Potassium Formate Brine for Refrigeration: Properties, Concentration, and System Guide

Potassium formate brine for refrigeration is an aqueous potassium formate solution used as a secondary coolant in indirect refrigeration and low-temperature cooling systems.

Instead of circulating the primary refrigerant through an entire facility, the refrigeration plant cools the potassium formate brine, which is then pumped to cold rooms, process equipment or heat exchangers.

ASHRAE defines secondary coolants as liquids that gain and lose heat without changing phase and notes that below-freezing secondary coolants are commonly called brines. Potassium formate is recognized as one of the less widely used secondary-coolant chemistries.

What Is Potassium Formate Brine?

Potassium formate is the potassium salt of formic acid.

Property	Typical Information
Chemical Name	Potassium Formate
Formula	HCOOK
CAS Number	590-29-4
Molecular Weight	Approx. 84.12 g/mol
Fluid Type	Aqueous formate brine
Main Role	Secondary refrigeration coolant
Common Concentrated Feedstock	Approx. 75% solution

The refrigeration brine normally contains:

• Potassium formate
• Water
• Corrosion inhibitors where required
• pH-control or other compatible additives

Potassium Formate 75% is generally used as a concentrated feedstock, not automatically as the final operating brine.

How Is Potassium Formate Brine Used in Refrigeration?

A typical indirect refrigeration loop works like this:

Primary refrigerant → chiller/heat exchanger → potassium formate brine → cooling load → return loop

The potassium formate solution:

1. Is cooled by the primary refrigeration system.
2. Circulates through pumps and piping.
3. Absorbs heat from the cooled area or process.
4. Returns to the refrigeration plant.
5. Releases the absorbed heat.

The brine normally remains liquid throughout this cycle.

Why Use Potassium Formate Brine?

Freeze Protection Below 0°C

Water alone cannot reliably circulate in sub-zero refrigeration systems.

Adding potassium formate lowers the solution's freezing or crystallization temperature, allowing it to remain pumpable below 0°C.

ASHRAE recommends that the secondary coolant freezing point be at least about 3 K below, and preferably about 8 K below, the lowest temperature the fluid may encounter.

This safety margin helps protect:

• Heat exchangers
• Evaporator circuits
• Pumps
• Valves
• Piping

Relatively Low Viscosity

Low-temperature viscosity strongly affects refrigeration-system efficiency.

As viscosity rises:

• Pump power increases
• Pressure drop increases
• Flow can decrease
• Larger piping may be required

Potassium formate is often considered where relatively low viscosity at sub-zero temperatures is important.

This can make it attractive for large industrial secondary loops and long-distance coolant circulation.

Concentration Must Match Operating Temperature

There is no single potassium formate concentration suitable for every refrigeration system.

Increasing concentration changes:

• Crystallization temperature
• Density
• Viscosity
• Specific heat
• Thermal conductivity
• Pumping requirements

The correct design sequence is:

Minimum fluid temperature → required safety margin → potassium formate concentration → hydraulic and thermal verification

The highest available concentration is not automatically the most efficient choice.

Potassium Formate 75% as Brine Feedstock

Vanchor currently supplies Potassium Formate 75% Solution for heat-transfer and refrigeration-fluid applications.

Its current product information lists approximately:

• 75% potassium formate by weight
• Clear or nearly colorless liquid
• Specific gravity around 1.57 at 20°C
• High water solubility
• Direct pumping and dosing capability

Vanchor also states that the concentrate can be diluted to achieve the required freezing point, viscosity and heat-transfer performance.

One metric ton of nominal 75% solution contains approximately:

750 kg potassium formate

Perstorp also commercially lists Potassium Formate 75% for use as a secondary heat-transfer fluid, confirming this established application.

Typical Refrigeration Applications

Cold-Storage Warehouses

Potassium formate brine can distribute cooling from a central refrigeration plant to multiple cold rooms.

Applications may include:

• Frozen-food warehouses
• Chilled storage
• Distribution centers

Food-Processing Plants

Secondary coolant loops can serve:

• Process heat exchangers
• Chilled production areas
• Cold rooms
• Refrigerated storage

Industrial Refrigeration

Potassium formate brine may transport cooling to:

• Production equipment
• Chemical processes
• Industrial heat exchangers
• Temperature-controlled manufacturing systems

Refrigerated Logistics

Large cold-chain centers can use secondary loops to distribute cooling across multiple zones.

Ice Rinks

Secondary brine can circulate beneath the rink surface to remove heat and maintain ice conditions.

Vanchor currently lists cold storage, food processing, industrial cooling, ice rinks, refrigerated logistics and process-temperature control among relevant applications.

Potassium Formate vs Calcium Chloride Brine

Calcium chloride and sodium chloride solutions have historically been widely used as refrigeration brines.

Factor	Potassium Formate	Calcium Chloride
Primary anion	Formate	Chloride
Sub-zero use	Yes	Yes
Pumped secondary loop	Yes	Yes
Chloride loading	Low/controlled impurity	Intrinsic
Corrosion control	Required	Required
Concentration design	Required	Required

Potassium formate may be attractive where operators want to reduce dependence on chloride-based brines.

However, it should not automatically be called non-corrosive.

Potassium Formate vs Glycol

Ethylene glycol and propylene glycol are also widely used secondary refrigeration fluids.

