Industry

Introduction

Energy is and remains an essential, economic basis for the industrialised world. Trade and industry can considerably reduce their energy consumption in the coming years without endangering productivity. In other words, energy efficiency equates to cost efficiency - a clear competitive advantage.

Picture: BMWi

Globally, in all fields of industry, the potential for improved energy efficiency through improved procedures is significant. The following industrial technologies are widely used: compressed air and pump systems as well as air, refrigeration and conveyor technology. Today, most companies could potentially reduce their consumption of electricity and associated costs for these cross-application technologies by 5% to 50%. In most cases, the payback period is less than two years and the return on investment is more than 25%. Therefore, measures that improve energy efficiency are extremely appealing to companies for economic reasons.

Refrigeration

Refrigeration technology is an inherent part of many production and logistics processes and is widely used in trade and industry. Therefore, various technologies are deployed and the size of refrigeration systems differs greatly. However, all of these systems have one thing in common, i.e. they generate cooling energy that must be incorporated into the product or process.

Even though refrigeration technology is used extensively, it was rarely considered as a  possibility for improving energy efficiency until now. However, in refrigeration technology, there is often great potential for reducing energy costs. In particular, this concerns the continuous operating costs of such systems, which may account for up to 80% of the total costs associated with a refrigeration system.

General approaches for improving efficiency:

• Improved heat insulation
• Reduced heat radiation
• Adjusted "busy" times and operating times
• Basic process design
• Optimised power, pressure and temperature levels
• Efficient control technology
• Detailed design and selection of individual components
• Use of thermal cooling machines, for example, with solar heat, district heating, industrial waste heat as well as waste heat from combined heat and power systems (CHPs)

Thorough planning and system optimisation can significantly lower the costs associated with the production of cooling energy. Therefore, it is important that the purchase price is not the primary determining factor when purchasing a refrigeration system. Rather, the total cost, including the very high lifetime operating costs associated with refrigeration systems, should be considered. German refrigeration technicians have expert knowledge of high-quality, energy-efficient systems. This is reflected, for example, in thermal cooling machines, which are an energy-saving alternative to electrical refrigeration systems. Thermal cooling machines use heat energy directly for cooling purposes. Accumulated industrial waste heat, which would otherwise go unused, provides a good source of heat in this case. If heat is generated from free solar energy through the use of solar-thermal technology, an almost CO2-neutral operation is achievable. It is also possible to combine refrigeration systems with combined heat and power systems (CHPs). The economic efficiency of CHPs is heavily dependent on a continuous heat requirement. By combining it with the refrigeration system, the CHP is utilised more during warmer times of the year and is therefore more economically efficient. German manufacturers provide highly efficient thermal cooling machines with cooling capacities for almost all areas of application. In Germany, approximately 2,200 companies active in the area of refrigeration and air-conditioning employ 15,000 people. Their annual combined turnover is in the region of three billion euro and exports account for 40% of their total sales.

Compressed Air

Trade and industry frequently require exceptionally large volumes of compressed air, which is one of the most widely used cross-application technologies.

Compressed air is used in the following areas:

• Pneumatics
• Active air (compressed air as a means of transport)
• Process air (for example, drying processes)
• Vacuum technology

Air, as a commodity, is an infinite resource and does not cost anything. However, compressed air/vacuums are usually supplied by electrical compressors. This generates costs of approximately 1.5 to 3 cent per cubic metre. The electricity required to generate compressed air can account for 20% to 80% of the overall energy costs in a company. Significant energy savings could be made here. If a company were to invest in efficient compressed air technology, it could yield energy savings of between 5% and 50% with a payback period of less than two years. Unfortunately, the overall efficiencies achieved with compressed air supply are extremely low. The electrical energy consumed by an air compressor does not compare favourably with the compressed air that is output at the end of the system chain. Even if air compressor efficiency is 50%, an efficiency of just 5% is achieved if we consider the overall system from its creation through to its use. However, the remaining 95% does not have to remain unused. Frequently, the waste heat accumulated when operating a compressor can be deployed.

