Overall-load performance and optimum operation strategy of gas turbine-based combined cooling and power systems considering energy price

The performance of cogeneration systems degrades at extreme loads under traditional operation strategies. In this paper, a multi-dimensional impact model was developed to evaluate gas turbine-based combined cooling and power (CCP) systems under the following electric load (FEL) and following cooling load (FCL) strategies. The model clarified system comprehensive performance across varying cooling-to-electricity ratio and gas-to-electricity price ratio, demonstrating energy-saving and economic operation boundaries. To address the limitations of traditional operation strategies such as FEL, FCL and following hybrid electric-thermal load (FHL), an improved FHL strategy (IFHL) was proposed for the loads exceeding the prime mover supply range. Further, Optimized strategies were proposed to maximize energy saving ratio (FHL-A) and minimize operating costs (FHL-B) under diverse energy prices and load conditions. The evaluation case of a data center CCP system shows that, the IFHL strategy improves annual primary energy saving ratio (PESR) by 0.27 %, cost saving ratio (CSR) by 0.58 %, and CO2 emission reduction ratio (CDER) by 0.45 % compared with FHL. FHL-A shows superior energy performance with 1.6 % higher annual PESR, while FHL-B achieves better economics with 3.64 % greater annual CSR. Across three typical daily scenarios, FHL-A outperforms in PESR and FHL-B in CSR compared to seven alternative strategies including energy storage and grid-sales.