their energy consumption, costs and CO2 emissions. This is not new, but the process of digitalisation and decarbonisation has accelerated to meet global energy transition and sustainability goals.
In addition, the constant increase in energy costs pushes companies to become more efficient and reduce overall expenditure to stay competitive. If you want to reduce your internal costs to avoid increasing prices charged to your customers, you have to seek cost-saving options. You can start by establishing energy efficiency measures.
Worldwide, manufacturing is a major energy consumer. In the UK, the industrial sector accounted for 17% of the total consumption.
Fortunately, given this high percentage of energy consumption, there are options available to use it more efficiently and even reuse it. Waste heat from your machines is a source of energy that you can exploit.
What is this residual heat?
Waste heat or residual heat is the heat produced by your machinery when creating products and by-products. It can be intentionally-created heat or heat released from the simple industrial manufacturing process (metals, automotive products, tiles, food products, etc.).
It can be qualified as a consequence of the production process, usually lost in the air. This is perfectly normal, as your operations team is ensuring that the production process is running smoothly and at a good pace. You might however be interested to know that some of that heat can be harnessed as an energy source in your factory.
Interesting, isn’t it?
In this article, we look at how you can utilise that waste heat to generate energy, the benefits it can bring and how to measure the impact of your utilisation strategy.
Harnessing Waste Heat in your Factory
We know that waste heat is produced during manufacturing processes, but can it really be recovered?
Yes, waste heat can be converted into energy that can be reused in other production processes in your factory, or for heating, among other things.
This is a complex process, as waste heat exists in different states: gas, liquid or solid. It can also vary in temperature, another factor that needs to be taken into account when defining utilisation strategies.
Fortunately, many energy and industry professionals have already explored ways of harnessing this kind of heat. The main idea is to use thermoelectric generation processes, to produce energy through heat. Although further development is still underway, this technique includes storage and condensation pipes to collectors and transformers.
Before outlining the technical details for harnessing waste heat, it is essential to first identify where the waste heat can be recovered. In other words, which processes generate it and at what temperature. For instance, those machines such as a furnace or a foundry require more energy and heat than they used would be the first targets.
Your industrial processes do not include furnaces? Boilers, batteries and large-scale cooling appliances also produce heat that can be used.
Another way in which an industrial building can exploit waste heat is through the provision of waste heat storage points. These thermal storage solutions have been developed to enable the heat generated by industrial processes to be reused afterwards.
You can also make use of the waste heat from a machine that remains warm for a long time after it has been turned off. In this case, heat collectors are used to taking advantage of heat transfer by radiation.
Let’s illustrate the theory with examples:
The European Union is funding several Research and Development (R&D) projects. One of the most recent is ETEKINA, a project to recover up to 70% of waste heat in energy-intensive industries. It is a collaboration between Brunel University in London, a technology company specialising in heat recovery, and three factories in Spain, Slovenia and Italy. The sectors chosen for this project were aluminium, steel and ceramics manufacturing.
The aim of this project is to develop a solution, based on heat exchangers and pipes (pipelines), to recover waste heat in factories. The results of the study have been quite favourable, allowing the recovery of heat from industrial elements as diverse as air, water and oil.
Although the recovery of heat itself is no new idea, the implementation of such type of project especially for large-scale applications plays an essential role in the process of the energy transition, CO2 emission reduction and energy efficiency in Europe.
Read more about the 3 benefits of waste heat utilisation in your factory in our article: