Technical Potential of Thermal Energy Accumulation in District Heating Networks
Abstract:
The use of electrothermal consumers-controllers (ETCC) in district heating systems is one of the possible variants for the frequency and active power control of the integrated power system of Ukraine. When ETCC discharges a large amount of thermal energy in the network (“night-time valley” period), it will inevitably lead to the need of the thermal energy accumulation. At present the theoretical foundation of the thermal power accumulation of ETCC in heating networks has not been adequately developed that may be an obstacle for its massive introduction into district heating systems.
The purpose of this paper is to determine the technologically feasible potential of thermal energy accumulation in district heating networks.
Prevention of the rise of heat carrier temperature above the maximum permissible level in the supply and return lines is one of the constraints stipulated by the need of ensuring the reliability of centralized heat supply system.
The performed analysis indicates that for ensuring the reliable operation of heat supply system the heat carrier temperature in the supply line during the thermal energy accumulation cannot have the maximum value in the entire range of ambient air temperature, it should decrease proportionally to the increase of air temperature.
Investigations revealed that the technical potential of thermal energy accumulation in district heating networks was below the theoretical potential by 35–50% (depending on the heat carrier temperature in the return line). Technical potential reduction is caused by impossibility of ensuring the simultaneous maintenance of the maximum admissible temperature of heat carrier both in supply and return pipelines during thermal energy accumulation in district heating networks.
References:
- Podobed, V.S. (2011). Akkumulirovaniie teplovoi enerhii v vodianykh teplovykh setiakh [Thermal Energy Accumulation in Hot-Water Heating Networks]. Minsk: Energeticheskaya strategiya - Energy Strategy, 5(23), 22–26 [in Russian].
- Derii, V.O. (2014). Tekhnichni ta instytutsiini factory vprovadzhennia spozhyvachiv-rehuliatoriv u systemakh tsentralizovanoho teplopostachannia [Technical and Institutional Factors Affecting the Introduction of Consumers-Controllers in District Heating Systems]. Problemy zahal`noi enerhetyky - The Problems of General Energy, 2(37), 52-58 [in Ukrainian].
- Derii, V.O. (2014). Potential of thermal energy accumulation in district heating systems networks. Problemy zahal`noi enerhetyky - The Problems of General Energy, 4(39), 29-33 [in English].
- Iakovlev, B.V. (2008). Manevrennost’ TETs pri ispol’zovanii akkumuliruiushchei sposobnosti tranzitnykh teplostei [Flexibility of TPP in Using the Accumulating Capacities of Main District Heating Networks]. Retrieved from http://www.combienergy.ru/stat1142.html [in Russian].