Potassium formate can offer a different balance:

Factor	Potassium Formate	Glycol
Chemistry	Aqueous salt	Aqueous glycol
Sub-zero operation	Yes	Yes
Low-temp viscosity	Often relatively low	Can become high
Thermal performance	Concentration-dependent	Concentration-dependent
Pumping energy	Can be favorable	Strongly viscosity-dependent
Corrosion inhibition	May be required	Usually required

Neither chemistry is universally better.

Engineers should compare:

Freeze protection + viscosity + specific heat + thermal conductivity + pumping power + lifecycle cost

Specific Heat and Thermal Conductivity Matter

A refrigeration fluid must transport heat efficiently, not simply resist freezing.

Important physical properties include:

Specific Heat

Determines how much heat the brine can carry for a given mass flow and temperature difference.

Thermal Conductivity

Influences heat transfer through evaporators and heat exchangers.

Density

Affects system hydraulics and concentration monitoring.

Viscosity

Influences pressure loss and pump energy.

These parameters should be evaluated at the actual operating concentration and temperature, not only at room temperature.

Corrosion Control

Potassium formate refrigeration brine may contact:

• Carbon steel
• Stainless steel
• Copper
• Brass
• Aluminum
• Pumps
• Valves
• Elastomers
• Seals

ASHRAE states that a secondary coolant should be compatible with system materials at the operating temperatures and pressures.

Vanchor likewise recommends evaluating the finished refrigeration fluid for:

• Corrosion
• Pump compatibility
• Seal and elastomer compatibility
• Storage stability
• Long-term concentration stability

Corrosion inhibitors may be required depending on equipment and operating conditions.

Chloride Control

Potassium formate itself is not a chloride salt.

However, commercial grades may contain trace chloride impurities.

For corrosion-sensitive refrigeration systems, buyers may specify limits for:

• Potassium formate concentration
• Chloride
• Iron
• Insoluble matter
• pH
• Density

These values should be verified through a batch-specific COA.

Dilution Water Quality

Water used to prepare refrigeration brine can introduce:

• Chloride
• Calcium
• Magnesium
• Iron
• Suspended solids

Poor water quality can contribute to:

• Scale
• Corrosion
• Deposits
• Heat-exchanger fouling

The final diluted brine should therefore be tested before system commissioning.

Concentrate Storage vs Brine Operating Temperature

A common misunderstanding is that a low-temperature coolant concentrate can always be stored at the same low temperature at which the diluted brine operates.

Vanchor notes that concentrated 75% potassium formate may have a crystallization or salt-out temperature above 0°C, depending on composition and concentration.

Therefore, engineers must distinguish between:

75% concentrate storage temperature

and

finished refrigeration brine crystallization temperature

Always follow the current TDS for the exact product.

What Engineers Should Check

Before specifying potassium formate brine for refrigeration, evaluate:

1. Minimum operating temperature
2. Required freeze-protection margin
3. Working concentration
4. Crystallization temperature
5. Viscosity at minimum temperature
6. Density
7. Specific heat
8. Thermal conductivity
9. System metallurgy
10. Corrosion-inhibitor requirements

The complete system calculation is more important than choosing a fluid based only on freezing point.

Potassium Formate Brine Raw Material From Vanchor

Vanchor currently positions Potassium Formate 75% Solution for:

• Heat-transfer systems
• Refrigeration systems
• Cold-storage warehouses
• Food-processing plants
• Industrial cooling
• Ice rinks
• Refrigerated logistics
• Low-temperature circulation systems.

The concentrated solution can be:

• Pumped
• Metered
• Diluted
• Blended
• Stored in bulk systems

For a refrigeration inquiry, buyers should provide:

Minimum operating temperature
Target working concentration
Application
System metallurgy
Required chloride limit
Quantity
Packaging
Destination

Frequently Asked Questions

What is potassium formate brine for refrigeration?

It is an aqueous potassium formate solution used as a secondary coolant to transport cooling in indirect refrigeration systems.

Why is it called brine?

ASHRAE notes that low-temperature secondary coolants are generally called brines in the refrigeration industry.

Is potassium formate a primary refrigerant?

Normally no. It is generally circulated as a secondary coolant rather than through the compressor refrigeration cycle.

Can Potassium Formate 75% be used directly?

Not necessarily. It is typically treated as a concentrate and diluted to achieve the required freezing point, viscosity and thermal performance.

Can potassium formate replace calcium chloride brine?

It can be an alternative in selected systems, particularly where reducing chloride-based chemistry is desirable. System corrosion, thermal performance and cost should still be compared.

Can potassium formate replace glycol?

It can be considered as an alternative secondary coolant, but engineers should compare freeze protection, viscosity, specific heat, thermal conductivity, material compatibility and pumping requirements.

Conclusion

Potassium formate brine for refrigeration can provide an effective secondary cooling medium for:

Cold storage
Food processing
Industrial refrigeration
Process cooling
Refrigerated logistics
Ice-rink systems

Its key technical value is the combination of sub-zero operation, concentration flexibility and suitability for pumped secondary refrigeration loops.

Reliable system performance depends on selecting the correct working concentration, crystallization point, viscosity, specific heat, thermal conductivity, corrosion protection and material compatibility.

For formulation, Potassium Formate 75% Solution can serve as a concentrated feedstock that is diluted and conditioned according to the actual refrigeration-system requirements.