This Doctor's Orders blog is a guest post from SRC Richmond's Director of Strategic Accounts, Louis Rogerson. 

Low-temperature heat transfer applications regularly use anti-freezing agents like propylene glycol (PG) to enable lower-temp operation. However, at very low ambient temps, properly calculating critical fluid properties like viscosity, fluid velocity, and their impacts on heat transfer becomes more complex. This post will analyze the correlation among those properties at low ambient temperatures and provide guidance for how to best model a coil’s performance at such conditions.