Naslov
District heating as the thermal storage – support to the power system with potential for a higher integration of RES

Autori
Balić, Dražen ; Maljković, Danica

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts, International Conference on Smart Energy Systems and 4th Generation District Heating / Henrik Lund - Kopenhagen : Aalborg University, 2015, 59-59

Skup
International Conference on Smart Energy Systems and 4th Generation District Heating

Mjesto i datum
Kopenhagen, Danska, 25.08.2015. - 26.08.2015

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
District heating; Thermal storage; Mathematical modelling; Operation strategy

Sažetak
Contemporary energy system faces new challenges on the energy market. Due to the fact that ratio of renewable energy sources characterised by the intermittent electricity production (mostly wind power and photovoltaics) increases steadily as well as the fact that energy efficiency in buildings is being improved, conventional power plants coupled with district heating system must reconsider their role in the energy system. Namely, it can be observed that existing energy system is over capacitated with the installed power of the conventional CHP plants. Moreover, the price of electricity determined by the merit-order system additionally decreases the load factor of such plants making them even more uncompetitive or they are even forced to operate with a financial loss. In the present paper the novel approach of how the conventional CHP plants coupled with district heating system can reinforce their position on the energy market is presented. The proposed solution is by participating in the ancillary services, through determination of dynamical performances of district heating system – capability of energy accumulation and thermal inertia. 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 the various situation of operation of power plant (CHP). In that way decoupling of the fast bond between production of electricity and heat is enabled. In the research presented in paper mathematical model is developed which simulates dynamics of simplified district heating system. In addition, mass flow control as well as rotation speed control of the circulation pump is developed and applied to the model. The input data are for the characteristic winter day for the continental part of Croatia. The simulation has shown that in the case of a network only 9000 m long it is possible to store approximately 870 kWh of thermal energy within 7 hours. However, with an increase in the network length the accumulation capacity of network increases with the gradient of 0.155 kWh per meter. Moreover, the capability of energy accumulation is explored for different parameters, such as: external temperature, distance of the network, supply water temperature etc.

Izvorni jezik
Engleski

Znanstvena područja
Strojarstvo

POVEZANOST RADA