Assessing Energy Efficiency of High Pressure Regenerative Feedwater Heaters in a Heating Unit of a Cogeneration Plant

Broadly understood technological progress, growth of the world's population and striving of individual countries for economic growth cause increased demand for energy. That energy is mainly obtained conventionally, from mineral fuels [16]. Limited fuel resources and high demand for fuels, which accompanies the increased demand for energy, result in continuous growth of fuel prices and, what it involves, the price of energy [6,16]. Another effect of the increased production of energy results is also the increased emission of combustion products which are harmful for the natural environment, mainly CO2 and NOx [6,9,10,]. Because of the above-mentioned factors, the importance of the assessment of energy efficiency, at the stage of energy production, distribution and end use as well as the problem of environmental protection gain more and more importance [4,5,15]. The idea of energy efficiency lies not only in energy conservation but also in finding ways for the present activities of producers and consumers to require reduced demand for primary energy expressed in tonnes of oil equivalent [3,7,13,14,17,19,21]. Energy companies must therefore respect a number of legal regulations concerning energy efficiency and environmental protection [3,4,5,15]. An energy company such as a cogeneration plant may achieve an improvement of energy efficiency mainly as a result of energy cogeneration itself but also as a result of improving the efficiency of internal processes (energy transformations) in the producing unit (in this case heating unit). Ensuring the maximum possible energy efficiency of the internal processes within the heating unit requires performing constant assessment of the entire unit and its components [7,11,12,13]. Even though energy cogeneration has been in use for a long time now [7,12,21], the problem of conducting a running energy efficiency assessment of the components of the heating unit still remains open [12].