Potassium Formate Heat Transfer Solution: Concentration, Performance, and Selection Guide

A potassium formate heat transfer solution is an aqueous potassium formate mixture used to transport thermal energy in industrial refrigeration, secondary cooling and low-temperature circulation systems.

Unlike a primary refrigerant, the potassium formate solution normally remains liquid while it circulates between a chiller and the cooling load.

ASHRAE describes these liquids as secondary coolants and notes that they may also be called heat-transfer fluids, brines or secondary refrigerants. Potassium formate is recognized as one of the less widely used secondary-coolant chemistries.

Typical applications include:

• Industrial refrigeration
• Cold-storage warehouses
• Food-processing cooling
• Process cooling
• Refrigerated logistics
• HVAC secondary circuits
• Ice-rink cooling
• Low-temperature circulation systems

What Is Potassium Formate Heat Transfer Solution?

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 salt solution
Common Concentrate	Approx. 75%
Main Role	Secondary heat-transfer medium

A complete working solution may contain:

• Potassium formate
• Water
• Corrosion inhibitors
• pH-control additives
• Other compatible formulation components

Therefore, Potassium Formate 75% Solution is generally a concentrated formulation feedstock rather than automatically a ready-to-use heat-transfer fluid.

Vanchor currently positions its 75% potassium formate as a concentrated raw material for preparing secondary cooling and heat-transfer fluids.

How Does the Solution Transfer Heat?

A typical indirect cooling system operates as:

Primary refrigeration plant → heat exchanger → potassium formate solution → cooling load → return loop

The solution:

1. Is cooled in the chiller.
2. Circulates through pumps and piping.
3. Absorbs heat from the process or refrigerated space.
4. Returns to the refrigeration plant.
5. Releases the absorbed heat.

The fluid normally changes temperature without undergoing the evaporation and condensation cycle of a primary refrigerant.

Why Use Potassium Formate Solution?

Low-Temperature Operation

Pure water freezes near 0°C.

Dissolving potassium formate changes the freezing and crystallization behavior of the aqueous solution, allowing it to be used in sub-zero circulation systems.

This is useful for:

• Freezer warehouses
• Process cooling
• Refrigerated production
• Ice rinks
• Low-temperature secondary loops

The working concentration should be selected according to the minimum system temperature rather than simply using the highest available concentration.

Relatively Low Viscosity

Viscosity strongly affects the energy required to circulate a heat-transfer solution.

High viscosity can increase:

• Pump power
• Pressure drop
• Pipe-size requirements
• Flow resistance

Research specifically evaluating aqueous potassium formate as a secondary refrigerant found lower viscosity than traditional aqueous alcohol and glycol solutions under the studied conditions. This helped keep pumping-power requirements competitive despite lower volumetric heat capacity.

This is one of the main technical reasons potassium formate is considered for low-temperature circulation.

Thermal Conductivity

A heat-transfer solution also needs to transfer thermal energy effectively through heat exchangers.

Published research on potassium formate reported good thermal conductivity, supporting effective heat transfer in secondary refrigeration systems.

However, thermal conductivity should not be evaluated alone.

Engineers should consider:

Thermal conductivity + specific heat + density + viscosity + flow rate

when comparing different fluids.

Concentration Is a Critical Design Variable

The physical properties of potassium formate solution change with concentration.

Changing concentration can affect:

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

Research measuring potassium formate solutions also shows that viscosity and thermal conductivity are strongly influenced by solution concentration. At higher concentrations, viscosity becomes increasingly temperature-sensitive.

Therefore, concentration should be engineered rather than selected arbitrarily.

Using Potassium Formate 75% Concentrate

Vanchor currently supplies Potassium Formate 75% Solution for heat-transfer and refrigeration applications. Its published information states that the concentrated solution 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

Advantages of liquid concentrate include:

• Direct pumping
• Accurate metering
• Easy dilution
• Rapid blending
• No powder-dissolution stage
• Convenient bulk handling

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

How Should the Working Concentration Be Selected?

A practical design sequence is:

1. Define the minimum operating temperature

Determine the lowest temperature the fluid may experience.

2. Establish a freeze-protection margin

The solution should remain safely above its crystallization limit during normal operation.

3. Determine the required potassium formate concentration

Use verified concentration/property data.

4. Check viscosity

Confirm that pumps and piping can maintain the required flow.

5. Check thermal performance

Evaluate density, specific heat and thermal conductivity.

6. Verify material compatibility

Test the finished inhibited solution against metals, seals and elastomers.

Higher concentration is therefore not automatically better.

Potassium Formate vs Glycol Heat Transfer Solution

Ethylene glycol and propylene glycol are common secondary fluids.

Factor	Potassium Formate Solution	Glycol Solution
Chemistry	Aqueous formate salt	Aqueous glycol
Sub-zero use	Yes	Yes
Low-temp viscosity	Relatively low in comparative studies	Can increase significantly
Thermal conductivity	Favorable	Concentration-dependent
Concentration design	Required	Required
Corrosion control	May be required	Usually required

Research comparing potassium formate with conventional alcohol and glycol solutions identified good thermodynamic properties, relatively low viscosity, low toxicity and non-flammability as useful characteristics.

