Energy Flow Function Research Articles

Thermodynamic analysis and the design of sensible thermal energy storages

Summary Thermal energy storage (TES) is an important technology for effective and efficient energy management. The proper design and operation of a TES require an understanding of its behavior and characteristics. Here, the transient behavior during charging and discharging of a fully mixed, open TES is modeled and analyzed. Included are developments and analyses of the charging temperature function and the maximum charging temperature of the TES, the charging energy flow function and the maximum heat flow capacity of the TES, the discharging temperature function and the minimum charging temperature of the TES, the discharging energy flow function and the maximum heat flow capacity of the TES, and the expression for one cycle of the TES. The impact of various factors on charging and discharging are investigated. The results show that, by increasing the input energy flow rate, the charging temperature of the TES is raised, and that an increase in the input energy flow rate raises the discharging temperature of the TES in the early stage of discharging, while a decrease in the outlet energy flow rate increases the discharging temperature of the TES in the late stage of discharging. Copyright © 2016 John Wiley & Sons, Ltd.

Energy Flow Function and Operational Strategy of CCHP System

The energy flow characteristics of Combined Cooling, Heating and Power (CCHP) system are analyzed in detail and the energy flow function is proposed for its two operational strategies: thermal load dominant mode and electrical load dominant mode. In order to improve its economic and environmental efficiency, an optimal economic and environmental dispatch model is built, which includes the fuel cost, power purchase cost and pollution emission penalty as environmental cost in its objective function and takes the energy flow function as its energy balance equality constraint. Case simulation shows that, the proposed energy flow function and model optimizes the dispatch of CCHP system, reduces the productive cost, improves the environmental efficiency and enhances the energy utilization level.

Dynamic Fracture in Single Crystal Silicon

We have measured the velocity of a running crack in brittle single crystal silicon as a function of energy flow to the crack tip. The experiments are designed to permit direct comparison with molecular dynamics simulations; therefore the experiments provide an indirect but sensitive test of interatomic potentials. Performing molecular dynamics simulations of brittle crack motion at the atomic scale we find that experiments and simulations disagree showing that interatomic potentials are not yet well understood.