Modelling of a combined heat and power system
Kallio, Sonja (2012)
Kallio, Sonja
2012
Ympäristö- ja energiatekniikan koulutusohjelma
Luonnontieteiden ja ympäristötekniikan tiedekunta - Faculty of Science and Environmental Engineering
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Hyväksymispäivämäärä
2012-09-05
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201209121281
https://urn.fi/URN:NBN:fi:tty-201209121281
Tiivistelmä
Due to rising global demands for energy and growing concerns about the accelerating greenhouse effect, efficient and clean energy generation is increasingly under a spotlight. At the moment and in the future the weather depending renewable energy production is increasing. This growth leads to higher demand for fast balancing energy production during unfavorable generation conditions. Additionally, overall electricity consumption is increasing which results in higher peak loads and decreasing transmission and distribution capacity in the electric grid. This requires more fast support for the grid and decentralized energy production. Combined heat and power (CHP) is the simultaneously generation of electricity and useful heat from a single fuel source at high efficiency. A high number of small internal combustion engine based CHP units can provide fast balancing energy, due to good dynamic behaviour, and simultaneously heat for heat sinks, such as residential and commercial buildings. The distributed structure of the heat sinks leads to a transformation towards a decentralized energy system in which small-scale distributed generation is connected to the distribution network instead of large central generators connected to the transmission network. This thesis models and examines a small CHP system operation under a new concept where the electricity utility can remote control a contracted CHP units within different heat sinks and gain a benefit by generating electricity during unfavourable weather conditions and peak loads. The main goal of this thesis was to construct a single CHP system model into the Matlab/Simulink and investigate the behaviour of the system.
The thesis is divided into two parts. In the literature study part, combined heat and power and different prime movers are introduced. Additionally, different CHP configurations and components are presented. Finally, the market research was conducted and market available internal combustion based small- and micro CHP units were introduced. In the second part, the model construction methodology was presented and results of two test cases were discussed. Finally, the optimization was performed using the model.
The result indicates that small CHP operation on the liberalized electricity market is profitable from the electricity utility point of view. In this case the CHP unit requires large thermal storage which enables long storage time and operation only during the high electricity price. This enables also to provide fast balancing energy for weather depending renewables energies and support for the grid during peak loads. The large storage decouples heat- and power driven CHP system because it can respond to both demand with the storage. Until now the heat-driven systems have been commonly used and electricity is produced as a by-product.
The thesis is divided into two parts. In the literature study part, combined heat and power and different prime movers are introduced. Additionally, different CHP configurations and components are presented. Finally, the market research was conducted and market available internal combustion based small- and micro CHP units were introduced. In the second part, the model construction methodology was presented and results of two test cases were discussed. Finally, the optimization was performed using the model.
The result indicates that small CHP operation on the liberalized electricity market is profitable from the electricity utility point of view. In this case the CHP unit requires large thermal storage which enables long storage time and operation only during the high electricity price. This enables also to provide fast balancing energy for weather depending renewables energies and support for the grid during peak loads. The large storage decouples heat- and power driven CHP system because it can respond to both demand with the storage. Until now the heat-driven systems have been commonly used and electricity is produced as a by-product.