DOWFROST HD

DOWFROST HD Inhibited Propylene Glycol Heat Transfer Fluid

94% Propylene Glycol Concentrate for HVAC, Process Heating, Cooling and Freeze Protection

DOWFROST HD is a concentrated inhibited propylene glycol heat transfer fluid designed for closed-loop HVAC systems, process heating and cooling, freeze and burst protection, geothermal systems, and other applications where a propylene glycol-based thermal fluid is preferred or required.

The concentrate contains 94% propylene glycol and 6% performance additives, including an industrial corrosion inhibitor package. It is dyed fluorescent yellow to make leaks easier to identify.

DOWFROST HD is designed for demanding thermal systems where corrosion protection, fluid stability, freeze protection, and operation at elevated temperatures are important. Its recommended use temperature range extends from approximately -50°F to 325°F (-45°C to 160°C).

Key Features

• 94% propylene glycol concentrate
• 6% performance additives and corrosion inhibitors
• Inhibited propylene glycol heat transfer fluid
• Recommended for heating and cooling applications
• Recommended use range of approximately -50°F to 325°F
• Provides freeze protection below -60°F at appropriate concentration
• Provides burst protection below -100°F at appropriate concentration
• Fluorescent yellow color aids leak detection
• Designed for closed-loop water-based HVAC systems
• Suitable for process heating and cooling
• Suitable for geothermal systems
• Provides corrosion protection for common heat-transfer system metals
• Higher thermal stability and reserve alkalinity than standard DOWFROST

HVAC and Closed-Loop Heat Transfer Applications

DOWFROST HD is widely used in closed-loop HVAC systems where water alone does not provide sufficient freeze or corrosion protection.

Typical applications include:

• Chilled-water systems
• Hydronic heating systems
• Outdoor HVAC piping
• Heat exchangers
• Cooling coils
• Process cooling loops
• Process heating systems
• Waste heat recovery
• Geothermal systems
• Refrigeration and defrost systems
• Data center facility cooling loops

The fluid is particularly useful where outdoor piping or equipment may be exposed to freezing temperatures or where the system requires long-term corrosion protection.

Freeze Protection vs. Burst Protection

Freeze protection is required when the heat-transfer fluid must remain pumpable and no ice crystals can be allowed to form. This generally requires a higher DOWFROST HD concentration.

Burst protection allows some ice or slush formation while maintaining enough unfrozen glycol solution to accommodate expansion and help prevent pipe rupture. This typically requires a lower concentration than full freeze protection.

The correct concentration depends on the lowest expected temperature, system design, and whether the system must continue operating during cold conditions.

Typical DOWFROST HD Concentrations

Values are typical guidance rather than specifications. For additional freeze-protection margin, select a concentration with a freezing point approximately 5°F (3°C) below the expected minimum ambient temperature. Very low glycol concentrations may not provide adequate inhibitor concentration for corrosion protection.

Corrosion Protection

DOWFROST HD contains an industrial corrosion inhibitor system designed to protect metals commonly found in HVAC and process heat-transfer systems.

The inhibitors help passivate metal surfaces and buffer organic acids that can form as propylene glycol degrades over time. This is particularly important in systems operating at elevated temperatures because glycol oxidation accelerates as temperature and oxygen exposure increase.

Compatible System Materials

DOWFROST HD can generally be used with common system materials including steel, cast iron, copper, brass, bronze, solder, many plastics, and compatible elastomers.

Aluminum can be used at fluid temperatures below approximately 150°F. Dow does not recommend aluminum at higher temperatures because the inhibitor system may not provide sufficient aluminum protection.

Galvanized steel is not recommended because zinc can react with the inhibitor system.

Diluting DOWFROST HD Concentrate

DOWFROST HD is supplied as a concentrate and is normally mixed with water to reach the required glycol concentration.

Water quality is important because contaminants can increase corrosion, consume inhibitors, form scale, and reduce heat-transfer performance.

Distilled or deionized water is preferred where practical. After filling the system, circulate the solution thoroughly and verify glycol concentration with an appropriate refractometer or other approved method.

Operating Temperature

DOWFROST HD has a recommended use temperature range of approximately -50°F to 325°F (-45°C to 160°C).

At elevated temperatures, the system should be designed to limit oxygen exposure and prevent localized boiling or excessive film temperatures.

