Potassium Formate Cold Storage Refrigerant: Low-Temperature Cooling Guide

A potassium formate cold storage refrigerant is an aqueous potassium formate solution used as a secondary coolant in indirect refrigeration systems for freezer warehouses, chilled storage facilities and refrigerated logistics centers.

In these systems, potassium formate normally does not replace the primary refrigerant inside the compressor cycle. Instead, it is cooled by the refrigeration plant and circulated through piping and heat exchangers to transport cooling to storage rooms or other loads.

ASHRAE defines this type of fluid as a secondary coolant, also commonly called a secondary refrigerant, brine or heat-transfer fluid. Potassium formate is recognized as one of the less commonly used secondary-coolant chemistries.

How Does Potassium Formate Work in Cold Storage?

A typical cold-storage refrigeration system may operate as:

Primary refrigeration plant → heat exchanger → potassium formate loop → cold room → return loop

The potassium formate solution:

1. Is cooled by the primary refrigeration system.
2. Is pumped to cold rooms or air coolers.
3. Absorbs heat from the refrigerated space.
4. Returns to the refrigeration plant.
5. Releases the absorbed heat and repeats the cycle.

The fluid remains liquid throughout normal circulation.

This type of indirect system can be useful in large refrigerated facilities where cooling must be distributed across multiple zones.

Why Use Potassium Formate in Cold Storage?

Sub-Zero Operation

Plain water freezes near 0°C and therefore cannot be used directly in many freezer applications.

Adding potassium formate lowers the freezing or crystallization temperature of the aqueous solution.

This allows it to circulate in:

• Freezer warehouses
• Frozen-food storage
• Refrigerated logistics hubs
• Chilled distribution centers
• Food-processing cold rooms
• Low-temperature process areas

ASHRAE recommends selecting a secondary coolant with a freezing point at least about 3 K below, and preferably around 8 K below, the lowest temperature the fluid may encounter.

Relatively Low Viscosity

Low-temperature viscosity is one of the most important considerations in cold-storage refrigeration.

As coolant viscosity increases:

• Pumping energy rises
• Pressure drop increases
• Flow can decrease
• Larger pumps or piping may be needed

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

This can be especially important in large cold-storage facilities with long piping runs and multiple evaporator or air-cooler circuits.

Heat-Transfer Performance

A cold-storage coolant must do more than resist freezing.

Engineers should also evaluate:

• Thermal conductivity
• Specific heat
• Density
• Viscosity
• Required flow rate

These properties determine how efficiently the fluid transports cooling between the refrigeration plant and the cold room.

The best coolant is therefore not simply the one with the lowest freezing point.

Potassium Formate 75% as Concentrated Feedstock

Vanchor currently supplies Potassium Formate 75% Solution as a concentrated aqueous product for selected refrigeration and heat-transfer applications. Its current page specifically lists:

• Cold-storage warehouses
• Food-processing plants
• Industrial cooling systems
• Ice rinks
• Refrigerated logistics facilities
• Process-temperature control
• Low-temperature circulation systems.

Vanchor also states that the concentrated solution can be diluted to achieve the required:

• Freezing point
• Viscosity
• Heat-transfer performance.

One metric ton of nominal 75% solution contains approximately:

750 kg potassium formate

Perstorp also currently identifies Potassium Formate 75% as suitable for secondary heat-transfer-fluid applications, confirming that this is an established industrial use.

Why 75% Is Not Automatically the Working Concentration

A 75% potassium formate solution is best treated as a concentrated feedstock.

The actual cold-storage working fluid may require a different concentration.

Changing concentration affects:

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

Therefore:

Higher concentration does not automatically mean better refrigeration performance.

A practical design sequence is:

Minimum operating temperature → freeze-protection margin → working concentration → hydraulic and thermal verification

Potassium Formate vs Glycol for Cold Storage

Propylene glycol and ethylene glycol are widely used in secondary refrigeration systems.

Potassium formate provides a different property profile.

Factor	Potassium Formate	Glycol
Chemistry	Aqueous formate salt	Aqueous glycol
Sub-zero use	Yes	Yes
Secondary refrigeration	Suitable	Suitable
Low-temperature viscosity	Often attractive	Can rise significantly
Concentration design	Required	Required
Corrosion inhibition	May be required	Usually required

Potassium formate may be attractive where pumping performance at low temperature is important.

However, no coolant is universally superior.

Cold-storage engineers should compare:

Freeze protection + viscosity + specific heat + thermal conductivity + pump energy + material compatibility + lifecycle cost

Potassium Formate vs Traditional Refrigeration Brine

Calcium chloride and sodium chloride solutions have historically been common refrigeration brines. ASHRAE continues to identify these as traditional salt-based brines.

Potassium formate differs because its primary anion is formate rather than chloride.

This may be attractive where operators want to reduce reliance on chloride-based refrigeration chemistry.

However:

Potassium formate should not automatically be described as non-corrosive.

The complete working fluid still requires corrosion evaluation.

