HOME Publications Profesional data Lectures Books Projects Computer programs

AN A PPROXIMATE A PPROACH OF HEAT TRANSFER ACCOMPAINED BY PHASE TRANSITION

Stanko Shtrakov and Plamen Gramatikov

1 Assoc. Prof. Dr. Stanko Shtrakov , South - West University “Neofit Rilski ” , Dept for Alternative Energy Sources, 66 Ivan Mihailov Str., 2700 - Blagoevgrad, BULGARIA, Tel.: +(359 2) - 263216; E-mail: Stanko@aix.swu.bg ,

2 Assoc. Prof. Dr. Plamen Gramatikov, South - West University “Neofit Rilski ” , Dept for Alternative Energy Sources, 66 Ivan Mihailov Str., 2700 - Blagoevgrad, BULGARIA, Tel./fax. +359 - (0)73-20767; Fax: +359 - (0)73 - 29325 PSGramat@aix.swu.bg

ABSTRACT

LOW TEMPERATURE HEAT (SOLAR ENERGY, GEOTHERMAL ENERGY, INDUSTRIAL AND DOMESTIC WASTE HEAT) IS WIDELY AVAILABLE FOR MANY APPLICATIONS. ENERGY STORAGE OF THAT HEAT IS NOW OF GREAT IMPORTANCE. PHASE CHANGE MATERIAL (PCM) IS PARTICULARLY ATTRACTIVE DUE TO ITS ABILITY TO PROVIDE A HIGH-ENERGY STORAGE DENSITY AND ITS CHARACTERISTICS TO STORE HEAT AT A CONSTANT TEMPERATURE. IN THE PRESENT STUDY, T HE PHASE CHANGE PROBLEM IS ANALYSED IN TYPE OF SHELL-AND-TUBE HEAT STORAGE SYSTEM WITH CLOSED TUBES (CAPSULES) FILLED WITH PCM AND THE HEAT TRANSFER FLUID (HTF) FLOWING IN THE SHELL SPACE. A TWO DIMENSIONAL MATHEMATICAL MODEL IN CYLINDRICAL COORDINATES WITH A SOURCE MEMBER IS USED TO DESCRIBE THE PHYSICAL PROCESSES . A COMPUTER PROGRAM BASED ON THE THEORETICAL MODEL IS DEVELOPED TO PREDICT THE TRANSIENT BEHAVIOUR OF HEAT TRANSFER BETWEEN HTF AND PCM. A SERIES OF NUMERICAL EXPERIMENTS IS UNDERTAKEN TO ASSESS THE EFFECT OF VARIOUS THERMAL AND GEOMETRIC PARAMETERS ON THE TRANSFER PROCESS. THE COMPUTATIONAL MODEL IS VALIDATED WITH EXPERIMENTAL DATA.