Another option is to improve the efficiency of the entire process by optimising the system components. German companies manufacture the entire range of compressed air technologies; from small compressors for small and medium sized enterprises through to complex compressed air systems with several megawatts of power. In the case of vacuum technology, which has become a key compressed air technology in industry and research, German
suppliers are the market leaders with approximately 80% of the world?s annual turnover. The prominent role occupied by German suppliers of compressed air technology is also reflected in the ever-increasing number of patent applications. This is particularly the case in the important application area of pneumatics. German companies not only supply components and complete systems, they also provide compressed air contracting. In particular, customers who have easily calculable requirements really get their money's worth with this all-inclusive package.

Electrical Drives

Trade and industry require electrical drives worldwide. Motor-driven systems consume 64% of all electricity used in industry. Here, there is also great potential for improved efficiencies.

Picture: BMWi

Electrical drive systems consist of the following units:
The electric motor, which converts electric power into mechanical power, A frequency converter, which converts the electrical power of the mains in a controlled form (electronic speed control), And the gearbox, which adjusts the mechanical power of the motor to the working point of the driven machine (reducing speed and increasing torque). The individual components have been highly optimised already. However, there remains an enormous savings potential in the use of optimum system concepts if such concepts are evaluated by their costs across the entire life cycle. When you consider the lifetime of an electric motor, the costs associated with the consumption of electricity account for up to 96% of the total cost. Therefore, when purchasing a motor, it is important to bear in mind its expected electricity consumption as this is a considerably greater factor than the initial purchase cost.

Great savings potential in electrical drive systems lies in the use of energy-saving motors. These energyoptimised motors convert electrical into mechanical energy with the fewest possible losses whilst maintaining the required technical properties. In industry, three-phase asynchronous motors are widely used as standard drives. They are good value for money and reliable machines that require very little maintenance. In terms of energy efficiency, strong efforts have been made in the past years to reduce the energy losses of such asynchronous machines substantially.

In the highest class of the European motor efficiency scale, EFF 1, losses are on average reduced by 40%. Higher efficiency levels may be obtained when using special motor types such as synchronous motors or EC motors:

• Synchronous motors have a very high electrical efficiency, even during partial load operation. Precise regulation of frequency converters is possible
• Electronically commutated (EC) motors, also known as brushless DC motors (BLDCs), supplement the positive attributes of synchronous machines by being able to adjust to their load. They are highly efficient, even when working with partial loads, have a high power spectrum and are easily regulated.

In 1998, the European motor manufacturers made a voluntary agreement towards the European Commission to promote selling energy-saving motors. The share of energy-saving motors of efficiency class EFF 1 has been rising constantly ever since. Simply replacing an old motor with an EFF 1 motor is, at first glance, the simplest step toward achieving energy efficiency. To assess, however, the economic efficiency of an electrical drive, it is not primarily the motor that determines the optimal efficiency but rather the way in which the motor or machine speed is controlled. The savings potential of electronic speed control is four to five times greater than that of highefficiency motors. Electronic speed control can save between 20% and 70% of the energy costs of conventional mechanical methods such as throttle valves or flaps.

Taking life cycle costs into consideration, investments made in energy-saving methods can often be redeemed within a matter of only a few months. Only about 12% of the motor capacity installed in Germany today is operated with energy-saving electronic speed controls. It is  estimated, however, that it would be beneficial for over 50% of this motor capacity to be equipped with electronic speed control.

There are basically two different types of industrial drive systems:

• Drive systems, which require an electronic speed control simply for them to work.
  Electrical drives that could be operated, in principle, without speed control. They run continuously at fullpower independent of the varying load requirements of the machine. It is in this group that the use of electronic speed controls opens up great energy savings potential.
• The great energy savings potential that lies in mechanical system optimization falls within the competence of mechanical engineers and designers of machinery and plants. It accounts for almost 60% of total energy savings potential in electric motor driven systems.

In drive engineering, there are numerous ways to save energy and increase efficiency:

•  Use motors that have the best possible efficiency class, for example, the "CEMEP seal of approval" (CEMEP: European Committee of Manufacturers of Electrical Machines and Power Electronics).
• Use motors that have variable power.
• Use frequency converters (recuperation of brake energy into the system). 

