Energy efficiency in the industry - Concepts & realisation

Industrial energy efficiency measures are an important component in a company’s balancing act to achieve profitability and growth on the one hand and the pursuit of environmental policy goals as well as the sustainable and responsible resource exploitation on the other hand. GETEC is offering economical and efficient energy supply solutions for industrial enterprises in Germany and Europe.

GETEC technologies for energy-efficient industries

GETEC safeguards the economic and efficient supply of many industrial customers with

  • Heat
  • Steam
  • Power
  • Cooling
  • Light
  • Industrial gas  

We focus on our customers’ needs and possibilities and our extensive repertoire of:

  • energy efficiency technologies
  • plant sizes and
  • fuels

Energy efficient supply solutions for industrial establishments

The decision in favour of measures aimed at boosting energy efficiency is not only an effective public relations effort, but likewise associated with economic benefits, not least because of nationally coordinated subsidies. The nature of measures varies greatly, ranging from simple upgrades of electric drives or illumination systems to complex conceptual designs within the scope of waste heat recovery as well as the integration of process heat by incorporating and developing new technologies. 

The economic payback periods stipulated by the companies and the failure to budget for these kinds of measures are the greatest hurdles for efficiency measures.

Relevance of energy efficiency

Any conceivable form of change, such as progression, chemical reactions, biological existence or growth is associated with a conversion of energy. Energy itself has many faces: it is present in molecules in the form of chemical bonds, it can be felt in the form of heat, it can be seen in the form of light, it is hidden in speed, waves and electric current. It is lurking in the lake high atop of a mountain, revealing its potential in raging torrents or thunderous storms. According to Albert Einstein, even the pure mass is a form of energy. 

Hundreds of thousands of years ago, the ability to use chemically bonded energy to generate heat and light by controlling fire already enabled our ancestors to develop new habitats and food sources. But the basis for the industrial revolution was only established by the discovery of the technical transformability of heat into kinetic energy. 

Now, the transformation and active exploitation of energy is no longer the sole privilege of nature, but find their way into all aspects of our lives. 

In this context, primary energy means the original form of energy, before the transformation by humans, which is available to them e.g. chemically bonded in coal, crude oil, natural gas and biomass, but also in the form of sunlight or as kinetic energy in wind, etc.

Since the outset of the industrial revolution, the primary energy consumption of a society has been a measure of prosperity and economic growth. But especially the latter, both the economic growth as well as the constantly growing global population, result in an exponential demand for primary energy – with well-known consequences. As has been proved, global climate change with all its facets is accelerated by the output of climate-damaging greenhouse gases as a result of energy consumption by humans. 

The emotional pressure and political efforts to protect fossil resources while promoting growth are rising, not least because of the responsibility opposite future generations, and also in view of the finite nature of fossil energy sources. 

A modern economy is characterised by an efficient as possible utilisation of existing resources. In contrast to the term efficiency, industrial energy efficiency is not a fixed unit, such as e.g. energy use to energy expenditure. In fact, it is a variable term that should be understood as measurement of the primary energy expenditure relative to any industrial product. Thus, energy efficient systems in the industry and in business conserve resources without compromising the product output and hence the offering and the economic growth. 

Political engagement and energy efficiency subsidies

By ratifying the Kyoto Protocol and the associated targets with regard to lowering CO2 emissions, the German Federal Government has agreed to a considerable reduction of its own emissions. 

In the years that followed, the term transition toward renewable energies has gained increasing popularity within the scope of the political engagement, especially in Germany. It stands for the expansion of renewable energies (often also referred to as alternative energies) within the scope of the Renewable Energies Act (EEG), as well as the phasing out of nuclear energy and the EEG levy. The EEG is designed to facilitate the market launch of technologies for the exploitation of alternative energies through statutory feed-in compensation. The costs incurred for this purpose are distributed among the consumers under the name of the EEG levy.

