Hot water coil and chilled water coil history and facts

The precursors of our current hot water coil and chilled water coil systems have been in existence for centuries. While the first “modern” water-tube boiler was invented by William Blakely in 1796, water-tube boilers date back almost 2,000 years. And chilled water has been a primary medium for the transfer of heat from building coils to refrigeration systems since the beginning of modern HVAC design.

Here are a few factoids about hot water coils and chilled water coils:• Hot water coils and chilled water coils are often viewed as completely different coils; however, a water coil is equally capable of handling hot water and chilled water.• The construction of hot water coils and chilled water coils is similar, including tube diameter, fin design and wall thickness.• A hot water coil typically has one or two rows, while a chilled water coil has three or more rows.• Fluid pressure drop and fluid velocity are critical to the operation and longevity of water coils.• Chilled water coils are often used for comfort cooling, dehumidifying, process cooling and heat reclamation.• Hot water coils are often used for preheating, reheating, comfort heating, booster heating, waste heat reclamation, and fluid process heat.

With such a long history of heating and cooling, is it any wonder hot water coils and chilled water coils are used in so many HVAC systems?