In general, the behaviour of the SSHEs when used for
crystallization processes can be characterized by the induction
time, defined as the maximum interim value between
two ice removal actions of the scraper. Anew Vaessen
(Vaessen et al., 2002) investigated the phenomenon of ice scale
formation on subcooled surfaces, finding that higher supercooling
degrees led to lower induction times, whereas the
opposite was found regarding the electrolyte solute content.
Qin et al. (2009) obtained a similar conclusion, finding that the
fouling induction time is mainly determined by the degree of
wall supercooling. Therefore, a constant presence of a thin ice
layer can be assumed, due to the inefficacy of the scrapers to
remove it completely, whereas the scale formation is only
avoidable by a real mechanical removal, entailing a sudden
decrease on heat transfer.