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Checking commercial freezer insulation using thermal imaging

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article image Improper welding has caused heat leakage in this section of the freezer insulation, as shown in this thermal image

FLIR thermal imaging cameras are being employed by thermography consultants in the Netherlands for inspecting the insulation in commercial refrigeration units.

Enterprises that need to store large quantities of goods at temperatures well below the freezing point often install large walk in freezers on their premises. However, cooling requires a lot of energy. It is therefore very important to prevent any outside heat from leaking into the freezer. To make sure the freezer's insulation is working properly, thermographers inspect the insulation material with a thermal imaging camera.

Dennis van Est, thermographer at the Uden, Netherlands based Thermografisch en AdviesbureauUden explains that inspecting walk in freezers, cold rooms and various types of large commercial refrigeration units is in essence very similar to building insulation inspections, the only difference being the direction of the heat. Building insulation inspections involve detection of heat leaking from the inside of the building to the outside air while refrigeration units are inspected for heat leaking inwards. 

The thermography consultant comments that any heat leakage can cause a huge unnecessary expenditure on energy bills; detecting these heat leaks at an early stage allows the owner to fix the insulation defects, preventing soaring energy bills. He has also observed a growing demand for walk in refrigerator and freezer inspections with the continuous rise in energy prices.

Van Est finds insulation problems in many of the walk in freezers and cold rooms he is hired to inspect. He says newly built refrigeration units often have a faulty construction; sometimes the joints between the insulation panels are not protected properly, creating heat bridges, which can increase energy consumption. Older units might develop insulation faults over time due to wear. 

In both scenarios the best way to detect these insulation defects is by using thermal imaging cameras. To Van Est the quality of the thermal imaging camera is crucial for these inspections. Only high quality thermal images can help detect heat bridges in the freezer insulation. 

Van Est has confidence in the FLIR P640 thermal imaging camera for his inspections. Offering an image resolution of 640x480, a thermal sensitivity of 30 mK (0.03°C) and an accuracy of ± 2°C or ± 2% of the reading, the thermal images produced by the FLIR P640 thermal imaging camera are of exceptionally high quality. He also finds the FLIR thermal imaging camera very user-friendly and its ergonomic design prevents backaches and arm strain.

Another important thermal imaging camera feature for this particular application is the calibration range, says Van Est. The FLIR P640 thermal imaging camera is calibrated to a minimum temperature of -40°C, which is very important to ensure accurate temperature measurements. Most freezers are kept at a temperature between -20°C and -30°C. However, even at temperatures just below the official calibration range, such as some exceptionally cold freezers that cool down their contents to -50°C or even -60°C, the FLIR P640 thermal imaging camera is still quite capable of visualising insulation leaks.

Ralf Grispen, commercial manager at Thermografisch en AdviesbureauUden comments that the quality of the camera is as important as the knowledge and skill of the thermographer. The company therefore makes sure all of their inspectors have at least a level I thermography certificate from the FLIR Infrared Training Center (ITC) and preferably level II as well. 

Van Est concludes that high quality thermal imaging cameras and good training come at a price, but they are definitely worth the money. Their FLIR cameras are used for a wide variety of applications, including building insulation inspections, industrial maintenance inspections, HVAC systems, airplane composite materials water ingress and refrigeration unit insulation inspections. 

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