Some sectors were exempt from the EEG levy to protect the competitiveness of energy-intensive industrial establishments. However, the granting of an EEG levy exemption was made more difficult again or the amount of the exemption decreased, depending on the industry and the technical framework conditions, because of the social pressures, rising energy costs incurred by private users as well as by companies not exempt from the EEG levy. This is yet another reason why the topic of efficient energy and resources utilisation is more than ever part of the social discourse. 

Moreover, a variety of incentives are being offered in Germany, aimed at realising such measures. For instance, the expansion of local cogeneration units (CHP units) is being promoted in the form of guaranteed feed-in tariffs within the scope of the Cogeneration Act (KWKG), but only, if the so-called high-efficiency criterion is met.  This means that the combined efficiency must demonstrably be at least 75% (thermal efficiency plus electric efficiency). As a rule of thumb, this can only be achieved if the majority of low-temperature waste heat of a CHP unit can be utilised. Measures that serve the purpose of satisfying the high-efficiency criterion can likewise be promoted with the KWKG. This can include for instance the expansion of special district or local heating networks or the development and utilisation of novel or special technologies aimed at the exploitation of low-temperature heat.     

In addition, various programmes to support energy efficiency measures were installed by both the Federal Ministries for Economic Affairs and Energy (BMWi) and for the Environment, Nature Conservation, Building and Nuclear Safety (BMU) as well as directly by the Federal Office for Economic Affairs and Export Control (BAFA) of the BMWi. 

These funds are usually provided as project subsidies in the form of equity financing and awarded as non-repayable grants. The percentage of the share ranges between 20 and 80%, depending on the funding programme and the subsidised project or undertaking and is limited to a maximum amount per project, grant recipient and timeframe. 

For example, the BMWi provides a further incentive to implement industrial energy efficiency measures with the announcement of the guideline governing the promotion of energy-efficient and climate-friendly production processes dated 12 December 2013 and the announcement of the amendment of this guideline dated 07 April 2014. Accordingly, the amount of the grant can cover up to 20% of eligible expenses, which are however capped at €1,500,000 per undertaking. The funding is provided mainly for the transformation of production processes and production methods to energy efficient technologies or measures aimed at the efficient utilisation of energy from production processes and production facilities (Waste heat recovery) within the company.

In addition, individual measures aimed at the systemic optimisation can be sponsored. These can for instance be the renewal of

  • electric engines and drives,
  • pumps,
  • fans,
  • air compressors

as well as heat recovery systems in air compressors or LED technology-based lighting systems.

Additional eligible measures can be expenses for energy consultants or for the installation of energy management systems as well as the electrical, instrumentation and control engineering (EMSR) required for this purpose.

Moreover, low priced loans for efficiency measures and climate protection projects can be taken out within the scope of various funding programmes offered by the KfW Bank.

Energy efficiency creates jobs      

When planning and realising industrial production processes in the past, the value set on an efficient use of primary energy sources was relatively low. This is in part due to the lack of alternative technologies, but mainly the low primary energy prices. From today’s point of view as well as based on future considerations, these framework conditions have and will change. This applies in particular to political aspects, stock exchange prices for primary and secondary energy as well as the availability of new technologies and efficient upgrades of existing technologies and production processes. 

In many industries, energy efficiency measures offer a great potential, both with regard to economic aspects as well as for individual entrepreneurs, external energy service providers and energy consultants. Not only does the realisation of such projects boost the growth of the energy service provider industry, which in turn creates jobs, but it also strengthens the long-term competitiveness of the more energy efficient company. As a result, the specific energy costs of a product will decrease along with its production costs. The company’s capacity, sales and profit can be increased and additional jobs created, depending on the price elasticity of the demand. 

