ANALYSIS ON THE THERMAL BEHAVIOUR OF THE THERMAL STORAGE UNITS FOR PHASE CHANGE MATERIALS

The promotion of the unconventional heating/cooling systems of dwelling/occupied spaces requires, in most cases, their equipping with heat storage units either in a sensitive environment or in phase change substances. The sizing of the systems components as well as the assessment of the energy efficiency in representative climatic conditions is an activity requiring knowledge of the Thermal Storage Units Thermal Response (TSU-TR) at the loads represented both by the climatic parameters variation and by the dwelling exigencies in occupied spaces. The basic problem in sizing the PCSU (Phase Change Storage Units) is the accumulation of the maximum heat/cold quantity in a time-lag associated to the capacity of the source to supply heat/cold. The storage units fall into three types of geometry, namely: plane; cylindrical; spherical. The fluid carrying the heat/cold (heat carrier) has a very low thermal capacity (the mass is limited by avoiding the sensitive thermal processes (detrimental in terms of energy as well as in terms of sizing). Two types of processes are considered, as follows: with temperature of the heat carrier variation in time and space and isothermal at value t(F).