Applicability of thermal energy storage in future district heating system - Design methodologies and performance evaluations
Licentiate thesis, 2021
To explore the practical challenges and optimal applications of short-term TES units in the future, a systematic design framework that considers the diverse factors from top-level targets to bottom-level implementations is developed in this study. The top-level theoretical analysis method is developed to identify the load shifting potentials and associated storage capacities for the whole energy system, by comparing and matching energy supply and demand profiles. Compared to current bottom-up detailed system models, the proposed method requires only the energy profiles, which has resulted in much shorter analysis time. The method is further validated by complex system models, and because a good agreement has been achieved, it can be applied in various scenarios to efficiently pre-study the storage potentials. Then, the design of the practical TES capacity is derived from the theoretical result by considering performance indicators during realistic operations, such as power-to-heat conversion efficiency and heat loss efficiency.
On bottom-level implementations, four typical short-term TES technologies were investigated including central water tank (CWT), district heating network inertia (DHNI), domestic hot water tank (DHWT), and building thermal mass (BTM). For this purpose, an integrated bottom-level model to simulate the operation dynamics of the district heating systems and to optimize the use of the TES units is developed. Techno-economic analysis and comparisons of TES technologies were performed on a variety of scenarios, which are representatives of the main characteristics of the current middle-temperature district heating system and future low-temperature district heating system. The changes in the source side, transportation networks and end-use building demands are considered. As a result, a performance map of the TES technologies indicating the strong links between the system characteristics and optimal TES applications has been identified. Based on that, the optimal combinations of TES technologies were proposed for a LTDH system. Consequently, combining this with top-level methods, the overall potentials and roles of short-term TES were identified by a systematic design framework.
low-temperature district heating
low energy buildings
Thermal energy storage
variable renewable energy
Chalmers, Architecture and Civil Engineering, Building Technology
Yichi Zhang, Pär Johansson, Angela Sasic Kalagasidis, Applicability of thermal energy storage in future low-temperature district heating systems - multi-scenarios analysis and evaluations
Yichi Zhang, Pär Johansson, Angela Sasic Kalagasidis, Utilizing the thermal inertia of district heating networks to improve energy system flexibility: potentials and feasibilities
iTES - Innovative compact heat storage technologies and operation schemes for buildings connected to smart grids
Formas (2018-01228), 2019-01-01 -- 2021-12-31.
Areas of Advance
Lic / Architecture and Civil Engineering / Chalmers University of Technology: 2021:6
ACE room SB-K373
Opponent: Prof. Rongling Li, Department of Civil Engineering DTU, Denmark