Rockefeller Center in midtown Manhattan is one of the most
recognized commercial properties in the world. Built during the
Art Deco period of the early 1930s, the 10-building real-estate,
shopping, and dining complex, which encompasses six square
blocks and consists of approximately 8 million sq ft of rentable
space, is home to NBC studios, Radio City Music Hall, and
perhaps the world’s most famous ice-skating rink and Christmas
tree. The buildings of Rockefeller Center are served by a
central chilled-water plant containing 14,500 tons of steam and
electric chillers. Water is distributed through a primary water
loop around the perimeter of the site. Six primary pumps—four
with 6,000-gpm capacity at 125 hp and two with 2,000-gpm
capacity at 50 hp—are located in the main plant. Seventeen
primary chilled-water riser pumps, which range in size from
1,000 gpm at 40 hp to 3,500 gpm at 200 hp, send chilled water to
heat exchangers located in each building. The secondary sides of
the heat exchangers have pumps that s