Modelling of cogeneration systems. Part 2: Development of a quasi-static cogeneration model (steam turbine cogeneration analysis)

Abstract

Steam turbine cogeneration analysis (STuCA) is a quasi-static cogeneration plant model that has been developed to simulate steam turbine cogeneration plants subject to varying loads. STuCA was developed to provide potential cogeneration plant users with a model that could simulate part-load performance over the expected operating range of the cogeneration plant using fundamental engineering analysis methods. The model was designed to bridge the gap between static designpoint models that could not accommodate part-load conditions and complex part-load models which are too expensive for small scale cogeneration proposals. In addition, the model contains economic analysis tools to analyse the thermoeconomic performance of the plant and to conduct a cash flow analysis. These features are an extension to the static and part-load models. The model consists of four submodels: a load, system, plant and economic model. The load submodel drives the cogeneration plant simulation, supplying utility demands to the system models. The system submodels calculate the steam required by the system components to meet the utility demands. The plant submodel then predicts turbine and boiler performance as they meet the steam demand. The primary plant submodel outputs are the electricity generated and quantity of coal consumed by the boiler, which are used by the economic submodel to conduct a thermoeconomic analysis of the site as well as a discounted cash flow analysis. This method of modelling results in a model that can predict plant performance with respect to varying load and then use those data to conduct a meaningful economic performance analysis of the site.

Feasibility analysis of a MED desalination plant in a combined cycle based cogeneration facility

“…This model performs on design analysis of the operating strategy [13,14] -relationship between power production and heat consumption plantsconsidering changes in heat demand in order to adapt the power plant to them. For the latter, combined cycle modelling has been done by applying equations of conservation of mass and energy at every single piece of equipment in the cycle [15], along with performance maps supplied by OEMs.…”

Modelling of cogeneration systems. Part 1: Historical perspective

“…It is a quasi-static cogeneration plant model that can be used to simulate the performance of steam turbine cogeneration plants for sites with fluctuating loads. The STuCA model is presented as Part 2 [20] of the series in the companion paper while the model is verified and tested in Part 3 [21].…”

Thermodynamic analysis of an in-situ cogeneration plant

“…Most available cogeneration system models concentrate largely on the economics of plant operation and installation, and calculate these for fixed load scenarios. The STuCA (steam turbine cogeneration analysis) model created by O'Brien and Bansal [5][6][7] uses a quasi-static approach to account for load fluctuations, but still concentrates on the economics of cogeneration. In this study static models concentrating on the energy flows within the cogeneration system have been developed.…”