基于单片机的电热水器热水预测与控制系统

针对智能储水式电热水器对未来热水用量的预测和控制需求,基于单片机的热水预测-控制系统以单片机为核心预测用户未来用水需求,并控制电热水器供应目标热水量。硬件上,温度和流量传感器检测并记录用户用水,继电器是控制电热水器加热的关键器件。软件程序上,主要通过最小二乘法对用户用水的时间序列数据找出用户用水规律,并根据用水周期预测未来的用水量需求,最后控制电热水器加热内胆冷水到目标温度。

学生宿舍空气源热泵热水系统的智能控制设计

学生宿舍热水需求量大,热水系统设备复杂,为实现热水系统的智能、节能运行,设计了热水系统的智能控制系统、配电系统,分析了单台空气源热泵的智能控制逻辑和热水系统的智能控制逻辑。同时,在阐明热水用量预测必要性的基础上,提出了热水用量预测方案。

Pool Boiling Heat Transfer in Dilute Water/Triethyleneglycol Solutions

Boiling of water/triethyleneglycol(TEG)binary solution has a wide-ranging application in the gas processing engineering.Design,operation and optimization of the involved boilers require accurate prediction of boiling heat transfer coefficient between surface and solution.In this investigation,nucleate pool boiling heat transfer coefficient has been experimentally measured on a horizontal rod heater in water/TEG binary solutions in a wide range of concentrations and heat fluxes under ambient condition.The present experimental data are correlated using major existing correlations.In addition a correlation is presented for prediction of pool boiling heat transfer for the system in which the vapour pressure of one component is negligible.This model is based on the mass transfer rate equation for prediction of the concentration at the bubble vapor/liquid interface.Based on this prediction,the temperature of the interface and accordingly,the boiling heat transfer coefficient could be straightforwardly calculated from the known concentration at the interface.It is shown that this simple model has sufficient accuracy and is acceptable below the medium concentrations of TEG when the vapor equilibrium concentration of TEG is almost zero.The presented model excludes any tuning parameter and requires very few physical properties to apply.

Analysis and prediction of fishtail during V-H hot rolling process

The fishtail in head and tail of the slabs was studied during V-H hot rolling process. With the application of ANSYS/LS-DYNA, simulation analysis was used to research this process. The various factors which have a great influence on fishtail shapes were analysed, such as initial width, initial thickness, radius of the edger roll and horizontal roll, edging draught,horizontal reduction rate, and friction coefficient of the surface. Then the curves that can describe the shapes were obtained. After a certain time of self-learning, the optimized curves were given out. At last, through the fitting of the simulation test results, the math models for the area of fishtail defect changing with the presented factors were received. The experimental results show that the accuracy of the prediction for the fishtail shapes is more than 95%. With the application of the prediction for the fishtail shapes and the area of the fishtail defect, the loss rate of the slab is decreased by about 0.1%.

Prediction of Thermal Behavior of Pyrolyzed Wet Biomass by Means of Model with Inner Wood Structure

A simplified one-dimensional transient model for biomass pyrolysis in a fixed bed cylindrical reactor has been formulated and experiments have been carded out to verify the calculation results regarding temperature distribu- tion. The mathematical model accounts for mass, momentum and heat transfer, including moisture evaporation and convection of pyrolysis gases. Numerical simulation has allowed to predict temperature and heat flux distri- bution, and the dynamics of feedstock devolatilization. Special attention has been devoted to the analysis of the effect of biomass moisture content on the pyrolysis process. The model of moisture vaporization in biomass bed was proposed, which included structure of surface of biomass particles. Assuming that vaporization occurs on the border of the dry and wet areas of the bed, the flux of water vaporization depends on the specific surface area of the particles and overall heat flux.