Corrosion and Material Compatibility

Cold-storage refrigeration loops may contain:

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

ASHRAE states that secondary coolants should be compatible with system materials under the temperatures and pressures encountered in service.

Vanchor similarly recommends testing the completed potassium formate refrigeration fluid for:

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

Corrosion inhibitors may be required depending on the system.

Chloride Control

Although potassium formate is not a chloride salt, industrial material can contain trace chloride impurities.

For long-life cold-storage systems, procurement specifications may therefore include:

• Potassium formate concentration
• Maximum chloride
• Iron
• Insoluble matter
• pH
• Density

Perstorp's current 75% product specification, for example, lists density of 1.57–1.58 g/cm³ at 25°C and pH 9–10, with chloride reported as a typical quality parameter rather than part of the primary sales specification.

Always use the actual supplier's current TDS and batch-specific COA.

Dilution Water Quality

Water used to prepare the final coolant becomes part of the refrigeration system.

Poor-quality dilution water can introduce:

• Chloride
• Calcium
• Magnesium
• Iron
• Suspended solids

These may contribute to:

• Scale
• Corrosion
• Deposits
• Heat-exchanger fouling

The final diluted fluid should therefore be tested before charging a critical cold-storage system.

Concentrate Storage Is Different From Coolant Operating Temperature

Another important distinction is:

Raw-material storage temperature ≠ final coolant operating temperature

Perstorp's current Potassium Formate 75% data sheet recommends storage above 10°C to reduce the possibility of crystallization.

Vanchor similarly notes that concentrated 75% solution can have crystallization or salt-out behavior above 0°C depending on concentration, temperature and product specification.

After dilution to the engineered working concentration, the final coolant will have different crystallization characteristics.

Cold Storage Applications

Freezer Warehouses

Potassium formate secondary fluid can distribute cooling across frozen-food storage areas.

Chilled Warehouses

The same indirect-cooling concept may be used for refrigerated but non-frozen storage zones.

Refrigerated Distribution Centers

Large logistics hubs can circulate secondary coolant between a central plant and multiple refrigerated rooms.

Food-Processing Facilities

Potassium formate coolant may serve cold rooms, process heat exchangers and chilled production areas.

Vanchor currently lists all of these broader cold-storage and refrigeration applications within its potassium formate heat-transfer guidance.

What Cold Storage Engineers Should Check

Before selecting potassium formate, evaluate:

1. Minimum coolant temperature
2. Freeze/crystallization margin
3. Working concentration
4. Viscosity at minimum temperature
5. Density
6. Specific heat
7. Thermal conductivity
8. Pumping requirement
9. System metallurgy
10. Corrosion-inhibitor requirement

The final selection should be based on the complete cooling system rather than chemical concentration alone.

What Buyers Should Request

When purchasing potassium formate for cold-storage refrigeration, request:

• Technical specification
• Batch-specific COA
• TDS
• SDS
• Potassium formate concentration
• Density with measurement temperature
• Chloride limit
• Crystallization information
• Storage requirements
• Packaging options

For a quotation, provide:

Minimum operating temperature
Cold-storage application
Required working concentration
System metallurgy
Quantity
Packaging
Destination

Potassium Formate for Cold Storage From Vanchor

Vanchor currently positions Potassium Formate 75% for refrigeration-fluid formulators and specifically lists cold-storage warehouses and refrigerated logistics facilities among its potential applications.

Its concentrated liquid format provides:

• Direct pumping
• Accurate dosing
• Adjustable dilution
• Reduced solid handling
• Integration with bulk fluid systems

The final coolant concentration and corrosion-control package should still be designed around the actual refrigeration system.

Frequently Asked Questions

What is potassium formate cold storage refrigerant?

It is an aqueous potassium formate solution used as a secondary coolant to distribute cooling in cold-storage and refrigerated warehouse systems.

Is potassium formate a primary refrigerant?

Normally no. It usually transports cooling through a pumped secondary loop rather than operating directly in the compressor refrigeration cycle.

Can potassium formate be used in freezer warehouses?

Yes. Vanchor currently identifies cold-storage warehouses and low-temperature circulation systems as potential applications for potassium formate 75%.

Can Potassium Formate 75% be used directly?

Not necessarily. It is generally treated as a concentrated feedstock that can be diluted to achieve the required freezing point, viscosity and heat-transfer performance.

Is potassium formate better than glycol?

Not universally. It should be compared using freezing point, viscosity, heat-transfer properties, pumping energy, material compatibility and lifecycle cost.

Does potassium formate require corrosion inhibitors?

Depending on system metallurgy and operating conditions, a suitable corrosion-control package may be required.

Conclusion

A potassium formate cold storage refrigerant can provide a practical secondary cooling medium for:

Freezer warehouses
Chilled storage
Frozen-food facilities
Refrigerated distribution centers
Food-processing cold rooms

Its main technical value is the combination of sub-zero operation, flexible concentration and suitability for pumped secondary refrigeration systems.

Reliable operation depends on selecting the correct working concentration, crystallization temperature, viscosity, thermal properties, pumping conditions and corrosion protection.

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