Glycol Heating & Water Cooling Coils

Standard hot water coils are effective in controlled environments, but when there is a risk of freezing on either the air side or fluid side of the coil, glycol becomes necessary. The correct glycol concentration depresses the freezing point of the fluid enough to prevent damage to the coil and connected equipment during cold-weather operation or system shutdowns.

Beyond freeze protection, glycol provides low-volatility heat transfer, which keeps the coil operating predictably across a wider temperature range than water alone. For facilities running outdoor make-up air units, heat recovery systems in cold climates, or processes that expose coils to ambient air below 32°F, a properly designed glycol heating coil is the more reliable long-term choice.

Glycol concentration has to be matched to your lowest expected operating temperature. Too little glycol leaves the coil exposed to freeze damage; too much reduces heat-transfer efficiency. Our engineering team calculates the appropriate concentration and flow rate as part of every design.

After assessing your application’s particular requirements, we will select appropriate materials, tube diameter, and fin design. Then, we calculate flow rate for optimal heat transfer. Finally, we design a uniform, efficient hot water coil circuit and work to minimize pressure drop through the system.

• Advanced Coil can design and build hot water & glycol coils for rigorous applications with the following considerations and solutions:
  • High-temperature loads and thermal expansion and contraction forces — free-floating segmented design
  • Corrosive environments — tubes made from unexpanded 304L or 316L stainless steel
  • High or low temperature or high-pressure applications — heavy walled tubes and TIG welded construction
• We also design water cooling coils for applications that require removing water or vapors from the air, such as air conditioning and dehumidification. As the air passes over the cooling coils, the temperature drops and causes the moisture in the air to condense on the surface of the coils.

We build glycol and water coils using 7/8" tubes in three wall thicknesses: 0.049", 0.083", and 0.109". For corrosive process environments, we specify unexpanded 304L or 316L stainless steel tubes, which resist chemical attack and maintain structural integrity at elevated temperatures. For applications involving lower-pressure service and less aggressive fluids, carbon steel tube options are also available. Heavier wall options are selected for high-pressure or high-temperature service, and all pressure-rated assemblies are built to ASME Section VIII, Division 1 standards.

Fins are available in 0.025" or 0.016" half-hard temper aluminum, half-hard temper copper, and 0.015" or 0.020" 304 or 316 stainless steel. The choice between these materials depends on the air-side environment, the corrosivity of the atmosphere, and the required service life. Fin spacing runs from 2.5 to 11 fins per inch. Closer spacing increases heat transfer surface area but also increases air-side pressure drop, so we calculate the optimal spacing for your air volume and velocity requirements.

Cases are fabricated from 12 gauge to 1/4" 304L or 316L stainless steel, or 12 gauge to 7 gauge galvanized steel depending on the installation environment. In corrosive or washdown environments, such as food processing facilities and chemical plants, stainless steel cases are standard. We also accommodate other materials upon request when a specific application calls for it.