In last month’s column, we discussed the common practice of sizing an earth loop circulator so that it could maintain turbulent flow in the earth loop circuits under design load conditions (e.g., when the antifreeze solution flowing through the earth loop was at its minimum expected temperature and thus its highest dynamic viscosity).
While this approach is “conservative,” it also sidesteps the fact that the fluid in the earth loop is warmer much of the heating season, and as such could remain turbulent at lower flow rates, which also implies lower pumping power.