HVAC & Geothermal Cooling

HVAC and geothermal cooling is where coolant chemistry turns into operating expense. A chiller plant, hydronic heat-pump loop, rooftop dry cooler, or buried geothermal field can look mechanically sound while the fluid is already consuming inhibitor reserve, loading the loop with minerals, or pushing pump energy higher than the design model assumed. Alliance Chemical now positions HVAC & geothermal around OAT-inhibited glycol coolants: Inhibited Propylene Glycol 30/70, 40/60, and 50/50 with OAT Inhibitor for lower-toxicity secondary loops, food-adjacent facilities, schools, and geothermal projects; and Inhibited Ethylene Glycol 30/70, 40/60, and 50/50 with OAT-908 where closed-loop efficiency and lower viscosity are the primary drivers. Deionized Water supports flushing, dilution, top-off, and make-up water. The goal is simple: help mechanical contractors and facility engineers stop treating glycol as commodity antifreeze and start treating it as a documented heat-transfer fluid with known inhibitor chemistry, freeze point, pH, refractive index, and maintenance cadence.

For HVAC and geothermal systems, grade means more than glycol percentage. It includes glycol type, inhibitor technology, dilution water, toxicity profile, and documentation. Propylene glycol is usually favored when a leak could reach food-contact equipment, occupied public buildings, groundwater, or environmentally sensitive sites. USP-grade propylene glycol may be required where the risk model or local code demands it, while OAT-inhibited PG blends give contractors a ready-to-use path for many closed secondary loops. Ethylene glycol remains attractive in closed commercial and industrial systems because it typically offers better heat transfer and lower viscosity than PG at comparable freeze protection. OAT-inhibited EG blends are useful where pump energy, coil performance, and cold-weather protection matter. Concentrates still have a place, but only when the contractor has validated water quality, mixing equipment, refractometer targets, and corrosion-control requirements.

The first mistake is buying glycol by freeze point alone. A 50/50 fluid with the wrong inhibitor package can still attack mixed-metal systems, foul heat exchangers, or create maintenance problems long before the first winter. The second mistake is using tap water for dilution or top-off. Calcium, magnesium, chloride, sulfate, and other ions can consume inhibitor reserve, raise conductivity, and create scale in plate heat exchangers and geothermal piping. The third mistake is treating ethylene glycol and propylene glycol as interchangeable. EG may move heat efficiently, but PG is often the better procurement decision for schools, food facilities, and geothermal projects with environmental exposure. The fourth mistake is failing to record the initial charge data. Without baseline refractive index, pH, reserve alkalinity, freeze point, and product documentation, the first annual maintenance test becomes guesswork instead of trend analysis.