Water-glycol mixtures are used where freeze protection is required. Glycol type and concentration depend on minimum temperature, the fluid supplier data, material compatibility and application requirements. Freezing point alone is insufficient.

Glycol changes heat transfer

Density, specific heat, viscosity and thermal conductivity differ from water. The same flow and temperature difference may carry a different heat duty. Higher viscosity affects pressure losses and pump requirements; equipment must be selected using the actual mixture properties.

Concentration and protection limits

Ethylene and propylene glycol products are not automatic substitutes. Freeze protection and burst protection can be different specifications. Use volume or mass concentration consistently with the supplier table.

Monitoring the fluid circuit

Use a refractometer calibrated for the correct fluid. Check concentration alongside pH, inhibitor condition, water quality and leakage. Food or medical suitability cannot be inferred from the glycol name alone; verify the actual product and process requirements.

Project inputs and calculation boundaries

For a quotation, specify approximate heat duty, fluid, inlet and outlet temperatures, flow, pressure loss and operating hours. Design ambient conditions, indoor or outdoor location and electrical infrastructure are also selection inputs. Flow and temperature readings must represent the same operating point. Do not transfer a catalogue capacity directly to different temperatures; confirm model performance at the required duty.

Commissioning and operating records

Check circuit cleanliness, filtration, air removal, proven flow and sensor readings. Record reference water temperatures and load conditions during commissioning. These values provide a baseline for maintenance and alarm investigations. Confirm pumps, tanks, connections and control options against the agreed quotation scope.

Frequently asked questions

Is the series capacity range sufficient for final selection?

No. Confirm the actual model at the required fluid temperature, ambient conditions, fluid properties and hydraulic duty.

Is cooling capacity the electrical consumption?

No. Cooling kW and electrical-input kW are different quantities. An energy assessment also needs actual load and operating hours.

What information is needed for a quotation?

Provide the industry or equipment, target temperature, approximate duty, flow, ambient conditions, operating hours and details of the existing system.

Technical reference

Dow — heat-transfer fluid technical information

These explanations provide general engineering guidance. Examples are not field measurements or performance guarantees for a particular model.