Performance comparison of a distributed energy system under different control strategies with a conventional energy system

Abstract

The distributed energy system (DES) has increasingly attracted considerable attention from researchers due to its environmental friendliness and high efficiency. In the hot summer and cold winter areas, DES is an efficient alternative for district cooling and heating. A case study located in Changsha, China, which is a typical hot summer and cold winter area, is analyzed. Four control strategies are proposed in this study. The four cases under different control strategies are compared in terms of energy, economy, environment, solar fraction, and soil annual heat imbalance rate. Results show that the DES can be an energy saving and environmentally friendly alternative. The primary energy saving (PES) is more than 36.70% and can reach up to 48.04%, whereas DES can realize economical operation and reduce the emission of carbon dioxide, sulphur dioxide, and dust. In addition, DES consumes more electricity and less natural gas than the conventional energy system. These features are beneficial to the optimization of China’s energy consumption structure. Moreover, the operation of seasonal thermal storage for the ground soil is effective in maintaining the balance of soil annual heat. The control strategy combining geothermal and solar energies is recommended due to its good performance and high flexibility. This study may provide guidance in the development of DESs in hot summer and cold winter climate zones.