The requirements regarding the payback periods are the greatest obstacle for the implementation of industrial efficiency measures. "An average payback period of 30 months is postulated for energy-efficient machinery across all industrial sectors. These requirements are too high." This is the conclusion of a survey regarding the 2013 energy efficiency index conducted by the Institute for Energy Efficiency in Production (EEP) of the University of Stuttgart, the Federation of German Industries (BDI), the German Energy Agency (dena) and the Technical Surveillance Society of Rhineland (TÜV Rheinland). Accordingly, the majority of companies are well aware of the potentials, possibilities and prospects of success, but the activities and goals aimed at boosting energy efficiency are muted and remain too low. "Compared to the actual potentials, the targets should be far more ambitious." This is another finding of the 2013 energy efficiency index survey.


Energy efficiency measures

The measures aimed at boosting industrial energy efficiency are very multifaceted. The options available to a company need to be reviewed and evaluated in detail. In so doing, the current and forecast energy prices will define the economic viability of certain measures in addition to industry-specific and technical characteristics. Aspects such as

  • supply and availability requirements,
  • risk management and
  • risk analyses

likewise play a role in the decision making process.

Energy management systems should be considered first when it comes to heat-related energy efficiency. This usually means the modernisation of the instrumentation and control engineering as well as the intuitive visualisation of energy and process parameters. For this purpose, suitable sensors need to be installed throughout the entire production process to record and evaluate heat flows. In so doing, systemic changes are often made as well. The maximum integration of process heat is the intended purpose. So-called pinch analyses help both identify potential "heat sources and sinks" within the entire production process as well as develop new concepts for consumption structures. This allows the maximum utilisation of the spent primary energy without generating unnecessary energy transformation-related losses.

Distribution- and transformation-related losses can be minimised by decentralising the energy supply toward modular and efficient CHP units. Aside from the conservation of the in-house electricity privilege (reduction of the EEG levy on the self-generated and utilised electricity), the high overall efficiency associated with the combined generation of power and heat is the core of this technology. Gas and oil engines are used in most cases. They are driving generators to produce power, while the accumulated waste and cooling heat can be utilised at the same time. Alternatively, it is also possible to use gas turbines, special fuel cell systems or Stirling engines as well as other fuel engineering with subsequent steam turbine or ORC processes. In order to obtain government-sponsored current feed-in within the scope of the KWKG, the goal must always be to satisfy the high-efficiency criterion (total efficiency of >75%).  

In classical physics, the 1st law of thermodynamics is known as law of conservation of energy: Energy cannot be generated and disappear out of nowhere. Energy can only be transformed from one form into another form. An additional thermodynamic parameter is used in the 2nd law, which is entropy. Thus, any spontaneous reaction leads to an increase of the latter, whereby it is also possible to define the technical usability of a form of energy by means of entropy. In so doing, anergy is the part of a form of energy that can no longer be technically used; in contrast, exergy is the useful part of it. 

Accordingly, heat is not equal to heat; the temperature level essentially determines the ratio of exergy and hence the quality of the heat. Within the scope of exergetic optimisation, potentials can thus be harnessed, which usually remain idle in large steam networks of companies. In so doing, pressure reducing stations usually serve the connection of high, medium and low pressure networks or individual steam distributors are supplied with a higher pressure/temperature level by way of regulating valves. Indeed, the energy is conserved in these locations, but part of the exergy is transformed into anergy unused. 

This potential can be utilised for the provision of technical work and electric power can for example be substituted when using microturbines or displacement machines instead of regulating valves.

The exploitation of waste heat can make a significant contribution to the effective utilisation of energy sources and hence to saving energy in the industry. In industrial processes, a considerable part of the expended energy often does not remain in the product, but is instead released into the environment in the form of heat. Reintegrating this heat back into the process is often associated with major technical efforts. An effort that is well worth it! 

On the overall balance of an energy generation system, the majority of costs over the course of the lifetime or contract period are incurred by fuel acquisition. Meanwhile, the capacity cost of the investment is a relatively small component. No fuel acquisition costs are incurred for waste heat recovery technologies. Correspondingly, the benefit, i.e. the recovered energy or the substitution of primary or secondary energy, is only offset by the capacity cost of the investment. In many cases, this justifies enormous equipment-based expenditures. 

