The experiment is studied on thermal distribution in the thermal energy
storage system with non-phase change materials (NPCM): NaNO
3, KNO
3 and NaCl in the range of 25
°C - 250
°C. The cylindrical storage
system was made of stainless steel with 25.6 cm-diameter and 26.8 cm-height
that was contained of these NPCM. There was one pipe for heat transfer fluid
(HTF) with 1.27 cm-diameter that manipulates in the storage tank and submerges
to NPCM. The inner pipe was connected to the 2.27 cm-diameter outer HTF tube.
The tube was further connected to the thermal pump, heater and load. The pump
circulates the synthetic oil (Thermia oil) within the pipe for heat
transferring purposes (charging and discharging). An electric heater is used as
the heat source. The limitation of the charging oil temperature is maintained
at 250
°C with the flow rates in the range of 0.58 to 1.45 kg/s whereas the
inlet temperature of the discharge oil is maintained at 25
°C. Thermal
performances of TES (thermal energy storage) such as charging and discharging
times, radial thermal distribution, energy storage capacity and energy efficiency
have been evaluated. The experimental results show that the radial thermal
distribution of NaCl for TR inside, TR middle and TR outside was optimum of
temperature down to NaNO
3 and KNO
3 respectively.
Comparison of NPCMs with oil, flow rates for NaCl were charging and discharging
heat transfer than KNO
3 and NaNO
3. The thermal stored
NaCl ranged from 5712 - 5912 J; KNO
3 ranged from 7350 - 7939 J and
NaNO
3 ranged from 6623 - 6930 J respectively. The thermal energy
stored for experimental results got with along the KNO
3, NaNO
3 and
NaCl respectively. The thermal energy efficiency of NaCl, KNO
3 and
NaNO
3 was in the range 66% - 70%.