Pilipenko A. Dynamics of ice crystallization on vertical cooled down pipes in elements of thermal energy accumulators within refrigeration and air-conditioning systems

The possibility of the reduction of power consumption at dairy plans and business centers has been proven. This reduction can be achieved due to a significant decrease in cold consumption during the peak consumption periods by means of the cold accumulation at night time with its further realization during the periods of cold maximum consumption. Compensation in peak cold consumption may be realized by the use of cold previously accumulated directed towards the reduction of cooling agent's temperature or by means of the reduction of condensation temperature within the cycle of the refrigeration unit. A mathematical model has been developed which accounts for ice growth rate over the cylindrical heat transfer surface which is being directly cooled down by the evaporating refrigerants or by means of convective one phase cooling agent. The model has been validated by the experimental data obtained by the author as well as by the data available in literature. It has been shown that under the conditions of the ice generated surface cooling by one phase cooling agent i.e. under the condition of the constant heat flux from the cooling surface, the model generalizes experimental data with an accuracy ±6 % and thus may be used directly for the design calculations of cold accumulators of the said type. Under the condition of the ice generating surface cooling directly by means of the evaporating refrigerant, a semi-empirical method of the experimental data correlation has been obtained. The developed method allows calculating the immediate ice thickness for any time within a cycle of icing at a range of 0…15000s. It also allows drawing the graphs of ice thickness growth in time. The method and software program for the design calculations of thermal accumulations with ice generations on the heat transfer surface with a direct cooling have been presented.