This does not mean potassium formate is universally better.

The correct fluid depends on:

• Temperature
• Pump design
• Heat exchangers
• Materials
• Safety requirements
• Lifecycle cost

Specific Heat Must Not Be Ignored

One trade-off is that potassium formate solution may have lower volumetric heat capacity than some conventional fluids.

This can require greater mass flow for the same cooling duty and temperature difference.

However, published research found that its lower viscosity can help offset this by reducing the pumping-energy penalty.

This is why fluid selection should be based on the whole system, not simply freeze point or viscosity.

Corrosion Control

A potassium formate solution should not automatically be described as non-corrosive.

Heat-transfer systems may contain:

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

The final formulation may require appropriate corrosion inhibitors.

Vanchor specifically recommends testing the complete heat-transfer formulation against the metals, seals, pumps and other materials present in the actual system.

Chloride Control

Potassium formate itself is a formate salt rather than a chloride salt.

However, industrial material can contain trace chloride impurities.

For corrosion-sensitive systems, buyers may specify:

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

A batch-specific COA should verify agreed limits.

Dilution Water Quality

Water quality can significantly influence the final heat-transfer solution.

ASHRAE recommends purified dilution water where possible because dissolved chloride, sulfate, calcium, magnesium and iron can increase corrosion, scaling or deposits and impair heat transfer.

Poor dilution water may cause:

• Corrosion
• Scaling
• Deposits
• Heat-exchanger fouling
• Reduced inhibitor performance

The final diluted solution should therefore be tested after preparation.

Where Is Potassium Formate Heat Transfer Solution Used?

Cold Storage

For secondary cooling of frozen or chilled warehouses.

Food Processing

For indirect refrigeration of production areas, cold rooms and process equipment.

Industrial Process Cooling

For machinery, heat exchangers and temperature-controlled processes.

Refrigerated Logistics

For centralized cooling in large cold-chain facilities.

Ice Rinks

For low-temperature secondary circulation beneath the ice surface.

HVAC Secondary Systems

For circuits requiring freeze protection below the operating range of plain water.

ASHRAE specifically recognizes salt solutions including potassium formate as single-phase secondary fluids in refrigeration applications.

Important Parameters to Check

Before specifying a potassium formate heat-transfer solution, evaluate:

1. Minimum operating temperature
2. Working concentration
3. Crystallization temperature
4. Viscosity
5. Density
6. Specific heat
7. Thermal conductivity
8. Pumping requirements
9. System metallurgy
10. Corrosion protection

These values should be checked at the actual operating concentration and temperature.

What Buyers Should Request

When purchasing potassium formate concentrate, request:

• Current product specification
• Potassium formate assay
• Density with test temperature
• pH
• Chloride specification
• Iron
• Insoluble matter
• COA
• TDS
• SDS

Also provide the supplier with:

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

Potassium Formate Heat Transfer Solution Raw Material From Vanchor

Vanchor currently supplies Potassium Formate 75% as a concentrated raw material for secondary cooling and heat-transfer formulations.

Its published application areas include:

• Industrial refrigeration
• Cold-storage systems
• Food-processing refrigeration
• HVAC secondary circuits
• Process cooling
• Low-temperature circulation systems.

The concentrate can be pumped, metered and diluted without the need for on-site solid dissolution.

The final fluid should still be engineered for the actual temperature range, heat-transfer duty, materials and corrosion requirements.

Frequently Asked Questions

What is potassium formate heat transfer solution?

It is an aqueous potassium formate mixture used as a circulating secondary fluid to transport heat in refrigeration and industrial cooling systems.

Is it the same as heat transfer fluid?

The terms overlap. “Heat transfer solution” emphasizes that potassium formate is dissolved in water at a controlled concentration.

Can Potassium Formate 75% be used directly?

Not necessarily. It is commonly used as concentrated feedstock and diluted according to the required freeze protection and thermal properties.

Why is potassium formate compared with glycol?

Both can be used as secondary heat-transfer fluids. Potassium formate is particularly notable for relatively low viscosity and useful thermal conductivity under low-temperature conditions.

Does potassium formate solution require corrosion inhibitors?

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

What concentration should be used?

There is no universal concentration. It should be selected according to minimum operating temperature, crystallization margin, viscosity and heat-transfer requirements.

Conclusion

A potassium formate heat transfer solution can provide an effective aqueous secondary fluid for:

Industrial refrigeration
Cold storage
Food processing
Process cooling
Refrigerated logistics
HVAC secondary systems

Its technical value comes from the combination of sub-zero operating capability, concentration flexibility, relatively low viscosity and useful heat-transfer properties.

For reliable operation, the final solution should be engineered around the actual working concentration, crystallization temperature, viscosity, specific heat, thermal conductivity, pumping requirements and corrosion compatibility.

Potassium Formate 75% can therefore serve as a concentrated raw material that is diluted and inhibited according to the specific heat-transfer system.