Energy flows and energy conversion efficiencies of commercial plug-in hybrid electric vehicles (PHEV) are analyzed for parallel and series PHEV topologies. The analysis is performed by a combined analytical and simulation approach. The paper reveals energy conversion phenomena of different PHEV topologies operating according to charge depleting and charge sustaining modes as well as according to different test cycles. The paper gives insightful guidelines for optimizing control strategies in term well-to-wheel efficiencies and different realistic well-to-tank efficiency scenarios.
COBISS.SI-ID: 11782939
The paper presents an experimental study of suspension flow patterns and velocity field inside two types of circular settling tanks with continuous operation. The two tanks differ in inlet- and outlet configurations. Research was focused on the influence of flow field on the sedimentation efficiency of both settling tanks. Experiment was carried out on a settling tank sections made of plexi-glass that represented radial slices of prototype circular settling tanks. Kinematic flow properties inside settling tank sections were determined by computer-aided visualization in order to analyse the whole instantaneous flow field at once. Sedimentation efficiency was assessed by measurements of inlet- and effluent suspension concentrations. Pronounced density current evolved in both tanks, which under certain conditions enhanced sedimentation. Flow field showed qualitative changes during operation and proved to be significantly dependent on average suspension density in the inner chamber of the settling tank. Centrally fed settling tank with peripheral effluent generally performed better in terms of sedimentation efficiency mainly due to insufficient height of the effluent baffle in the peripherally fed settling tank.
COBISS.SI-ID: 12106523
A methodology for the evaluation of a natural draft cooling tower (CT) that is a part of a power plant is proposed. In this work the connection between CT performance and power output is established. The methodology consists of three subparts, i.e. Cooling Tower Profiler (CTP) method, CT model and model of a power plant. In the first part of the paper the three subparts of the methodology are described. Focus is given to the empirical model of the plant and a new application of the Poppe model. The simple empirical model enables accurate prediction of the power increase as a function of cooling water temperature and load to the plant. On the other hand, Poppe governing equations were derived for application on the local basis of CT. Moreover, the constraints and assumptions of CT analysis are discussed. The methodology is presented on real data from the power plant and CT. This is the base for application of the methodology presented in the second part of the paper where the focus is given on minimizing the error of the methodology. A small area with irregularities is analyzed and results are reported. Furthermore, a simplified computational approach to solving the Poppe equations is proposed yielding faster calculation with preserved accuracy.
COBISS.SI-ID: 11909403