Besides the waste heat source and hence the type of heat transfer media, which are usually highly contaminated combustion, ventilation or drying gases as well as waste water, waste lyes or even hot solid matter, it is mainly the often low temperature of the waste heat that is problematic.

From an energetic point of view, it should always be checked first whether there is a need for heat of this temperature anywhere in the production, e.g. if there are any process or space heating needs. If this is not the case, different technologies are available for the high-loss transformation of waste heat into electric power, into heat with a higher temperature, into cooling or for use in district heating networks, depending on the performance and temperature level.

The exploitation of low-temperature heat is one of the greatest potentials for sustainable energy resources management. Depending on the balance scope, heat is always the end of every energy transformation chain. 

In so doing, the temperature level is not a direct predictor of the amount of energy, but only of the quality of the heat. Huge amounts of energy are released into the environment every day by companies and industries in the form of heat at temperatures ranging between 40 and 90 °C. 

If we succeed in exploiting this type of heat at least partially, energy conservation can be realised in large quantities and in a broad spectrum.

Heat transformation

Many drying, evaporation and distillation processes, especially in the food and paper industry, require large amounts of heat at a temperature level of about 100-120 °C, while at the same time generating large quantities of waste heat in the range of 80 to 90 °C.

GETEC is currently pursuing a promising technological approach aimed at increasing the temperature of waste heat by about 20-40 K, which is precisely harnessing the potentials mentioned above. Unlike with conventional heat pumps, no additional secondary energy (e.g. electric power) is used in this process, but the operating energy in fact originates from the waste heat itself. In so doing, nearly 50% of the recovered waste heat is raised to a higher temperature level. The temperature level of the remaining waste heat is lowered by about the same amount.

Absorption chiller with low-temperature heat  

Cooling is of vital importance in the modern industrial society. Particularly the food and beverage industry is consuming a large share of primary energy for cooling. In this context, a distinction is made between

  • climatic cooling (approx. 6/12 °C),
  • process cooling with temperature levels of approx. 0 °C or – 10 °C and
  • intense cooling with temperatures below – 30 °C,

since different refrigerating agents and technological methods are used for the generation, depending on the temperature level of the cooling. 

Cooling is generated mainly by means of compression refrigeration systems, as the investment and space requirements for them are low. Their poor thermodynamic effectiveness is undoubtedly a disadvantage, because compression refrigeration machines consume electric energy as operating power, which is provided with a COP (Coefficient of Performance, ratio of usable refrigeration to spent electrical power) value of 1.5 to 5 – depending on the temperature level – in addition to the high internal losses.

The energetic and climatic challenges of our time require us to focus on a high energetic effectiveness of the transformation and use, the efficient recovery of waste heat and the avoidance of refrigerants with a high GWP (Global Warming Potential). The waste heat recovery and associated substitution of high-quality electric energy is an indispensable contribution to an efficient energy transformation and exploitation.

The development of a novel absorption refrigeration machine is another approach pursued by GETEC. It is designed to help companies requiring process cooling to considerably increase their energy productivity. The goal is to utilise mainly the heat potentials and/or waste heat underused in the past, with an approximate temperature level of 80°C (e.g. from the combined heat and power generation) for the provision of process cooling at a temperature level of up to -10 °C. In this regard, new ground is broken in the field of working materials systems and a knowledge application gap bridged in the field of absorption refrigeration.

A substantial portion of the total energy consumption is generated by the driving of:

  • Pumps
  • fans
  • air compressors
  • compression cooling machines
  • belt conveyors

In so doing, the greatest energy savings potential can be attained with the often oversized pumps and fans. An electronic drive control by means of frequency converters (FCs) can achieve a formidable increase in efficiency. In the past, drives were initially produced with larger sizes because of the lower investment costs, and a mechanical or hydraulic throttle or control was implemented during the operation. In these cases, 30% of the electrical power requirement can be reduced on average by removing the throttle and implementing a control by means of frequency converters. With today’s electricity rates and investment costs for FCs, this measure often pays for itself after just a few years. 

