Balić, Dražen and Maljković, Danica and Lončar, Dražen (2015) District heating system as a dynamical energy storage – opportunities and limitations. = District heating system as a dynamical energy storage – opportunities and limitations. In: 10th Conference on Sustainable Development of Energy, Water and Environment Systems – SDEWES Conference, 27.09-2.10. 2015., Dubrovnik, Croatia.
Full text not available from this repository.Abstract
The contemporary energy system is faced with new challenges on the energy market. Both rising share of renewable-based electricity (characterised by intermittent production) and increasing energy efficiency in buildings induce the reconsideration of the traditional role of conventional power plants coupled with district heating systems along with its impact on energy system. Considering these new circumstances it can be observed that the existing energy system is over capacitated with the installed power of conventional cogeneration (CHP) plants. Moreover, the price of electricity determined by the merit-order system additionally decreases load factor of such plants making them less competitive or even inflicting financial loss in operation. The research presented in this paper has a focus on novel approach towards conventional CHP plants coupled with district heating systems. With the aim of reinforcing their position on the contemporary energy market, a new role of such systems has been identified and an innovative solution is proposed. It involves an analysis of dynamical performances of district heating system – capability of energy accumulation and thermal inertia – in order to assess its potential to become part of ancillary services. It is concluded that district heating system, i.e. network of pipelines can be considered as a dynamical thermal energy storage in which excess energy can be stored during operation of power plant (CHP). As a consequence, generation of electricity and heat production could be decoupled enabling higher flexibility for electricity and heat supply that do not have to be performed simultaneously. A comprehensive analysis of dynamic behaviour of district heating system has been performed by means of mathematical model developed as a part of this research. The model is implemented on a theoretical case consisting of simplified district heating system with three final users and the pipeline network of 9000 m in length. In order to determine the capability of energy accumulation within pipeline network, supply water temperature was varied. Moreover, the temperature drops of the supply water temperatures were imposed on the system in order to further investigate the possibility of decoupling of the electricity generation from heat production. The simulation has shown that in the case of a network only 9000 m long it is possible to store approximately 915 kWh of thermal energy within 7 hours. In addition, it has been found that the temperature drops in certain situations do not inflict problems to the system - it is possible to reduce heat supply to the pipeline network for 2.5 hours without jeopardizing the final users comfort. Moreover, the capability of energy accumulation is explored for different parameters, such as: external temperature, distance of the network, supply water temperature etc.
| Item Type: | Conference or Workshop Item (Lecture) |
|---|---|
| Keywords (Croatian): | District heating, CHP, dynamical thermal storage, mathematical modelling, operation strategies |
| Subjects: | TECHNICAL SCIENCE > Mechanical Engineering |
| Divisions: | 500 Department of Energy, Power Engineering and Environment > 510 Power Engineering and Energy Management Chair |
| Indexed in Web of Science: | No |
| Indexed in Current Contents: | No |
| Date Deposited: | 14 Apr 2016 09:47 |
| Last Modified: | 16 May 2017 14:48 |
| URI: | http://repozitorij.fsb.hr/id/eprint/5610 |
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