Seasonally shutting down a cooling tower by draining the tower is often not possible for three reasons: (1) In large buildings in colder temperatures they still have a need for cooling. For instance a data center will need cooling due to the heat generated from the server racks year around (2) in sections of the United States, the occasional warm winter day necessitates sporadic air conditioning operation and (3) year-round one or two shift industrial heating loads require cooling during the day but freeze protection at night.
Basin heaters are such a small inexpensive part when looking at a cooling tower. But these basin heaters serve a huge purpose in keeping the water in the basin above freezing. These heaters will not protect the fill or the piping from freezing. Basin heaters are normally selected to maintain 38° – 40°F basin water temperatures at 0°F ambient conditions. Basin heaters for cooling tower duty are constructed with copper heating elements and because the elements are fully immersed, they are 100% efficient and easily controlled.