Next Generation Phase Change Materials as Multifunctional Watery Suspension for Heat Transport and Heat Storage
- PDF / 8,186,705 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 37 Downloads / 272 Views
1188-LL06-02
Next Generation Phase Change Materials as Multifunctional Watery Suspension for Heat Transport and Heat Storage M. Hadjieva1, M. Bozukov1, I.Gutzov2 Bulgarian Academy of Sciences: 1 Central Laboratory of Solar Energy and New Energy Sources, 72 Tzarigradsko Schosse blvd., 1784 Sofia, Bulgaria 2 Institute of Physical Chemistry, Acad G. Bonchev, bl. 11, 1113 Sofia, Bulgaria
ABSTRACT The phase change materials (PCM) were modified to paraffin watery dispersions, well structured as multifunctional fluids for both, heat transport and heat storage in thermal cooling technology. Two types PCM dispersions, paraffin microcapsule watery suspension (Slurry A) and paraffin microemulsion (Slurry B), absorbed and released heat in a temperature range of phase transition from 20C to 120C. Thermal capacity of paraffin Slurry A was about 53 kJ/kg, while paraffin Slurry B exchanged about 83 kJ/kg amount of heat during phase transition. Systematization of thermophysical data and structural imaging of Slurry A and Slurry B, studied before and after thermal cycling, allowed comparison of thermal efficiency and structural stability during multiple phase transitions. The correlation between structural properties and thermal storage capacity allows recommendation of a paraffin emulsion Slurry (B) suitable for practice as a watery dispersion architectured stable in limits of year and thermally efficient. INTRODUCTION The PCM, well known since past century, are modified to the next generation of PCM intended to respond to new functions and requirements of the present-day thermal technology. Impact of phase change technology on energy balance of dwellings includes reduced energy consumption of heating/cooling, moderate temperature swings, reduced of peak power needs. Modern cooling technology developments use the PCM slurry for storage and transport of heat.[1],[2],[3],[4]. PCM slurries are multifunctional fluids composed of microstructures dispersed in a solvent as: phase change watery suspension with micro-capsulated paraffin [3], [4], phase change paraffin emulsion slurry [2], clathrate hydrate slurry. Advantages of architectured PCM watery dispersions comprise multifuncionality of heat storage and heat transfer processes; tailoring the temperature range of heat storage; improvement of energy storage capacity of heat transfer fluids; structural stability of PCM during thermal cycling at repeatable phase transition; improved thermal conductivity. PURPOSE Long-term effectiveness of the architectured PCM watery dispersions, PCM slurries depends on thermal energy storage capacity, on structural stability of PCM at multiple melting/solidification and on structural stability of the PCM slurry during repeatable thermal cycling at heating and cooling. Long-term pumpability and a heat flow transfer of PCM slurry,
which proceeds as a heat transfer fluid are of practical importance. Progress in solving the material requirements is crucial for PCM slurry technology developments. Thus, structural and thermophysical properties of two types
Data Loading...
