For the same heat duty, water flow and temperature difference are inversely related: flow ≈ Q / (1.163 × ΔT). This approximate water calculation must also satisfy the evaporator minimum and maximum flow limits.

Effects of low flow

Blocked filters, closed valves or air in the pump can reduce actual flow. Temperature difference may rise and evaporator freeze protection can activate. Bypassing the flow switch does not resolve the fault and may damage equipment.

More flow is not always better

Excessive flow increases pressure loss and pumping energy. Low delta T may be caused by sensors, bypasses, load conditions or controls. Increasing pump speed alone will not solve every issue.

Measurement sequence

Measure inlet and outlet temperatures simultaneously and check measurement locations and sensor offset. Verify flow with suitable instruments, then interpret the pump curve and differential pressure together. For glycol, use mixture properties instead of the water coefficient.

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.

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