In any case, replacing old drives with new motors boosts the energy efficiency. The economic benefit is relatively small and is highly dependent on the energy rate. If old motors are not capable to be operated with FCs, replacing them with a new motor makes sense in any case. 

According to the German Energy Agency (dena), the sale of motors with a relatively low efficiency has been restricted since the middle of 2011. Accordingly, motors have been divided into efficiency classes, with the following regulation in effect globally since 2009:

Energy efficiency classes of electric motors in effect since 2009:

Energy efficiency class

Meaning

Efficiency in %

IE1

Standard

90 and higher

IE2

High efficiency

94 and higher

IE3

Premium efficiency

Approx. 96

IE4

Super premium

97 and higher

Aside from saving electric power, it is also possible to recover heat with modern compressors including drives and their control within the provision of compressed air. In so doing, several sources can be harnessed, e.g. the waste heat of the drives, the heated refrigerant/lubricant and the heat absorbed by the environment in connection with the expansion, which is released again during the compression. 

All in all, up to 96% of the supplied electric driving power can be harnessed, provided that there is a need for low-temperature heat, such as e.g. room heating.

The requirements are high for lighting concepts of modern workplaces. Not only the optimal illumination and adequate brightness are essential, but the colour reproduction is also vital, depending on the task.

"In Germany, the basic lighting requirements with regard to the safety and health at the workplace are governed in the Workplace Ordinance (ArbStättV). The ArbStättV is applicable to all workplaces. The general lighting requirements set forth in the ArbStättV are specified in more detail in the Technical Rules for Workplaces ASR A3.4 "Lighting". Additional industry-specific information regarding the topic "Lighting" can be found in the brochures issued by the accident insurers. The accident prevention regulation "Principles of Prevention" (BGV [Regulations of the Professional Association] A1 and GUV [Statutory Accident Insurance] V A1) refers to the ArbStättV and is additionally applicable to individuals with voluntary insurance coverage. The generally accepted engineering practice represented in DIN EN 12464-1 in Germany must be observed when planning the lighting layout in consultation with the employers." The above is an excerpt from the guide to DIN EN 12464/1 issued by the Association for the Promotion of Adequate Lighting.

In addition, the lighting design and the selection of lamps are determined by economic factors, both for new lighting as well as upgrades of an existing lighting system.  Depending on the required economic payback period of upgrades or the planning/balancing period of the concept development, both the energy efficiency of lamps as well as the incorporation of time and motion switches play a role. In addition, a complex light control system can be used, which also controls the daylight- and zone-dependent light intensity aside from production- and vacation-related influences.

Based on experience, the energy efficiency of the entire lighting system can be improved by more than 60%, when the lighting requirements of the respective workplace outlined above are taken into account.

In addition to the energy efficiency, the service life and maintenance costs of the lamps or luminaires also have a significant impact on the economic rating of the lighting system. This currently leads to a growing use of LED technology, thanks in large part to its favourable score in terms of maintenance costs and long operating times.


Innovative energy services for the industry and complex large-scale properties

For companies, rising energy costs and changing framework conditions are always also associated with the issue of competitiveness and location. Profitability, environmental protection and resource conservation are the main issues related to energy. GETEC has the answers to these issues.

We provide relief to our customers by helping them safely navigate the energy market, providing them with economic and environmentally friendly solutions and forward-looking answers to all questions related to the energy supply.

Learn more about our innovative energy services by clicking on the adjacent brochure.


Development of the ORC process

Meanwhile, established ORC system manufacturers have accumulated more than 30 years of experience with the development and production of ORC systems. Consequently, the availability of the systems technology is high and can be used for individual as well as multifaceted applications.