HD is specifically designed for applications requiring greater high-temperature capability and thermal stability than standard DOWFROST.

DOWFROST HD vs. DOWFROST

Both products are inhibited propylene glycol-based heat transfer fluids, but they are formulated for different operating requirements.

DOWFROST HD uses a heavier-duty industrial corrosion inhibitor package and provides higher maximum operating temperature, greater reserve alkalinity, and greater thermal stability.

Standard DOWFROST uses food-grade corrosion inhibitors and is the formulation more specifically intended for applications requiring food-grade raw materials or incidental food-contact considerations.

DOWFROST HD should therefore not automatically be treated as interchangeable with standard DOWFROST in applications with specific food-contact or regulatory requirements.

Typical Properties of DOWFROST HD Concentrate

Typical properties should not be treated as product specifications. Refer to the current Dow Technical Data Sheet and system-design guidance when determining concentration and operating limits.

Frequently Asked Questions

What is DOWFROST HD?
DOWFROST HD is an inhibited propylene glycol-based heat transfer fluid used in closed-loop HVAC, process heating and cooling, geothermal, refrigeration, and other thermal-fluid systems.

Is DOWFROST HD propylene glycol?
Yes. The concentrate contains approximately 94% propylene glycol by weight and 6% performance additives, including corrosion inhibitors.

Is DOWFROST HD a concentrate?
Yes. DOWFROST HD is supplied as a concentrated heat-transfer fluid and is normally diluted with suitable water to the concentration required for the system's freeze, burst, and corrosion protection requirements.

What temperature range can DOWFROST HD handle?
The current Dow Technical Data Sheet gives a recommended use temperature range of approximately -50°F to 325°F (-45°C to 160°C).

How much DOWFROST HD do I need for -20°F freeze protection?
Dow's concentration table lists approximately 46% DOWFROST HD by volume for freeze protection at -20°F. Burst protection at the same temperature requires approximately 30%.

What is the difference between freeze protection and burst protection?
Freeze protection prevents ice crystals from forming so the fluid remains pumpable. Burst protection allows some slush or ice formation while helping prevent expansion from rupturing piping. Freeze protection therefore generally requires a higher glycol concentration.

What is the difference between DOWFROST and DOWFROST HD?
DOWFROST HD uses a heavier-duty industrial inhibitor system and is designed for higher operating temperatures and greater thermal stability. Standard DOWFROST uses food-grade corrosion inhibitors and is intended for applications where those regulatory characteristics are required.

Is DOWFROST HD food grade?
DOWFROST HD contains high-purity propylene glycol, but its corrosion inhibitor system is described by Dow as an industrial inhibitor package. It should not simply be described as a food-grade heat-transfer fluid. Standard DOWFROST is the formulation Dow specifically identifies as using food-grade propylene glycol and food-grade corrosion inhibitors.

Can DOWFROST HD be used in HVAC systems?
Yes. Closed-loop, water-based HVAC systems are one of the primary applications identified for DOWFROST HD.

Can DOWFROST HD be used for geothermal systems?
Yes. Dow currently identifies geothermal systems among the applications for DOWFROST HD.

Can DOWFROST HD be used in data center cooling systems?
Yes. Dow currently positions DOWFROST HD for facility and primary HVAC cooling loops supporting data centers, including chilled-water and facility-water systems.

Can DOWFROST HD be used with aluminum?
It can be used with aluminum at fluid temperatures below approximately 150°F. Dow does not recommend aluminum at higher temperatures because the inhibitors may not adequately protect aluminum components.

Can DOWFROST HD be used with galvanized steel?
Galvanized steel is not recommended because zinc can react with the inhibitor system and contribute to precipitate formation and inhibitor depletion.

What water should be used to dilute DOWFROST HD?
Distilled or deionized water is preferred. Dow recommends keeping chloride and sulfate concentrations below 25 ppm each and total hardness below 100 ppm as CaCO3.

What color is DOWFROST HD?
DOWFROST HD is dyed fluorescent yellow or yellow-green to make leaks easier to detect.

Is DOWFROST HD automotive antifreeze?
No. DOWFROST HD is formulated as an inhibited propylene glycol heat-transfer fluid for HVAC, process, geothermal, and related closed-loop thermal systems. It should not be substituted for an automotive coolant unless specifically approved for the equipment.