Potassium Formate Heat Transfer Fluid: Performance, Applications and Selection Guide

A potassium formate heat transfer fluid is an aqueous salt solution used to move thermal energy through secondary refrigeration, process cooling and low-temperature circulation systems.

It is not normally the primary refrigerant.

Instead, the primary refrigeration plant cools the potassium formate solution through a heat exchanger. The solution is then pumped through pipes to cold rooms, production equipment or other cooling loads, absorbs heat, and returns to the refrigeration plant.

Basically, it works as a circulating thermal carrier.

Potassium formate is attractive for this role because properly selected aqueous solutions can combine sub-zero operating capability with relatively low viscosity and useful thermal conductivity.

Research specifically evaluating potassium formate as a secondary refrigerant reported good thermodynamic properties, low toxicity, non-flammability and lower viscosity than traditional aqueous alcohol or glycol systems under the conditions studied.

For manufacturers preparing industrial cooling fluids, Potassium Formate 75% Solution can be used as concentrated feedstock and diluted or conditioned according to the final operating temperature and equipment requirements.

How Does Potassium Formate Work as a Heat Transfer Fluid?

In an indirect refrigeration system, the cooling loop may look like this:

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

The potassium formate solution normally remains liquid throughout this circulation.

It can be used to transfer cooling to:

• Cold-storage warehouses
• Food-processing areas
• Refrigerated logistics centers
• Industrial process equipment
• Ice rinks
• HVAC secondary circuits
• Production cooling systems
• Low-temperature storage facilities

ASHRAE describes liquids used this way as secondary coolants. Depending on the application, they may also be called brines, secondary refrigerants or heat-transfer fluids. Potassium formate is among the less widely used secondary-coolant chemistries.

Why Potassium Formate Is Considered for Low-Temperature Cooling

Plain water is an excellent heat-transfer medium.

The problem is obvious: it freezes around 0°C.

Adding potassium formate lowers the freezing or crystallization temperature of the aqueous solution, allowing it to operate below the freezing point of water.

That makes it useful where chilled water alone cannot provide enough freeze protection.

The real engineering advantage, however, is not just low-temperature capability.

A secondary cooling fluid needs to balance several properties at the same time.

Property	Why It Matters
Freezing/crystallization point	Determines low-temperature operating limit
Viscosity	Affects pump energy and pressure drop
Thermal conductivity	Influences heat-exchanger performance
Specific heat	Affects how much heat the fluid can carry
Density	Influences mass flow and system calculations
Corrosion behavior	Affects long-term equipment life

A fluid with an extremely low freezing point but very high viscosity may actually be a poor system choice.

That is why concentration has to be optimized rather than simply maximized.

Low Viscosity Can Be an Important Advantage

Viscosity matters a lot in refrigeration.

As fluid becomes thicker, the pump must work harder to move it through pipes and heat exchangers.

High viscosity can increase:

• Pressure loss
• Pumping energy
• Required pipe diameter
• Flow resistance
• Difficulty maintaining turbulent flow

Published research on aqueous potassium formate found relatively low viscosity compared with traditional glycol and alcohol solutions under the studied operating conditions. Although potassium formate can have lower volumetric heat capacity, the lower viscosity helped keep pumping-power requirements competitive.

This becomes especially useful in systems with:

• Long piping runs
• Large cooling loads
• Multiple refrigerated zones
• Low operating temperatures

At low temperature, viscosity often becomes one of the biggest differences between competing heat-transfer fluids.

Thermal Conductivity Also Matters

The purpose of a heat-transfer fluid is to move heat.

So thermal conductivity cannot be ignored.

Research into potassium formate secondary refrigerants has reported useful thermal conductivity, helping the fluid exchange heat effectively through system heat exchangers.

Still, thermal conductivity should never be evaluated alone.

An engineer should consider the complete fluid:

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

For example, one fluid may have slightly better specific heat but become very viscous at -25°C.

