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
- improved heat transfer
- 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.
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.
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.
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.
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.
Other innoivations are outlined below.
Waste heat reduction
Reducing waste heat hrough 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,
New materials, including alloys and composites, are offering opportunities to improve the efficiency of steam systems through better insulation, heat recovery and 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, steam production and product drying.
Cheaper sensors and smarter control systems
Sensors and smafrt controls offer potential to improve the management and optimisation of heating processes.
Energy Efficiency Best Practice Guide - Steam, Hot Water and Process Heating Systems (PDF 1MB) Sustainability Victoria
Process heat systems Energy Efficiency and Conservation Authority
Process Heating Systems US Department of Energy
Solar Heat for Industrial Processes - Technology Brief (PDF 5747KB) International Renewable Energy Agency.