ORC – The key for the cost-effective operation of small CHP plants
Today, the incineration of biomass in combustion chambers combined with the generation of high-pressure steam is the method mostly used to generate electricity and heat from solid biomass. The steam powers the turbine units, which in turn utilise generators to generate electricity. In addition, it is also sensible to operate the plants in cogeneration mode, in other words, they generate both heat and electricity.
However, to provide the steam with the energy, which substantiates the use of a steam turbine, the pressure and temperature of the steam must be as high as possible. This in turn requires a complex plant technology and constant plant supervision by qualified professional personnel.
For safety reasons, the legislature has enacted provisions governing the compliance of technical regulations for steam boilers, pressure vessels and other similar regulations. Additionally, requirements are issued mandating that professional personnel maintain constant supervision of the plant or at fixed intervals, depending on the integrated safety measures.
These measures are a good idea; however, they increase the investment and operating costs and thus prevent the cost-effective usage of such plants, especially in smaller-scale plants.
Steam Power Plant
In this case, the ORC (Organic Rankine Cycle) technology provides an interesting alternative. The Scottish professor William Rankine already developed the technology for using low temperature sources to generate electricity back in 1850. This technology also involves a steam-power system; however, instead of using water, an organic medium is evaporated at low boiling conditions. As in conventional steam technology, the steam is also released into a steam turbine and a generator is powered to generate electricity. However, the steam pressure is considerably lower and therefore does not require the use of expensive high-pressure technology.
Plant operation is also simpler:
the plant need not be supervised and since the system is closed, the maintenance of the medium required in steam plants is no longer necessary. ORC plants have a relatively simple structure, can usually be unitised and transported to the location in prefabricated components, which also considerably simplifies installation.
Due to the thermodynamic characteristics of the used media, the partial load capability of ORC plants is superior and the plant’s efficiency achieves higher values than those of comparable steam plants. This provides numerous interesting advantages, which make ORC technology unbeatable in power ranges below 2 MWel.
ORC Biomass Power Plant
The usage of ORC technology has now virtually become an everyday tool for utilising biomass and geothermal energy. The systems offered on the market have long since proven their suitability for daily use: among other things, the low maintenance requirements have been completely confirmed over many years of operation.
ORC technology is also being increasingly developed for individual applications, which until now could hardly be utilised for the cogeneration of heat and power (CHP) due to insufficient profitability. This includes, for example, low temperature heat in the range of approximately 100°C, as extracted from the geothermal water in the lowlands of Northern Germany, biomass in the smaller-scale agricultural sector or the exhaust-gas heat from gas engines in a CHP plant. Another interesting area is the usage of industrial waste heat. In many cases, such heat is still considered a harmful by-product in the process technology and energy is being used to destroy it.
Advantages of ORC technology |
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Low investment, maintenance and operating costs |
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Easy and straightforward operation without monitoring |
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High efficiency, i.e. optimum usage of the available fuels |
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Practically tested system concepts |
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ADORATEC ORC technology
The further development of ORC technology is one of the declared business goals of ADORATEC. We have many years of experience as specialists in the heat transfer and process and energy technology sectors and have acquired in-depth expert knowledge in these areas. The partnership with an established heat system manufacturer also provides us with the technical as well as the commercial support, which is essential in the implementation of larger-scale projects.
We provide our customers with specialised modules, which suit their tailor-made concepts for the respective application, from an extensive delivery programme.