The ORC process was developed to make heat usable for the generation of energy at a relatively low temperature level. A conventional water/steam circuit process requires a relatively high temperature level in order to be able to generate the specific energy required for the evaporation of water. In so doing, the efficiency of the entire process is highly dependent on the parameters pressure and temperature of the water vapour that is expanded in a turbine.

The working medium used in the Organic Rankine Cycle consists of organic components. The evaporation pressure and evaporation temperature vary, depending on the composition of the working medium. However, these two parameters are generally much lower than the evaporation parameters of water. As a result, it is also possible to use heat sources with a low temperature, as a smaller amount of specific energy is required for the evaporation.

Over the course of many years, the ORC technology was adapted to diverse and numerous areas of application, and a broad scope has thus been created for ORC systems. By varying the working media, it is possible to manufacture modules that are adapted specifically to the temperature level of the heat source, thereby achieving the best possible efficiency of the system.

With high-temperature use (temperature level near 300 °C), the efficiency of ORC systems is close to 20%. Efficiencies of 24% may be achieved with special developments.

With low-temperature systems (temperature levels between 90 and 150 °C), the efficiency is normally around 6 to 10%.

The electrical power range of ORC modules currently ranges from small-scale systems with < 100 kWel to large-scale systems with > 10 MW.



Functional principle of the ORC process

The thermodynamic cyclic process in essence resembles the one of the Clausius Rankine Cycle.

 

The working fluid is heated in the heat exchanger by means of the heat transfer medium (thermal oil or compressed water) of the intermediate cycle and evaporated (1 → 2). The superheated steam is then expanded in the turbine (2 → 3). The heat released in the context of the isobaric cooling of the steam is used to preheat the working fluid in the regenerator (3 → 4). The expanded steam of the working medium is cooled further and condensed in the condenser (4 → 5). The heat of condensation is either conducted away via cooling towers or used further as hot water for heating purposes. A pump re-increases the pressure in the working medium (5 → 6). After the working fluid has been preheated in the regenerator (6 → 1), the working fluid is re-evaporated in the evaporator and superheated. This completes the cyclic process. The difference compared with the Clausius Rankine Cycle is the incorporation of an additional heat exchanger, the regenerator, which is crucial for increasing the efficiency.



Technical characteristics, advantages and disadvantages of ORC technology

As described above, an organic medium is used as working medium, which can be evaporated at very low pressures and temperatures. By using a variety of fluids with correspondingly different characteristics, the process can be adapted optimally to the respective application. This guarantees the greatest possible efficiency of the ORC system at all times.

Another striking feature of ORC modules is their compact design. All components, such as the evaporator, turbine, regenerator and condenser are usually installed tightly in a case (or on a steel frame). Therefore, the thermal energy required for the evaporation of the working medium is normally transported to the ORC module via an intermediate cycle. Thermal oils are usually used as heat transfer medium in this intermediate cycle. Alternatively, compressed water is used to transport heat from the exhaust heat source to the Organic Rankine Cycle.

In regard of energy generation, the ORC competes with the conventional highly-developed technology of steam turbines. However, the Organic Rankine Cycle has several advantages that make ORC technology an interesting proposition for a number of applications.

  1. Temperature levels of 90°C to 800°C can be utilised for the conversion into electricity.
  2. As the expansion takes place virtually fluid-free, the turbine is not affected by any signs of erosion and corrosion.
  3. ORC systems display excellent partial load behaviour. In individual cases, a working status can be achieved with 10% of the rated load.
  4. The operation of the system is fully automated and unsupervised. The ORC module does not contain any pressure elements according to the Technical Rules for Steam Boilers [Technische Regeln für Dampfkessel, TRD], for which supervision would be necessary.
  5. In contrast to steam turbines, the start-up and shut-down is relatively simple and user-friendly.
  6. With generated electric powers below 2 MWel, ORC systems often prove to be more economical than conventional steam turbines.

Still, the advantages described above are pitted against several disadvantages.

