Enterprises that need to store large amounts of goods at temperatures well below the freezing point of water often install large walk in freezers on their premises. These large freezers are capable of keeping whole rooms full of these goods, usually foodstuffs, at very low temperatures. There is just one downside: cooling requires a lot of energy. It is therefore very important that no outside heat leaks in. To make sure that the freezer’s insulation is working properly, thermographers inspect the insulation material with a thermal imaging camera.
“In essence inspecting walk in freezers, cold rooms and other types of large commercial refrigeration units is in essence very similar to building insulation inspections”, explains Dennis van Est, thermographer at the Uden, Netherlands, based Thermografisch en Adviesbureau Uden. “The only difference is the direction of the heat. With building insulation inspections we generally try to detect heat leaking from the inside of the building to the outside air, but with refrigeration units we want to detect heat leaking inwards. But the mechanism of heat leakage is just the same.”
The thermography consultant is called out to Leeuwarden to inspect two walk in freezers. “If there is any heat leakage this can cause a huge unnecessary expenditure on energy bills” says Van Est. “Detecting these heat leaks in an early stage allows the owner to fix the insulation defects, preventing soaring energy bills. With the energy prices continually rising, the demand for walk in refrigerator and freezer inspections is also growing.”
Heat bridges
Van Est finds insulation problems in many of the walk in freezers and cold rooms he is hired to inspect. “This particular freezer which I’m inspecting at the moment seems to be very well insulated, but you’d be surprised to see how often newly built refrigeration units have a faulty construction. Sometimes the joints between the insulation panels are not protected properly, creating heat bridges. This can cause a lot of unnecessary energy consumption. In other cases 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. Other methods, like spot pyrometers and such, really are not an option with this type of inspection. It is simply too easy to miss problems that you can relatively easily detect using thermal imaging.”
