Optimization of a seawater once-through cooling system with variable speed pumps in fossil fuel power plants

Optimization of a seawater once-through cooling system using variable speed pumps (VSPs) is presented to improve the efficiency of power plants. This study is focused on the VSP running number optimization and VSP speed optimization. A novel method is proposed to optimize the VSP running number with the varying condenser inlet water temperature and unit load. A novel method is also proposed to determine the optimum VSP speed by dividing the system operating conditions into two parts with different optimization algorithms. The method helps to choose the proper optimization algorithm at different operating conditions, which will reduce workload and improve working efficiency. A case study shows that the VSP running number optimization could help to reduce annual costs for VSPs by 14%.