THERMAL IMAGING


BSEE


Minimising freezer energy consumption thanks to thermal imaging


A highresoluon thermal imaging camera is the ideal tool for ensuring industrial freezers work opmally with no energy waste. In a single pass, the camera provides visual evidence of any failure in insulaon that will compromise the facility’s performance


n a sense, inspecting freezers, cold rooms and other types of large commercial refrigeration units is very similar to checking the integrity of building fabric. Indeed, the only clear difference is the direction the heat is travelling. The main concern in the built environment is heat leaking out whereas with refrigeration the need is to prevent higher ambient temperatures influencing the sub-zero freezer space.


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The outcome of any insulation failure can lead to product quality issues, particularly in the case of foodstuffs. The price the facility owner pays is a damaged reputation and also a soaring energy bill as the cold room or freezer struggles to maintain temperature. And in the light of escalating energy prices this is an important issue. As a result, the need for regular thermal image inspection has never been greater in this sector. It would also be wrong to assume that ageing refrigeration units are the worst offenders. Frequently, the joints between the insulation panels on new installations are not protected properly, creating heat bridges. As the air temperature outside the walk-in freezer is naturally higher, it will follow a path with least resistance into the unit, resulting in more energy being required to maintain the sub-zero temperatures.


Resolution matters


The Dutch consultancy, Thermografisch en Adviesbureau, is frequently commissioned to conduct thermal inspection of commercial freezers, and its senior thermographer explains: “Thermal sensitivity, accuracy and resolution are crucial to the accurate detection of thermal bridges. You need to be able to interpret what you see in a thermal image and if you are using a thermal imaging camera that is below 640 x 480 pixels then you are missing information that you need to draw the right conclusions.” The most sophisticated Flir thermal imaging camera the consultancy uses for its work combines high resolution with 30mK thermal sensitivity and an accuracy of ±2°C. And another important feature for freezer inspection the company cites is calibration range. Its Flir camera is calibrated to a minimum temperature of -40°C and this is very important to ensure accurate temperature measurement. Most freezers are kept at a temperature between -20°C and -30°C. However, some freezers cool their contents down to -50°C or


even -60°C and the Flir camera is still capable of visualising insulation leaks.


“High quality thermal imaging cameras and good training come at a price but they are definitely worth the money,” the thermographer concludes.


IR for preventive maintenance


Although detailed thermal imaging and advanced analysis is clearly needed in fault finding applications, less sophisticated cameras still have a role to play in cold storage. Many companies use the technology as part of their preventative maintenance routines and a good example is Gubba Cold Storage that chose an entry-level troubleshooting camera to flag up any potential problems.


Gubba Cold Storage offers its customers cold storage facilities for a wide range of products from plant seeds to pharmaceuticals. Every product has its own prescribed storage requirements so it is essential that Gubba’s eleven cold storage units maintain an accurate and consistent temperature 24/7. Not only is this important from a customer service standpoint but also to optimise the cost of operation. Historically, Gubba did not conduct any preventive maintenance for insulation leaks, they


uGubba Cold Storage uses thermal imaging to guarantee best cold storage condions


were simply repaired when they became evident. Although the company was swift to act, there was always the danger that moisture ingress would disturb the required relative humidity. Also, the moisture could condense and freeze which would ultimately weaken the structure of the unit’s wall and diminish its insulation properties. A chance meeting with Flir at an exhibition proved the turning point. “I found out that it’s possible to scan large areas to look for insulation problems, find moisture beneath the insulation surface and much more,” explained company owner, Gubba Prashant. “So, we decided to buy a handheld thermal imaging camera and haven’t looked back since.”


Gubba Cold Storage chose a Flir entry-level troubleshooting camera and it is now in regular use spotting both insulation defects and electrical problems in their infancy. Engineers can now scan electrical cabinets, components and connections to get an instant picture of potential trouble. “We use our Flir camera extensively for safety checks in electrical panels and chiller rooms across various cold storage buildings,” Prashant adds. “When it shows us an electrical cable that is much hotter than its environment, we instantly intervene to prevent the problem becoming serious.”


He confirms: “A significant reduction in energy costs has also resulted from the repairs and we have been able to achieve that with the information from our thermal imaging camera.” Thermal imaging has also given Gubba Cold Storage the confidence that it is providing the very best service for its customers and, because it is a visual technology, those customers can also see proof. After performing a thermal audit with the Flir camera, the company is now able to give its customers a report that certifies the accuracy of the unit’s temperature and relative humidity.


About Flir Systems


Founded in 1978, Flir Systems is a world-leading industrial technology company focused on intelligent sensing solutions for defence, industrial, and commercial applications. Flir Systems’ vision is to be “the world’s sixth sense,” creating technologies to help professionals make more informed decisions that save lives and livelihoods.


uLeaks in the insulaon material covering the cold storage unit can be a threat to the temperature uniformity inside the unit Read the latest at: www.bsee.co.uk www.flir.com BUILDING SERVICES & ENVIRONMENTAL ENGINEER SEPTEMBER 2019 27


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