DEVELOPMENT OF CRITERIA OF CHARGE AND DISCHARGE EFFICIENCY OF SOLID STATE OF HEAT ACCUMULATOR

Abstract

Purpose. Development of similarity criteria for different modes of operation of the solid-state heat accumulator working due to accumulation of heat in the volume of the heat storage material without phase transition, and the creation of systematic criteria of heat accumulator efficiency for determination the weight / size parameters and operating modes at the design stage. Methodology. To achieve the objectives of the study the theory of similarity and dimensional analysis were used as well as planning and carrying out techniques of physical experiments. Findings. Based on the theory of similarity and dimensional analysis similarity criteria operation of solid-state heat accumulators, under given basic parameters were obtained. These are performance criteria for charge, discharge and full criterion. Three theorems of similarity theory in application to the solution of engineering problems were used. The criterion of efficiency of the heat accumulator charge characterizes the effectiveness of achieving the specified value of the specific amount of heat in the material of heat accumulator under charge, under received materials, geometrical ratios, and heat flow of the heat input. The efficiency criterion characterizes the discharge efficiency of the heat accumulator, at the accepted materials; mass of heat-retainer and the total accumulated amount of heat when the value of the heat flow and the time of discharge. Full coefficient of the heat accumulator performance characterizes the efficiency of the heat accumulators for a full cycle. Originality. Accordingly to the analysis the implementation of any system of solid-state heat accumulator is possible on the basis of structural schemes of this type of device. The similarity criteria of the efficiency of the charge, the efficiency of discharge and the full criterion of solid-state heat accumulators’ efficiency based on the solid storage material without phase transition were obtained. Practical value. Criteria presented in this work are of a comparative nature. In accordance with the obtained criteria we can compare designed and existing heat accumulators that are similar to structures. Feasibility analysis indicates that the proposed assessment methodology of solid-state heat accumulators’ efficiency in different modes of operation is effective, technically feasible and allows determining the weight / size parameters and modes of operation of the solid-state heat accumulator at the design stage.