A multi-timescale cold storage system within energy flexible buildings for power balance management of smart grids

Chengchu Yan, Nanjing Tech University
Fengling Wang, Nanjing Tech University
Yan Pan, Technological and Higher Education Institute of Hong Kong
Kui Shan, The Hong Kong Polytechnic University
Risto Kosonen, Nanjing Tech University


Energy storage is widely used in energyflexible buildings, which have great potential for relieving thepower imbalance of electrical grids. However, most of the existing energy storage systems are designedfor short-term storage, and only a few systems reported for long-term or multi-time scale storage. Thispaper introduces a new type of multi-timescale cold storage system consisted of a heat pipe-basednatural ice storage subsystem and a dual-operation chiller for buildings to enhance their energyflexi-bility. The proposed system operated in different modes to provide the seasonal cold storage, nighttimechilled water storage, and urgent demand response services, which can be used for relieving the powerimbalance in the timescale of the long-term, short-term and real-time respectively. The working prin-ciple, system configuration, operation modes, and the implementation of the proposed system for multi-timescale power management, are presented. A case study has been conducted in a building in Beijing todemonstrate the application and effectiveness. Results show that building load factors are greatlyimproved seasonally (from 19.5% to 49.5%) and daily (from 55.7% to 72.2%), and the power consumptionis also considerably decreased (41.2%) during the demand response (DR) event