Investigation of effective factor on ice formation process of ice thermal energy storage using water-Oil emulsion - effects of wall material and cooling rate to ice adhesion on cooling wall

摘要

An emulsion which was a mixture of silanol - aqueous solution and silicone oil was examined as a thermal storage material for dynamic-type ice thermal storage. It was cooled and frozen under stirring in various vessels which were immersed in a controlled temperature bath. The vessels were made of stainless steel (SUS 304), Pyrex glass, polycarbonate, or Teflon (PFA). The ice formation process was examined under different cooling conditions until a predetermined amount of ice was formed. The heat transfer rate and overall heat transfer coefficient were measured and the condition under which ice did not adhere on the vessel wall was examined. For all vessels, ice adhered on the wall when the heat transfer rate through the vessel wall was high. Conversely, by decreasing the heat transfer rate, a slurry ice formed without adhesion. SUS304 vessel coated with PFA material was also examined. It was shown that ice adhesion on SUS304 wall was restrained by PFA coating even though the overall heat transfer coefficient was larger than that of PFA vessel.