Several projects are currently underway in a bid to unlock more potential energy savings in trade and industry. One such project, in particular, is the "Motor Challenge Programme". Its goal is to motivate companies to optimise the efficiency of their electric motor systems. For decades, electrical drive engineering has been one of the German economy?s main export items. Both a proclivity for innovation and comparatively high energy costs in Germany contribute to Germany?s high-tech products receiving increasing levels of global attention because of their impressive energy efficiency.

Pumps

Pump systems presently account for a good 25% of the industrial electricity consumed worldwide. It is believed that approximately 40% of this energy could be saved. Centrifugal and displacement pumps occupy a large market share, with centrifugal pumps accounting for 73%. Centrifugal pumps, in particular, represent great potential for energy savings because approximately 75% of these pumps are oversized, frequently by more than 20%.

Picture: BMWi

The German Energy Agency (dena) has an ongoing campaign entitled "Energy-Efficient Systems in Trade and Industry", which advises companies active in the following industries on measures that they can introduce to increase their energy efficiency: chemicals, paper, electrical, food manufacturing, plastics, metal processing, water supply and waste water disposal. In particular, this campaign demonstrates that all companies, irrespective of their industry classification,
will benefit financially from any energy-saving efforts that they undertake. Depending on its size, a company could potentially save between €2,000 and €50,000 per year. The payback period for the corresponding investment is generally two to three years. This campaign also shows that, on average, companies can reduce the electricity consumed by their pumps by  approximately 30%.

In addition to comprehensive system optimisation, the use of efficient high-tech products and highly developed controls are the two main ways to increase energy efficiency:

• Replace oversized pumps with smaller pumps that have highly efficient motors
• Use highly efficient pumps
• Use frequency converters for variable-speed operations
• Equip pumps with proportional control
• Optimise downstream heat exchangers 

Germany is the second-largest global supplier of pumps and compressors. German companies are frequently the market leaders in highly efficient highend pumps and compressors for specific purposes. 

Process Heat

Process heat is the heat required for numerous technical processes and procedures in trade and industry. Unlike room heat, process heat is available at a considerably higher temperature level, which is optimised for each application. Process heat is necessary for cooking, baking, sterilising, drying, smelting, forging, welding and producing steam. Due to the high temperature level of process heat, it is generally not possible to use waste heat from other processes, which means that process heat is generated by combustion processes or electricity. 40% of the energy used in Germany is consumed in trade and industry and in the services sector. Approximately 66% of industrial energy consumption is required to generate process heat. Therefore, this is a large area of activity in which measures can be taken to save energy. Approximately half of all process heat required is below 300 °C / 572 °F; the remaining half is below 180 °C / 356 °F.

Generally, the greatest energy savings potential for reducing costs is to change the energy resource from electricity to gas. This generally cuts down on CO2. However, it does not necessarily reduce the quantity of energy required i.e. simply changing from one energy resource to another does not automatically increase the efficiency of a process. Increased energy efficiency is mostly achieved by optimising the system technology. Potential energy savings can be attained, for example, by using energy-saving motors. This improves energy efficiency and reduces losses. The use of combined heat and power (CHP) or combined cooling and power (CCP) should also be considered. Poor insulation is frequently associated with energy loss. Heat recovery is an important consideration for potential energy savings. When smelting metals, it makes sense to constantly monitor the smelting temperature and adjust the smelting cycle to the throughput of the casting machine. First and foremost, a policy of efficient load management should be adopted. The total energy savings potential is at least 15%. Process heat can also be generated using solar energy. This is of particular interest, given the rising energy prices and the reduction of greenhouse gas emissions. Germany is working intensively on the further development of solar process heat. Possible areas of application include agricultural drying plants and industrial operations such as washing, cooking, drying and pasteurisation. Solar energy can also be used for processes at high temperatures.