  1. When thermal oil is used as heat transfer medium, corrosion may develop on the heat exchanger.
  2. At high electric powers (> 2 MWel), the system technology is relatively cost-intensive.


Areas of application of ORC technology

ORC modules are versatile and very flexible in their applications. The diagram below illustrates the range of applications of ORC technology and its placement with respect to other technologies in the field of the conversion of thermal energy into useful energy.



Utilisation of industrial waste heat at high- and low-temperature levels

The use of ORC systems for the industrial waste heat utilisation on high- and low-temperature level is one of the main areas of application of ORC technology. Depending on the temperature levels and available exhaust heat quantities, the heat is normally transported to the ORC module via an intermediate cycle. The heat transfer medium releases its heat in the evaporator, thereby evaporating the organic working fluid in the ORC. In most cases, thermal oils or hot water are used as heat transfer medium in the intermediate cycle.

Therefore, fields of application are found in virtually all branches of industry, where a corresponding amount of waste heat is available. Examples include in particular the cement industry, the glass industry and the metal industry.

Depending on the application, amounts of exhaust heat at different temperature levels may be present at the same location. A so-called “split” system was developed for this purpose, which makes it possible to utilise heat sources on two different temperature levels in one ORC module.

Another development on the part of Organic Rankine Cycle module manufacturers is the elimination of the intermediate cycle for the heat transport. The instrument-based time and effort in connection with a conventional exhaust heat utilisation concept that features an intermediate cycle are high and cost-intensive. Therefore, the manufacturers developed a variety of direct evaporators. With them, the medium, for example hot exhaust gas, is guided directly through the evaporator of the ORC module. The instrument-based time and effort are considerably lower. As great diligence must be demonstrated during the extraction of the thermal energy especially when using waste gases derived from combustion processes and manufacturing processes, an intermediate cycle may still be conducive in spite of the higher time and effort involved. With a direct evaporator, there is a risk of corrosion and damage of the evaporator directly at the ORC module in the worst case.

The use in biomass cogeneration power plants is a common field of application of ORC modules. In that application, biomass combustion plants are combined with ORC modules.

The thermal energy generated with the combustion of the biomass is transferred to a thermal oil cycle via the boiler. The thermal oil cycle then supplies heat to the Organic Rankine Cycle.

In addition, district heat becomes available through the cooling water that is required for the ORC. While ORCs are cooled with cooling water that has a temperature of approximately 25°C for the utilisation of waste heat, in order to achieve an electric efficiency that is as high as possible, the ORC in this case is cooled with 70°C-warm water and heated to 90°C. As a result, the removed condensation heat is not released into the environment via cooling towers, but made available for further utilisation instead. This increases the ORC system's overall efficiency. Moreover, the generated electricity may be reimbursed through the Renewable Energy Sources Act (EEG).

Furthermore, the ORC’s outstanding partial load behaviour enables an unproblematic heat-led control of the combined heating and power station.

With geothermal energy, the temperature levels available for utilisation range from 90 to 150°C. The thermal utilisation of geothermal energy by means of a heat pump is a well-established practice in the private sector and in the housing industry. Thanks to ORC technology and the working media that can be used, it is possible to transform heat into electricity, in spite of the low temperature level.

The ORC’s efficiency is around 6 to 10%, which is also due to the low temperatures.

In this application, the exhaust heat of a CHP unit is used in an ORC module for the energy supply, thereby increasing the electrically generated efficiency of the entire system.

Firstly, this combination is used to amplify the generated power, and secondly, the thermal energy of the CHP unit is made available for another use, if the heat was not consumed in its entirety. Under certain conditions, this may be relevant for the fulfilment of the high-efficiency criterion, which used among other things for the decision regarding the allowance of the CHP premium for the energy generated by the CHP unit.


We embody partnership –
find your counter­part.

With close to 30 locations throughout Germany and Europe, we are always at your doorstep.
Contact us. We are here for you.

You are looking for a counterpart near you?
Simply enter your zip code
Karte wird geladen...