Optimal control strategies for multi-chiller system based on probability density distribution of cooling load ratio

Probability density distribution profile of cooling load ratio is obtained by Parzen window density estimation method, which is used to describe the building cooling load variation. Based on the analysis of this profile, the optimal sequence control strategies (AI, AII and AIII) are presented. In order to optimize the COP of total chillers, the optimal load allocation control strategy B is presented. The optimal load allocation control strategy BI is presented to improve the strategy B for simplifying the process of the optimal calculation and maintaining stability of the system operating. Simulation results show that these optimal control strategies presented can save more power consumption of chillers operating than the original sequence control strategy. Comparing the strategy B, the strategy BI can avoid unnecessary switch on/off actions of chillers and decrease computational costs.     

The characteristics of space cooling load and indoor humidity control for residences in the subtropics

For residential buildings located in the subtropics, it is more challenging and difficult to deal with space latent cooling load than space sensible load, using a room air conditioner (RAC), partly due to hot and humid climates. This paper reports a simulation study on the characteristics of space cooling load and indoor humidity control for residences in the subtropics, using a building energy simulation program. Both the weather conditions and the typical arrangements of high-rise residential blocks in subtropical Hong Kong were used in the simulation study. The simulation results on both the space cooling load characteristics and the hourly application sensible heat ratio (SHR) in the living/dining room and the master bedroom in a selected west-facing apartment under different operating modes of RACs in the summer design day are presented. The problem of indoor humidity control due to the mismatching between an application SHR and an equipment SHR in the two rooms both in the summer design day and during part load operations and the influences of indoor furnishings acting as moisture capacitors on indoor RH level are discussed.     

基于随机场理论的地基稳定性模糊可靠度分析

根据Vanmarcke提出的随机场理论描述土性参数的空间变异性,建立了考虑土性参数空间变异性的地基失稳模糊概率公式,并通过实例分析了两种情况下地基的模糊失效概率值,得出用随机场理论空间均值方差计算的模糊失效概率值比不考虑土性参数的空间变异性计算模糊失效概率值偏低的结论.