Performance analysis of a novel hybrid power generation system integrated diesel generator with compressed heat energy storage

ABSTRACT

The time-dependent energy demand of energy islands may frequently change the operating condition of diesel generator (DG), leading to diesel engine operating under off-design conditions with low efficiency. In order to make the DG operate under efficient conditions and balance the mismatch of energy supply and demand in time, a novel hybrid power generation system integrated DG with compressed heat energy storage (CHEST) using sensible and latent thermal energy storage is proposed in this study. The overall efficiency of the proposed system could be further improved due to the waste heat recovery of exhaust and cooling water. Firstly, a parametric analysis of the CHEST unit is conducted to select optimal parameters and conditions for the CHEST unit. Then a comparative analysis between the traditional DG system and the proposed DG-CHEST coupling system with three operating strategies is carried out. Results indicate that Strategy A, B, and C could save fuel of 45.48 kg (17.74%), 44.22 kg (16.19%), and 38.89 kg (14.23%) a day, corresponding to the overall efficiency of 28.02%, 27.83%, and 26.22%, respectively, while it is only 20.89% for the conventional DG system. The comparative results among the three strategies show that the discharged power index (DPI) and discharged fraction (DF) decrease with the increase of control level of load factor.

KEYWORDS:

• Diesel generator
• hybrid power generation system
• compressed heat energy storage
• waste heat recovery
• operating strategy

Additional information

Funding

This research was funded by the National Natural Science Foundation of China (NSFC) under grant numbers No. 51976176 and No. 51806189, the Fundamental Research Funds for the Central Universities under grant No. 2020QNA4008, and the Royal Academy of Engineering through the Transforming Systems through Partnerships program under grant number TSPC1098.