Another may carry slightly less heat per unit mass but circulate far more easily.

The total energy consumption of the system may favor the second fluid.

Potassium Formate vs Glycol Heat Transfer Fluid

Ethylene glycol and propylene glycol are widely used secondary cooling fluids.

Potassium formate provides another option.

Factor	Potassium Formate	Glycol Solution
Fluid type	Aqueous salt solution	Aqueous organic solution
Sub-zero use	Yes	Yes
Low-temperature viscosity	Often attractive	Can increase significantly
Flammability	Non-flammable aqueous salt system	Depends on glycol and concentration
Heat-transfer performance	Good when properly designed	Widely established
Corrosion inhibitors	Usually required	Usually required
Food-related system selection	Application-specific	PG often selected
System familiarity	More specialized	Very common

There is no reason to say potassium formate is always better than glycol.

Glycol systems are familiar, widely supported and available in many inhibited commercial formulations.

Potassium formate becomes especially interesting when low-temperature viscosity and pumping performance are important.

The correct comparison should be made at the actual operating temperature, not only at room temperature.

Potassium Formate vs Calcium Chloride Brine

Calcium chloride brine has long been used in industrial refrigeration.

It is inexpensive and can provide substantial freeze protection.

However, system designers may also need to consider:

• Chloride-related corrosion
• Material compatibility
• Concentration control
• Maintenance requirements

Potassium formate uses formate rather than chloride as its primary anion.

That can be attractive in applications where reducing chloride exposure is important.

But once again, this does not mean potassium formate is automatically non-corrosive.

The complete formulation still needs appropriate corrosion control.

Vanchor's Potassium Formate Heat Transfer Solution Guide also emphasizes that the working fluid may contain corrosion inhibitors, pH-control additives and other compatible components rather than being only potassium formate and water.

Concentration Should Follow the Operating Temperature

One of the biggest mistakes when selecting a potassium formate heat transfer fluid is assuming that stronger concentration is always better.

It is not.

Increasing potassium formate concentration changes:

• Crystallization temperature
• Viscosity
• Density
• Specific heat
• Thermal conductivity
• Pump requirements
• Raw-material cost

Research measuring potassium formate aqueous solutions has confirmed that properties such as density, specific heat and viscosity change significantly with both concentration and temperature.

The better design sequence is:

Minimum fluid temperature → safety margin → target crystallization point → concentration → viscosity and heat-transfer check

For more detail, Vanchor's Potassium Formate Freezing Point Guide explains why concentration should be selected around system temperature rather than simply using the strongest available solution.

Is 75% Potassium Formate Ready to Use?

Not necessarily.

A 75% solution is often better understood as a concentrated raw material.

Vanchor currently positions its 75% potassium formate as a concentrated feedstock that can be used to prepare secondary refrigeration and heat-transfer fluids. The final formulation should be adjusted according to freezing point, viscosity, heat-transfer performance and equipment compatibility.

That means the final working fluid might contain:

• Potassium formate
• Water
• Corrosion inhibitors
• pH-control additives
• Other compatible treatment chemicals

The exact formulation depends on the system.

Using concentrated material directly without checking the required crystallization margin may give unnecessary viscosity or poor overall economics.

Corrosion Protection Is Essential

Any heat-transfer fluid that circulates through a closed system for years needs material compatibility.

Potential system materials may include:

• Carbon steel
• Stainless steel
• Copper
• Brass
• Aluminum
• Elastomers
• Pump seals
• Gaskets

Formate-based heat-transfer-fluid technology often includes buffers and corrosion inhibitors specifically because untreated salt solutions are not automatically suitable for every metal combination.

Before putting a new fluid into service, engineers should check:

• Fluid pH
• Corrosion-inhibitor package
• Metal compatibility
• Seal compatibility
• Concentration stability
• Long-term corrosion behavior

Do not assume that “chloride-free” means “maintenance-free.”

Where Is Potassium Formate Heat Transfer Fluid Used?

