Process heating and steam production are significant sources of energy use for Australian industrial companies and some commercial sub-sectors. On a typical industrial site, boilers can account for up to 60% of energy costs and represent up to 35% of all potential energy efficiency improvements.
Process heating and steam systems require large amounts of energy and can easily decline in energy efficiency because system losses are often difficult to measure or observe.
Energy use in process heating systems can be reduced by lowering demand for heating services, improving the efficiency of heat production, heat containment and improved heat transfer, and by recovering heat for reuse.
Improved maintenance and management, such as using sensors and controls, can also help optimise performance. These measures reduce energy costs while increasing resilience to energy supply failure and providing improved workplace comfort.
Opportunities to save
Reduce demand for process heat and steam services
Reducing requirements for process heat and steam services can involve a number of measures. These include minimising the amount of material to be heated. This can be achieved through product design, managing reject rates and controlling the equipment transporting the item. Consideration should also be given to whether greater precision can be applied in the heat process and management of heat loads.
Improve the efficiency of existing process heat systems
The energy efficiency of existing process heat systems can be improved through efficient heat production, heat containment (reducing heat losses), ensuring efficient heat transfer and increasing heat recovery. Heat losses from distribution and transfer equipment can generally be managed and reduced. In some cases, shifting from centralised to decentralised heating equipment can also be advantageous.
Improve the efficiency of existing steam systems
The energy efficiency of steam systems can be improved by improving the efficiency of boilers and the reticulation system, point of use equipment and control systems used throughout the process.
Upgrade old equipment
Replacing old heating equipment, for example with modern, high efficiency boilers, can produce substantial savings.
Advances in chemistry, materials science and engineering, as well as the capacity to manipulate substances, means it is increasingly possible to either eliminate some heating processes or carry them out at lower temperatures.
Technical innovations include the use and production of enzyme-based detergents, micro-filtration, centrifuging, new catalysts and fluxes. Using non-metal materials such as plastics and composites in manufacturing processes is also reducing the need for high temperature production processes.
Waste heat reduction through the use of lower-energy processing techniques such as microwave (for brick-making), ultraviolet, and other electromagnetic processing.
Computerised design and the use of new materials, including alloys and composites, are offering potential opportunities in the future to improve the efficiency of process heat and steam systems through better insulation, heat recovery and the internal lining of pipes and process heating hardware.
Solar thermal technologies can potentially be used to fulfil a substantial amount of heat demand in industrial and agricultural food processes by providing energy needed for hot water and steam production, and product drying.
Cheaper sensors and smarter control systems also offer potential to improve the management and optimisation of heating processes.
Energy Efficiency Best Practice Guide: Steam, Hot Water and Process Heating Systems Sustainability Victoria
Technologies: process heat systems NZ Energy Efficiency and Conservation Authority
Process Heating Systems US Department of Energy
Solar Heat for Industrial Processes International Renewable Energy Agency.