| Abstract [eng] |
After shutting down the Ignalina atomic power plant, Lithuania have received a huge blow to it‘s national energetic safety. Not only pressure from The European Union, but risen electricity and natural gas import dependency has forced Lithuania to search for a quick solution. Intuitive way to solve both of the problems was combined heat and power promotion and development. Lithuania was very quick to master the sophisticated biofuel burning technologies. At the beginning biofuel was used for water heating and steam supply to various technological processes. Not long after, international experience using biofuel for cogeneration has rooted down in Lithuania too. Nowadays these plants energy production prime cost is particularly cheap. To hop into the market it is necessary to find effectiveness increasing capabilities. In this study two different ways of heat pump integration into a regular biofuel CHP are examined. First one is based on full waste heat energy transformation of water steam cycle, second – additional flue gas cooling after the economizer and greater latent heat recovery. Detailed termodinamic and economic calculations have shown that because of very high compressor power and it‘s electricity consumption the first version heat pump actually lessens annual profit. A lot less heat quantity is in the flue gas after the economizer. Heat pump designed to cool them down and gather condensing water vapour heat is many times less powerful. This is because of high coefficient of performance (COP=9.899), which is only possible when having low temperature difference between low grade heat pool and heat pump condensator condensing temperature. This kind of heat pump does not require high investment costs and increases annual profit by 264 thousand € or 13,5 %. |