Typical applications include several industries.

Cold Storage

Potassium formate can circulate between the refrigeration plant and multiple cold rooms or evaporator units.

Food Processing

Indirect cooling can help keep the primary refrigerant confined to the refrigeration plant while secondary fluid distributes cooling throughout production areas.

Industrial Process Cooling

Factories may use secondary loops to control temperatures in production machinery, reactors or process equipment.

Refrigerated Logistics

Large distribution facilities may require cooling across several zones and long pipe runs.

Ice Rinks

Secondary refrigeration fluids can distribute cooling beneath the ice surface through extensive piping networks.

HVAC and Low-Temperature Circulation

Certain commercial or industrial systems may require below-zero secondary coolant temperatures where ordinary chilled water is unsuitable.

Vanchor also identifies industrial refrigeration, cold storage, food processing, HVAC secondary circuits and process cooling as potential applications for potassium formate-based secondary heat-transfer fluids.

What Should Buyers Check?

A heat-transfer-fluid formulator buying potassium formate should evaluate both raw-material quality and system requirements.

Purchasing Item	Reason
Potassium formate concentration	Controls formulation basis
Density	Useful for incoming QC
pH	Important for fluid conditioning
Chloride	Relevant to corrosion control
Iron	Helps monitor raw-material quality
Insoluble matter	Protects pumps and filters
COA	Confirms batch properties
TDS	Supports formulation work
SDS	Supports handling and storage
Batch consistency	Important for repeat production

For commercial production, several representative COAs can provide a better picture of supplier consistency than a single sample.

How to Request a Quote

A practical RFQ could look like:

Product: Potassium Formate
Application: Heat Transfer Fluid / Secondary Refrigerant
Preferred Form: 75% Aqueous Solution
Quantity: 100 MT
Packaging: IBC / Flexitank / Bulk
Required Documents: COA, TDS and SDS
Key Requirements: Stable concentration, controlled chloride and insoluble matter
Operating Application: Industrial Refrigeration / Cold Storage
Minimum Fluid Temperature: Please Specify

Providing the minimum expected fluid temperature is particularly useful.

It helps the supplier understand whether you are simply purchasing concentrate or also need technical discussion around final working concentration.

Final Thoughts

A potassium formate heat transfer fluid can be an effective secondary coolant for industrial refrigeration and low-temperature circulation systems.

Its main technical advantages can include:

• Sub-zero operation
• Relatively low viscosity
• Useful thermal conductivity
• Non-flammable aqueous chemistry
• Good suitability for pumped secondary loops

But the best fluid is not automatically the one with the highest potassium formate concentration.

System designers need to balance crystallization point, viscosity, thermal conductivity, specific heat, flow rate, pumping energy and corrosion control.

That is the real selection process.

Potassium formate provides the base chemistry.

The final heat-transfer fluid needs to be engineered around the actual refrigeration system.

FAQ

What is potassium formate heat transfer fluid?

It is an aqueous potassium formate solution used as a secondary coolant to transfer thermal energy in refrigeration and process-cooling systems.

Is potassium formate a primary refrigerant?

Normally no. It usually circulates as a liquid secondary coolant between the refrigeration plant and the cooling load.

Why use potassium formate instead of glycol?

Potassium formate can offer attractive low-temperature viscosity and heat-transfer characteristics. The better option depends on temperature, pumping requirements, materials and total system economics.

Can 75% potassium formate be used directly as heat transfer fluid?

Not necessarily. It is commonly used as concentrated feedstock and may need dilution, corrosion inhibitors and other formulation adjustments.

Does potassium formate heat transfer fluid need corrosion inhibitors?

Usually the complete system should include appropriate corrosion control based on the metals, seals and operating conditions present.

Where can potassium formate heat transfer fluid be used?

Potential applications include cold storage, food processing, industrial refrigeration, refrigerated logistics, process cooling, ice rinks and HVAC secondary circuits.