Heat Recovery

Heat recovery is a collective term for the practice of reusing the thermal energy generated during a manufacturing process and frequently emitted into the environment as unused waste heat. This waste heat can be deployed effectively in heat recovery. Therefore, the potential energy savings are huge. Return air streams or flue gas streams that deploy heat recovery technologies can be used to pre-heat room air or combustion air. By linking procedures in an intelligent manner, it is possible to considerably reduce the amount of primary energy consumed.

Heat recovery measures result in both lower energy costs by reducing the use of primary energy and lower investment costs for heat production plants. Furthermore, the volume of greenhouse gases emitted is reduced considerably. Heat recovery is responsible for achieving sustained conservation or renewal of energy streams ultimately released by manufacturing processes into the environment. Therefore, heat recovery can be regarded as a renewable energy.

Picture: BMWi

The advantages associated with heat recovery can be summarised as follows:
Heat recovery can reduce the connection power for heat energy and cooling energy, the level of energy consumption for heating and cooling, investment costs and operating costs as well as pollutant emissions. System technology can be scaled down; heating boilers, refrigerators, re-cooling plants, piping, stacks etc. are no longer required. Numerous technical possibilities are associated with heat recovery. Process heat can be transferred directly to solids. Furthermore, it can also be transferred to gases and liquids, for example, when pre-heating water or combustion air for furnaces or dryers.

Possible heat sources include:

• Use of condenser heat from steam systems and boiler systems
• Heat recovery from ventilation and air-conditioning systems
• Extraction of residual heat from waste heat in order to pre-heat heating water or domestic water

Germany's expertise in this area ranges from heat recovery in large plants to possible applications of heat recovery technologies in small and medium-sized companies.

German companies are especially committed to energy efficiency because Germany has state sponsorship programmes (for example, the European Recovering Programme ERP) as well as financing concepts backed by financial institutions and leasing companies for energy-saving measures. The government also finances energy consultations for companies. All of the above has given rise to a domestic business market for innovations in industrial heat recovery. The resulting expert knowledge can also be applied globally.

Decentralised Supply

Today's still largely centralised energy supply uses a power plant to supply energy to a large number of consumers in different geographical locations. However, a great deal of energy is lost while it is being transferred along very long routes to the consumer. Frequently, a decentralised energy supply would be more efficient. This concerns the supply of energy by small plants located in close proximity to the consumer. The plants are located directly where the energy is used.

The following advantages are associated with a decentralised energy supply:

• Efficient use of electricity and heat production
• Significantly lower transmission losses
• Independence
• Safe supply
• Operator directly influences the energy source
• Diversification of energy sources
• Job creation
• Regional accumulation of value
  

Centralised and decentralised energy supplies are not mutually exclusive. Both systems can co-exist and complement each other (integral energy supply).

Germany has recognised this fact and has been promoting the use of decentralised energy supply for years now. As a result of the support and promotion of renewable energies and the incentive to use combined heat and power, which was provided by the Renewable Energy Sources Act (Erneuerbare Energien Gesetz) and the combined Heat-Power Cogeneration Act (Kraft-Wärme-Kopplungsgesetz), Germany has had the foundation necessary to promote technologies in these areas since 2000.

Possibilities associated with a decentralised energy supply:

• Greater efficiency through the use of combined heat and power
• Use of renewable energies

First and foremost is the use of combined heat and power systems (CHP), which is characterised by the simultaneous generation and use of heat and power. In Germany, there are CHP systems in power classes from 0.8 kWel upwards for every application. Furthermore, expertise in this area continues to grow.

Different renewable energies can also work together. This is evident in the example of the German "combined renewable energy power plant".

The combined renewable energy power plant uses 36 wind, solar, biomass and hydraulic plants that are spread throughout Germany. Through joint control of small and decentralised plants, it is possible to provide a reliable source of electricity to meet requirements. The objective is to combine and benefit from the advantages associated with various renewable energies. Since the volume of electricity generated by wind turbines and solar heating systems depends on how much wind and sun is available, biogas power plants and hydraulic turbines are used to supply energy at times of peak demand. With a sophisticated control strategy, it is possible to achieve a fully decentralised energy supply through renewable energy alone.