Simulation on transportation safety of ice slurry in ice cooling system of buildings

Ice storage systems are capable of shifting the electricity demand from on-peak hours to off-peak hours, and ice slurry becomes more widely used as an efficient cooling medium for replacing the traditional ice-on-coil system. However, ice blockage is a severe problem threatening the transportation safety of ice cooling systems. In this paper, a method for determining the critical velocity for safe transportation is proposed. Moreover, mechanical analysis is carried out to find out the stratification mechanism. This paper focuses on numerical simulation of ice slurry flow, and aims to find out influences of the following factors on transportation safety: ice packing fractions, ice particle size, additive concentrations and pipe size. According to the simulation, the IPF is suggested to be 20-25%; ice particle diameters are suggested to be within 100 pm; ethanol concentrations are suggested to be in the range of 5-10 wt%. In addition, reducing pipe diameters is beneficial to transportation safety. The results and proposed guidelines are of significance for predicting the critical velocity for safe transportation and guiding the safety design and operation of ice cooling systems. (c) 2014 Elsevier By. All rights reserved.